The general process of document processing for the primary command C#.
The ELP_Command line generator is a great tool to configure the most needed command sets, but does only support via his user interface the most important ELP functions. Beside that you have access to over 50 command sets, which we are pretty sure, that minimum one of the sets comes pretty close to your requirements.
An ELP_Command is valid for the whole data stream, even if it contains several print jobs. However ELP provides an additional PCL command which turns the ELP functionality through the processing of the data stream temporary off <Esc>)s-996Z and back to on again<esc>s996Z. There is also an ini file key calls ELP_Command_Active, which deactivates the provided ELP_Command from the beginning of the job. In this case a <esc>s996Z is needed for activation.
These commands can be used any time, but they make only sense between two jobs. If used within a job, most likely the begin page commands from the ELP_Command may already been performed before the off command <esc>s-996Z is found. Or the other way around, the top of page commands are not performed, when the command is turned somewhere on the page on.
In that case the command needs to start with two trigger characters, default <<, and end with a also 2 trigger characters, default >>. These trigger characters can be changed to any other character, using the keys ELP_CMD_Start_Char and ELP_CMD_Stopp_Char.
The ELP Server will erase the command[s] out of the data stream.
ALL: The whole data stream is searched and the last found command is used.
A) Use only proportional printer internal fonts, best choice is ARIAL.
B) Do not expand the command over one line, if required: reduce the font size to fit the whole command in one line.
This command is executed as if it was in the rule GLOBAL.
The maximum length of an ELP_Command can be 2048 bytes. As the the ini file entry length is maximum 512 Bytes, a second key: ELP_Command_Add can be used to extend the existing ELP_Command.
Looking at the ELP_Command table here you may have noticed, that there are primary and secondary so-called C#-commands available.
Every primary command starts with one or two command character[s] and MUST be ended with a semicolon. There is no required order for the specification of a single command in the full command line.
Secondary C#-commands can only be used within the primary commands: C#, and also in EI, EJ or EX.
those variables must be available latest at the end of all trigger analyses.
The key ELP_Replace_Variables=ON advises ELP to replace the variables already when the ELP command is found in a rule. If at that time the variable does not exist, it is not replaced. This key can be used with ELP_Command_ADD and the Search_xxx keys to build a page dynamic ELP_Command. But remember maximum up to 2K Bytes.
Most of the primary ELP_Command keys are used to the complete data stream, like stapling T#; or printing copies with K#; or R#; commands.
So first number # after the C defines, for which printed copy of the incoming data stream this command is valid. Like C1 for the first copy, the original, C2 for the second and so on.
To understand the syntax you must look at the command line from the printing process. ELP is just in a copy 1, 2 or 3 etc and on a specific page. The following table explains how ELP finds a valid C-command. Whenever the printed page number falls in the range or page described by the C-command, the valid command is found and the execution of the command starts.
If the Command C#:# is not provided, then this is the second searched choice.
4. D#; Just in case the copy number C# is not defined at all, ELP Looks for the primary D#; default copy command. The number # after the D defines the number of the default copy description. So ELP will run the page number again against the copy # .
Whether a C# command from above is found or not, this C-commands will be evaluated.
; Here the first page get form 1100, The last page is drawn form a different paper tray (i9) and all pages in between gets form 1000.
C#:L Additional command which will be executed only for left pages right after the standard C#Command, if available This command will help to use forms specific on left and right handed pages.
C#:X This is a very special command. It is only executed, if an EX; (C-Command at the end of the job) or EA; (C-Command at the beginning of the job) is defined. In this case the given commands are executed directly before the EA command, so at the beginning or at the end of the print data stream.
This command is used to give the EA; and EX; command some copy specific settings.
Tip: If you only want to attach to the first copy a special form, then use an dummy EX; command like EXF54711; where the form 4711 is not defined at all, and use C1:XF1234; for example to print the Form 1234. For the second copy the dummy form 4711 is still called, but as the C2:X..; command is missing, there will be no additional page/form inserted.
Additional pages which are inserted using the C-command FF are counted.
Example: If on the first page the T&Cs are inserted on the back, the second printed page is for ELP the third processed page.
C#:L and/or C#:R definitions are always executed after the C#:#/C#:#-#/C# C-command.
The Default Copy Command D#; has got the lowest priority. It will be performed on every page on a particular copy, which is not addressed with a C# and/or C#:# <and/or C#:# C-command;.
It is also possible to use variables within ELP_Commands. One major usage of this functionality is to generate dynamic ELP_Commands.
; replaced by reading the section.
The limitation is the maximum length of the ELP_Command with 2048 Bytes. Or with the above routine a document with about 220 payment forms.
The highest priority is the ELP_Command found in the data stream.
Beside the highest option, an ELP:Command can also be located in a record in the ELP data base. So if any of the rules searches a data base file, the stored ELP_Command has a higher priority as the probably found ELP_Command of the rule itself.
Those keys after call C#-commands as it always need a copy # definition after the C.
- If there is another A# command in the ELP_Command without minus, then the existing page size commands will be erased!
- The page size selection command itself is invisible to the ELP process. So you may need to set on the next page / paper sheet the data stream back to the default page size.
If pages are not printed in duplex: Why does my duplex ELP command fail?
This command may perform a form feed, but in case it does, the page will not be counted, as ELP only count Form Feeds! In this case no next page definitions are performed.
This command should be used always in conjunction with the duplex command, which needs to be defined first in the ELP command.
Note: This command is set for the full page. It is not possible to set the printed data to monochrome/gray printing, and turn back later for the form to color. If this is your intention, then use a black and white driver. Usually those drivers do NOT use the responsible PCL command, and you can switch to color in the form itself.
- If there is another A# command in the ELP_Command without minus, then the existing print direction commands will be erased!
- The print direction selection command itself is invisible to the ELP process. So you may need to set on the next page / paper sheet the data stream back to the default print direction .
Once this command is found, ELP will not proceed any further outsearch_binary or outsearch_windows or outsearch_text commands. See also the Search_Only_Once key.
; and add the € sign character Hex D5 behind selecting PCL symbol set 13U (PC-858) for correct working.
F#; The minimum definition F# calls the macro/form with the ID number (#) on the actual with the C command defined page. Any number between 1 and 32000 is valid. But especially for SAP users, it is strongly recommended not to use any macro number below 1000.
C1:1F500F100;C1F502; ELP inserts on page 1 of copy 1 the forms 500 and 100, on all other pages of copy 1 the macro 501. Demo-macro 500 is a letter head, macro 100 the watermark "Original", macro 502 just the company logo, which needs to be printed on all pages. the forms are loaded only once.
F#[,x[,y[,d]]]; Sometimes the macro/s is/are needed to be positioned on the page, like a signature for example. Therefore the new position coordinates can follow the macro number separated with commas. The first number is the x position and the optional second the y position.
In any case, those commands are send right before the macro call and remain active until they are changed. Either using other offsets in the next F# command, or the general PL and PS or PX commands. If those P commands need to be positioned behind the F C-Command, in order to change back the offset settings.
Note: PX can't be used at the beginning of the page, so if you want to reset positioning done in the C#_Commands F and G use PL0PS0 on the next page.
C1F1000,100,200F1010,0,0; Print form 1000 and 1010 on every page, but the form 1000 is moved 100 units to the right and 2000 units down the print orientation. Form 1010 is printed on it natural position, and all pages after it as well.
C1PXF1000,100,200; The form is always printed with an offset, and PX resets the next page to the default coordinating system.
A second alternative is to set during the generation of the form a default offset just for that form.
F-#; If the form number is provided as a negative value, ELP searches for the positive form file, but at the end of the job, the mac/form file will be deleted from the storage media! Use this method to delete temporary form files, which may have been previously generated by another print job using the F# command.
FL#; FP#; The form is only loaded if the page is printed in portrait (P) or landscape (L).
Note:The data stream must have from the first page on the PCL statements for the page orientation (Esc&l#O). if not, then you need to declare with the key Variable=#VAR_ORIENTATION#:Number the default orientation. The values for the numbers are: 0 Portrait, 1 Landscape, 2 reverse Portrait and 3 reverse Landscape.
FRL#; FRP#; The form is only loaded if the page is printed in reverse portrait (RP) or reverse landscape (RL).
ELP inserts in the first step the PCL5 command for macro select and call. If the download switch is active (Macro_Download=ON), and the macro file (*.mac) is located in the actual ini-File path (default ...\forms), ELP will automatically download the macro to the printer. If the macro cannot be found in the Ini-File path and the macro is not stored in the printer, the command has no effect.
In order to work correctly, this command needs Form Feed as the page separator in the data stream. If you use for example on the last page \x1BE instead of Form Feed, there will be no forms added on that last page!
You can add in one C command as many F statements as you like. Again note, the maximum length of the total ELP command is limited to 1023 bytes.
All command options can be combined FRL-5555,300,40,-90; Print on reverse landscape printed pages [RL] the form 5555.mac shifted 300 units to left, 90 units up and even rotated by 90 degrees. Also delete the physical form file after the job.
Forms can be loaded by its file name. If the file name comes with only one backslash, ELP assumes, that the full path is provided. If there is none, the Working Directory path is added. This path can be changed with the WKDIR key.
Moving the forms or rotation follows the same syntax as described above at the F command.
This command inserts a Form Feed into the data stream. This function can be used to print for example a terms and condition form on the backside of the actual side. This is possible, because all F commands are performed on the end of the page. See below C-Command S for an example.
Important: Be careful using this parameter, because a recursive situation happens very easily. So C1F2000FFF3000; is absolutely such an invalid command. Form 2000 is printed on the first page, then Form Feed, and a second page is inserted. But during the phase of the process the second page is again a first page. So you will get a lot of empty pages with Form 2000 and 3000 on.
This command is pretty the same as the form feed, (FF command). The printer will move the cursor to the next page. The difference is, that ELP will not recognize, that the page change happened.
This command is mainly used to arrange 2 printed pages on one page. So e.g. N A4 pages can be printed on A3, but using only 5% of the paper, e.g. first page left, second to the right, third back page left, fourth back page right etc. See F1 online help for an detailed Example.
Same like C#F, but called at the beginning of the page. This function is pretty similar to the F-Command, but has the benefit, that colored forms are printed underneath the printing data.
For further information Printing colored forms and watermarks underneath black text .
If using the G#,x,y form move command, and you want to reset the offsets for data stream, use the PL and PS commands which need to be set after the G command.
If the form number is provided as a negative value, ELP searches for the positive form, but at the end of the job, the mac/form file will be deleted! Use this method to delete temporary form files, which may have been previously generated by another print job using the F# command.
In any case, all page commands must be set in front of the G command. If set behind the form, it will be separate printed from the data, one page in front.
; no additional page is printed!
Same as above C#Ffile, but the forms are loaded by their file name. If the name does come with only one back slash, ELP assumes, that the full path is provided. If there is none, the Working Directory path is added. This path can be changed with the WKDIR key.
Moving the forms or rotation is now possible, PL0PS0 behind the G command will set the print origin back to 0.
This command should only be used, if the designated printer is not able to handle the next described I#; command.
This command uses for the paper source selection the old PCL commands \x1B&l##H.
- If there is another A# command in the ELP_Command without minus, then the existing paper tray selection commands will be erased!
Search for &l (lower case L) and look if there is an h or H in the Escape Sequence. The number before this character is the searched H-value for this command.
This command defines the input paper tray. Instead of using the PCL sequences for paper tray, which are unfortunately different form printer to printer, the digit behind the I command defines the requested paper type.
This Command is only supported by HP LaserJet Series 4000, 2100 and newer.
You may use any tray for a special type of paper. This gives the user the benefit, that he can load the printer with paper according to his needs. Those needs are certainly in a production environment different than for example in the bookkeeping area.
If the application wants to draw a special type of paper, you have either different kinds of papers loaded in the printer trays, or the user is notified through the front panel of the printer, to load a special paper.
In both cases, the printer needs to stop if the tray is empty. In order to achieve this, each tray needs to be assigned to one of the above listed paper types. In this case the programmer doesn't need to know, how the printer is loaded.
The name of the paper does not need to match the real type of paper, which you want to print on. It is just a name, nothing else.
If the command is not given, the data stream will not be changed. But if the command is once given, the converter will erase all tray selection commands, \x1B&l_H, \x1B&n_Wxxxxxx and \x1B&l_M.
The \x1B&l0H remains unchanged in the data stream (eject page).
Example: C1:1I2;C1I3;C2I3F1000; Page 1 of copy 1 is drawn put of tray bond. The rest pages of copy 1 and all pages from copy 2 are drawn out of tray Color. In addition C2 prints watermark macro 1000 on every page.
A J in any C-command enables the Job Offset mode. There are no arguments needed.
If the command is not given, the data stream will not be changed. If the command is once given, the converter will erase all PCL5 job offset commands, \x1B&l_T and turn the Job Offset on!
It is enough to send this command only once on any page. Note: not all manufacturers support that command.
3 to 15 selects the destination bin of the mailbox or stapler bin.
- If there is another A# command in the ELP_Command without minus, then the existing paper out tray selection commands will be erased!
This command does not work for the last page of a job. However, in this case, instead of the data, a blank page will be printed.
In that case please use PJL commands.
Always use the N command on a specific page. The command C1N; does not make sense, because there will be only a blank page printed for the first copy.
This function is not supported in conjunction with the R command.
See here for more samples of not printing pages.
The N1 command can be used to combine 2 pages to one page. There is an example in the F1 Online help how to handle an DIN A5 data stream that always 2 pages are printed together on an A4 sheet.
the form will be automatically called on every page, the printer feeds.
The value of 0 disables the actual enabled overlay macro.
Per C-command is only one Overlay command possible. If you want to call more than one as an overlay, generate by hand a new macro, which calls the other ones.
If the form number is provided as a negative value, ELP searches for the positive form, but at the end of the job, the mac/form file will be deleted! Use this method to delete temporary form files, which may have been previously generated by another print job using the <<F#>> command.
Any positive or negative digit will move the long-edge origin of the page coordinating system to the new value. A value of 0 is setting the default value.
Negative values move the origin out of the page. But note that printing information can be lost, when they are positioned outside the unprintable area.
Positive values move the origin to the right. Printing information can be lost on the other side of the page, when printed outside the unprintable area.
If the command is not given, the data stream will not be changed. If the command is once given, the converter will erase all related sequences in the data stream.
In order to reset any movement in front of the form call F#,x,y use the PX command.
If using the G#,x,y form move command, and you want to reset the offsets for the data stream, set the PL command after the G command.
Same functionality as PL#, but on the short edge of the paper.
Using PL and/or PS will result in setting a new 0x0 coordinate point and ELP deletes all related PCL sequences in the data stream and forms.
However, very uncommon, the data stream or the forms use those commands to set their cursor (not very smart). In that case the result might look totally rubbish.
Using the PM parameter will set the provide new 0x0 point onto of the requested pages, but when an offset command is found in the data stream or form, ELP adds the new positive or negative offset value. So the print out is only moved.
As those commands in loaded Forms are also modified, you might not use the offset definition in the form, but instead move it in the ELP F or G with the add-on ,x,y option.
If this command is given, the previous defined PL# and PS# moves will be set to 0,0 right before the form feed and before any macro using C-command F# is called.
If only this command is used, any \x1B&lU or \x1B&lZ in the data stream will not be erased!
The reprint factor must be a positive digit larger than 0.
This command reprints a single page # times, as it is defined 1:1, no additional forms or other ELP_Commands are issued.
Please note: Any Esc&l#X commands, which are already defined in the incoming data stream may overwrite the Q# command.
The command is normally not used in duplex mode, as the pages are simply copied by the printer. For the page counter, those additional pages are currently NOT counted!
Example: K1;C1:1Q2;C1:2Q3; The complete document is printed once K1; but the first page 2 times and the second (and all following pages) 3 times.
This command resets the page counter. It can be used to create page number based recursive ELP_Commands actions. But note: If accounting is enabled, this command will lead into wrong accounting results.
If no page number is set, then next page will be treated as page 1. Otherwise set the number to one less then the next page should be looked at.
Example: A data stream is endless. It contains n times 3 pages, and the pages have to be drawn out of different paper trays.
The result of the R command in the definition of the 3rd page is, that the 4th page is performed as it is would be the first page, the 6th also again as the first etc.
This method only works for jobs which have constantly the same amount of pages. If this is not the case, then the new ELP Escape Sequence \x1B)s-995Z can also be uses on the last page of a section. Whenever this sequence is found , ELP will then reset the page counter on the next page to 1.
Invoice printing by a huge data stream with a lot of invoices: On the first page form 2000 is requested on all the other pages form 3000. If the text "Payment period 30 days" is found on the page, the next page will be again a page 1.
Doing it this way, ELP will lose the total page counter. But there are other ways, you may have a look at the key OutPort.
Any other # number then 0,1,2 are ignored.
Once this command is used, all PCL commands for simplex/duplex in the data stream are erased. This means, if you want to set the complete job in duplex, then simply turn it on the first page C1:1S2 on.
A duplex command needs to be always sent on the front page.
Turn off duplex printing also on the front page!
Example: C1:1F1100S1FFF1000;C1:3S0; This example demonstrates how to print terms and conditions on the first page only. Copy 1 page 1 starts printing in duplex S1 before the page form feed, the macro 1100 is inserted, then the Form Feed FF and on the new page 2 the macro 1000. After that point the original Form Feed from page 1 is performed. So next page is number 3 and the duplex mode is turned off.
Any values form 0 to 70 lines. The line spacing is either 6 lines per inch or a before set lpi setting.
Note: The A (paper size) command does reset the command to 1 line.
This C-command is used to suppress the command on a specific page. It is important to use the command right after the C-definition.
The purpose of this example is to print a duplex job. On the first page the letterhead form 5000 needs to be printed. No forms are printed on the back pages. Finally a different logo than on page 1 needs to be printed on each following front pages.
Once this command is used, text can be positioned on the page from the very top to the very button. However, this does not mean that the printer is able to print the text at that location. So it is strongly recommended to use Form Feed to go to the next page.
The practice the printer does by default perform a form feed if the text cursor is set in the approximately range of the last centimeter of the page. Once turned on, you still can print there text.
2. the selected command is inserted on the requested pages.
5. See here why: Why does my duplex ELP command fail?
For example: Once set the paper size to A4 for example. It remains A4 until the end of job, or it is changed. For pure ASCII data stream this page size can survive even all copies. This may become critical, when you print has an odd amount of pages and needs to be printed in duplex. So the first page of the second copy will be on a back page. In this case enter the command ET; which will add a separator between the copies.
The command value # defines, which C# command definition will be selected by default, when there is no C-command defined for the actual copy number.
This command will print the data stream 3 times. For the first copy the definition of C1 is used, for the second C2. The D2; command now defines, that if there is no page copy description, the description of the number of the D command is used. In our example, the copies 3 and 4 are treated the same way, as copy 2.
Using the optional + sign after D, you can define two D definitions in the ELP_Command. The plus indicates the definition for odd copy numbers. The second D in the command line without plus the definition for even copy numbers.
This command is used also for initializing the printer. The $$$$ can be any combinations of C# commands, like macros, simplex/duplex commands etc.
Example 1: EAS2B2F4711; This command will set the data stream to duplex printing, and selects the backside as the first printing page. Also on this back page the form 4711 is printed. If there is after this command in the data stream no PCL command which will make perform a Form Feed, the following data starts printing on that back side page.
Example 2: EAS2B2F4711FF;C1:2S0; Pretty much the same command, but the first page will have only the form, maybe the forms is using same variables for printing the user name and print time, but then the form feed tells the printer to feed the page. As the B2 command is not performing a form feed, the page counter is set to 2 after the FF command. The C1:2 command will set the rest of the data stream to simplex printing.
The major difference compared to the EB command is, the EB loads a form in front of the data stream; The EA command can then set the printer within the data stream to any initialization; The K-copy command does even reprint this initialization, which is not the case for the EB command.
Any page initialization of C1 or C1:1 command will be sent out before the EA commands.
In order to enable copy specific tray selections, the Command C#:X is searched and if defined executed right before the EX commands.
Those commands can only be used in conjunction with an EB#; If you do not want to call a macro right at the beginning of the data stream, please enter a unused macro number, like for example 9999.
Those commands set the printer to a specific resolution, 300 or 600 dpi.
The # in the command is the macro/form ID number, which is called right before = EB and right after = EE the provided data stream (See F command).
In most cases, the EB command is used to initialize the real data stream, like the job_ini.mac, or downloading forms or setting the printer into a specific state. But it can also be used as a cover sheet, in this case do not convert a print file into a macro, as the job itself is the macro including all initializations, so print your form to file and store it with the name ###.mac (### is the macro number) direct in the folder c:\ProgramData\WELP.
Example for a cover sheet: EB22000; Inserts the ELP provided demo form 22000 at the beginning of the print job.
The EB and EE command can be used several times in the ELP_Command. The intention is to have for example loaded several items at the beginning of the data stream specific fonts, like normal or bold, depending on the real addressed fonts.
The macro ID number must be larger than 0 and less than 32000.
There is no other ELP Command performed on those 2 inserted jobs. This means, the first ELP page is the first page of the provided data stream. The EE pages do not count.
The Search Binary and Windows definitions in the ini file are performed on these macros, as well as the variable replacements.
There will be an UEL inserted right at beginning of the data stream (EB only).
If the data stream itself contains an UEL (\x1B%-12345X) or a PCL Reset (\x1BE) statement, this method can't be used to set the printer, ELP does NOT add any MacroCalls, nor page ejections..
EE#; and EB#; commands ale also performed on every splitted data stream using OutPort or OutArchiveDir command keys.
If the footer pages (EE#; ) should be stapled to the remaining document, then you need to remove the PJL headers and take care about your own header, see next link for further details.
Right before the # reprint copy of the job, the provided ELP command is performed. This command is only performed if the K#; command is provided.
Example: K300;EI51I9FF;EI101I9FF; There are 300 copies in order 123... 123... 123... printed. After every 50th and 100th copy and before the 51th copy an empty sheet is drawn from paper try with media type preprinted.
K2;EI1F501FF; will print in front of copy 1 the terms and conditions document.
K2;EI1F501FF;D1; will print in front of all two copies the terms and conditions document.
This command can`t be used while splitting a data stream to an archive or another queue.. If needed try to use search and add commands to add your needed functionality at the end of a job in the PCL section.
If the command is for all copies the same, try to use the PCL_EXIT_PCL ini-file command key.
You can use different EI# commands for each copy.
Mostly same as above described EI command but at the end of the copy. Note: EI2F501; and EJ1F501; lead to the same result. There is one exception compared to the EI command:!
Example: ELP_Command=EJ1I9F8000FFF8001; Prints after the first copy form 8000 - form feed - 8001 on next page and both are drawn out of the preprinted assigned paper tray.
Important limitation note: Any macro used the first time in the job and AFTER(!) the last copy will NOT be loaded! Also any macros after the previous copy which had been used before, and they should be reloaded, as they are above macro number 25000, are NOT reloaded, so in this case after the previous copy the same addon is printed as the copy before!
Print 3 copes (K3) and after each copy print form 28000 (because of D1 always EJ1 is used). Macro 28000 which is a sort of cover page with variables on.
Here the EJ3 will hit after the last copy and the C# command will do nothing. Finally the Form 28000 is again loaded, the variables replaced and added.
This command should be used, if the data stream provides only ASCII characters, and doesn't initialize the job correctly: No BEGIN and no END-OF-JOB Sequences.
ET; wraps the data stream into well defined PCL5 PJL commands. As the result the printer treats the output stream as one job.
ETJ;K#; The parameter J is only usable in conjunction with the K#; parameter. If both are used ELP wraps each copy job independently. Maybe used to staple each job together, if the job itself is not well bounded.
This command is used to add forms at the end of the data stream. The syntax of the command is similar to the EA command. $$$$ can be any combinations of C# commands, like macros, simplex/duplex commands etc.
However you may always use C-Command FF for ending the last page.
This command is only activated the before the reset sequence \x1BE or before the UEL commands \x1B%-12345X, whatever comes first. So minimum one of those 2 commands need to be used at the end of the data stream!
You may use several EX statements in a command line, if they are combined while processing with ELP_COMMAND_ADD.
You may also combine several pages even from different trays using duplex.
The macros 1000 to 1003 are added at the end of the job, separated by FF, so each macro is printing on one page, using long edge duplex printing and finally the paper is drawn from paper tray with media type preprinted.
This command will store the actual data stream up to the first form feed into a macro file named #.mac. You may use this command to generate new forms on the fly, without using PPAdmin. A second need for this command is to select printing pages and combine them to one print job.
Like the macro conversion by PPAdmin, all escape sequences, which may cause form feeds are erased, even when they are defined in the ELP_Command! Example 1: F4711;C1S2I5; file 4711.mac is created, but all C1 commands are ignored.
Example 2: F4712;C1:F1999; file 4711.mac is created, and at the end of the new form, the form 1999 is called. Note: PCL allows only 2 levels of nesting.
Previous stored files are overwritten, without any warning!
If this printing file needs to be called by another print file, then use simply the newly predefined number.
The positive number # tells the system how often the complete data stream has to be printed, original + reprints. The minimum value is 1 for the original. If there is no K,Q or R factor in the ELP command defined, K1 is assumed.
The K-factor can be overwritten by a copy factor defined in the print file. ELP Key: ELP_Use_Qty_Factor or you may use any own defined variables .
If the copy number is more than 1, the total size of the data stream is limited to the heap memory available in the system. The limitation is different for each supported platforms. For a printer internal version about 2 to 3 Megabyte, otherwise mostly 10 Gigabytes.
If the 1 MB is not enough, then use ELP_MAX_HEAP key in the ELP ini File to redefine the maximum available heap to any size.
The K#; should only be used once in the ELP command line.
As each page is stored as a macro, do not define any additional macro within the data stream.
For Unix: if bar codes are used on the page, therefore in definit.h remark out the definition: TEXT_WITH_MACRO. It is not enough to set the definition value to 0.
For MS Windows: If bar codes are needed, do not print the bar code with readable text, or ask your local distributor to send you a system with the TEXT_WITHMACRO turned off.
The value can be overwritten using those keys: ELP_SET_COPYFACTOR and ELP_USE_QUANTITY_FACTOR.
Print jobs can be splitted for each copy using the OutArchiveDir or OutPort commands, in conjunction with the SplitAfterEachCopy key.
This command will switch the ELP functionality to pass-through. There will be no changes made on the data stream beside to present the content of the file job_init.mac, if the file exists.
ELP will not print any data. This ELP command can be used to avoid the print out, but in conjunction with archiving the data it still can be sent to another directory or port, like fax.
The positive number # tells the system how often the complete data stream has to be printed. The minimum and default value is 1. This command should not be used in conjunction with the R#; or K#; command.
Compared to K#; parameter, this Q#; parameter works totally different. The document will be copied using the printers copy function. This means, that the data stream goes only once to the printer.
Note: Only the C1[:#]commands can be used, all other C commands for copies higher then 1 are ignored!
The R#; command produces the same page print order like the Q#; command. But on each printed page/copy you may select any C#[:#] command.
The R factor can be overwritten by a copy factor defined in the print file.
ELP Key: ELP_Use_Qty_Factor or you may use any own defined variables.
That the job contains a t the beginning an PJL command: @PJL JOB NAME, (if not, please contact the ELP support) and add this rule.
S; - Flip front and back side in a duplex job.
There are no macros definitions allowed in the printing data stream. If this is the case, please get in contact with your distributor for a quotation to overcome this requirement.
As some PCL sequences perform page breaks when used, it must be ensured with the ELP_Command, that they are set on the first page ONLY. Those commands are especially: Paper size (A) and orientation (D), input (I or H) and output trays (M) as well as the duplex command itself (S).
S; turns the exchange on.
C1:1 defines the first page setup, as a side effect if one of those commands come in the data stream thereafter, they will be erased, and the second problem is not applicable anymore.
This command also ensures that the PCL sequences for front / next and back page selections are recognized and converted to form feeds if needed.
Currently no forms are allowed to be called in the ELP_Command key, beside the C1:LF####; command. A form can be only be inserted on the incoming left hand pages, which then, after the S; Command, will be the front page.
1. Run the job again through ELP, and the second time add on every (!) page the form. Every page means C1F####; Every because only after the switched pages comes the form feed, so on the reversed back page.
2. Insert at the beginning of the job the form needed on the new back page, for example with a searched rule. Here in this sample the forms 1000.mac is inserted just even before the first PCL page command.
Then add on each new back page the form.
Tray / simplex / duplex settings can be called anytime, but only on front pages! Same technical reason as above.
If the document it not duplexed anymore, or the form and data on the back page printed on two separate pages, then you need to move the tray commands to the first page. See here for more details.
The T#; command is used to staple, punch or add any other PJL Command to a print job, or add any ot. Once used, the existing PJL commands for stapling and punching are deleted.
To add more commands is pretty easy, Open the file c:\ProgramData\WELP\stapling.ini and add new functionality if needed.
Be sure, that the out bin escape sequence in the data stream is set to the correct out bin! If there is an ELP command, which changes the out bin to a non stapling bin, the T command will have no effect.
For mail merge support, the option :# can be added. This static option defines how many pages should be stapled. Usually it is the amount of pages per single mail document. If you intend to print mail merge stapled document with Microsoft word, then please have a look at the Microsoft Word chapter of the installation manual . There is an easier way described.
In order to work correctly, a print job needs to begin with an UEL command (\x1B%-12345X). If you are not sure, then load the print file into any editor. If this command is missing, use the ET; ELP_Command.
Keep in mind that a defined ELP command in the data stream is sent with every printed record, but ELP looks only for the first true command. In order to not print the commands on the second and following records, either prints them in white color, put the print command into a contraction: "If first record then print command, else do nothing", or use the IniFilemethod.
Mail merge with variable page numbers is NOT supported! Each record needs to print Tx:# pages.
There should be no additional UEL statements in the middle of the data stream.
B) from the programmer standpoint, there some speed tuning could be made, but this needs to be weighed up against cost.
Example: Your MS Word mail merge document contains 3 pages, and you want to staple all 3 pages together, then your ELP_Command may look like this: T1:3; For huge jobs, printing may getting slower and slower. In that case use the OutPort method for splitting files.
Through the development phase of your project, you may have the wish to test if your syntax of the ELP command is correct. As by default, the Server is not generating any output, the X; command was inserted for testing purposes.
Any Warning or wrong syntax in your ELP command will be dumped to the standard output, while the command is interpreted. Of course if the Log_Mode is set minimum to the Error-Level, the entry is also printed into the log-file.
You can capture any incoming data in the IN_data.prn file, using the -o command call, or using the archive or debug ini-file keys.
The HP LaserJet hardware version does ignore this function.


text:
Jazzcampus
Coaches 20/21
Band 20/21
Jeff Ballard
Chris Cheek
Kris Davis
Sullivan Fortner
Larry Grenadier
Guillermo Klein
Ingrid Laubrock
Linda May Han Oh
Wolfgang Muthspiel
Elena Pinderhughes
Jorge Rossy
Becca Stevens
The craft of composition has been a part of Guillermo
Klein's life since his childhood in Argentina.
Klein's father presented
him
with a piano when he turned 11 years old and, inspired by the legendary
Argentinean composer Astor Piazzolla, he promptly began his experimentation with writing songs.
www.mariahwilkins.com
Klein left
Argentina to attend
Berklee College of Music
after
hearing
a
moving speech
by the former
dean Gary
Burton about
his relationship working with Piazzolla.
Klein intended to study
classical music
on
his arrival
but
found
himself
among peers that were
passionate about jazz.
The
music of Wayne
Shorter provided the bridge from classical to jazz
studies. Being
a fan of unique
harmonic expression, Klein was
easily drawn
to the work of
this
master composer who
is deemed
to
be one of the most intriguing harmonic architects in
jazz. Klein was also able to develop a talented
network
of musical
friends,
many of which came
to Berklee from South
America. This group of
colleagues provided the frame work
for what would
eventually become Klein's main
musical
voice, the
Big Van
large
ensemble that would later become Los Guachos.
After
graduating from
Berklee, Klein moved
to New York City like many of his fellow
graduates.
He
settled
into Greenwich Village and quickly became
associated with a
jazz
club
called Smalls where he
established a weekly engagement with his 17‐piece
Big
Van
band
that incorporated musicians living
in
New
York
as well as commuters
from
Boston. Smalls was
critical in
fostering a community of young
artists
that would
ultimately
be some of
the
most
influential voices of modern jazz.
Klein later scaled
the band down to a more streamlined 11 piece unit that began to be known
as Los
Guachos (roughly translated, the bastards).
The band
continued
to
develop with the help of residences
at Smalls and,
later, the Jazz
Standard. After
recording
an
album that was ultimately shelved, Klein was
able to find a home
with
Sunnyside
Records.
The
label released two CDs by Los Guachos, Los Guachos
II
(1999)
and Los Guachos III
(2002).
Even
with media attention and devoted fans, Klein found
it increasingly
difficult to
make
a living as a
working musician in the States.
He
moved
back to Argentina in the
early fall of 2000 with his wife.
While in Argentina, Klein was
able to make another recording a long side loca l
musicians, Una Nave
(2005). He stayed in
Argentina for two
years before moving to Barcelona, Spain.
Currently,
Klein lives in Buenos Aires with his wife and
children. Los Guachos' latest
recording, Filtros,
was released 2008
on Sunnyside Records.
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text:
satyamkapoor
I work at ValueFirst Digital Media Private Ltd. I am a Product Marketer in the Surbo Team. Surbo is Chatbot Generator Platform owned by Value First. ...
I work at ValueFirst Digital Media Private Ltd. I am a Product Marketer in the Surbo Team. Surbo is Chatbot Generator Platform owned by Value First.
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This year at CES, which is perhaps the world's biggest electronics show, thousands of companies will showcase their products at Las Vegas. However, out of all the companies coming, Google stands out from the rest.
This will be for the first time that Google will have it's own large, standalone booth in the middle of the convention center. But Google has gone far beyond just buying space on the convention center. It has also commissioned several large advertisements around the city. In fact, one of them is so unique, you just can't miss it.
The words "Hey Google" are currently plastered along the outside of the city's public transportation system which happens to shuttle thousands of attendees into the conference center throughout the week. This makes it clear, that Google wants people to interact with its voice operated devices and get used to them.
Although CES will begin on 9th January, there is still a lot that one can make out before the show begins. Artificial Intelligence is going to get integrated into our day to day lives and become a part of our everyday household items.
In future, Digital assistants are going to be built into everything that is platform agnostic. Your digital life across multiple rooms, appliances & devices will be connected together by artificial intelligence.
For Google, CES 2018 will be a watershed moment, specially for its artificial intelligence products. It's is quite clear that lot of manufactures are going to roll out products that are built around the Google Assistant in the near future. Perhaps, many of these companies may also integrate with Amazon Alexa. However, it appears for now that Google may be able to regain back its position in this race even after having lost the first few rounds.
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text:
\section{Introduction}\label{sec:introduction}

Magnetic reconnection is the process by which magnetic energy is converted to plasma energy via a rapid topological rearrangement of magnetic-field lines \citep{zy09,ykj10,lu16}. It is usually preceded by a slow phase in which magnetic flux is accumulated in an increasingly thin current sheet (CS). Recently, it has been conjectured that this preparatory phase of CS formation, along with the material properties of the host plasma, determine the characteristics of the tearing modes that ultimately disrupt the sheet and thereby set the maximum aspect ratio above which CSs cannot survive \citep{pv14,tenerani15,lu16,ul16,comisso17,huang17}. This maximum aspect ratio is important for (at least) two reasons. First, the large aspect ratio of the Sweet--Parker CS \citep{parker57,sweet58} in high-Lundquist-number plasmas, being violently unstable to the plasmoid instability \citep{loureiro07,bhattacharjee09}, may not be realizable during CS formation. Second, the maximum aspect ratio may define a disruption scale in critically balanced Alfv\'{e}nic turbulence, below which the intense, sheet-like structures become tearing unstable and break up \citep{bl17,lb17a,lb17b,mallet17a,mallet17b}.

All of the work thus far on CS formation and tearing-mediated disruption was either couched within a collisional magnetohydrodynamic (MHD) framework or focused on collisionless plasmas with $\beta\doteq{8}\upi{nT}/B^2\lesssim{1}$ ($n$ is the plasma density, $T$ the temperature, and $B$ the magnetic-field strength). The latter restriction precludes application of those results to many dilute, weakly collisional astrophysical plasmas, whose large temperatures and relatively weak magnetic fields imply $\beta\gg{1}$. For example, $n\sim{10}^{-3}~\mrm{cm}^{-3}$, $T\sim{5}~\mrm{keV}$, and $B\sim{1}~\mu\mrm{G}$ in the hot intracluster medium (ICM) of galaxy clusters imply $\beta\sim{10}^2$ \citep{ct02,sc06}; $n\sim{100}~\mrm{cm}^{-3}$, $T\sim{2}~\mrm{keV}$, and $B\sim{1}~\mrm{mG}$ near the accretion radius of Sgr A$^\ast$ at the Galactic center imply $\beta\sim{10}$ \citep{quataert03,marrone07}. The hallmark of such plasmas is that the embedded magnetic field, while energetically subdominant, nevertheless has a strength tens of orders of magnitude above that required to magnetize the plasma (i.e.~$\Omega_i\tau\ggg{1}$ and $\rho_i\lll{L}$, where $\Omega_i\doteq{eB/m_ic}$ is the ion Larmor frequency, $m_i$ is the ion mass, $\rho_i\doteq{v}_{\mrm{th}i}/\Omega_i$ is the ion Larmor radius, $v_{\mrm{th}i}\doteq(2T/m_i)^{1/2}$ is the ion thermal speed, and $\tau$ and $L$ are representative macroscopic time and length scales, respectively). This hierarchy of scales, particularly in weakly collisional plasmas with collision frequencies $\nu$ satisfying $\nu\tau\ll{1}$, biases the plasma properties with respect to the magnetic-field direction \citep{braginskii65}. Notably, the thermal pressure becomes {\em anisotropic}.

There is a relatively large body of work on the impact of pressure anisotropy on tearing modes \citep{cd81,coppi83,cp84,cl85,ambrosiano86,shi87,karimabadi05,haijima08,quest10,matteini13,gingell15}, as well as on the production and impact of pressure anisotropy during the reconnection process itself \citep{drake06,le09,schoeffler11,egedal13,cassak15,le16}. Here we focus instead on the pressure anisotropy adiabatically produced during the CS formation, prior to the reconnection event. Namely, as the CS thins, the magnetic-field strength in the in-flowing fluid elements increases. An increase in field strength in a weakly collisional, magnetized plasma leads, by adiabatic invariance, to an increase (decrease) in the thermal pressure perpendicular (parallel) to the field lines \citep{cgl56}. Above an $\mc{O}(1/\beta)$ threshold, this pressure anisotropy drives the mirror instability \citep{barnes66,hasegawa69,sk93}, which produces strong distortions in the field lines and traps particles on ion-Larmor scales \citep{kunz14,riquelme15}. In what follows, we ask how the production of pressure anisotropy during CS formation and the consequent triggering of ion-Larmor-scale mirror instabilities in a $\beta\gg{1}$ plasma impacts the onset of tearing-mediated reconnection.

\section{Prerequisites}

\subsection{CS formation and pressure anisotropy}

We first establish that pressure anisotropy is produced during CS formation. For that, we adopt a simple local model for CS formation based on a one-dimensional generalization of the Chapman--Kendall solution \citep[][\S 2]{ck63,tolman18}. A sheared magnetic field $\bb{B}(x,t)=B_\mrm{r}[x/a(t)]\hat{\bb{y}}+B_\mrm{g}\hat{\bb{z}}$ is frozen into an incompressible, time-independent fluid velocity $\bb{u}(x,y)=-(x\hat{\bb{x}}-y\hat{\bb{y}})/2\tau_\mrm{cs}$, where $B_\mrm{r}$ and $B_\mrm{g}\doteq \thetaB_\mrm{r}$ are constants describing the strengths of the reconnecting and guide components of $\bb{B}$, respectively, and $\tau_\mrm{cs}$ is the characteristic CS-formation timescale. These expressions satisfy the reduced MHD equations provided that the CS half-thickness $a(t)$ and length $L(t)$ satisfy $a(t)/a_0=L_0/L(t)=\exp(-t/\tau_\mrm{cs})$, where the ``$0$'' subscript denotes an initial value. This model may be regarded as a Taylor expansion about the neutral line ($x=0$) of a more complicated (e.g.~Harris) CS profile, and so we restrict its validity to $|y|\ll{L(t)}$ and $|x|\lesssim{a(t)}$, beyond which $\bb{B}$ is taken to be spatio-temporally constant. (Indeed, this simple model is only meant to illustrate that $\Delta_p>0$ can be driven during CS formation.) We assume $\sqrt{\rho_{i,\mrm{r}}/a }\ll\theta\lesssim{1}$ and $\Omega_i\tau_\mrm{cs}\gg{1}$, where $\rho_{i,\mrm{r}}$ is the ion-Larmor radius computed using $B_\mrm{r}$, so that the entire CS is well magnetized (even near $x=0$).\footnote{This guarantees that any particle whose guiding center lies near $x=0$ executes Larmor motion about $B_\mrm{g}$ rather than a betatron orbit with turning points at ${\sim}\sqrt{\rho_{i,\mrm{r}}a}$ \citep[as in][]{dobrowolny68}.}

Using these fields, it is straightforward to show that the magnetic-field strength in a fluid element starting at $x=\xi_0$ (with $|\xi_0|\le{a_0}$) and moving towards $x=0$ is
\begin{equation}
B(\xi(t),t)=B_\mrm{r}\bigl[\theta^2+\exp(t/\tau_\mrm{cs})(\xi_0/a_0)^2\bigr]^{1/2} ,
\end{equation}
where $\xi(t)=\xi_0\exp(-t/2\tau_\mrm{cs})$ is a Lagrangian coordinate co-moving with the fluid element. This change in $B$ drives field-aligned pressure anisotropy, $\Delta_p\doteq{p}_\perp/p_\parallel-1$, adiabatically in the fluid frame. Using $\mu$ conservation in the form $p_\perp\propto{B}$ and assuming $\Delta_p(x,t=0)=0$,
\begin{equation}
\Delta_p(\xi(t),t)	= \biggl[\frac{\theta^2+\exp(t/\tau_\mrm{cs})(\xi_0/a_0)^2}{\theta^2+(\xi_0/a_0)^2}\biggr]^{1/2}-1 \approx \frac{t}{2\tau_\mrm{cs}} \frac{(\xi_0/a_0)^2}{\theta^2+(\xi_0/a_0)^2}\doteq\frac{t}{\tau_\mrm{pa}}
\label{eqn:Deltaapprox}
\end{equation}
for $t/\tau_\mrm{cs}\ll{1}$.\footnote{If the second adiabatic invariant, $J$, were also conserved -- unlikely in a $\beta\gg{1}$ plasma with Alfv\'{e}nic, incompressible flows -- the exponent $1/2$ in \eqref{eqn:Deltaapprox}  becomes $3/2$ and $\tau_\mrm{pa}$ changes by an inconsequential factor of $3$.} Thus, pressure anisotropy increases in all fluid elements.

If nothing interferes with the adiabatic increase in pressure anisotropy, the plasma in a fluid element will eventually become mirror unstable when $\Delta_p\gtrsim{1}/\beta_\perp$, where
\begin{equation}
\beta_\perp(\xi(t),t) = \beta_0(\xi_0)\biggl[\frac{\theta^2+(\xi_0/a_0)^2}{\theta^2+\exp(t/\tau_\mrm{cs})(\xi_0/a_0)^2}\biggr]^{1/2} \approx \beta_0 \biggl(1-\frac{t}{3\tau_\mrm{pa}}\biggr)
\label{eqn:betaapprox}
\end{equation}
is the adiabatically evolving perpendicular plasma beta in the fluid frame ($\beta_0$ is its initial value). Comparing (\ref{eqn:Deltaapprox}) and (\ref{eqn:betaapprox}), this occurs at $t_\mrm{m}\sim\tau_\mrm{pa}/\beta_0$ for $\beta_0\gg{1}$. If the guide field is small compared to the local reconnecting field ($\theta\ll\xi_0/a_0$), this time is a small fraction of the CS-formation time scale, $t_\mrm{m}\sim\tau_\mrm{cs}/\beta_0$, and so the CS becomes mirror-unstable early in its evolution. With a larger guide field ($\theta\gg\xi_0/a_0$), $t_\mrm{m}\sim\tau_\mrm{cs}(a^2_0/\xi^2_0)(\theta^2/\beta_0)$. This time is also early in the CS evolution for $\xi_0\lesssim{a}_0$, since $\theta\ll\beta^{1/2}$ is required in this model for the plasma to reliably exceed the mirror-instability threshold.\footnote{\label{fn:thetaLim} If the asymptotic value of the reconnecting field, $B_\mrm{r}$, is constant, then the maximum change of $B$ in a fluid element is bounded, $B(t)/B(0)< (1+\theta^{-2})^{1/2}$, and so $\Delta_p<(1+\theta^{-2})^{1/2}-1$. Therefore, $\theta\lesssim\beta^{1/2}$ is required to reach the mirror threshold. In other models where $B_\mrm{r}$ increases in time \citep[e.g.][]{tolman18}, no such limit on $\theta$ exists.}

These times must be compared to the characteristic time scales for tearing modes that facilitate magnetic reconnection in the forming CS. Before doing so, we review the basic properties of the mirror instability.

\subsection{Mirror instability}

As $B$ increases, adiabatic invariance drives $\Delta_p>0$, with plasma becoming mirror-unstable when $\Lambda_\mrm{m}\doteq\Delta_p-1/\beta_\perp>0$. Just beyond this threshold ($0<\Lambda_{\rm m}\ll{1}$), oblique modes with wavenumbers $k_{\parallel,\mrm{m}}\rho_i\sim (k_{\perp,\mrm{m}}\rho_i)^2\sim\Lambda_\mrm{m}$ and polarization $\delta{B}_\perp/\delta{B}_\parallel\sim\Lambda_\mrm{m}^{1/2}$ grow exponentially at a maximum rate $\gamma_\mrm{m}\sim\Omega_i\Lambda_\mrm{m}^2$ \citep{hellinger07}. Once this growth rate becomes larger than the rate at which $\Delta_p$ is produced ($\gamma_\mrm{m}\tau_\mrm{pa}\gtrsim{1}$), the growth of $\Delta_p$ stops. This yields a maximum mirror-instability parameter,  $\Lambda_\mrm{m}\gtrsim(\Omega_i\tau_\mrm{pa})^{-1/2}\doteq\Lambda_\mrm{m,max}$. Kinetic simulations show that, once $\Lambda_\mrm{m}(t)\sim\Lambda_\mrm{m,max}$, mirrors rapidly drain $\Lambda_\mrm{m}(t)\rightarrow{0}^+$ and attain amplitudes $\delta{B}_\parallel/B\sim\Lambda^{1/2}_\mrm{m,max}$ \citep{kunz14}. This is the end of the linear stage; for $\beta_0\gg{1}$, this occurs at $t/\tau_\mrm{pa}\sim{1}/\beta_0+\Lambda_\mrm{m,max}$.

As the CS continues to thin, $\Delta_p>0$ is continuously driven. Mirror modes then maintain marginal stability ($\Lambda_\mrm{m}\simeq{0}^+$) by growing secularly, $\delta{B}^2_\parallel\propto{t}^{4/3}$, and trapping an increasing fraction of particles \citep{schekochihin08,kunz14,rincon15}. Independent of $\Lambda_\mrm{m,max}$, saturation occurs at $t\sim\tau_\mrm{pa}$ and $\delta{B}/B\sim{1}$, when these particles pitch-angle scatter off sharp bends in the magnetic field occurring at the mirror boundaries at a rate $\nu_\mrm{m}\sim\beta/\tau_\mrm{pa}$; this maintains marginal stability by severing the adiabatic link between $\Delta_p$ and changes in $B$ \citep{kunz14,riquelme15}. Thereafter, $\Delta_p\simeq{1}/\beta_\perp$, even as $B$ changes.

This evolution was found for situations in which $\tau_\mrm{pa}$ is comparable to the dynamical time in the system (e.g., linear shear flows). However, for locations $\xi_0\ll\theta{a}_0$ deep inside the CS, $\tau_\mrm{pa}\gg\tau_\mrm{cs}$. In this case, local mirror growth cannot outpace CS formation, and any potential mirrors are advected and distorted faster than they can grow. When $\theta\gg{1}$, $\tau_\mrm{pa}\gg\tau_\mrm{cs}$ in the entire CS. We thus focus only on cases with $\theta\lesssim{1}$ and locations $\xi_0\gtrsim\theta{a}_0$.

\subsection{Collisionless tearing instability}

Next we review the theory of collisionless tearing modes, applicable when the inner-layer thickness of the tearing CS, $\delta_\mrm{in}\lesssim\rho_e$. To determine under what condition this criterion is satisfied, we use standard MHD tearing theory \citep{fkr63} to estimate
\begin{equation}\label{eqn:din}
\delta_\mrm{in}^\mrm{MHD}=\bigl[\gamma_\mrm{t}(\ktv_\mrm{A,r})^{-2}a^2\eta\bigr]^{1/4}=a\bigl[\gamma_\mrm{t}\tau_\mrm{A,r}(k_\mrm{t}{a})^{-2}S^{-1}_a\bigr]^{1/4},
\end{equation}
where $v_\mrm{A,r}\doteqB_\mrm{r}/(4\upi{m}_in_i)^{1/2}$ is the Alfv\'{e}n speed of the reconnecting field, $\tau_\mrm{A,r}\doteq{a}/v_\mrm{A,r}$ is the Alfv\'{e}n crossing time of the CS, $\eta$ is the (collisional) resistivity, and $S_a\doteq{a}v_\mrm{A,r}/\eta$ is the Lundquist number. Using an estimate for the growth rate $\gamma_\mrm{t}$ of the fastest-growing collisional tearing mode with wavenumber $k_\mrm{t}$ oriented along the CS \citep{fkr63,coppi76,ul16}, the validity condition for collisionless tearing theory to hold becomes
\begin{equation}\label{eqn:Scollisionless}
S_a\gtrsim(a/\rho_e)^4.
\end{equation}
This gives $a\lesssim{10}^{-6}~\mrm{pc}$ for the ICM parameters listed in \S\ref{sec:introduction}, a satisfiable constraint given that $\rho_i\sim{10}^{-9}~\mrm{pc}$ and the outer scale of ICM magnetic-field fluctuations is observationally inferred to be ${\sim}10~\mrm{kpc}$ \citep{ev06,guidetti08,bonafede10,vacca12,govoni17}, comparable to the collisional mean free path. At the accretion radius of Sgr A$^\ast$, this constraint is $a\lesssim{10}^{-10}~\mrm{pc}$, which is ${\sim}10^2$ larger than $\rho_i$ and ${\sim}10^8$ times smaller than the collisional mean free path. As long as \eqref{eqn:Scollisionless} is satisfied (which becomes easier as $a$ shrinks), $\gamma_\mrm{t}$ and $k_\mrm{t}$ are estimated as follows.

In a $\beta\gtrsim{1}$ plasma when the tearing-mode instability parameter $\Delta'(k_\mrm{t})$ \citep{fkr63} is small, satisfying $\Delta' \delta_\mrm{in} \sim (\Delta' d_e)^2 \ll 1$ (``FKR-like''; \citet{karimabadi05}),
\begin{equation}\label{eqn:gammat_smallDelta}
\gamma_\mrm{t}^{\rm FKR}\tau_\mrm{A,r}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/2}\biggl(\frac{d_i}{a}\biggr)^2 \,k_\mrm{t}{a}\,\Delta'a ,
\end{equation}
where $d_e$ and $d_i\doteq\rho_i/\beta^{1/2}_{i}=d_e(m_i/m_e)^{1/2}$ are, respectively, the electron and ion skin depths \citep{fitzpatrick04,fitzpatrick07}. (Our CS formation model leaves $d_e,d_i$ constant.) This growth rate is approximately independent of $k_\mrm{t}$ in a Harris sheet, for which $\Delta'a=2(1/k_\mrm{t}{a}-k_\mrm{t}{a})\sim(k_\mrm{t}{a})^{-1}$ at $k_\mrm{t}{a}\ll{1}$. The large-$\Delta'$ (``Coppi-like'') growth rate satisfies
\begin{equation}\label{eqn:gammat_largeDelta}
\gamma_\mrm{t}^{\rm Coppi}\tau_\mrm{A,r}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/5}\biggl(\frac{d_i}{a}\biggr)\,k_\mrm{t}{a},
\end{equation}
independent of $\Delta'$ \citep{fitzpatrick07}. An estimate for $\gamma_\mrm{t}$ and $k_\mrm{t}$ of the fastest-growing Coppi-like mode in a Harris sheet can be obtained by balancing \eqref{eqn:gammat_smallDelta} and \eqref{eqn:gammat_largeDelta}:
\begin{subequations}\label{eqn:tearingn}
\begin{align}
\gamma_\mrm{t}^\mrm{max}\tau_{\rm A,r}	&\sim \biggl(\frac{m_e}{m_i}\biggr)^{1/2}\biggl(\frac{d_i}{a}\biggr)^{2},\label{eqn:tearingn:g}\\*
k_\mrm{t}^\mrm{max} a 					&\sim \biggl(\frac{m_e}{m_i}\biggr)^{3/10}\biggl(\frac{d_i}{a}\biggr) .\label{eqn:tearingn:k}
\end{align}
\end{subequations}
These modes are the fastest growing provided they fit into the length $L$ of the CS, i.e.~$k_\mrm{t}^\mrm{max} L>1$. Otherwise, the fastest-growing mode is FKR-like.\footnote{\citet{fitzpatrick04,fitzpatrick07} obtained \eqref{eqn:gammat_smallDelta} and \eqref{eqn:gammat_largeDelta} using a two-fluid model assuming cold ions and that the compressional Alfv\'{e}n wave propagates much faster than any other wave in the system (as it would in a high-$\beta$ plasma), thus guaranteeing pressure balance along field lines and nearly incompressible flow. The former (small-$\Delta'$) growth rate agrees with the corresponding kinetic expression in \citet[][their equation (16)]{dl77a} up to a factor of $1/\sqrt{1+\beta_\mrm{g}}$, which is ${\sim}1$ given those authors' assumption of small $\beta$ and large guide field. Both results assumed a Maxwellian background. Alternatively, \citet{cp84} allowed for a spatially uniform $\Delta_p\ne{0}$ in their linear kinetic tearing calculation, but assumed $B_\mrm{g}=0$ and thus obtained different scalings after accounting for axis-crossing particle orbits (see also \citet{cl85} and \citet{quest10}). While we have opted to use the \citet{fitzpatrick04,fitzpatrick07} expressions for $\gamma_{\rm t}$, our analysis can be generalized for any alternative scalings without a significant change in the main qualitative conclusions summarized in \S\ref{sec:summary}. The ``FKR-like'' and ``Coppi-like'' designations are adaptations of those introduced by \citet{ul16}.}

In what follows, we {\em assume} that pressure anisotropy does not appreciably modify these growth rates. This is because saturated mirrors maintain $\Delta_p\simeq{1}/\beta_\perp\ll{1}$, and so the resulting viscous stress effectively enhances the magnetic tension responsible for driving the tearing by a factor of only ${\simeq}3/2$. Other works that postulate an initial $\Delta_p$ (customarily taken to be uniform and thus non-zero even at $x=0$) do not consider its rapid regulation by the mirror instability prior to the onset of tearing, and the enhanced $\gamma_\mrm{t}$ often found in linear calculations when $\Delta_p > 0$ is largely because the assumption $B_\mrm{g}=0$ permits axis-crossing particle orbits in the inner regions of the CS and allows threshold-less instabilities such as the Weibel instability \citep[e.g.][]{cp84}.

\section{Reconnection onset when $\Delta_p=0$}

Before determining how mirror-unstable pressure anisotropy affects a gradually forming CS, we recapitulate the theory of CS disruption by tearing modes \citep{pv14,tenerani15,lu16,ul16}, specialized to the case of collisionless tearing in a high-$\beta$ plasma. That is, we ignore the production of pressure anisotropy during CS formation and instead determine when $L/a$ has increased enough for tearing modes to prompt reconnection.

As the CS's aspect ratio $L/a$ increases in time, modes with progressively larger mode number $N\doteqk_\mrm{t}(t)L(t)={\rm const}$ become unstable and undergo linear evolution with $\gamma_\mrm{t}(N,t)$ increasing (see figure \ref{fig:gamma-t0}). \citet{ul16} argued that the first tearing mode $N$ to reach the end of its linear stage at the critical time $t_\mrm{cr}(N)$ (when $\gamma_\mrm{t}\tau_\mrm{cs}\gtrsim{1}$, neglecting logarithmic corrections \citep{comisso17}) will also be the first to undergo X-point collapse (defined by when the island width $w\sim{1}/\Delta'$) and, soon thereafter, disrupt the CS ($w\sim{a}$). We adopt this argument and estimate the CS disruption time $t_\mrm{disrupt}$ for a collisionless Harris sheet with $L(t)a(t)={\rm const}$. (The same procedure can be used to investigate alternative CS profiles and evolution.) Note that, for the Harris-sheet profile, $\gamma_\mrm{t}^{\rm FKR}\approx\gamma_\mrm{t}^\mrm{max}$ for $k_\mrm{t}{a}\ll{1}$ (see \eqref{eqn:gammat_smallDelta} and \eqref{eqn:tearingn:g}), so the only difference between these modes are their wavenumbers and, thus, their $\Delta'\sim{1}/k_\mrm{t}{a}^2$.

\begin{figure}
\centering
\includegraphics[width=0.75\textwidth]{fig1.eps}
\caption{Qualitative plot of tearing growth rate $\gamma_\mrm{t}$ vs.~mode number $N$ (see \eqref{eqn:gammat_smallDelta} and \eqref{eqn:gammat_largeDelta}) shortly after mirror production at $k^\mrm{max}_{y,\mrm{m}}a>{1}$. Arrows indicate evolution as the CS aspect ratio ($L/a$) increases, with $\gamma_\mrm{t}$ approaching $\tau_\mrm{cs}^{-1}$ (blue dashed line), $k_\mrm{t}$ approaching the large-$\Delta'$ regime ($k_\mrm{t}\lesssimk_\mrm{t}^\mrm{max}$), and mirrors affecting an increasing number of tearing modes (those with $k_\mrm{t}\gtrsim{k}^\mrm{max}_{y,\mrm{m}}$).}
\label{fig:gamma-t0}
\end{figure}

Each unstable mode $N$ starts in the small-$\Delta'$ (``FKR-like") regime ($N>N_\mrm{max}(t)$), with $\gamma_\mrm{t}$ roughly independent of $k_\mrm{t}$ for $k_\mrm{t}{a}\ll{1}$. However, because $N_\mrm{max}\propto(L/a)(d_i/a)\propto{a}^{-3}$ increases in time, these FKR-like modes approach the large-$\Delta'$ (``Coppi-like'') regime, making the transition at $t=t_\mrm{tr}(N)$ when
\begin{equation}
\frac{a(t_\mrm{tr}(N))}{a_0}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/10}\biggl(\frac{L_0d_i}{a^2_0}\biggr)^{1/3}N^{-1/3}.
\end{equation}
Larger $N$ corresponds to larger $t_\mrm{tr}(N)$, and so the first mode to make this transition is $N=1$; i.e.~at $t=t_\mrm{tr}(1)$, the fastest Coppi-like mode (see \eqref{eqn:tearingn:k}) just fits inside the CS. All modes satisfying $k_\mrm{t}^\mrm{max} a\lesssimk_\mrm{t}{a}\ll{1}$ obtain growth rates $\gamma_\mrm{t}\tau_\mrm{cs}\gtrsim{1}$ at roughly the same time, $t=t_\mrm{cr}$, when (using \eqref{eqn:tearingn:g})
\begin{equation}\label{eqn:tearingDisrupts}
\frac{a(t_\mrm{cr})}{a_0}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/6}\biggl(\frac{d_i}{a_0}\biggr)^{2/3}M_\mrm{A,0}^{-1/3} ,
\end{equation}
where $M_\mrm{A,0}\doteq\tau_\mrm{A,r}(t=0)/\tau_\mrm{cs}$ is the initial Alfv\'{e}nic Mach number of the CS formation. These modes have
\begin{equation}\label{eqn:tearingDisrupts_N}
\frac{L(t_\mrm{cr})}{a(t_\mrm{cr})}\gg{N}\ge{N}_\mrm{cr}\doteq\biggl(\frac{m_e}{m_i}\biggr)^{-1/5}\biggl(\frac{L_0}{d_i}\biggr)M_\mrm{A,0}.
\end{equation}
This is an important distinction from the collisional MHD case, in which larger $N>N_\mrm{cr}$ corresponds to larger $t_\mrm{cr}(N)$ (since $\gamma_\mrm{t}^{\rm FKR}\proptok_\mrm{t}^{-2/5}$ at $k_\mrm{t}{a}\ll{1}$ instead of $k_\mrm{t}^{0}$).

Another important distinction from the MHD case lies in the nonlinear evolution, during which the MHD FKR modes behave differently than the MHD Coppi modes. While the latter are expected to rapidly evolve towards X-point collapse soon after $t=t_\mrm{cr}$ due to their large $\Delta'$, the former undergo secular ``Rutherford'' evolution that increases $\Delta'(k_N)w_N$ for a given mode $N$ until $w_N\sim{1}/\Delta'$ \citep{rutherford73,waelbroeck89,waelbroeck93,loureiro05,arcis09}. However, in the collisionless case, the FKR-like modes reach $\gamma_\mrm{t}\tau_\mrm{cs}\sim{1}$ at the same time as the fastest Coppi-like mode. If the latter is accessible, then the fastest-growing mode $N_\mrm{max}$ already has $\Delta'd_e\sim{1}$ at $t_\mrm{cr}(N_\mrm{max})$ and so X-point collapse likely occurs soon after \eqref{eqn:tearingDisrupts} is satisfied. The CS is then said to be ``disrupted'' at $t_\mrm{disrupt}\sim{t}_\mrm{cr}(N_\mrm{max})$. For there to be no Coppi-like modes when \eqref{eqn:tearingDisrupts} is satisfied (i.e.~$N_\mrm{cr}<{1}$), $M_\mrm{A,0}\lesssim(m_e/m_i)^{1/5}(d_i/L_0)$, a rather stringent condition that is difficult to satisfy when $\beta_0\gg{1}$ and $\rho_{i0}/L_0\ll{1}$.

That being said, given the uncertainties in the nonlinear evolution of collisionless tearing modes in a high-$\beta$, magnetized plasma -- especially regarding the existence (or nonexistence) of a secular ``Rutherford'' phase and the production of pressure anisotropy during X-point collapse -- we focus primarily on the critical time for reconnection onset (when $\gamma_\mrm{t}\tau_\mrm{cs}\gtrsim{1}$) rather than the CS disruption time (when $w\sim{a}$).\footnote{Another reason for prudence is Drake \& Lee's (1977{\it b})\nocite{dl77b} argument that single-mode tearing with a guide field saturates via trapped-electron effects with an amplitude comparable to the inner-layer thickness, $w\sim\delta_\mrm{in}$. This argument was confirmed, and refined by incorporating finite-Larmor-radius effects, by \citet{karimabadi05}.}

\begin{figure}
\centering
\includegraphics[width=0.6\textwidth]{fig2.eps}
\caption{Qualitative illustration of magnetic-field lines in an evolving, mirror-infested Harris CS with $\theta \ll 1$.}
\label{fig:CS_with_mirrors}
\end{figure}

\section{Reconnection onset when $\Delta_p \ne 0$}

We now consider the effects of  mirrors on an evolving CS subject to tearing modes. Because different portions of the CS have different $\rho_i$ and $\tau_\mrm{pa}$, there will be a range of mirror wavenumbers, $k_{y,\mrm{m}}(x)$, along the CS (see figure \ref{fig:CS_with_mirrors}).

The smallest $k_{y,\mrm{m}}$ will be located the nearest to $x=0$ where mirrors can form, since these regions have the largest values of $\rho_i$ and $\tau_\mrm{pa}$. We argue that, since tearing modes with wavenumbers $k_\mrm{t}$ much smaller than this $k_{y,\mrm{m}}^\mrm{min}$ will see a rapidly $y$-varying magnetic field that averages to its unperturbed value, these modes are likely unaffected by the mirrors (or at least less affected than other modes). The largest $k_{y,\mrm{m}}$ will be located near $|x|\sim{a}$, where $\rho_i$ and $\tau_\mrm{pa}$ are at their smallest values. All tearing modes with $k_\mrm{t}\ggk_{y\mrm{,m}}^\mrm{max}$ will see an approximately uniform-in-$y$ magnetic field, but will have their $\Delta'(k_\mrm{t})$ enhanced by the mirrors' effect on the $x$-variation of the CS profile. If the CS is able to stretch to the point where $k_{y\mrm{,m}}^\mrm{max}\lesssimk_\mrm{t}^\mrm{max}$ before the onset of tearing, then all of the modes that are unaffected by the mirrors will have smaller growth rates and thus be unimportant for CS reconnection. The condition $k_{y\mrm{,m}}^\mrm{max}\lesssimk_\mrm{t}^\mrm{max}$ is thus a sufficient (but not necessary) condition for mirrors to matter.

We now follow the evolution of $k_{y,\mrm{m}}^\mrm{max}$ as the CS evolves, and investigate the evolution of tearing modes with $k_\mrm{t}\gg{k}_{y,\mrm{m}}^\mrm{max}$. We treat two cases, depending upon the size of the guide field and thus the component of the mirrors' wavevector along the CS at $|x|\sim{a}$,
\begin{equation}\label{eqn:ky}
k_{y,\mrm{m}}\sim k_{\parallel,\mrm{m}}\frac{B_{\rm r}}{B}+k_{\perp,\mrm{m}}\frac{B_{\rm g}}{B}=k_{\parallel,\mrm{m}} \frac{B_{\rm r}}{B}\biggl(1+\theta\frac{k_{\perp,\mrm{m}}}{k_{\parallel,\mrm{m}}}\biggr) .
\end{equation}
With $k_{\perp,\mrm{m}}/k_{\parallel,\mrm{m}}\sim\Lambda^{-1/2}_\mrm{m,max}$ for the fastest-growing mirror mode, we have $k_{y,\mrm{m}}\sim{k}_{\parallel,\mrm{m}}$ for $\theta\ll\Lambda^{1/2}_\mrm{m,max}$ and $k_{y,\mrm{m}}\sim\theta{k}_{\perp,\mrm{m}}$ for $\Lambda^{1/2}_\mrm{m,max}\ll\theta\lesssim{1}$. (In both cases, $\Lambda_\mrm{m,max}\sim(d_i/a_0)^{1/2}M_\mrm{A,0}^{1/2}$.)

\subsection{When mirrors affect tearing if $\theta\ll\Lambda^{1/2}_\mrm{m,max}$}\label{sec:smalltheta}

At $x\sim{a}$, the local reconnecting field is near its asymptotic value and $\tau_\mrm{pa}\sim\tau_\mrm{cs}$. Starting at time $t_\mrm{m}\sim\tau_\mrm{cs}/\beta_0\ll\tau_\mrm{cs}$, unstable mirror modes grow rapidly at this location ($a$ and $\tau_\mrm{A,r}$ hardly change from their initial values in a time $t_\mrm{m}$.) Unless tearing modes disrupt the CS within $t_\mrm{disrupt}\lesssim\tau_\mrm{cs}$ -- which is extremely unlikely, requiring \eqref{eqn:tearingDisrupts} to be satisfied within $\tau_\mrm{cs}$ -- these mirrors will saturate with $\delta{B}\simB_\mrm{r}$ and
\begin{equation}\label{eqn:kpar}
k_{y,\mrm{m}}^\mrm{max}(t)\rho_i\sim\frac{L_0}{L(t)}(\Omega_i\tau_\mrm{cs})^{-1/2}\sim\frac{a(t)}{a_0}\biggl(\frac{d_i}{a_0}\biggr)^{1/2}M_\mrm{A,0}^{1/2},
\end{equation}
where we have accounted for the Lagrangian stretching of the perturbations during CS formation.

To determine the effect of these mirrors on tearing, it is useful (as argued above) to first establish when $k^\mrm{max}_{y,\mrm{m}}(t)$ enters the large-$\Delta'$ regime in which $\gamma_\mrm{t}\propto{k}$ (the leftmost portion of figure \ref{fig:gamma-t0}), i.e.~when the mirrors influence the fastest-growing tearing modes. Combining \eqref{eqn:tearingn:k} and \eqref{eqn:kpar}, we find that $a(t)$ must satisfy
\begin{equation}\label{eqn:mirrorsCoppi1}
\frac{a(t)}{d_i}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/10}\biggl(\frac{d_i}{a_0}\biggr)^{-1/2}\beta_0^{1/6}M_\mrm{A,0}^{-1/6}
\end{equation}
for $k^\mrm{max}_{y,\mrm{m}}(t)\lesssimk_\mrm{t}^\mrm{max}(t)$. Equation (\ref{eqn:mirrorsCoppi1}) happens before the sheet would be disrupted in the absence of mirrors (see (\ref{eqn:tearingDisrupts})) if
\begin{equation}\label{eqn:CoppiWins1}
\frac{a_0}{d_i}\gtrsim\biggl(\frac{m_e}{m_i}\biggr)^{2/5}\beta_0^{-1}M_\mrm{A,0}^{-1},
\end{equation}
which is easily satisfied under the conditions of interest. Thus, there will be a time at which all tearing modes with $k_\mrm{t}\gtrsimk_\mrm{t}^\mrm{max}$ are affected by mirrors. How the tearing progresses after \eqref{eqn:mirrorsCoppi1} is satisfied will be discussed once the corresponding conditions for the other $\theta$-regime are derived.

\subsection{When mirrors affect tearing if $\Lambda^{1/2}_\mrm{m,max}\ll\theta\lesssim{1}$}

As $B_\mrm{g}$ is increased, things will continue in much the same way as in \S\ref{sec:smalltheta} except that the initial $k^\mrm{max}_{y,\mrm{m}}\sim\theta{k}_{\perp,\mrm{m}}$. That is, equation \eqref{eqn:kpar} is replaced by
\begin{equation}\label{eqn:kperp}
k_{y,\mrm{m}}^\mrm{max}(t)\rho_i\sim\frac{L_0}{L(t)}\theta(\Omega_i\tau_\mrm{cs})^{-1/4}\sim\frac{a(t)}{a_0}\biggl(\frac{d_i}{a_0}\biggr)^{1/4}\thetaM_\mrm{A,0}^{1/4}.
\end{equation}
This means that the condition on $a(t)$ that $k^\mrm{max}_{y,\mrm{m}}(t)\lesssimk_\mrm{t}^\mrm{max}(t)$ (cf.~\eqref{eqn:mirrorsCoppi1}) becomes
\begin{equation}\label{eqn:mirrorsCoppi2}
\frac{a(t)}{d_i}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/10}\biggl(\frac{d_i}{a_0}\biggr)^{-5/12}\theta^{-1/3}\beta_0^{1/6}M_\mrm{A,0}^{-1/12}.
\end{equation}
If the initial state satisfies
\begin{equation}\label{eqn:CoppiWins2}
\frac{a_0}{d_i}\gtrsim\biggl(\frac{m_e}{m_i}\biggr)^{4/5}\theta^4\beta_0^{-2}M_\mrm{A,0}^{-3},
\end{equation}
then \eqref{eqn:mirrorsCoppi2} occurs before \eqref{eqn:tearingDisrupts}, when the sheet would be disrupted without the mirrors.

\subsection{Mirror-stimulated onset of reconnection}

If either \eqref{eqn:CoppiWins1} or \eqref{eqn:CoppiWins2} is satisfied, then mirrors influence all tearing modes before they could otherwise disrupt the CS in the absence of mirrors. We now quantify that influence, focusing on those tearing modes with $k_\mrm{t}\gg{k}^\mrm{max}_{y,\mrm{m}}$ (see \eqref{eqn:kpar} and \eqref{eqn:kperp}). As argued previously, these modes see a magnetic field that is roughly uniform in $y$ but is rapidly varying in $x$ due to the mirrors, with an initial $k_{x,\mrm{m}}\sim{k}_{\perp,\mrm{m}}$ that is then compressed by the CS formation with $k_{x,\mrm{m}}(t)a(t)\sim{\rm const}$. This rapid variation enhances $\gamma_\mrm{t}(k_\mrm{t})$ for these modes due to the smaller effective sheet thickness (estimated below), which affects both $\Delta'(k_\mrm{t})$ and the Alfv\'{e}n-crossing time $\tau_\mrm{A,r}$ (see \eqref{eqn:gammat_smallDelta} and \eqref{eqn:gammat_largeDelta}).

\subsubsection{Model for a mirror-infested CS}

We argue that $\tau_\mrm{A,r}$ changes by a small amount, since mirrors modify $\mrm{d}B_y/\mrm{d}x|_{x=0}$ by only a factor of order unity. To determine how $\Delta'(k)$ is modified, we adopt the following simple model for the magnetic-field profile of a mirror-infested Harris CS:
\begin{equation}\label{eqn:Bymodel}
B_y(x)=B_\mrm{r}\tanh\Bigl(\frac{x}{a}\Bigr)\Bigl[1+\varepsilon\sin\Bigl(2k_\mrm{max}a\sech\Bigl(\frac{x}{a}\Bigr)\Bigr)\Bigr] ,
\end{equation}
where $k_\mrm{max}\gg{a}^{-1}$ is a parameter characterizing the peak $k_{x,\mrm{m}}$ occurring at the edge of the CS. This is a WKB approximation describing saturated mirrors with amplitude $\varepsilon\sim\mathcal{O}(1)$ times the local reconnecting field and wavenumber in the $x$-direction given by $k_x(x)=2k_\mrm{max}\sech(x/a)\tanh(x/a)$. This model was chosen because $k_x(x=0)=0$, $k_x(x\to\infty)\to{0}$, and $k_x(x)$ is maximal near the edge of the CS, as anticipated. (What follows is not particularly sensitive to this choice of $k_x(x)$.)

The resulting $\Delta'(k_\mrm{t})$ is obtained by numerically integrating the outer differential equation for the flux function, $\psi$ \citep{fkr63}:
\begin{equation}\label{eqn:psi}
\DD{x}{\psi}-\biggl(k^2+\frac{B_y''}{B_y}\biggr)\psi=0,
\end{equation}
with $B_y(x)$ given by \eqref{eqn:Bymodel}. Then $\Delta'\doteq\mrm{d}\ln\psi/\mrm{d}x|_{x=0}$ for the solution that obeys reasonable boundary conditions; an example result is shown in figure \ref{fig:Deltap-vs-k}({\it a}). (Its shape does not change significantly as $\varepsilon$ and $k_\mrm{max}$ vary.) Generally, $\Delta'>0$ for $k_\mrm{t}$ smaller than the inverse of the effective sheet thickness, $a_\mrm{eff}$, which we identify with the location $x_\mrm{m}$ of the peak in $B_y(x)$ closest to $x=0$ (i.e.~the location of the innermost mirror). As $k_\mrm{t}$ decreases from this value, $\Delta'(k_\mrm{t})$ rises sharply to saturate at $k_\mrm{t}=k_\mrm{sat}$ with value $\Delta'_\mrm{sat} \sim 1/a_\mrm{eff} \sim 1/x_\mrm{m}$, at which it is approximately constant until it nears the Harris-sheet $\Delta'(k_\mrm{t})\sim{1}/k_\mrm{t}{a}^2$, which it then follows.

The corresponding $\gamma_\mrm{t}(k_\mrm{t})$ shown in figure \ref{fig:Deltap-vs-k}({\it b}) depends on whether or not $\Delta'_\mrm{sat}d_e\ll{1}$. However, the maximum growth rate always occurs at $k_\mrm{sat}\sim{1}/x_\mrm{m}$, because of the $k_\mrm{t}$-dependence of \eqref{eqn:gammat_smallDelta} and \eqref{eqn:gammat_largeDelta}. Thus, to determine the new $t_\mrm{cr}$, we must calculate $x_\mrm{m}$. This yields two cases based on the size of $\theta$.

\begin{figure}
\centering
\includegraphics[width=0.65\textwidth]{fig3.eps}%
\caption{({\it a}) $\Delta'(k_\mrm{t})$ and ({\it b}) $\gamma_\mrm{t}(k_\mrm{t})$ for a Harris CS (red dashed line) and its mirror-infested counterpart (blue solid line), using $k_\mrm{max}a=200\upi$ and $\varepsilon=1/2$ in Eq.~\eqref{eqn:Bymodel}. $\Delta'$ rises rapidly at $k_\mrm{t} x_\mrm{m}\lesssim{1}$ and plateaus for ${k}_\mrm{sat}\gtrsimk_\mrm{t}\gtrsim{1}/(\Delta'_\mrm{sat}a^2)$. Mirror-stimulated tearing thus peaks at $k_\mrm{t}\sim{k}_\mrm{sat}$, regardless of whether $\Delta'_\mrm{sat}d_e\ll{1}$ (blue solid line) or $\Delta'_\mrm{sat}d_e\gtrsim1$ (orange dotted line).}
\label{fig:Deltap-vs-k}
\end{figure}

\subsubsection{Mirror-stimulated tearing for $\theta\ll{x}_\mrm{m}/a$}

When the reconnecting field is the dominant field on the scale of the innermost mirrors, the total ion-cyclotron frequency is $\Omega_i\sim(x_\mrm{m}/a)\Omega_{i,\mrm{r}}$ and $\tau_\mrm{pa}\sim\tau_\mrm{cs}$. The $x$-wavenumber of the mirrors at that location is then
\begin{equation}\label{eqn:kxm}
k_{x,\mrm{m}}(t,x_\mrm{m}(t))\rho_{i,\mrm{r}}\sim\biggl(\frac{x_\mrm{m}}{a(t)}\biggr)^{3/4}\biggl(\frac{d_i}{a_0}\biggr)^{1/4}\frac{a_0}{a(t)}M_\mrm{A,0}^{1/4},
\end{equation}
where we have accounted for the Lagrangian compression due to CS formation. The innermost mirror is located at $x_\mrm{m}\sim{k}^{-1}_{x,\mrm{m}}$, an $x$-wavelength away from the center. Substituting this into \eqref{eqn:kxm} yields
\begin{equation}\label{eqn:xm}
\frac{x_\mrm{m}}{a(t)}\sim\biggl(\frac{d_i}{a_0}\biggr)^{3/7}\beta_\mrm{r}^{2/7}M_\mrm{A,0}^{-1/7}.
\end{equation}
For this estimate to be self-consistent, we require $\theta\ll{x}_{\rm m}/a$ or, using \eqref{eqn:xm},
\begin{equation}\label{eqn:smallThReq}
\theta\ll\biggl(\frac{d_i}{a_0}\biggr)^{3/7}\beta_\mrm{r}^{2/7}M_\mrm{A,0}^{-1/7}.
\end{equation}
Provided this is satisfied, the fastest-growing tearing mode, having $\gamma_\mrm{t}(k_{\rm sat})$, is either FKR-like, if $d_e/x_\mrm{m}\ll{1}$, or Coppi-like, if $d_e/x_\mrm{m}\gtrsim{1}$.

In the former case, the maximum tearing growth rate is (using \eqref{eqn:gammat_smallDelta} with $k_\mrm{t}\sim{1}/x_\mrm{m}$ and $\Delta'\sim{1}/x_\mrm{m}$)
\begin{equation}\label{eqn:gammaFKRsmallTh}
\gamma_\mrm{t,m}^\mrm{FKR}\tau_\mrm{A,r}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/2}\Biggl(\frac{d_i^{8/7}a_0^{6/7}}{a^2}\Biggr)\beta_\mrm{r}^{-4/7}M_\mrm{A,0}^{2/7} .
\end{equation}
The critical time for onset, $t^\mrm{FKR}_\mrm{cr}$, occurs when $\gamma_\mrm{t,m}^\mrm{FKR}\tau_\mrm{cs}\sim{1}$, or
\begin{equation}\label{eqn:FKRdisrupts}
\frac{a(t^\mrm{FKR}_\mrm{cr})}{a_0}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/6}\biggl(\frac{d_i}{a_0}\biggr)^{8/21}\beta_\mrm{r}^{-4/7}M_\mrm{A,0}^{-5/21}.
\end{equation}
In the latter (Coppi-like) case, which happens when
\begin{equation}\label{eqn:CoppiSmallTh}
\frac{a(t_\mrm{tr})}{a_0}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/2}\biggl(\frac{d_i}{a_0}\biggr)^{4/7}\beta_\mrm{r}^{-2/7}M_\mrm{A,0}^{1/7},
\end{equation}
the maximum growth rate is
\begin{equation}\label{eqn:gammaCoppiSmallTh}
\gamma_\mrm{t,m}^\mrm{Coppi}\tau_\mrm{A,r}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/5}\beta_\mrm{r}^{-2/7}M_\mrm{A,0}^{1/7}\Biggl(\frac{d_i^{4/7}a_0^{3/7}}{a}\Biggr) ,
\end{equation}
and so the critical time $t^\mrm{Coppi}_\mrm{cr}$ occurs when $\gamma_\mrm{t,m}^\mrm{Coppi}\tau_\mrm{cs}\sim{1}$, or
\begin{equation}\label{eqn:Coppidisrupts}
\frac{a(t^\mrm{Coppi}_\mrm{cr})}{a_0}\lesssim \biggl(\frac{m_e}{m_i}\biggr)^{1/10}\biggl(\frac{d_i}{a_0}\biggr)^{2/7}\beta_\mrm{r}^{-1/7}M_\mrm{A,0}^{-3/7}.
\end{equation}
If the smallest parameter in the problem is $d_i/a_0$, so that (\ref{eqn:FKRdisrupts}) occurs before (\ref{eqn:CoppiSmallTh}) (i.e.~$t^\mrm{ FKR}_\mrm{cr} < t_\mrm{tr}$), then the CS will go unstable to mirror-stimulated FKR-like modes before the fastest-growing mode enters the large-$\Delta'$ regime. In this case, the critical CS thickness, $a_\mrm{cr}$, is given by \eqref{eqn:FKRdisrupts}. Comparing this to the expression for $a_\mrm{cr}$ when pressure anisotropy is {\em not} considered, equation \eqref{eqn:tearingDisrupts}, we see that mirrors increase $a_\mrm{cr}$ by a factor of ${\sim}(d_i/a_0)^{-2/7}\beta_\mrm{r}^{-4/7}M_\mrm{A,0}^{2/21}$. If, instead,  $t^\mrm{FKR}_\mrm{cr} > t_{\rm tr}$, then the fastest-growing mirror-stimulated tearing mode becomes Coppi-like before tearing onsets, and $a_\mrm{cr}$ is effectively increased by a factor of ${\sim}(m_e/m_i)^{-1/15}(d_i/a_0)^{-8/21}\beta_\mrm{r}^{-1/7}M_\mrm{A,0}^{-2/21}$.

\subsubsection{Mirror-stimulated tearing for $\theta\sim{x}_\mrm{m}/a$}

If \eqref{eqn:smallThReq} is not satisfied, then the innermost mirror does not reach the center of the CS (i.e.~$k_{x,\mrm{m}}x_\mrm{m}\gg{1}$). Instead, the mirrors closest to the center with growth rate comparable to $\tau_\mrm{cs}^{-1}$ are most important, i.e.~those located at $x_\mrm{m}\sim\theta{a}$ (see \eqref{eqn:Deltaapprox}). Then the scaling laws in the previous section are modified; equations \eqref{eqn:gammaFKRsmallTh}--\eqref{eqn:Coppidisrupts} become, respectively,
\begin{gather}
\gamma_\mrm{t,m}^\mrm{FKR}\tau_\mrm{A,r}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/2}\biggl(\frac{d_i}{\theta a}\biggr)^2, \\
\label{eqn:FKRdisruptsTha}
\frac{a(t^\mrm{FKR}_\mrm{cr})}{a_0}\lesssim \biggl(\frac{m_e}{m_i}\biggr)^{1/6}\biggl(\frac{d_i}{\theta a_0}\biggr)^{2/3}M_\mrm{A,0}^{-1/3}, \\
\label{eqn:CoppiTha}
\frac{a(t_\mrm{tr})}{a_0}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/2}\biggl(\frac{d_i}{\theta a_0}\biggr), \\
\gamma_\mrm{t,m}^\mrm{Coppi}\tau_\mrm{A,r}\sim\biggl(\frac{m_e}{m_i}\biggr)^{1/5}\biggl(\frac{d_i}{\theta a_0}\biggr), \\
\label{eqn:CoppiDisruptsTha}
\frac{a(t^\mrm{Coppi}_\mrm{cr})}{a_0}\lesssim\biggl(\frac{m_e}{m_i}\biggr)^{1/10}\biggl(\frac{d_i}{\theta a_0}\biggr)^{1/2}.
\end{gather}
Comparing \eqref{eqn:FKRdisruptsTha} and \eqref{eqn:CoppiTha}, we see that, if $d_i/(\theta a_0)\lesssim(m_e/m_i)^{-1}M_\mrm{A,0}^{-1}$, tearing will onset before the fastest-growing mode can enter the large-$\Delta'$ regime (i.e.~$t^\mrm{FKR}_\mrm{cr}<t_\mrm{tr}$). In this case, $a_\mrm{cr}$ is given by \eqref{eqn:FKRdisruptsTha}, which is larger by a factor of ${\sim}\theta^{-2/3}$ than $a_\mrm{cr}$ derived without consideration of the mirrors, equation \eqref{eqn:tearingDisrupts}. Therefore, tearing will onset much sooner if $\theta\ll{1}$, whereas $t_\mrm{cr}$ is largely unaffected when $\theta\sim{1}$. If, instead, $t^\mrm{FKR}_\mrm{cr}>t_\mrm{tr}$, the mirror-stimulated tearing is Coppi-like, and $a_\mrm{cr}$ is given by \eqref{eqn:CoppiDisruptsTha}. However, the condition  \eqref{eqn:smallThReq} still must be satisfied, allowing only a narrow range of validity for $\theta$. Moreover, this range only exists if $d_i/a_0\gg(m_e/m_i)^{-7/4}\beta_\mrm{r}^{1/2}M_\mrm{A,0}^{-2}$, a constraint not likely to be satisfied in the regime of interest. We therefore choose \eqref{eqn:FKRdisruptsTha} as the relevant condition for the onset of mirror-stimulated tearing for $\theta\sim x_\mrm{m}/a$.

\section{Discussion}\label{sec:summary}

While the specific quantitative model of CS evolution and mirror-stimulated tearing formulated herein is perhaps debatable, it nevertheless demonstrates an important, {\em qualitative} point: a gradually forming CS in a high-$\beta$, collisionless plasma easily produces enough pressure anisotropy to trigger the mirror instability, and the effect of this instability on the magnetic-field-line topology, and thus the tearing modes that instigate CS disruption via reconnection, ought to be considered.\footnote{In this respect, it is worth re-documenting the following prescient quote from the scarcely cited \citet{coppi83}: ``Thus we may consider the anisotropy-driven modes as a precursor of the spontaneous [tearing] ones and regard their effect as that of creating a region of macroscopic magnetic field turbulence near the neutral plane.''} For reasonable parameters, our theory predicts that the onset of reconnection in an evolving CS, driven by mirror-stimulated tearing modes, likely occurs earlier and at smaller scales than it would have without the mirrors, thereby placing a tighter upper limit on the aspect ratio of any forming CS (e.g.~compare \eqref{eqn:FKRdisrupts}, \eqref{eqn:Coppidisrupts}, and \eqref{eqn:FKRdisruptsTha} for the critical CS thickness at which mirror-stimulated tearing onsets to their $\Delta_p=0$ counterpart, equation \eqref{eqn:tearingDisrupts}). Whether or not these mirror-stimulated tearing modes ultimately grow to amplitudes $w\sim{a}_\mrm{eff}$, and perhaps beyond to ${\sim}a$ via island coalescence, to disrupt the CS awaits further work.

An immediate practical implication of this result is that numerical simulations of collisionless reconnection in high-$\beta$ plasmas should not initialize with a Maxwellian plasma embedded in an equilibrium CS. Instead, the CS should be allowed to evolve, and the particle distribution function self-consistently with it. A natural testing ground for this theory is the kinetic magnetorotational instability (MRI) \citep{quataert02,hq14}, thought to be the main driver of turbulence and enhanced transport in collisionless accretion flows, such as that onto the supermassive black hole at the Galactic center \citep{sharma06}. Historically, the linear MRI, at least in its MHD guise \citep{bh91}, was quickly shown to be a nonlinear ``channel'' solution in a differentially rotating disk \citep{gx94}, and various studies followed that employed Kelvin-Helmholtz and tearing ``parasitic'' modes to disrupt the otherwise resilient channels. In some theories, this disruption is credited for setting the steady-state level of magnetorotational turbulence as a function of the dissipative properties of the underlying magnetized fluid \citep[e.g.][]{pg09}. Given that the kinetic MRI both linearly and nonlinearly drives pressure anisotropy \citep{squire17}, it is worthwhile to contemplate a similar sequence of events, in which the kinetic MRI breaks down due to tearing modes stimulated by ion-Larmor-scale mirrors. Kinetic simulations of the MRI \citep[e.g.][]{riquelme12,hoshino13,hoshino15,kunz16,inchingolo18} may already be capable of testing this idea.

\begin{acknowledgments}
Support for A.A.~and M.W.K.~was provided by U.S.~DOE contract DE-AC02-09CH11466. This work benefited greatly from conversations with Nuno Loureiro, Alexander Schekochihin, and Dmitri Uzdensky, and from comments by the anonymous referees.
\end{acknowledgments}

redpajama_set_name: RedPajamaArXiv


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MARCUS MACHADO & FRIENDS - BACK BY POPULAR DEMAND!
From Rolling Stone's 2016 "Next Top Gun" and considered to be a "Smoking Gun" on today's best musical feature presentations these days this former child prodigy is absolutely on fire as one of the world's preeminent guitarist on the rise. With Marcus most recent musical feature playing alongside none other than the multi-talented Robert Glasper and Lalah Hathaway for the "Mr. Soul" documentary Marcus is proving his guitar playing and eclectically influenced Jimi Hendrix style is an added essential to the completion of what will be lauded as a masterpiece.
From blues and jazz to rock and hip-hop, Marcus style brings an essence of flavor and originality all its own. In 2017 Marcus performed an electrifying National Anthem before an audience of 20,000 at Madison Square Garden for the New York Knicks. With his most recent revered performances and collaborative offerings with Hip Hop Aficionado DJ Pete Rock and the Soul Brother Project along with drummer phenomenon Daru Jones the treacherous trio have rocked select cities throughout the country. If that weren't enough, Marcus along with Daru Jones (Jack White, Slum Village) and legendary bass player Doug Wimbush (Living Colour) established "DMD" a supergroup of musicianship who performed earlier this year a remarkable halftime show at Madison Square Garden.
Moving well ahead of his time, Marcus has played all over the world professionally since the tender age of ten with many of today's notable giants like, Buddy Miles, Marcus Miller, Ramsey Lewis, Sandra St. Victor, Zakk Wylde, Vernon Reid, Corey Glover, DJ Logic, Tony Royster, Kid Capri, Gary Hoeyand many others. True to form, Marcus himself is on his way to following in the steps of giants as his works continue to unfold. Marcus versatility of style as a guitarist is most recently showcased on "Goin, Goin, Gone" a country song featuring Robert Glasper and Ro James for the new Johnny Cash tribute album called "Forever Words" which reached #8 on the Billboard Country album charts.
Recognized as one of industry's best kept secrets, Marcus is no stranger to the stage with an in depth indoctrination to the world of music; Marcus Machado has been playing the acoustic guitar since the age of one and the electric guitar since the age of two. With one of the first of his performances as a kindergartner being a rendition of "The Wind Cries Mary" by Jimi Hendrix on a guitar synthesizer it's no wonder he was dubbed the "Young Jimi Hendrix " Coming full circle, Marcus had the esteemed opportunity to perform the Hendrix Flat Sessions in London on location at Jimi Hendrix old apartment which can be viewed on YouTube. Although influenced by many greats like Jimi Hendrix, Marcus wants to be known for his original music, which contains influences of Jazz, R&B, Funk, Rap, Rock and Gospel as displayed in his 2015 debut EP "29" released through Purpose Music Group showcasing his enormous musical talents.
Coupled with Marcus' management team The A.R.T. Agency Group, Marcus Machado will delight audiences during the summer of 2018 with a number of pop-up performances hosting musical guests in the SoHo neighborhood of New York City. These performance jam-sessions are expected to provide a lead introduction to Marcus long awaited single release, with a follow up album in the fall of 2018 as part of a soundtrack he scored for the upcoming short film "Blue Diamonds" Through his works and much anticipated sought after performances, Marcus Machado smoking style is a force to be reckoned with!


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