upright configuration and with a controlled separation alternatively the nanotubes 28 may be attached to the wire 22 after fabrication by their sidewall in a u201c layed down u201d configuration the extremely small radius 17 of the nanotubes 28 less than 100 nm and typically on the order of a few nanometers produces an extremely small volume of plasma region 15 in proportion to a discharge area such as defines the current flow into the plasma region 15 accordingly dependent in part on the orientation spacing and length of the carbon nanotube 28 the discharge area may be controlled independently of the volume of the plasma region 15 to decrease the formation of ozone while maintaining a high production of charge carriers generally the radius 17 is smaller than the mean free path of charge carriers 18 in the plasma region 15 peek 39 s equation generally predicts that the higher radius of curvature of the nanotubes will also decrease the voltage necessary to produce atmospheric corona discharge decreasing the power needed for corona discharge however it was not known whether peek 39 s equation breaks down for very small radii because peek 39 s equation is empirically based one possibility is that an increase in field emission for small radii may cause early initiation of a negative corona preventing advantageous production of positive coronas for reduced ozone production as will be described below however the present inventor has determined that the decrease in radius of carbon nanotubes does result.