for the plasma gas the generator is coupled in a known manner to two in particular ring or disk shaped parallel interspaced electrodes each having at least one through opening and for at least one isolator to be positioned between the electrodes the isolator having at least one particularly circular through opening assigned to the through opening of the electrode whose through opening is designed to confine the plasma formed by a plasma gas at a pressure of at least 0 01 bars but preferably between 0 1 and 5 bars the inside diameter of the through opening of the electrodes is at least double but especially approximately four to eight times that of the inside diameter of the through opening of the isolator for confining the plasma application_number US 38934999 A description in fig1 two parallel interspaced ring or disk shaped electrodes are designated as 1 and an isolator 2 made for example of ruby sapphire or generically any poorly or non conducting oxide ceramic is positioned between said electrodes wherein the isolator 2 has a through opening 3 in which subsequently a plasma of small dimensions which idealized can be regarded as point like is formed each electrode 1 has a through opening 4 which significantly exceeds the dimensions of through opening 3.