1. An ion generator comprising:a vacuum chamber;
an anode in the vacuum chamber, wherein the anode is a hollow anode formed by a metallic matrix and adapted to be positively charged and pressurized by a gas whereby electrons of the gas can be stripped off and diffused through the metallic matrix, whereby a purer reactive ionized gas can be supplied to interact enhancing the potential of high energy plasma double layers;
two movable cathodes in the vacuum chamber; and
a servo actuated motor operably connected to each movable cathode to move the two movable cathodes;
whereby the position of the two movable cathodes relative to the anode can be varied.