ION CHARGE-STATE DISTRIBUTION IN A HIGH-POWER PULSED ELECTRON-CYCLOTRON-RESONANCE DISCHARGE SUSTAINED BY MILLIMETER-WAVELENGTH RADIATION

Measurements have been made of the ion charge-state distribution in a high-power, pulsed, electron-cyclotron discharge in argon sustained by millimeter radiation. It has been observed that the maximum of the di stribution is shifted toward higher charge states compared with the di stributions in conventional cw sources of multiply charged ions pumped by centimeter radiation. This shift of the distribution maximum evide ntly occurs because a so-called quasigasdynamic plasma confinement reg ime can be established in a magnetic trap when higher-power, shorter-w avelength gyrotron radiation is used, and in this regime, an increase in plasma density is accompanied by an increase in the confinement par ameter N-tau, which determines the ion charge distribution. (C) 1997 A merican Institute of Physics. [S1063-7850(97)02704-3].