Y. Okuno et al., 2-DIMENSIONAL ION VELOCITY DISTRIBUTION-FUNCTIONS IN ELECTRON-CYCLOTRON-RESONANCE PLASMA UNDER A DIVERGENT MAGNETIC-FIELD, Journal of applied physics, 74(10), 1993, pp. 5990-5996
Two-dimensional ion velocity distribution functions are measured in el
ectron cyclotron resonance (ECR) argon plasmas under a divergent magne
tic field configuration using a directional analyzer. Ions produced in
the ECR source grow to a beam in the downstream region inside an allo
wed angle, while the distribution function is almost isotropic outside
the angle. The beam energy corresponds to the potential difference be
tween the ECR source and downstream locations. The ion beam is almost
parallel to an applied magnetic field, the beam being deflected along
the divergent magnetic field lines. The energy spread and the temperat
ure of the ion beam, and the temperature of the bulk ions are also sho
wn as a function of the distance from the ECR source or of the gas pre
ssure. The validity of the directional analyzer measurements is discus
sed by considering the motion of an ion in a sheath in front of the an
alyzer.