R. Krimke et al., PIC MC SIMULATION OF A STRONGLY ASYMMETRIC LOW-PRESSURE RF DISCHARGE, Journal of physics. D, Applied physics, 27(8), 1994, pp. 1653-1659
A PIC/MC simulation is performed on a cylindrical low-pressure gas dis
charge between two coaxial electrodes in an axial magnetic field. This
case study employs an asymmetry ratio of 1:7 between inner and outer
electrodes. It is based on natural mass argon gas with experimentally
given cross sections for elastic, excitation and ionization electron c
ollisions, as well as elastic and charge exchange ion collisions. The
simulation shows that ionization occurs mostly at the inner sheath edg
e. Negative space charge regions build up in front of the momentary an
ode sheath. These lower the plasma potential with respect to the elect
rode and induce electron leakage currents to the anode. The ionization
degree is 3 x 10(-4) , and 10% of the dissipated power goes into ioni
zation in this particular case. The improvement of these features for
the design of an ion source is discussed.