COLLISIONLESS ELECTRON HEATING BY RADIOFREQUENCY PLASMA SHEATHS

Collisionless rf sheaths have been investigated in a self-consistent particle simulation. The one-dimensional simulation is bounded by an rf driven electrode on one side and quasineutral plasma on the other so that the sheath can be examined in isolation from other discharge processes. The simulations indicate that electron velocity distributions arriving at the electrode are distorted when the ratio of the maximum velocity of the moving electron front in the rf sheath to the thermal velocity is greater than approximately 0.5. Both electron heating and power loss to the electrode increases as this ratio is increased. At ratios greater than approximately 0.8-1 a positive net energy flux returning from the rf sheath is observed. Electron inertia is not negligible in this regime.