Electron and Ion Heating Through Resonant Plasma Oscillations

We present an analytic solution for the resonant oscillations of a cold, inhomogeneous, one-dimensional plasma under the influence of a sinusoidal applied field. The model approximates the response to obliquely incident electromagnetic radiation. Energy can be absorbed collisionlessly through either electron wave breaking or ion bunching, when the driven field is strong or weak, respectively. The two regimes are distinguished by eE_L≷0.02Lm²ω² / M, where L is the plasma scale length and E_L the longitudinal driver. In the weak-driver case, ions with keV emergies can be produced in the resonance region.