Drive and damping govern resonant electron energy redistribution in a kinetic model informed by helium discharges

Abstract

Energetic electrons exchange energy with electrostatic waves in low-temperature plasmas, but wave amplitude alone does not determine the direction or cumulative effect of that exchange. We analyse nonlinear electron redistribution using a single-mode kinetic model parameterized by published helium-discharge measurements. Frequency and pressure comparisons are combined with a controlled damping scan and explicit particle-current and energy diagnostics. Across the frequency cases, the inferred resonant drive varies by a factor of 2.7 while background damping varies by only about 9%. Reducing pressure from 33.3 to 10.66 Pa at 37 MHz increases the net drive by a factor of 2.24. In the damping scan, the peak wave energy and residual parallel-energy deficit both decrease by approximately 93%, consistent with quadratic field-amplitude scaling at the reported endpoints. An integrated energy identity connects retained wave energy, background loss and distribution recovery, and distinguishes cessation of wave growth from reversal of energy transfer. Quantitative timescale and directional-distribution tests define the connection between this reduced model and discharge kinetics. The analysis provides a common interpretation of resonant redistribution, coherent current and energy exchange, together with observables for testing that interpretation in kinetic simulations and phase-resolved measurements.