Long-term rotating-wall compression with plasma cooling

Develop a diffusion or cooling term for the spectral macroparticle simulation of trapped non-neutral plasma and use it to investigate long-term compression behavior and the transition from the weak-drive to the strong-drive rotating-wall regime.

Background

The simulations reproduce rotating-wall compression in the weak-drive regime and identify the onset of nonlinear mode mixing at higher drive amplitudes. However, the model contains no cooling mechanisms, so external excitation heats the plasma, shifts its eigenfrequencies, and limits the simulations to short times and low drive amplitudes. In particular, the current model cannot address long-term compression or the strong-drive regime relevant to rotating-wall operation.

The conclusion identifies the proposed remedy—adding a diffusion/cooling term—as future work intended to enable studies of the transition regime. This is a concrete unresolved modeling and simulation problem because the missing term is required to counteract drive-induced heating and extend the accessible parameter range.