Theoretical and Numerical Study of Cavity Cooling of Lepton Plasmas

Electron plasmas confined in Malmberg-Penning traps cool via cyclotron emission. Recently experiments [A. Povilus, et al., PRL 117, 175001 (2016); E. D. Hunter, et al., Phys. Plas. 25, 011602 (2018)] demonstrated that the cooling rate is significantly increased over its free space value by resonant interaction with a mode of a microwave cavity. T. M. O’neil [Phys. Fluids 23 (1980)], using Vlasov theory, predicted plasma cooling is enhanced in a cavity, and emphasized the importance of cyclotron detuning and frequency spread. Here, a simple model of the system based on interacting oscillators is derived and studied. We explore how the cooling rate depends on the spatial dependence of the microwave mode, the number of electrons, resonance detuning, spatial dependence of the magnetic field, and other system parameters.