Maxwellianization of Hot Electrons Observed in a Pure Electron Plasma

The non-neutral electron plasma trap at UC Berkeley is used to study lepton plasma dynamics and optimize routines used at CERN in producing trappable antihydrogen. Some of the parameters explored at Berkeley include electrostatic shaping, confinement time, and magnetic field profile. This experiment also features high sensitivity, at the level of single plasma electron detection. Maxwellianization is the tendency for the distribution function to evolve towards the maximum entropy state f(v)~exp(-mv^2/2kT). In the context of this experiment, Maxwellian (or thermal) electrons form this characteristic distribution when the plasma is held long enough in its confinement well. Under some conditions a fraction of the population may be excited to a higher energy. When such a plasma is released from confinement into a parallel energy analyzer, we may observe the "Non-Maxwellian" electrons. These electrons relax collisionally with the "bulk", or the part of the plasma which is thermalized at a lower temperature. By observing the distribution at various points during this relaxation, we can test the rules for test particle relaxation in a cold stationary background outlined in the plasma formulary.