Electron kinetics in a high-Z plasmoid

The problem of the electron dynamics on a closed magnetic field line passing through a high-Z plasmoid is considered. The electron kinetic equation is integrated over bounce motion and pitch angle, reducing the independent variables to a single adiabatic invariant plus time. Integration of the full Landau self-collision operator is carried out exactly, resulting in a nonlinear integro-differential operator in the new invariant. Conservation laws and the H theorem of the integrated self-collision operator are proven. Numerical solutions of the integrated kinetic equation are obtained with a self-consistent quasineutral electric potential, given the initial condition of a cold plasmoid immersed in a hot ambient plasma. The fact that cold electrons are deeply trapped in a potential with a parabolic peak leads to exactly 3/4 the usual rate of collisional heating by the ambient plasma, independent of any other parameters.

Automated summary

The problem of electron dynamics on a closed magnetic field line passing through a high-Z plasmoid is studied. The electron kinetic equation is integrated over bounce motion and pitch angle, resulting in a nonlinear integro-differential operator in a new invariant. Numerical solutions are obtained, showing the unique collisional heating rate by the ambient plasma due to the deep trapping of cold electrons in a potential with a parabolic peak.