Relaxation processes of electrons and positrons in gases in electric and magnetic fields crossed at arbitrary angles

A multi-term solution of the Boltzmann equation has been developed and used to investigate the temporal relaxation of charged-particle swarms under the influence of electric and magnetic fields crossed at arbitrary angles. A Monte Carlo simulation technique has been used to verify the Boltzmann equation analysis under hydrodynamic conditions and for an independent study of spatial relaxation of the electrons under non-hydrodynamic conditions. We present results for model and real gases highlighting the explicit influence of the magnetic field and non-conservative collisions on temporal and spatial relaxation characteristics, including the existence of transiently negative electron diffusivity. We present results for thermalization of the positrons in nitrogen highlighting the applicability of our theory for contemporary kinetic studies in the domain of positron physics.