Non-equilibrium transport of positron and electron swarms in gases and liquids

The transport properties of positron and electron swarms in gases and liquids find application in many and varied fields. In this paper we present a time-dependent multi-term solution of Boltzmann's equation valid for electrons and positrons, and benchmark it against an independent Monte-Carlo simulation where possible. The transport properties of positrons in dilute gaseous and liquid argon are considered and compared. The sensitivity of the macroscopic transport properties to the anisotropic nature of elastic scattering is highlighted. The temporal non-locality of diffusion for electron swarms in gases under the influence of time-dependent electric and magnetic fields is addressed through the consideration of their associated relaxation profiles.