Two-dimensional bounce-averaged collisional particle transport in a single species non-neutral plasma

In this paper we describe a new theory of like particle collisional transport for a non-neutral plasma confined in a Penning trap. The theory is valid in the regime ωb>ωE, ωb>νc, and rc<λD where ωb is the axial bounce frequency, ωE is the E×B rotation frequency, νc is the collision frequency, rc is the cyclotron radius, and λD is the Debye length. In this regime each particle can be bounce averaged into a long rod and the transport understood as arising from the E×B drift motion of the rods due to long-range mutual interactions. This is a very different mechanism than is considered in the classical theory of transport, where a particle guiding center undergoes a step of order rc as a result of a velocity scattering collision. For the parameter range considered, the new theory predicts transport rates that are orders of magnitude larger than those predicted by classical theory and that scale with magnetic field strength like 1/B rather than 1/B4. The new theory differs from a previous analysis of transport due to E×B drift interactions of charged rods, in that the finite length of the rods is taken into account. This enables transport to occur even for the case of an E×B drift rotation frequency that is a monotonic decreasing function of radius (as was the case in recent experiments).