The classical theory of collisional transport grossly underestimates the cross magnetic flux of particles and heat in plasmas for which the cyclotron radius is small compared to the Debye length. Non-neutral plasmas typically operate in this parameter regime, and experiments have measured test particle flux that is an order of magnitude larger than the classical prediction, heat conduction a factor of 300 larger, and viscosity a factor of 10⁴ larger [1]. The enhancement is not due to turbulent fluctuations; the non-neutral plasmas are very quiescent, nearly in thermal equilibrium. The problem with the classical theory is that it omits an important class of collisional interactions: large impact parameter interactions that can be treated with guiding center drift theory. New theory that incorporates these dominant collisions predicts transport rates that are in good agreement with the measurements. The theory and experiment will be discussed.
In the limit of rapid axial bounce motion, particles may be approximated by bounce-averaged particles (charged rods) that undergo 2D ExB drift motion in the field of mutual interaction. Seminal theory and simulations by Taylor and McNamara [2] and Dawson and Okuda [3] predict that for a shear free plasma the 2D transport is associated with large scale thermally excited convective cells or vortices. Preliminary experiments in a regime of ultra-low shear show evidence that the transport is indeed convective in nature, rather than diffusive. However, small to moderate shear in the rotational flow reduces the transport, presumably tearing apart the larger vortices. Recent theory and experiment for the shear reduction of the transport will be discussed. There are obvious analogies between the shear reduction of transport here and the shear reduction in tokamak transport barriers; however, here the vortices are excited thermally, and in transport barriers they are excited by turbulence.^*

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