The CNT experiment probes the physics of non-neutral plasmas confined on magnetic surfaces..

The equilibrium equations for a pure electron plasma on magnetic surfaces were recently derived [Pedersen and Boozer, Phys. Rev. Lett. 88, 205002, 2002]. The equilibrium is fundamentally different from pure electron equilibria in other confinement configurations, such as the Penning trap, and is also fundamentally different from equilibria of quasi-neutral plasmas on magnetic surfaces. This implies that new physics is involved. Finite temperature pure electron equilibria have been calculated in two dimensions, using a cylindrical approximation and elliptical magnetic surfaces [Pedersen, Phys. Plasmas 10, p. 334 (2003)] and in three dimensions (Lefrancois et al., Phys. Plasmas 12, p. 072105).

Equilibria are stable against low frequency perturbations, as long as these perturbations do not violate parallel force balance, particle and entropy conservation, and parallel temperature equilibration [ A. H. Boozer, Phys. Plasmas 11 p. 4709 (2004)].

A stellarator configuration can confine plasmas with an arbitrary degree of neutralization, all the way from pure electron to quasi-neutral. This will allow studies of non-neutral ion-electron plasmas and may facilitate the creation of the first confined positron-electron plasmas [Pedersen et al., Journal of Physics B 36, p. 1029 (2003)]. There are many issues in this area that are still largely unexplored.

The CNT theory program is supported by a grant from the National Science Foundation Division of Physics.