A collisional treatment of the trapped particle mode in multiregion mirror systems

Abstract

A method of analysis has been developed for treating the trapped particle mode in magnetic mirror systems in which three or more spatially distinct regions are present. The method applies for plasmas in which the electrons are sufficiently collisional that a Krook collision operator can be used. The ions have been treated as trapped within individual regions. The approximations allow the problem to be reduced to coupled algebraic equations, which are solved numerically. The numerical solutions are compared with asymptotic analytic solutions including known results. The results are applied to the multiple mirror experiment at Berkeley [Phys. Fluids 29, 1208 (1986)], which has three mirror cells of equal length but variable density, in which the central cell contains a potential barrier produced by a hot electron distribution.