Nonlinear bound on unstable fluctuation level in low-density non-neutral plasma

A cold-fluid model is used to describe the nonlinear evolutions of low-density non-neutral plasma immersed in a strong axial magnetic field. It is assumed that there is no axial dependence, and that the electron fluid moves with the usual E x B drift velocity. Use is made of global (spatially averaged) conservation constraints satisfied by the continuity and Poisson equations to obtain a non-linear bound on the unstable fluctuation level for a general initial density profile. (author)