Influence of Axial Energy Spread on the Negative-Mass Instability in a Relativistic Nonneutral E-Layer.

摘要

This paper investigates the influence of an axial energy spread on the negative-mass instability in a relativistic nonneutral E-layer aligned parallel to a uniform axial magnetic field (B sub 0)(e sub z). The stability analysis is carried out within the framework of the linearized Vlasov-Maxwell equations. It is assumed that the E-layer is thin with radial thickness much smaller than the mean radius and that nu gamma sub 0 << 1, where nu is Budker's parameter and gamma sub 0 mc-squared is the mean electron energy. Stability properties are investigated for the choice of electron distribution function in which all electrons have the same value of canonical angular momentum and a step-function distribution in axial momentum p sub z. The negative-mass growth rate is calculated including the important stabilizing influence of axial energy spread, and it is shown that modest energy spread is sufficient to stabilize perturbations with axial wavenumber.