Particle saturation of the outer zone: A nonlinear model

Properties of the steady state and transient behavior of geomagnetically trapped radiation are analyzed by means of phenomenological equations that concisely summarize the operative dynamical processes. The equations provide for a realistic coupling between electromagnetic wave energy, particle intensity, and pitch-angle anisotropy in the context of the outer zone. Applications include magnetospheric enforcement of a limit on stably trapped particle flux. the smooth transition between weak pitch-angle diffusion and strong diffusion, parasitic particle precipitation by natural and man-made radio signals, natural and artificial injections of trapped radiation, and the consequences of magnetospheric cold-plasma injection.