On the time needed to reach an equilibrium structure of the radiation belts

摘要: In this study, we complement the notion of equilibrium states radiation belts with a discussion on dynamics and time needed to reach equilibrium. We solve for obtained using 1-D radial diffusion recently developed hiss chorus lifetimes at constant values Kp = 1, 3, 6. find that moderately low Kp, when plotted versus L shell (L) energy (E), display same interesting S shape inner edge outer belt as observed by Van Allen Probes. The is also produced dynamically evolve toward state initialized simulate buildup after massive dropout or loss due outward from saturated state. Physically, shape, intimately linked slot structure, dependence electron rate (originating wave-particle interactions) both shell. Equilibrium flux profiles are governed Biot number (τDiffusion/τloss), large corresponding fluxes fluxes. it takes specific (L, E) value associated state, starting these different initial states, belts, property (diffusion coefficients), size domain computation. Its structure shows rather complex scissor form in plane. (phase space density flux) practically reachable only selected regions geomagnetic activity. Convergence requires hundreds days E > 300 keV moderate Kp (≤3). It less during disturbed conditions (Kp ≥ 3), system evolves faster. Restricting our interest region, below L = 4, small can value: E ~ [200, 300] keV L = [3.7, 4] E~[0.6, 1] MeV L = [3, Kp = 3, E~300 keV L = [3.5, Kp = 6 assuming no new incoming electrons.