Inward Diffusion and Acceleration of Particles Driven by Turbulent Fluctuations in Magnetosphere

TL;DR

This paper investigates how turbulent fluctuations in a magnetosphere cause inward diffusion and energization of charged particles, revealing density gradients and anisotropic heating consistent with observations.

Contribution

It introduces a numerical simulation approach on constrained phase space to study inward diffusion, highlighting the effects of micro-scale invariants on particle dynamics.

Findings

Emergence of inhomogeneous density gradients

Anisotropic heating of particles

Consistency with spacecraft and experimental observations

Abstract

Charged particles in a magnetosphere are spontaneously attracted to a planet while increasing their kinetic energy via inward diffusion process. A constraint on particles' micro-scale adiabatic invariants restricts the class of motions available to the system, giving rise to a proper frame on which particle diffusion occurs. We investigate the inward diffusion process by numerical simulation of particles on constrained phase space. The results reveal the emergence of inhomogeneous density gradient and anisotropic heating, which is consistent with spacecraft observations, experimental observations, and the recently formulated diffusion model on the constrained phase space.