Charged Particle Diffusion in a Magnetic Dipole Trap

Abstract

When particles are magnetized, a diffusion process is influenced by the ambient magnetic field. While the entropy increases, the constancy of the magnetic moment puts a constraint. Here, we compare the E-cross-B diffusion caused by random fluctuations of the electric field in two different systems, the Penning-Malmberg trap and the magnetic dipole trap. A Fokker-Planck equation is derived by applying the ergodic ansatz on the invariant measure of the system. In the dipole magnetic field particles diffuse inward and accumulate in the higher magnetic field region, while, in a homogeneous magnetic field, particles diffuse out from the confinement region. The properties of analogous transport in a more general class of magnetic fields are also briefly discussed.

arXiv comment10 pages, 5 figures

References in corpus (5)

• Self-organization in foliated phase space: Construction of a scale hierarchy by adiabatic invariants of magnetized particles
• Up-Hill Diffusion Creating Density Gradient - What is the Proper Entropy?
• A Stochastic Model of Inward Diffusion in Magnetospheric Plasmas
• Thermal equilibrium of non-neutral plasma in dipole magnetic field
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Cited by in corpus (3)

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• Guiding Center Derivation of the Generalized Hasegawa-Mima Equation for Drift Wave Turbulence in Curved Magnetic Fields
• Hamiltonian Structure and Nonlinear Stability of Steady Solutions of the Generalized Hasegawa-Mima Equation for Drift Wave Turbulence in Curved Magnetic Fields