Effect of the electronic pressure on the energy and magnetic moment of charged test particles in turbulent electromagnetic fields

Abstract

In this work we perform direct numerical simulations of three-dimensional magnetohydrodynamics with a background magnetic field, representing solar wind plasma, and introduce test particles to explore how a turbulent electromagnetic environment affects them. Our focus is on the terms of the electric field present in the generalized Omh's Law that are usually dismissed as unimportant. These are the Hall and the electronic pressure (EP) terms, but we concentrate primarily on the latter. We discover that the EP term generates an acceleration of the particles, which represent protons, in the direction parallel to the background magnetic field, in contrast to the known preferential perpendicular energization. By studying the electric field itself, we are able to detect the type of structures of the EP field that produce such parallel acceleration. These are thin and elongated structures placed on top of a monotonic and near-zero background. A statistical study to understand the real significance of the electronic pressure term is also performed.

References in corpus (6)

• The Structure of Plasma Heating in Gyrokinetic Alfvénic Turbulence
• Ion and Electron Acceleration in Fully Kinetic Plasma Turbulence
• Magnetic reconnection as a mechanism to produce multiple protonpopulations and beams locally in the solar wind
• Acceleration of Particles in Imbalanced Magnetohydrodynamic Turbulence
• Spatio temporal analysis of waves in compressively driven magnetohydrodynamics turbulence
• Test particle energization of heavy ions in magnetohydrodynamic turbulence