Kinetic Theory of Strongly Magnetized Plasmas

Strongly magnetized plasmas characterized by an electron gyroradius smaller than the Debye length are known to exhibit novel transport properties. Traditional plasma kinetic theories, such as Boltzmann, Landau, and Lennard-Balescu, assume that collisions between particles occur at a much smaller length scale than the gyromotion of the particles, making them ineffective in describing strongly magnetized plasmas. Here, we present a generalized Boltzmann kinetic theory for strongly magnetized plasmas. Our findings show significant modifications to how momentum and energy relax in strongly magnetized conditions. It is found that the friction force on the test ion has components perpendicular to its velocity in addition to the stopping power component aligned antiparallel to its velocity. During the temperature equilibration of ions and electrons, strong magnetization is found to significantly suppress the perpendicular energy exchange rate, resulting in long-lasting temperature anisotropies during temperature evolution. It is also found that the strong magnetization breaks the fundamental symmetry of charge independence of the interaction known as the Barkas effect. The theoretical calculations are compared with the molecular dynamics simulations and previously published experimental results and are found to be in good agreement, thus validating the theory.