Laboratory Studies of Laser-Driven, Ion-Scale Magnetospheres

Abstract:

Ion-scale magnetospheres have been observed around comets, weakly-magnetized asteroids, and localized regions on the Moon. These mini-magnetospheres provide a unique environment to study kinetic-scale plasma physics, in particular in the collisionless regime, but are difficult to study directly. Laboratory experiments can thus provide a controlled and reproducible platform for understanding fundamental magnetospheric physics and helping validate models of larger, planetary magnetospheres. In this work, we present preliminary experiments of ion-scale magnetospheres performed on the Large Plasma Device (LAPD) at UCLA. Utilizing high-repetition rate lasers to drive super-Alfvénic plasma flows into a dipole magnetic field embedded in a uniform background magnetic field, these experiments examine the evolution of local and global magnetosphere structure for a range of dipole and upstream parameters. PIC simulations are employed to interpret the highly-resolved, volumetric experimental datasets, and used to determine the magnetospheric structure, kinetic-scale structures of the plasma current distribution, and dynamics of the laser-driven plasma. Single and multiple ion species simulations are compared to investigate the role of heavy ions ablated from the laser target in the interaction.

Supported by the NSF.