Simulation of ultracold plasma expansion in homogeneous magnetic field

Abstract: We present molecular dynamics simulation results for an ultracold $<sup>{40}$Ca plasma in a constant, homogeneous magnetic field. The magnetic field induces a significant spatial separation of charges. Furthermore, a significant fraction of the electrons escapes from the region bounded by the ions, in contrast to the case of plasma expansion into a vacuum. This leads to the formation of a quasineutral plasma core containing the remaining electrons and surrounded by an outer, thick ion shell, where the ion density drops sharply. Anisotropy in the ion kinetic energy is also observed, depending on the direction of ion motion relative to the magnetic field lines. The simulation results are in agreement with experimental data on ion dynamics.