Does the Magnetic Field Affect the Electronic Screening Cloud Around Ions in Ultracold Neutral Plasmas?*

The Bohr-van Leeuwen theorem predicts a spherical screening cloud around ions in equilibrium plasmas. However, the behavior of this screening cloud in non-equilibrium conditions, such as in ultracold neutral plasmas (UNPs) under strong magnetic fields, remains an open question. In this study, we investigate the effects of strong magnetic fields on disorder-induced heating (DIH) in UNPs. Using molecular dynamics (MD) simulations, we analyze the evolution of ion and electron temperatures in UNPs subjected to varying strengths of magnetic fields. Our simulations aim to understand how the anisotropic electron screening cloud influences the heating dynamics of ions and electrons.

Contrary to our initial hypothesis that the non-spherical shape of the electron cloud induced by strong magnetic fields would lead to significant anisotropy in ion temperatures, our MD simulations reveal no substantial differences in the ion and electron temperatures compared to the field-free case. These findings are corroborated by recent experimental measurements, which show similar temperature evolution in UNP under strong magnetic fields.