The Effect of Magnetization on Electron Heating in Low-Density Ultracold Neutral Plasmas

Abstract

Ultracold neutral plasmas provide a useful system for studying extreme parameter regimes plasma physics in an accessible laboratory setting. The parameter space of plasma physics can be characterized in part by coupling strength and degree of magnetization. The range of achievable strong coupling is determined in part by the lowest possible temperatures that can be achieved. This work examines the early-lifetime electron heating of moderately coupled, strongly magnetized plasmas. This heating is dominated by disorder-induced heating and heating due to Rydberg atom formation. By using experimentally informed simulations, it is found that disorder-induced heating has a large influence in electron temperature well into the plasma lifetime. Additionally, the dependence of the minimum achievable electron temperature on magnetization and initial electron energy is examined. In this work, we find electron temperatures as low as $0.52_{-.05}^{+.10}\mathrm{K}$ (for electron density, $n_e$, of $6.1\times 10^{12}{\mathrm{m}}^{-3}$), which determines the maximum coupling strength for the measured experimental conditions.

9 Pages, 7 figures

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