Marshall N. Rosenbluth Outstanding Doctoral Thesis Award Talk: Preventing or exploiting turbulence during plasma compression*

Inspired by experimental Z-pinch results\footnote{E. Kroupp \emph{et al.}, Phys. Rev. Lett. {\bf 107}, 105001 (2011).}, we investigate plasma turbulence undergoing compression. We demonstrate a ``sudden viscous dissipation'' effect that can occur in compressing plasma turbulence\footnote{S. Davidovits and N. J. Fisch, Phys. Rev. Lett. {\bf 116}, 105004 (2016).}, but not in neutral gases, because of the stronger plasma viscous dependence on temperature. The TKE, having been amplified by compression, is suddenly dissipated by viscosity into thermal energy; this effect leads to a new paradigm for inertial fusion or for making X-ray bursts. We produce a model that captures this effect\footnote{S. Davidovits and N. J. Fisch, Phys. Plasmas {\bf 24}, 122311 (2017).}. Additionally, we find stability and saturation results, and a bound, for the TKE in compressing plasmas. We apply these insights in various systems with compressing turbulence, including inertial fusion, Z-pinch, and astrophysical plasmas. Applying the bound to molecular clouds, we find that an existing TKE model may be too dissipative\footnote{S. Davidovits and N. J. Fisch, The Astrophysical Journal {\bf 838}, 118 (2017).}. Applying our results to inertial fusion hot-spots allows us to predict compression trajectories, in rho-R vs. temperature space, where TKE growth is suppressed, and also allows us to predict a maximum TKE at burn time\footnote{S. Davidovits and N. J. Fisch, Phys. Plasmas {\bf 25}, 042703 (2018).}. Returning to the Z-pinch measurements that started our studies, we show the need for a new spectroscopic analysis in highly turbulent plasmas\footnote{E. Kroupp {\it et al.}, Phys. Rev. E {\bf 97}, 013202 (2018).}, in order to account for non-uniformity in the density.