The impact of anomalous resistivity in vacuum contaminant plasmas on the electrothermal instability

POSTER

Abstract

This manuscript presents an assessment of the electrothermal instability (ETI) in the presence of anomalous resistivity (AR) in vacuum contaminant plasmas (VCP) when applied to a magnetized liner inertial fusion (MagLIF)-like load. Pulsed-power driven dielectrically coated metallic liners, like in MagLIF, experience the current-driven electrothermal instability which occurs when a material's resistivity changes with temperature and is subject to ohmic heating. Large scale pulsed-power facilities that use magnetically insulated transmission lines (MITL) have been shown to generate low-density plasma which enters the target chamber and coalesces around the load. The low-density high-temperature vacuum contaminant plasmas (VCP) can parasitically divert current from the load through causing a short in the anode-cathode gap inside the target chamber. Resistive magnetohydrodynamic (MHD) simulations of these VCP experience unphysical runaway ohmic heating due to under predicting the resistivity by using a purely collisional resistivity model. AR provides a physics-based way to address this runaway heating through increasing the resistivity in a proportional way with the drift speed. The effect that AR in VCP has on the magnetic diffusion rate is assessed through 1D simulations, and 2D simulations show how this effect manifests in the nonlinear striation form of the ETI for a MagLIF-like load. Beryllium and aluminum dielectrically coated liners are used for the 1D and 2D simulations to explore the impact of AR in VCP has on striation ETI.

*A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. This work is supported through the U.S. Department of Energy under grants DE-NA0003881 and DE-SC0016515.

Presenters

  • Robert L Masti

    • Virginia Tech

Authors

  • Robert L Masti

    • Virginia Tech
  • Bhuvana Srinivasan

    • Virginia Tech
  • William A Farmer

    • Lawrence Livermore Natl Lab