title: Pressure-driven, resistive magnetohydrodynamic interchange instabilities in laser-produced high-energy-density plasmas.
abstract: Recent experiments using proton backlighting of laser-foil interactions provide unique opportunities for studying magnetized plasma instabilities in laser-produced high-energy-density plasmas. Time-gated proton radiograph images indicate that the outer structure of a magnetic field entrained in a hemispherical plasma bubble becomes distinctly asymmetric after the laser turns off. It is shown that this asymmetry is a consequence of pressure-driven, resistive magnetohydrodynamic (MHD) interchange instabilities. In contrast to the predictions made by ideal MHD theory, the increasing plasma resistivity after laser turn-off allows for greater low-mode destabilization (m>1) from reduced stabilization by field-line bending. For laser-generated plasmas presented herein, a mode-number cutoff for stabilization of perturbations with m> approximately [8pibeta(1+D_{m}k_{ perpendicular};{2}gamma_{max};{-1})];{1/2} is found in the linear growth regime. The growth is measured and is found to be in reasonable agreement with model predictions.
authors: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. li@psfc.mit.edu
authors: C K
authors: CK
authors: Li
authors: J A
authors: JA
authors: Frenje
authors: R D
authors: RD
authors: Petrasso
authors: F H
authors: FH
authors: Séguin
authors: P A
authors: PA
authors: Amendt
authors: O L
authors: OL
authors: Landen
authors: R P J
authors: RP
authors: Town
authors: R
authors: R
authors: Betti
authors: J P
authors: JP
authors: Knauer
authors: D D
authors: DD
authors: Meyerhofer
authors: J M
authors: JM
authors: Soures