The magnetised Richtmyer–Meshkov instability in two-fluid plasmas

Bond, D.; Wheatley, V.; Li, Y.; Samtaney, Ravi; Pullin, D. I.

The magnetised Richtmyer–Meshkov instability in two-fluid plasmas

Files

2003.00275.pdf (9.88 MB)

Type

Article

Authors

Bond, D.

Wheatley, V.
Li, Y.
Samtaney, Ravi

Pullin, D. I.

KAUST Department

Fluid and Plasma Simulation Group (FPS)
Mechanical Engineering Program
Physical Science and Engineering (PSE) Division

KAUST Grant Number

URF/1/3418-01

Online Publication Date

2020-09-30

Print Publication Date

2020-11-25

Date

2020-09-30

Submitted Date

2020-02-02

Abstract

We investigate the effects of magnetisation on the two-fluid plasma Richtmyer–Meshkov instability of a single-mode thermal interface using a computational approach. The initial magnetic field is normal to the mean interface location. Results are presented for a magnetic interaction parameter of 0.1 and plasma skin depths ranging from 0.1 to 10 perturbation wavelengths. These are compared to initially unmagnetised and neutral fluid cases. The electron flow is found to be constrained to lie along the magnetic field lines resulting in significant longitudinal flow features that interact strongly with the ion fluid. The presence of an initial magnetic field is shown to suppress the growth of the initial interface perturbation with effectiveness determined by plasma length scale. Suppression of the instability is attributed to the magnetic field’s contribution to the Lorentz force. This acts to rotate the vorticity vector in each fluid about the local magnetic-field vector leading to cyclic inversion and transport of the out-of-plane vorticity that drives perturbation growth. The transport of vorticity along field lines increases with decreasing plasma length scales and the wave packets responsible for vorticity transport begin to coalesce. In general, the two-fluid plasma Richtmyer–Meshkov instability is found to be suppressed through the action of the imposed magnetic field with increasing effectiveness as plasma length scale is decreased. For the conditions investigated, a critical skin depth for instability suppression is estimated.

Citation

Bond, D., Wheatley, V., Li, Y., Samtaney, R., & Pullin, D. I. (2020). The magnetised Richtmyer–Meshkov instability in two-fluid plasmas. Journal of Fluid Mechanics, 903. doi:10.1017/jfm.2020.661

Acknowledgements

This research was supported by the KAUST Office of Sponsored Research under Award URF/1/3418-01.