Finite Larmor radius magnetohydrodynamic analysis of the RayleighTaylor instability in Z pinches with sheared axial flow
Abstract
The RayleighTaylor (RT) instability in Z pinches with sheared axial flow (SAF) is analyzed using finite Larmor radius (FLR) magnetohydrodynamic theory, in whose momentum equation the FLR effect (also referred to as the effect of gyroviscosity) is introduced through an anisotropic ion (FLR) stress tensor. A dispersion relation is derived for the linear RT instability. Both analytical and numerical solutions of the dispersion equation are given. The results indicate that the shortwavelength modes of the RT instability can be stabilized by a sufficient FLR, whereas the longwavelength modes can be stabilized by a sufficient SAF. In the smallwavenumber region, for normalized wavenumber K<2.4, the hybrid RT/KH (KelvinHelmholtz) instability is shown to be the most difficult to stabilize. However the synergistic effect of the SAF and gyroviscosity can mitigate both the RT instability in the largewavenumber region (K>2.4) and the hybrid RT/KH instability in the smallwavenumber region. In addition, this synergistic effect can compress the RT instability to a narrow wavenumber region. Even the thorough stabilization of the RT instability in the largewavenumber region is possible with a sufficient SAF and a sufficient gyroviscosity.
 Authors:
 Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China)
 Publication Date:
 OSTI Identifier:
 20974870
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 3; Other Information: DOI: 10.1063/1.2717583; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANISOTROPY; DISPERSION RELATIONS; DISPERSIONS; EQUATIONS; HELMHOLTZ INSTABILITY; IONS; LARMOR RADIUS; MAGNETOHYDRODYNAMICS; NUMERICAL SOLUTION; PLASMA; RAYLEIGHTAYLOR INSTABILITY; SHEAR; STABILIZATION; STRESSES; TENSORS; WAVELENGTHS
Citation Formats
Qiu, X. M., Huang, L., and Jian, G. D. Finite Larmor radius magnetohydrodynamic analysis of the RayleighTaylor instability in Z pinches with sheared axial flow. United States: N. p., 2007.
Web. doi:10.1063/1.2717583.
Qiu, X. M., Huang, L., & Jian, G. D. Finite Larmor radius magnetohydrodynamic analysis of the RayleighTaylor instability in Z pinches with sheared axial flow. United States. doi:10.1063/1.2717583.
Qiu, X. M., Huang, L., and Jian, G. D. Thu .
"Finite Larmor radius magnetohydrodynamic analysis of the RayleighTaylor instability in Z pinches with sheared axial flow". United States.
doi:10.1063/1.2717583.
@article{osti_20974870,
title = {Finite Larmor radius magnetohydrodynamic analysis of the RayleighTaylor instability in Z pinches with sheared axial flow},
author = {Qiu, X. M. and Huang, L. and Jian, G. D.},
abstractNote = {The RayleighTaylor (RT) instability in Z pinches with sheared axial flow (SAF) is analyzed using finite Larmor radius (FLR) magnetohydrodynamic theory, in whose momentum equation the FLR effect (also referred to as the effect of gyroviscosity) is introduced through an anisotropic ion (FLR) stress tensor. A dispersion relation is derived for the linear RT instability. Both analytical and numerical solutions of the dispersion equation are given. The results indicate that the shortwavelength modes of the RT instability can be stabilized by a sufficient FLR, whereas the longwavelength modes can be stabilized by a sufficient SAF. In the smallwavenumber region, for normalized wavenumber K<2.4, the hybrid RT/KH (KelvinHelmholtz) instability is shown to be the most difficult to stabilize. However the synergistic effect of the SAF and gyroviscosity can mitigate both the RT instability in the largewavenumber region (K>2.4) and the hybrid RT/KH instability in the smallwavenumber region. In addition, this synergistic effect can compress the RT instability to a narrow wavenumber region. Even the thorough stabilization of the RT instability in the largewavenumber region is possible with a sufficient SAF and a sufficient gyroviscosity.},
doi = {10.1063/1.2717583},
journal = {Physics of Plasmas},
number = 3,
volume = 14,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}

The effects of compressibility on the RayleighTaylor (RT) instability in a finite Larmor radius (FLR) plasma of magnetic field acceleration are studied by means of FLR magnetohydrodynamic (MHD) theory. FLR effects are introduced in the momentum equation of MHD theory through an anisotropic ion stress tensor. The linear mode equation which includes main equilibrium quantities and their highorder differential terms is derived. The dispersion equation is solved numerically. The main results indicate that in the compressible FLR plasma the growth rate of the RT instability displays faster growing and broader wavenumber range; and a new branch of lowfrequency and longwavelengthmore »

Finite Larmor radius magnetohydrodynamics of the Rayleigh{endash}Taylor instability
The evolution of the Rayleigh{endash}Taylor instability is studied using finite Larmor radius (FLR) magnetohydrodynamic (MHD) theory. Finite Larmor radius effects are introduced in the momentum equation through an anisotropic ion stress tensor. Roberts and Taylor [Phys. Rev. Lett. {bold 3}, 197 (1962)], using fluid theory, demonstrated that FLR effects can stabilize the Rayleigh{endash}Taylor instability in the shortwavelength limit ({ital kL}{sub {ital n}}{gt}1, where {ital k} is the wave number and {ital L}{sub {ital n}} is the density gradient scale length). In this paper a linear mode equation is derived that is valid for arbitrary {ital kL}{sub {ital n}}. Analytic solutionsmore »