Analytical modeling of magnetic Rayleigh-Taylor instabilities in compressible fluids

作者：Liberatore Stephane^*; Bouquet Serge

来源：Physics of Fluids, 2008, 20(11): 116101.

DOI：10.1063/1.3025832

The magnetic Rayleigh-Taylor instability (MRTI) is investigated in the case of compressible plasmas. The goal of this work is highlighting the influence of both the magnetic field and the compressibility of the material on the growth rate of the Rayleigh-Taylor instability, compared to the classical growth rate derived for incompressible fluids. Our analytical linear models are derived in the framework of the ideal magnetohydrodynamics theory. Three general dispersion relations are obtained: (1) Two for stratified fluids, including compressible (denoted CS(parallel to) when the wave vector k is parallel to the equilibrium magnetic field B(0) and CS(perpendicular to) when k perpendicular to B(0)) and incompressible (denoted IS(parallel to) and IS(perpendicular to)) and (2) one for incompressible uniform density fluids, including finite mass (denoted Ifm) and infinite (denoted IU). For k perpendicular to B(0), Ifm, IU, and IS(perpendicular to) are unmagnetized cases. Comparisons of those various configurations are performed and several differences are pointed out. The main results are as follows: Stratification weakens the MRTI while compressibility has a destabilizing effect. The magnetic field enhances these phenomena. The CS(parallel to) and IU configurations have an identical cutoff wave number. The upper fluid (also called heavy fluid) is more sensitive to compressibility than the light one when k parallel to B(0). Finally, the CS(parallel to) case is more sensitive than the CS(perpendicular to) one to physical variations.

• 出版日期2008-11
• 单位中国地震局