The Non-Linear Growth of the Magnetic Rayleigh-Taylor Instability

Abstract

This work examines the effect of the embedded magnetic field strength on the non-linear development of the magnetic Rayleigh-Taylor Instability (RTI) (with a field-aligned interface) in an ideal gas close to the incompressible limit in three dimensions. Numerical experiments are conducted in a domain sufficiently large so as to allow the predicted critical modes to develop in a physically realistic manner. The ratio between gravity, which drives the instability in this case (as well as in several of the corresponding observations), and magnetic field strength is taken up to a ratio which accurately reflects that of observed astrophysical plasma, in order to allow comparison between the results of the simulations and the observational data which served as inspiration for this work. This study finds reduced non-linear growth of the rising bubbles of the RTI for stronger magnetic fields, and that this is directly due to the change in magnetic field strength, rather than the indirect effect of altering characteristic length scales with respect to domain size. By examining the growth of the falling spikes, the growth rate appears to be enhanced for the strongest magnetic field strengths, suggesting that rather than affecting the development of the system as a whole, increased magnetic field strengths in fact introduce an asymmetry to the system. Further investigation of this effect also revealed that the greater this asymmetry, the less efficiently the gravitational energy is released. By better understanding the under-studied regime of such a major phenomenon in astrophysics, deeper explanations for observations may be sought, and this work illustrates that the strength of magnetic fields in astrophysical plasmas influences observed RTI in subtle and complex ways.

Accepted for publication by A&A. 10 pages, 9 figures

References in corpus (6)

• Athena: A New Code for Astrophysical MHD
• The Magnetic Rayleigh-Taylor Instability in Three Dimensions
• Rayleigh-Taylor instability in Magnetohydrodynamic Simulations of the Crab Nebula
• Nonlinear Evolution of the Magnetohydrodynamic Rayleigh-Taylor Instability
• Secondary Rayleigh-Taylor type Instabilities in the Reconnection Exhaust Jet as a Mechanism for Supra-Arcade Downflows
• On the nature of the magnetic Rayleigh-Taylor instability in Astrophysical Plasma: The case of uniform magnetic field strength

Cited by in corpus (6)

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• Particle acceleration by magnetic Rayleigh-Taylor instability: mechanism for flares in black-hole accretion flows
• Current-sheet Oscillations Caused by Kelvin-Helmholtz Instability at the Loop Top of Solar Flares
• Supergiant Fast X-ray Transients uncovered by the EXTraS project: flares reveal the development of magnetospheric instability in accreting neutron stars
• Self-similarity and growth of non-linear magnetic Rayleigh-Taylor instability -- Role of the magnetic field strength
• The Rayleigh Taylor instability in partially ionized plasmas: ambipolar diffusion effects in the non linear phase