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Influence of Alfven waves on the Thermal Instability in the Interstellar Medium

P. Hennebelle·T. Passot
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Abstract

The effect of Alfvén waves on the thermal instability of the Interstellar Medium (ISM) is investigated both analytically and numerically. A stability analysis of a finite amplitude circularly polarized Alfvén wave propagating parallel to an ambient magnetic field in a thermally unstable gas at thermal equilibrium is performed, leading to a dispersion relation which depends on 3 parameters, namely the square ratio of the sonic and Alfvén velocities ($β$), the wave amplitude and the ratio between the wave temporal period and the cooling time. Depending on the values of these 3 parameters, the Alfvén waves can stabilize the large-scale perturbations, destabilize those whose wavelength is a few times the Alfvén wavelength $λ_{AW}$ or leave the growth rate of the short scales unchanged. In order to investigate the non-linear regime, two different numerical experiments are performed in a slab geometry. (TBC)

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P. Hennebelle, T. Passot. 2005-10-14. Influence of Alfven waves on the Thermal Instability in the Interstellar Medium. https://doi.org/10.1051/0004-6361%3A20053510

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