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arXiv · 2401.07830

The magnetohydrodynamic equations in terms of waveframe variables

Tom Van Doorsselaere·Norbert Magyar·M. Valeria Sieyra·Marcel Goossens
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Abstract

Generalising the Elsasser variables, we introduce the Q-variables. These are more flexible than the Elsasser variables, because they also allow to track waves with phase speeds different than the Alfven speed. We rewrite the MHD equations with these Q-variables. We consider also the linearised version of the resulting MHD equations in a uniform plasma, and recover the classical Alfven waves, but also separate the fast and slow magnetosonic waves in upward and downward propagating waves. Moreover, we show that the Q-variables may also track the upward and downward propagating surface Alfven waves in a non-uniform plasma, displaying the power of our generalisation. In the end, we lay the mathematical framework for driving solar wind models with a multitude of wave drivers.

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Tom Van Doorsselaere, Norbert Magyar, M. Valeria Sieyra, Marcel Goossens. 2024-01-15. The magnetohydrodynamic equations in terms of waveframe variables. https://arxiv.org/abs/2401.07830

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