Energy of eigenmodes in magnetohydrodynamic flows of ideal fluids

Khalzov, I. V.; Smolyakov, A. I.; Ilgisonis, V. I.
May 2008
Physics of Plasmas;May2008, Vol. 15 Issue 5, p054501
Academic Journal
Energy of eigenmodes in magnetohydrodynamic (MHD) flows of ideal fluids is studied analytically. It is shown that the energy of unstable modes is zero, while the energy of stable oscillatory modes (waves) can assume both positive and negative values. Negative energy waves always correspond to eigenmodes with a finite component of the wave-vector along the flow. Coupling of negative and positive energy waves is shown to be a universal mechanism of MHD instabilities in flowing media. As an example, the energy of eigenmodes of magnetorotational instability is calculated.


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