Alfvén cascades with downward frequency sweeping

Marchenko, V. S.; Reznik, S. N.
April 2011
Physics of Plasmas;Apr2011, Vol. 18 Issue 4, p040701
Academic Journal
It is suggested that relatively rare, but challenging for the existing theory Alfvén cascades with downward frequency sweeping are actually the infernal Alfvén eigenmodes (IAEs). Such modes exist in discharges with flat or weakly reversed q-profile in the broad central region, when the value of the safety factor in this region is slightly above the integer or low-order rational. Similar to the toroidal Alfvén eigenmode, but in contrast to the 'conventional' Alfvén cascade with upward frequency sweeping, the spectrum of IAE is almost degenerate with respect to the mode numbers. Both features mentioned above are consistent with experimental observations.


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