Mode Conversion and Period Doubling at Plasma-$\beta$ Unity in an Alfvén-Wave Experiment with Liquid Rubidium

Abstract

We report Alfvén-wave experiments with liquid rubidium at the Dresden High Magnetic Field Laboratory (HLD). Reaching up to 63 T, the pulsed magnetic field exceeds the critical value of 54 T at which the Alfvén speed becomes equal to the sound speed (plasma-$\beta$ unity). At this threshold we observe a period doubling of an applied 8 kHz CW excitation, a clear footprint for a parametric resonance between magnetosonic waves and Alfvén waves.

5 pages, 4 figures

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• Experimental evidence for magnetorotational instability in a helical magnetic field
• Two-wave interaction in ideal magnetohydrodynamics
• Spectral line width decrease in the solar corona: resonant energy conversion from Alfv{é}n to acoustic waves
• Weakly magnetized, Hall dominated plasma Couette flow

Cited by in corpus (1)

• Conservation of Total Wave Action in the Expanding Solar Wind