Title
Observation of Turbulent Intermittency Scaling with Magnetic Helicity in an MHD Plasma Wind Tunnel
Document Type
Article
Version
Final Published Version
Publication Title
Physical Review Letters
Volume
112
Publication Date
2014
Abstract
The intermittency in turbulent magnetic field fluctuations has been observed to scale with the amount of magnetic helicity injected into a laboratory plasma. An unstable spheromak injected into the MHD wind tunnel of the Swarthmore Spheromak Experiment displays turbulent magnetic and plasma fluctuations as it relaxes into a Taylor state. The level of intermittency of this turbulence is determined by finding the flatness of the probability distribution function of increments for magnetic pickup coil fluctuations B_ðtÞ. The intermittency increases with the injected helicity, but spectral indices are unaffected by this variation. While evidence is provided which supports the hypothesis that current sheets and reconnection sites are related to the generation of this intermittent signal, the true nature of the observed intermittency remains unknown.
Publisher's Statement
© 2014 American Physical Society. http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.112.165001
Citation
D. A. Schaffner, A. Wan, and M. R. Brown. 2014. Observation of Turbulent Intermittency Scaling with Magnetic Helicity in an MHD Plasma Wind Tunnel. Phys. Rev. Lett. 112, 165001.
DOI
http://dx.doi.org/10.1103/PhysRevLett.112.165001