Observation Of Turbulent Intermittency Scaling With Magnetic Helicity In An MHD Plasma Wind Tunnel
Physical Review Letters
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(t). 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.
D. A. Schaffner; Adrian H. J. Wan , '15; and Michael R. Brown.
"Observation Of Turbulent Intermittency Scaling With Magnetic Helicity In An MHD Plasma Wind Tunnel".
Physical Review Letters.
This work is freely available courtesy of the American Physical Society.