Document Type
Article
Version
Final Published Version
Publication Title
Physics of Plasmas
Volume
20
Publication Date
2013
Abstract
Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) [W. Gekelman et al., Rev. Sci. Instr. 62, 2875 (1991)] has been achieved using a biasable limiter. This flow control has allowed a careful study of the effect of flow shear on pressure-gradient-driven turbulence and particle transport in LAPD. The combination of externally controllable shear in a turbulent plasma along with the detailed spatial diagnostic capabilities on LAPD makes the experiment a useful testbed for validation of shear suppression models. Motivated by these models, power-law fits are made to the density and radial velocity fluctuation amplitudes, particle flux, density-potential crossphase, and radial correlation length. The data show a break in the trend of these quantities when the shearing rate ( γs=∂Vθ/∂r ) is comparable to the turbulent decorrelation rate ( 1/τac ). No one model captures the trends in the all turbulent quantities for all values of the shearing rate, but some models successfully match the trend in either the weak ( γsτac<1 ) or strong ( γsτac>1 ) shear limits.
Publisher's Statement
© 2013 AIP Publishing LLC
Citation
D. A. Schaffner, T. A. Carter, G. D. Rossi, D. S. Guice, J. E. Maggs, S. Vincena, and B. Friedman. 2013. Turbulence and transport suppression scaling with flow shear on the Large Plasma Device. Phys. Plasmas 20, 055907.
DOI
http://dx.doi.org/10.1063/1.4804637
