Faster-than-Bohm cross-B electron transport in strongly pulsed plasmas.
We report the empirical discovery of an exceptionally high cross-B electron transport rate in magnetized plasmas, in which transverse currents are driven with abruptly applied high power. Experiments in three different magnetic geometries are analyzed, covering several orders of magnitude in plasma density, magnetic field strength, and ion mass. It is demonstrated that a suitable normalization parameter is the dimensionless product of the electron (angular) gyrofrequency and the effective electron-ion momentum transfer time, omega(ge)tau(EFF), by which all of diffusion, cross-resistivity, cross-B current conduction, and magnetic field diffusion can be expressed. The experiments show a remarkable consistency and yield close to a factor of 5 greater than the Bohm-equivalent values of diffusion coefficient D(perpendicular), magnetic-diffusion coefficient D(B), Pedersen conductivity sigma(P), and transverse resistivity eta(perpendicular).
Brenning
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Division of Space and Plasma Physics, EE, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
Merlino
R L
RL
Lundin
D
D
Raadu
M A
MA
Helmersson
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U