Nonambipolar magnetic-fluctuation-induced particle transport and plasma flow in the MST reversed-field pinch.

First direct measurements of nonambipolar magnetic fluctuation-induced charge transport in the interior of a high-temperature plasma are reported. Global resistive tearing modes drive the charge transport which is measured in the vicinity of the resonant surface for the dominant core resonant mode. Finite charge transport has two important consequences. First, it generates a potential well along with locally strong electric field and electric field shear at the resonant surface. Second, this electric field induces a spontaneous E x B driven zonal flow.

Analytical and numerical modeling of radio frequency electron cyclotron resonance power absorption within the cold plasma picture.

We present a one dimensional model of radio frequency (RF) power absorption in electron cyclotron resonance (ECR) ion sources based on a modified cold plasma dielectric description. The absorption is modeled by an imaginary collision frequency (damping coefficient) whose value is related to physical parameters such as magnetic field and its spatial derivative, electron temperature, and RF frequency and power. Properties and scaling laws of ECR power absorption are discussed within this model. Numerical benchmarking against a more accurate kinetic plasma code shows very good agreement.

Measurement of the Hall dynamo effect during magnetic reconnection in a high-temperature plasma.

The fluctuation-induced Hall electromotive force, [deltaJ x deltaB]/nee, is experimentally measured in the high-temperature interior of a reversed-field pinch plasma by a fast Faraday rotation diagnostic. It is found that the Hall dynamo effect is significant, redistributing (flattening) the equilibrium core current near the resonant surface during a reconnection event. These results imply that effects beyond single-fluid MHD are important for the dynamo and magnetic reconnection.