(EX/P3-19) Tearing Mode Driven Charge Transport and Zonal Flow in the MST Reversed Field Pinch

W.X. Ding1), D.L. Brower1), D. Craig2), B.H. Deng1), G. Fiksel2), V. Mirnov2), S. C. Prager2), J.S. Sarff2), V. Svidzinski2)
1) Univeristy of California Los Angeles, Los Angeles, CA , United States of America
2) University of Wisconsin-Madison, Madison, Wisconsin, United States of America

Abstract.  Magnetic reconnection is characterized by discrete sawtooth-like bursts in many high temperature toroidal plasmas such as tokamaks and the Reversed Field Pinch (RFP). These magnetic reconnection events, which are associated with magnetic field and current density fluctuations, enhance radial transport and degrade energy confinement. In this paper, we report the first measurement of magnetic fluctuation-induced charge transport. This transport is driven by resistive tearing modes and occurs near a resonant surface in the core of a hot plasma. Charge transport results from an imbalance between the ion and electron radial flux due to particles streaming along stochastic field lines. It bursts during the sawtooth crash. Transport related charge flux 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 results in a spontaneous driven zonal flow which impacts plasma momentum and energy transport. Magnetic and current density fluctuation measurements are achieved using a high-speed laser-based Faraday rotation diagnostic on MST RFP plasmas providing an opportunity to explore magnetic flutter induced transport in the core of a plasma.

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