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Observation of hollow impurity density profiles in MST

Author: Santhosh T. A Kumar
Requested Type: Poster Only
Submitted: 2009-12-02 13:32:44

Co-authors: D. J. Den Hartog, R. M. Magee, G. Fiksel, D. Craig

Contact Info:
Department of Physics, UW-Madison
1150, University Avenue
Madison, WI   53706
USA

Abstract Text:
Impurity accumulation in the plasma core is a serious concern in fusion devices. Centrally peaked density profile usually results in core impurity accumulation. Recent experiments on the MST reversed-field pinch indicate a flat/weakly hollow C$^{+6}$ density profile for standard discharges, and a clearly hollow profile for improved confinement plasmas where electron density and temperature are peaked at the core. Sawtooth events in standard discharges result in significant increase and radial redistribution of impurity levels, whereas no significant temporal variation has been observed in improved confinement plasmas. Experimental results are presented; modeling efforts are underway using a collisional-radiative impurity transport code.

Characterization: A5

Comments:
This work is supported by the U.S. Department of Energy