Classical Impurity Ion Confinement in a Toroidal Magnetized Fusion Plasma

S. T. A. Kumar, D. J. Den Hartog, K. J. Caspary, R. M. Magee, V. V. Mirnov, B. E. Chapman, D. Craig, G. Fiksel, and J. S. Sarff

Phys. Rev. Lett. 108, 125006 – Published 22 March 2012

Abstract

High-resolution measurements of impurity ion dynamics provide first-time evidence of classical ion confinement in a toroidal, magnetically confined plasma. The density profile evolution of fully stripped carbon is measured in MST reversed-field pinch plasmas with reduced magnetic turbulence to assess Coulomb-collisional transport without the neoclassical enhancement from particle drift effects. The impurity density profile evolves to a hollow shape, consistent with the temperature screening mechanism of classical transport. Corroborating methane pellet injection experiments expose the sensitivity of the impurity particle confinement time to the residual magnetic fluctuation amplitude.

Received 25 September 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.125006

Authors & Affiliations

S. T. A. Kumar^1,2,*, D. J. Den Hartog^1,2, K. J. Caspary¹, R. M. Magee^1,†, V. V. Mirnov^1,2, B. E. Chapman¹, D. Craig³, G. Fiksel^2,4, and J. S. Sarff^1,2

¹Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
²Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
³Wheaton College, Wheaton, Illinois, USA
⁴Laboratory for Laser Energetics, University of Rochester, New York, USA

^*stkumar@wisc.edu
^†Present address: West Virginia University, Morgantown, WV, USA.