Alfv\'en Modes in the MST Revised Field Pinch

POSTER

Abstract

This work presents a theoretical and computational analysis of core-localized energetic particle driven modes observed near the magnetic axis in MST[L. Lin, W. X. Ding, D. L. Brower, et al., Phys. Plasmas 20, 030701 (2013)]. Using the measured safety factor and plasma pressure profiles as input, the linear ideal MHD code AEGIS [L. J. Zheng and M. Kotschenreuther, J. Comp. Phys. 211, 748 (2006)] reveals Alfv\'enic modes close to the measured frequencies. The AEGIS results together with a reduced analytical model demonstrate that the modes are essentially cylindrical and dominated by a single poloidal component (m = 1). The calculated modes are localized in the plasma core where the magnetic shear is weak and continuum damping is minimal. Detailed analysis establishes constraints on the safety factor and plasma pressure under which two modes can exist simultaneously as seen in experiment.

*The work is supported by US DOE.

Authors

  • Meng Li

    • Institute for Fusion Studies, The University of Texas at Austin

  • Boris Breizman

    • Institute for Fusion Studies, The University of Texas at Austin
    • Institute for Fusion Studies, The University of Texas, Austin, Texas, 78712 USA

  • Linjin Zheng

    • Institute for Fusion Studies, The University of Texas at Austin
    • Institute for Fusion Studies, University of Texas at Austin, TX 78712

  • L. Lin

    • University of California Los Angeles
    • UCLA

  • Weixing Ding

    • University of California, Los Angeles
    • University of California Los Angeles
    • Department of Physics and Astronomy, University of California Los Angeles

  • David Brower

    • University of California Los Angeles