Novel internal measurements and analysis of ion cyclotron frequency range fast-ion driven modes in DIII-D

POSTER

Abstract

Novel measurements and analysis of fast-ion driven modes in the ion cyclotron frequency range in DIII-D are presented, including local internal density fluctuations ($\~{n}$) obtained via an array of Doppler Backscattering systems. Two types of modes are excited simultaneously by co-current neutral injection via the more tangential of the two beamlines: 1) Alfvén eigenmodes (AE) at $f\sim0.4f_{ci}$, identified as global AEs (GAE) driven by Landau resonance with the fast ions, and 2) modes at low harmonics of $f_{ci}$, identified as collective ion cyclotron emission (ICE). Multiple aspects of theory for the underlying instabilities are validated. For instance, the GAE observations are compared with analytic theory and simulation via the HYM hybrid MHD code. Also, observations of ICE $\~{n}$ in both core and edge test prevalent theories for spatial localization of ICE and are compared to simulations via the EPOCH PIC code, which uses a locally uniform approximation.

* Work supported by US DoE grants DE-FC02-04ER54698, DE-FG02-99ER54527, DE-SC0019352, DE-SC0020337, DE-AC02-09CH11466 and RCUK grant EP/T012250/1. Partly carried out within EUROfusion Consortium framework, with funding from Euratom research and training programme 2014-2018 and 2019-2020, grant 633053.

Authors

  • N. A. Croker

    UCLA, University of California, Los Angeles

  • GH DeGrandchamp

    UCI

  • SX Tang

    University of California, Los Angeles, UCLA

  • K. E. Thome

    General Atomics, GA

  • JB Lestz

    University of California, Irvine, UCI

  • EV Belova

    Princeton Plasma Physics Laboratory, PPPL

  • AI Zalzali

    U. Warwick

  • RO Dendy

    U. Warwick

  • W.A. Peebles

    UCLA, University of California, Los Angeles

  • K. Barada

    UCLA

  • R. Hong

    UCLA

  • Terry Rhodes

    UCLA, University of California, Los Angeles

  • G. Wang

    UCLA

  • L. Zeng

    UCLA, University of California, Los Angeles

  • WW Heidbrin

    UCI