Visualization of Fast Ion Phase-Space Flow Driven by Alfven Instabilities
Journal article, 2021

Fast ion phase-space flow, driven by Alfven eigenmodes (AEs), is measured by an imaging neutral particle analyzer in the DIII-D tokamak. The flow firstly appears near the minimum safety factor at the injection energy of neutral beams, and then moves radially inward and outward by gaining and losing energy, respectively. The flow trajectories in phase space align well with the intersection lines of the constant magnetic moment surfaces and constant E - (omega / n)P-zeta surfaces, where E, P-zeta are the energy and canonical toroidal momentum of ions; omega and n are angular frequencies and toroidal mode numbers of AEs. It is found that the flow is so destructive that the thermalization of fast ions is no longer observed in regions of strong interaction. The measured phase-space flow is consistent with nonlinear hybrid kinetic-magnetohydrodynamics simulation. Calculations of the relatively narrow phase-space islands reveal that fast ions must transition between different flow trajectories to experience large-scale phase-space transport.

Author

X. D. Du

General Atomics

M. A. Van Zeeland

General Atomics

W. W. Heidbrink

University of California at Irvine (UCI)

J. Gonzalez-Martin

University of California at Irvine (UCI)

Konsta Särkimäki

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

A. Snicker

Aalto University

D. Lin

University of California at Irvine (UCI)

C. S. Collins

General Atomics

M. E. Austin

The University of Texas at Austin

G. R. McKee

University of Wisconsin Madison

Z. Yan

University of Wisconsin Madison

Y. Todo

National Institutes of Natural Sciences

W. Wu

General Atomics

Physical Review Letters

0031-9007 (ISSN) 1079-7114 (eISSN)

Vol. 127 23 235002

Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium (EUROfusion)

European Commission (EC) (EC/H2020/633053), 2014-01-01 -- 2019-01-01.

Running away and radiating (PLASMA)

European Commission (EC) (EC/H2020/647121), 2015-10-01 -- 2020-09-30.

Subject Categories

Other Physics Topics

Fluid Mechanics and Acoustics

Fusion, Plasma and Space Physics

DOI

10.1103/PhysRevLett.127.235002

More information

Latest update

12/17/2021