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Title: Observation of rapid frequency chirping instabilities driven by runaway electrons in a tokamak

Abstract

In this work, we report the first observation of chirping instabilities driven by runaway electrons (REs) in a tokamak. The instabilities are accessed during the post-disruption RE beam stage in a low density background plasma (n e < 10 19 m -3) on DIII-D. The chirping instabilities are observed when a decelerating loop voltage is applied to the RE beam. The frequency chirping is detected in two distinct frequency bands: 0.1–10 MHz and 30–80 MHz. The mode frequency increases linearly when the toroidal magnetic field sensed by the RE beam increases. The frequency chirps by 0.3–2.4 MHz on a timescale of 1 ms. Modification of the RE distribution function is directly measured during the chirping in the low-frequency band consistent with the hole–clump model for frequency chirping. The low-frequency instabilities also correlate with an increase of intermittent RE loss from the plasma. Lastly, these observations provide a novel experimental platform for fundamental studies of nonlinear chirping. They also support continued investigation of opportunities to utilize kinetic instabilities for RE mitigation in a tokamak reactor.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4];  [5]; ORCiD logo [3]; ORCiD logo [5];  [4]; ORCiD logo [3]
  1. Oak Ridge Associated Univ., Oak Ridge, TN (United States)
  2. Univ. of California, Irvine, CA (United States)
  3. General Atomics, San Diego, CA (United States)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Università di Milano-Bicocca, Milan (Italy)
Publication Date:
Research Org.:
Dept. of Energy (DOE), Washington DC (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1569036
Alternate Identifier(s):
OSTI ID: 1648937
Grant/Contract Number:  
FC02-04ER54698; AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 12; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Lvovskiy, A., Heidbrink, W. W., Paz-Soldan, C., Spong, D. A., Dal Molin, A., Eidietis, N. W., Nocente, M., Shiraki, D., and Thome, K. E. Observation of rapid frequency chirping instabilities driven by runaway electrons in a tokamak. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab4405.
Lvovskiy, A., Heidbrink, W. W., Paz-Soldan, C., Spong, D. A., Dal Molin, A., Eidietis, N. W., Nocente, M., Shiraki, D., & Thome, K. E. Observation of rapid frequency chirping instabilities driven by runaway electrons in a tokamak. United States. doi:10.1088/1741-4326/ab4405.
Lvovskiy, A., Heidbrink, W. W., Paz-Soldan, C., Spong, D. A., Dal Molin, A., Eidietis, N. W., Nocente, M., Shiraki, D., and Thome, K. E. Thu . "Observation of rapid frequency chirping instabilities driven by runaway electrons in a tokamak". United States. doi:10.1088/1741-4326/ab4405. https://www.osti.gov/servlets/purl/1569036.
@article{osti_1569036,
title = {Observation of rapid frequency chirping instabilities driven by runaway electrons in a tokamak},
author = {Lvovskiy, A. and Heidbrink, W. W. and Paz-Soldan, C. and Spong, D. A. and Dal Molin, A. and Eidietis, N. W. and Nocente, M. and Shiraki, D. and Thome, K. E.},
abstractNote = {In this work, we report the first observation of chirping instabilities driven by runaway electrons (REs) in a tokamak. The instabilities are accessed during the post-disruption RE beam stage in a low density background plasma (n e < 10 19 m -3) on DIII-D. The chirping instabilities are observed when a decelerating loop voltage is applied to the RE beam. The frequency chirping is detected in two distinct frequency bands: 0.1–10 MHz and 30–80 MHz. The mode frequency increases linearly when the toroidal magnetic field sensed by the RE beam increases. The frequency chirps by 0.3–2.4 MHz on a timescale of 1 ms. Modification of the RE distribution function is directly measured during the chirping in the low-frequency band consistent with the hole–clump model for frequency chirping. The low-frequency instabilities also correlate with an increase of intermittent RE loss from the plasma. Lastly, these observations provide a novel experimental platform for fundamental studies of nonlinear chirping. They also support continued investigation of opportunities to utilize kinetic instabilities for RE mitigation in a tokamak reactor.},
doi = {10.1088/1741-4326/ab4405},
journal = {Nuclear Fusion},
number = 12,
volume = 59,
place = {United States},
year = {2019},
month = {9}
}

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Works referenced in this record:

Perturbative and non-perturbative modes in START and MAST
journal, September 2006


Physics of Alfvén waves and energetic particles in burning plasmas
journal, March 2016


Identify the nonlinear wave-particle interaction regime in rising tone chorus generation: CHORUS EXCITATION
journal, April 2017

  • Tao, Xin; Zonca, Fulvio; Chen, Liu
  • Geophysical Research Letters, Vol. 44, Issue 8
  • DOI: 10.1002/2017GL072624

The nonlinear saturation of beam‐driven instabilities: Irregular bursting in the DIII‐D tokamak
journal, December 1994

  • Heidbrink, W. W.; Danielson, J. R.
  • Physics of Plasmas, Vol. 1, Issue 12
  • DOI: 10.1063/1.870822

Neutron fluctuation measurements on TFTR
journal, August 1986

  • Heidbrink, W. W.
  • Review of Scientific Instruments, Vol. 57, Issue 8
  • DOI: 10.1063/1.1139176

The role of kinetic instabilities in formation of the runaway electron current after argon injection in DIII-D
journal, November 2018

  • Lvovskiy, A.; Paz-Soldan, C.; Eidietis, N. W.
  • Plasma Physics and Controlled Fusion, Vol. 60, Issue 12
  • DOI: 10.1088/1361-6587/aae95a

Observation of toroidal Alfvén eigenmodes during minor disruptions in ohmic plasmas
journal, December 2016

  • Liu, Yangqing; Tan, Yi; Gao, Zhe
  • Physics of Plasmas, Vol. 23, Issue 12
  • DOI: 10.1063/1.4973230

Interpretation of quasi-periodic frequency sweeping in electron cyclotron emission of nonequilibrium mirror-confined plasma sustained by high-power microwaves
journal, June 2019

  • Shalashov, A. G.; Gospodchikov, E. D.; Viktorov, M. E.
  • Plasma Physics and Controlled Fusion, Vol. 61, Issue 8
  • DOI: 10.1088/1361-6587/ab27a5

Kinetic instabilities in a mirror-confined plasma sustained by high-power microwave radiation
journal, March 2017

  • Shalashov, A. G.; Viktorov, M. E.; Mansfeld, D. A.
  • Physics of Plasmas, Vol. 24, Issue 3
  • DOI: 10.1063/1.4978565

Scenarios for the nonlinear evolution of alpha-particle-induced Alfvén wave instability
journal, June 1992


A theoretical investigation of banded chorus
journal, April 1974


Role of Kinetic Instability in Runaway-Electron Avalanches and Elevated Critical Electric Fields
journal, June 2018


Postmidnight chorus: A substorm phenomenon
journal, January 1974

  • Tsurutani, Bruce T.; Smith, Edward J.
  • Journal of Geophysical Research, Vol. 79, Issue 1
  • DOI: 10.1029/JA079i001p00118

Observation of quasi-periodic frequency sweeping in electron cyclotron emission of nonequilibrium mirror-confined plasma
journal, December 2016


Excitation of Chirping Whistler Waves in a Laboratory Plasma
journal, June 2015


Limit on stably trapped particle fluxes
journal, January 1966


Characteristics of hiss-like and discrete whistler-mode emissions: HISS-LIKE AND DISCRETE WHISTLER WAVES
journal, September 2012

  • Li, W.; Thorne, R. M.; Bortnik, J.
  • Geophysical Research Letters, Vol. 39, Issue 18
  • DOI: 10.1029/2012GL053206

Applying the new gamma ray imager diagnostic to measurements of runaway electron Bremsstrahlung radiation in the DIII-D Tokamak (invited)
journal, August 2016

  • Cooper, C. M.; Pace, D. C.; Paz-Soldan, C.
  • Review of Scientific Instruments, Vol. 87, Issue 11
  • DOI: 10.1063/1.4961288

Spatiotemporal Evolution of Runaway Electron Momentum Distributions in Tokamaks
journal, June 2017


Radio frequency measurements of energetic-particle-driven emission using the ion cyclotron emission diagnostic on the DIII-D tokamak
journal, October 2018

  • Thome, K. E.; Pace, D. C.; Pinsker, R. I.
  • Review of Scientific Instruments, Vol. 89, Issue 10
  • DOI: 10.1063/1.5035561

Observation of Nonlinear Frequency-Sweeping Suppression with rf Diffusion
journal, May 2003


Banded chorus-A new type of VLF radiation observed in the magnetosphere by OGO 1 and OGO 3
journal, June 1969


A design retrospective of the DIII-D tokamak
journal, May 2002


Resolving runaway electron distributions in space, time, and energy
journal, May 2018

  • Paz-Soldan, C.; Cooper, C. M.; Aleynikov, P.
  • Physics of Plasmas, Vol. 25, Issue 5
  • DOI: 10.1063/1.5024223

Experimental characterization of nonlinear processes of whistler branch waves
journal, May 2016

  • Tejero, E. M.; Crabtree, C.; Blackwell, D. D.
  • Physics of Plasmas, Vol. 23, Issue 5
  • DOI: 10.1063/1.4946020

Major minority: energetic particles in fusion plasmas
journal, March 2011


A theory of discrete VLF emissions from the magnetosphere
journal, October 1967


Alfvénic instabilities driven by runaways in fusion plasmas
journal, August 2014

  • Fülöp, T.; Newton, S.
  • Physics of Plasmas, Vol. 21, Issue 8
  • DOI: 10.1063/1.4894098

Basic physics of Alfvén instabilities driven by energetic particles in toroidally confined plasmas
journal, May 2008


First Direct Observation of Runaway-Electron-Driven Whistler Waves in Tokamaks
journal, April 2018


Low-frequency whistler waves in quiescent runaway electron plasmas
journal, November 2018

  • Heidbrink, W. W.; Paz-Soldan, C.; Spong, D. A.
  • Plasma Physics and Controlled Fusion, Vol. 61, Issue 1
  • DOI: 10.1088/1361-6587/aae2da

Development of a new compact gamma-ray spectrometer optimised for runaway electron measurements
journal, October 2018

  • Dal Molin, A.; Martinelli, L.; Nocente, M.
  • Review of Scientific Instruments, Vol. 89, Issue 10
  • DOI: 10.1063/1.5038803

Study of High-Beta Magnetohydrodynamic Modes and Fast-Ion Losses in PDX
journal, March 1983


Nonlinear Frequency Oscillation of Alfvén Eigenmodes in Fusion Plasmas
journal, July 2012


Dissipation of post-disruption runaway electron plateaus by shattered pellet injection in DIII-D
journal, March 2018


Experimental Observation of a Magnetic-Turbulence Threshold for Runaway-Electron Generation in the TEXTOR Tokamak
journal, June 2013


Scattering by chorus waves as the dominant cause of diffuse auroral precipitation
journal, October 2010

  • Thorne, Richard M.; Ni, Binbin; Tao, Xin
  • Nature, Vol. 467, Issue 7318
  • DOI: 10.1038/nature09467

Gamma ray imager on the DIII-D tokamak
journal, April 2016

  • Pace, D. C.; Cooper, C. M.; Taussig, D.
  • Review of Scientific Instruments, Vol. 87, Issue 4
  • DOI: 10.1063/1.4945566

Alpha particle physics in a tokamak burning plasma experiment
journal, May 2002