skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Numerical simulation of runaway electrons: 3-D effects on synchrotron radiation and impurity-based runaway current dissipation

Abstract

Numerical simulations of runaway electrons (REs) with a particular emphasis on orbit dependent effects in 3-D magnetic fields are presented. The simulations were performed using the recently developed Kinetic Orbit Runaway electron Code (KORC) that computes the full-orbit relativistic dynamics in prescribed electric and magnetic fields including radiation damping and collisions. The two main problems of interest are synchrotron radiation and impurity-based RE dissipation. Synchrotron radiation is studied in axisymmetric fields and in 3-D magnetic configurations exhibiting magnetic islands and stochasticity. For passing particles in axisymmetric fields, neglecting orbit effects might underestimate or overestimate the total radiation power depending on the direction of the radial shift of the drift orbits. For trapped particles, the spatial distribution of synchrotron radiation exhibits localized “hot” spots at the tips of the banana orbits. In general, the radiation power per particle for trapped particles is higher than the power emitted by passing particles. The spatial distribution of synchrotron radiation in stochastic magnetic fields, obtained using the MHD code NIMROD, is strongly influenced by the presence of magnetic islands. 3-D magnetic fields also introduce a toroidal dependence on the synchrotron spectra, and neglecting orbit effects underestimates the total radiation power. In the presence of magneticmore » islands, the radiation damping of trapped particles is larger than the radiation damping of passing particles. Results modeling synchrotron emission by RE in DIII-D quiescent plasmas are also presented. The computation uses EFIT reconstructed magnetic fields and RE energy distributions fitted to the experimental measurements. Qualitative agreement is observed between the numerical simulations and the experiments for simplified RE pitch angle distributions. However, it is noted that to achieve quantitative agreement, it is necessary to use pitch angle distributions that depart from simplified 2-D Fokker-Planck equilibria. Finally, using the guiding center orbit model (KORC-GC), a preliminary study of pellet mitigated discharges in DIII-D is presented. The dependence of RE energy decay and current dissipation on initial energy and ionization levels of neon impurities is studied. Furthermore, the computed decay rates are within the range of experimental observations.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of California-San Diego, La Jolla, CA (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1465053
Alternate Identifier(s):
OSTI ID: 1427891
Grant/Contract Number:  
AC05-00OR22725; AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

del-Castillo-Negrete, Diego B., Carbajal, Leopoldo Gomez, Spong, Donald A., and Izzo, V. A.. Numerical simulation of runaway electrons: 3-D effects on synchrotron radiation and impurity-based runaway current dissipation. United States: N. p., 2018. Web. https://doi.org/10.1063/1.5018747.
del-Castillo-Negrete, Diego B., Carbajal, Leopoldo Gomez, Spong, Donald A., & Izzo, V. A.. Numerical simulation of runaway electrons: 3-D effects on synchrotron radiation and impurity-based runaway current dissipation. United States. https://doi.org/10.1063/1.5018747
del-Castillo-Negrete, Diego B., Carbajal, Leopoldo Gomez, Spong, Donald A., and Izzo, V. A.. Thu . "Numerical simulation of runaway electrons: 3-D effects on synchrotron radiation and impurity-based runaway current dissipation". United States. https://doi.org/10.1063/1.5018747. https://www.osti.gov/servlets/purl/1465053.
@article{osti_1465053,
title = {Numerical simulation of runaway electrons: 3-D effects on synchrotron radiation and impurity-based runaway current dissipation},
author = {del-Castillo-Negrete, Diego B. and Carbajal, Leopoldo Gomez and Spong, Donald A. and Izzo, V. A.},
abstractNote = {Numerical simulations of runaway electrons (REs) with a particular emphasis on orbit dependent effects in 3-D magnetic fields are presented. The simulations were performed using the recently developed Kinetic Orbit Runaway electron Code (KORC) that computes the full-orbit relativistic dynamics in prescribed electric and magnetic fields including radiation damping and collisions. The two main problems of interest are synchrotron radiation and impurity-based RE dissipation. Synchrotron radiation is studied in axisymmetric fields and in 3-D magnetic configurations exhibiting magnetic islands and stochasticity. For passing particles in axisymmetric fields, neglecting orbit effects might underestimate or overestimate the total radiation power depending on the direction of the radial shift of the drift orbits. For trapped particles, the spatial distribution of synchrotron radiation exhibits localized “hot” spots at the tips of the banana orbits. In general, the radiation power per particle for trapped particles is higher than the power emitted by passing particles. The spatial distribution of synchrotron radiation in stochastic magnetic fields, obtained using the MHD code NIMROD, is strongly influenced by the presence of magnetic islands. 3-D magnetic fields also introduce a toroidal dependence on the synchrotron spectra, and neglecting orbit effects underestimates the total radiation power. In the presence of magnetic islands, the radiation damping of trapped particles is larger than the radiation damping of passing particles. Results modeling synchrotron emission by RE in DIII-D quiescent plasmas are also presented. The computation uses EFIT reconstructed magnetic fields and RE energy distributions fitted to the experimental measurements. Qualitative agreement is observed between the numerical simulations and the experiments for simplified RE pitch angle distributions. However, it is noted that to achieve quantitative agreement, it is necessary to use pitch angle distributions that depart from simplified 2-D Fokker-Planck equilibria. Finally, using the guiding center orbit model (KORC-GC), a preliminary study of pellet mitigated discharges in DIII-D is presented. The dependence of RE energy decay and current dissipation on initial energy and ionization levels of neon impurities is studied. Furthermore, the computed decay rates are within the range of experimental observations.},
doi = {10.1063/1.5018747},
journal = {Physics of Plasmas},
number = 5,
volume = 25,
place = {United States},
year = {2018},
month = {3}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 6 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Synchrotron radiation from a runaway electron distribution in tokamaks
journal, September 2013

  • Stahl, A.; Landreman, M.; Papp, G.
  • Physics of Plasmas, Vol. 20, Issue 9
  • DOI: 10.1063/1.4821823

Radiation reaction effects on radiation pressure acceleration
journal, December 2010


Growth and decay of runaway electrons above the critical electric field under quiescent conditions
journal, February 2014

  • Paz-Soldan, C.; Eidietis, N. W.; Granetz, R.
  • Physics of Plasmas, Vol. 21, Issue 2
  • DOI: 10.1063/1.4866912

Relativistic limitations on runaway electrons
journal, June 1975


Control and dissipation of runaway electron beams created during rapid shutdown experiments in DIII-D
journal, July 2013


Simulation of beams or plasmas crossing at relativistic velocity
journal, May 2008


On the synchrotron emission in kinetic simulations of runaway electrons in magnetic confinement fusion plasmas
journal, October 2017

  • Carbajal, L.; del-Castillo-Negrete, D.
  • Plasma Physics and Controlled Fusion, Vol. 59, Issue 12
  • DOI: 10.1088/1361-6587/aa883e

Runaway electron drift orbits in magnetostatic perturbed fields
journal, March 2011


Effect of Partially Screened Nuclei on Fast-Electron Dynamics
journal, June 2017


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


Observation of runaway electron beams by visible color camera in the Experimental Advanced Superconducting Tokamak
journal, March 2010

  • Shi, Yuejiang; Fu, Jia; Li, Jiahong
  • Review of Scientific Instruments, Vol. 81, Issue 3
  • DOI: 10.1063/1.3340909

Pitch angle scattering and synchrotron radiation of relativistic runaway electrons in tokamak stochastic magnetic fields
journal, November 2008

  • Martín-Solís, J. R.; Sánchez, R.
  • Physics of Plasmas, Vol. 15, Issue 11
  • DOI: 10.1063/1.3013849

Plasma–surface interactions during tokamak disruptions and rapid shutdowns
journal, August 2011


Relativistic guiding centre drift orbits in canonical and magnetic coordinates
journal, June 1997


Test particles dynamics in the JOREK 3D non-linear MHD code and application to electron transport in a disruption simulation
journal, December 2017


Runaway electron confinement modelling for rapid shutdown scenarios in DIII-D, Alcator C-Mod and ITER
journal, May 2011


SOFT: a synthetic synchrotron diagnostic for runaway electrons
journal, January 2018


Runaway snakes in TEXTOR-94
journal, January 1999

  • Entrop, I.; Jaspers, R.; Cardozo, N. J. Lopes
  • Plasma Physics and Controlled Fusion, Vol. 41, Issue 3
  • DOI: 10.1088/0741-3335/41/3/004

Direct observations of runaway electrons during disruptions in the JET tokamak
journal, February 2000


Disruptions in ITER and strategies for their control and mitigation
journal, August 2015


Theory of Two Threshold Fields for Relativistic Runaway Electrons
journal, April 2015


First demonstration of rapid shutdown using neon shattered pellet injection for thermal quench mitigation on DIII-D
journal, March 2016


On the Classical Radiation of Accelerated Electrons
journal, June 1949


Spatially and temporally resolved measurements of runaway electrons in the TEXTOR tokamak
journal, November 2008


A synchrotron radiation diagnostic to observe relativistic runaway electrons in a tokamak plasma
journal, January 2001

  • Jaspers, R.; Lopes Cardozo, N. J.; Donné, A. J. H.
  • Review of Scientific Instruments, Vol. 72, Issue 1
  • DOI: 10.1063/1.1318245

Electron and Ion Runaway in a Fully Ionized Gas. I
journal, July 1959


Space dependent, full orbit effects on runaway electron dynamics in tokamak plasmas
journal, April 2017

  • Carbajal, L.; del-Castillo-Negrete, D.; Spong, D.
  • Physics of Plasmas, Vol. 24, Issue 4
  • DOI: 10.1063/1.4981209

Observation of infrared synchrotron radiation from tokamak runaway electrons in TEXTOR
journal, May 1990


Chapter 3: MHD stability, operational limits and disruptions
journal, June 2007


    Works referencing / citing this record:

    Emission of diamonds, leucosapphire, and KU-1 quartz in the range of 200–800 nm excited by electron beams with a pulse duration of 0.5 and 12 ns
    journal, June 2019

    • Tarasenko, V. F.; Oleshko, V. I.; Erofeev, M. V.
    • Journal of Applied Physics, Vol. 125, Issue 24
    • DOI: 10.1063/1.5094956

    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

    Spatial transport of runaway electrons in axisymmetric tokamak plasmas
    journal, January 2019

    • McDevitt, Christopher J.; Guo, Zehua; Tang, Xian-Zhu
    • Plasma Physics and Controlled Fusion, Vol. 61, Issue 2
    • DOI: 10.1088/1361-6587/aaf4d1

    Electron acceleration in a JET disruption simulation
    journal, August 2018


    Runaway electron modelling in the self-consistent core European Transport Simulator
    journal, June 2019