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

Title: The effects of kinetic instabilities on the electron cyclotron emission from runaway electrons

Journal Article · · Nuclear Fusion
ORCiD logo [1];  [2]; ORCiD logo [1];  [3]; ORCiD logo [4]; ORCiD logo [5];  [6]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Univ. of California, Irvine, CA (United States)
  3. Princeton Univ., NJ (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Princeton Univ., NJ (United States)
  5. General Atomics, San Diego, CA (United States)
  6. Univ. of Texas, Austin, TX (United States)

In this paper we show that the kinetic instabilities associated with runaway electron beams play an essential role for the production of high-level non-thermal electron–cyclotron-emission (ECE) radiation. Most of the non-thermal ECE comes from runaway electrons in the low-energy regime with large pitch angle, which are strongly scattered by the excited whistler waves. The power of ECE from runaway electrons is obtained using a synthetic diagnostic model based on the reciprocity method. The electron distribution function is calculated using a kinetic simulation model including the whistler wave instabilities and the quasilinear diffusion effects. Simulations based on DIII-D low-density discharge reproduces the rapid growth of the ECE signals observed in DIII-D experiments. Unlike the thermal ECE where radiation for a certain frequency is strongly localized inside the resonance region, the non-thermal ECE radiation from runaway electrons is nonlocal, and the emission-absorption ratio is higher than that of thermal electrons. The runaway electron tail is more significant for ECE with higher frequencies, and the ECE spectrum becomes flatter as RE population grows. The nonlinear behavior of the kinetic instabilities is illustrated in the oscillations of the ECE waves. In conclusion, the good agreement with the DIII-D experimental observations after including the kinetic instabilities clearly illustrate the significance of the scattering effects from wave-particle interactions, which can also be important for runaway electrons produced in disruptions.

Research Organization:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC02-09CH11466; SC0016268; FG02-97ER54415
OSTI ID:
1460952
Journal Information:
Nuclear Fusion, Vol. 58, Issue 9; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 15 works
Citation information provided by
Web of Science

References (40)

Pivotal issues on relativistic electrons in ITER journal January 2018
Electron and Ion Runaway in a Fully Ionized Gas. I journal July 1959
Electron and Ion Runaway in a Fully Ionized Gas. II journal January 1960
Relativistic limitations on runaway electrons journal June 1975
Theory for avalanche of runaway electrons in tokamaks journal October 1997
Disruption mitigation by massive gas injection in JET journal November 2011
An ITPA joint experiment to study runaway electron generation and suppression journal July 2014
Growth and decay of runaway electrons above the critical electric field under quiescent conditions journal February 2014
Effective Critical Electric Field for Runaway-Electron Generation journal March 2015
Stability analysis of runaway-driven waves in a tokamak journal March 2015
Electron cyclotron emission and absorption in fusion plasmas journal September 1983
Absorption of cyclotron waves at down-shifted frequencies by an energetic electron tail in the PLT tokamak journal November 1985
Nonthermal electron velocity distribution measured by electron cyclotron emission in Alcator C tokamak journal January 1986
Radially localized measurements of superthermal electrons using oblique electron cyclotron emission journal November 1996
Electron cyclotron emission from nonthermal tokamak plasmas journal February 1993
On application of the reciprocity theorem to calculation of a microwave radiation signal in inhomogeneous hot magnetized plasmas journal April 2002
Electron Cyclotron Emission from a Tokamak Plasma: Experiment and Theory journal September 1974
Electron cyclotron emission in Alcator tokamak journal October 1977
Electron cyclotron emission measurements on T-10 with a grating polychromator journal March 1986
Role of Kinetic Instability in Runaway-Electron Avalanches and Elevated Critical Electric Fields journal June 2018
Nonlinear frequency shift of electrostatic waves in general collisionless plasma: Unifying theory of fluid and kinetic nonlinearities journal August 2015
Electron cyclotron emission radiometer upgrade on the DIII-D tokamak journal March 2003
ECE-imaging of the H-mode pedestal (invited) journal October 2012
Synthetic diagnostics platform for fusion plasmas (invited) journal August 2016
Numerical calculation of the runaway electron distribution function and associated synchrotron emission journal March 2014
A gyrokinetic collision operator for magnetized Lorentz plasmas journal March 2011
Quasilinear Diffusion of an Axisymmetric Toroidal Plasma journal January 1972
Destabilization of magnetosonic-whistler waves by a relativistic runaway beam journal June 2006
Kinetic instabilities in a mirror-confined plasma sustained by high-power microwave radiation journal March 2017
Monte Carlo method and High Performance Computing for solving Fokker–Planck equation of minority plasma particles journal March 2015
Numerical characterization of bump formation in the runaway electron tail journal January 2016
Theory of Two Threshold Fields for Relativistic Runaway Electrons journal April 2015
The kinetic theory of runaway electron beam instability in a tokamak journal March 1978
Zur Theorie des Durchgangs schneller Elektronen durch Materie journal January 1932
Fokker-Planck simulations mylb of knock-on electron runaway avalanche and bursts in tokamaks journal November 1998
Theory of runaway electrons in ITER: Equations, important parameters, and implications for mitigation journal March 2015
Resolving runaway electron distributions in space, time, and energy journal May 2018
Advanced 3-D Electron Fokker-Planck Transport Calculations
  • Peysson, Y.
  • RADIO FREQUENCY POWER IN PLASMAS: 15th Topical Conference on Radio Frequency Power in Plasmas, AIP Conference Proceedings https://doi.org/10.1063/1.1638086
conference January 2003
Heat flux viscosity in collisional magnetized plasmas journal May 2015
Momentum transport and nonlocality in heat-flux-driven magnetic reconnection in high-energy-density plasmas journal October 2017

Similar Records

Role of Kinetic Instability in Runaway-Electron Avalanches and Elevated Critical Electric Fields
Journal Article · Thu Jun 28 00:00:00 EDT 2018 · Physical Review Letters · OSTI ID:1460952

Low-frequency whistler waves in quiescent runaway electron plasmas
Journal Article · Mon Nov 12 00:00:00 EST 2018 · Plasma Physics and Controlled Fusion · OSTI ID:1460952

Runaway electrons in tokamaks
Thesis/Dissertation · Sat Apr 01 00:00:00 EDT 2017 · OSTI ID:1460952