Search Menu
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information
Search Scholarly Publications

Title: Injection of multiple shattered pellets for disruption mitigation in DIII-D

Abstract

Plasma shutdown experiments in DIII-D have injected multiple shattered pellets at different toroidal locations for the first time, as is planned for the ITER disruption mitigation system. Systematically varying the relative timing of the two pellets suggests that simultaneously injected pellets may influence the assimilation of each other, altering the resulting disruption characteristics compared to a single pellet injecting similar neon quantities. Thermal quench (TQ) radiation measured near the injection location is reduced with the dual pellets, contrary to TQ radiation measured away from the injection ports, which does not show a clear difference between single or dual pellet injections. The mitigation of other disruption loads, such as the current quench (CQ) duration and divertor heat loads, decrease when the pellets enter the plasma simultaneously compared to single shattered pellet injections with similar neon quantities. This similar reduction in mitigation of CQ and conductive loads is consistent with the observed reduction in total TQ radiation. The time between initial pellet injection and the end of the TQ is shorter when both pellets are injected simultaneously compared to a single pellet. This lower cooling duration may limit the amount of the neon assimilated by the plasma prior to the end ofmore » the TQ, consistent with the observed reduction in radiation. The injected impurities spread primarily in the parallel direction, away from the source at the injection location. The addition of two shattered pellet injectors shows that the initial poloidal radiation is spread out into two distinct regions, cooling multiple flux tubes simultaneously, which may induce global MHD instabilities more rapidly than a single flux tube of impurities leading to a shorter cooling duration. The electron density increased by approximately a factor of two with the addition of multiple pellets, but is highly sensitive to the time between injections. Here, a maximum density increase is found when both pellets arrive at the plasma prior to the start of the TQ.« less

Authors:
ORCiD logo [1];  [1];  [1]; ORCiD logo [2];  [3];  [4];  [3]
+ Show Author Affiliations
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of California San Diego, La Jolla, CA (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1593101
Alternate Identifier(s):
OSTI ID: 1608090
Report Number(s):
DOE-GA-54698; LLNL-JRNL-806822
Journal ID: ISSN 0029-5515; TRN: US2101640
Grant/Contract Number:  
FC02-04ER54698; AC05-00OR22725; FG02-07ER54917; AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 10; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tokamak; disruption mitigation; shattered pellet injection; multiple shattered pellet injection

Citation Formats

Herfindal, J. L., Shiraki, D., Baylor, L. R., Eidietis, N. W., Hollmann, E. M., Lasnier, C. J., and Moyer, R. A. Injection of multiple shattered pellets for disruption mitigation in DIII-D. United States: N. p., 2019. Web. doi:10.1088/1741-4326/ab3693.
Copy to clipboard
Herfindal, J. L., Shiraki, D., Baylor, L. R., Eidietis, N. W., Hollmann, E. M., Lasnier, C. J., & Moyer, R. A. Injection of multiple shattered pellets for disruption mitigation in DIII-D. United States. https://doi.org/10.1088/1741-4326/ab3693
Copy to clipboard
Herfindal, J. L., Shiraki, D., Baylor, L. R., Eidietis, N. W., Hollmann, E. M., Lasnier, C. J., and Moyer, R. A. Wed . "Injection of multiple shattered pellets for disruption mitigation in DIII-D". United States. https://doi.org/10.1088/1741-4326/ab3693. https://www.osti.gov/servlets/purl/1593101.
Copy to clipboard
@article{osti_1593101,
title = {Injection of multiple shattered pellets for disruption mitigation in DIII-D},
author = {Herfindal, J. L. and Shiraki, D. and Baylor, L. R. and Eidietis, N. W. and Hollmann, E. M. and Lasnier, C. J. and Moyer, R. A.},
abstractNote = {Plasma shutdown experiments in DIII-D have injected multiple shattered pellets at different toroidal locations for the first time, as is planned for the ITER disruption mitigation system. Systematically varying the relative timing of the two pellets suggests that simultaneously injected pellets may influence the assimilation of each other, altering the resulting disruption characteristics compared to a single pellet injecting similar neon quantities. Thermal quench (TQ) radiation measured near the injection location is reduced with the dual pellets, contrary to TQ radiation measured away from the injection ports, which does not show a clear difference between single or dual pellet injections. The mitigation of other disruption loads, such as the current quench (CQ) duration and divertor heat loads, decrease when the pellets enter the plasma simultaneously compared to single shattered pellet injections with similar neon quantities. This similar reduction in mitigation of CQ and conductive loads is consistent with the observed reduction in total TQ radiation. The time between initial pellet injection and the end of the TQ is shorter when both pellets are injected simultaneously compared to a single pellet. This lower cooling duration may limit the amount of the neon assimilated by the plasma prior to the end of the TQ, consistent with the observed reduction in radiation. The injected impurities spread primarily in the parallel direction, away from the source at the injection location. The addition of two shattered pellet injectors shows that the initial poloidal radiation is spread out into two distinct regions, cooling multiple flux tubes simultaneously, which may induce global MHD instabilities more rapidly than a single flux tube of impurities leading to a shorter cooling duration. The electron density increased by approximately a factor of two with the addition of multiple pellets, but is highly sensitive to the time between injections. Here, a maximum density increase is found when both pellets arrive at the plasma prior to the start of the TQ.},
doi = {10.1088/1741-4326/ab3693},
journal = {Nuclear Fusion},
number = 10,
volume = 59,
place = {United States},
year = {Wed Sep 04 00:00:00 EDT 2019},
month = {Wed Sep 04 00:00:00 EDT 2019}
}
Copy to clipboard
Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1088/1741-4326/ab3693
Copyright Statement
Other availability
Search WorldCat Search WorldCat to find libraries that may hold this journal
Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

Works referenced in this record:

Soft x-ray array system with variable filters for the DIII-D tokamak
journal, November 2011

  • Hollmann, E. M.; Chousal, L.; Fisher, R. K.
  • Review of Scientific Instruments, Vol. 82, Issue 11
  • DOI: 10.1063/1.3660816

Poloidal radiation asymmetries during disruption mitigation by massive gas injection on the DIII-D tokamak
journal, October 2017

  • Eidietis, N. W.; Izzo, V. A.; Commaux, N.
  • Physics of Plasmas, Vol. 24, Issue 10
  • DOI: 10.1063/1.5002701

Equilibrium analysis of current profiles in tokamaks
journal, June 1990

Chapter 3: MHD stability, operational limits and disruptions
journal, December 1999

  • Mhd, ITER Physics Expert Group on Disrup; Editors, ITER Physics Basis
  • Nuclear Fusion, Vol. 39, Issue 12
  • DOI: 10.1088/0029-5515/39/12/303

Wide-angle ITER-prototype tangential infrared and visible viewing system for DIII-D
journal, November 2014

  • Lasnier, C. J.; Allen, S. L.; Ellis, R. E.
  • Review of Scientific Instruments, Vol. 85, Issue 11
  • DOI: 10.1063/1.4892897

The role of MHD in 3D aspects of massive gas injection
journal, June 2015

Thermal quench mitigation and current quench control by injection of mixed species shattered pellets in DIII-D
journal, June 2016

  • Shiraki, D.; Commaux, N.; Baylor, L. R.
  • Physics of Plasmas, Vol. 23, Issue 6
  • DOI: 10.1063/1.4954389

Disruption Mitigation System Developments and Design for ITER
journal, September 2015

  • Baylor, L. R.; Barbier, C. C.; Carmichael, J. R.
  • Fusion Science and Technology, Vol. 68, Issue 2
  • DOI: 10.13182/FST14-926

Mitigation of upward and downward vertical displacement event heat loads with upper or lower massive gas injection in DIII-D
journal, October 2015

  • Hollmann, E. M.; Commaux, N.; Eidietis, N. W.
  • Physics of Plasmas, Vol. 22, Issue 10
  • DOI: 10.1063/1.4932999

Time resolved radiated power during tokamak disruptions and spectral averaging of AXUV photodiode response in DIII-D
journal, February 2004

  • Gray, D. S.; Luckhardt, S. C.; Chousal, L.
  • Review of Scientific Instruments, Vol. 75, Issue 2
  • DOI: 10.1063/1.1642745

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

Design and Commissioning of a Three-Barrel Shattered Pellet Injector for DIII-D Disruption Mitigation Studies
journal, June 2017

Alternative Techniques for Injecting Massive Quantities of Gas for Plasma-Disruption Mitigation
journal, March 2010

  • Combs, S. K.; Meitner, S. J.; Baylor, L. R.
  • IEEE Transactions on Plasma Science, Vol. 38, Issue 3
  • DOI: 10.1109/TPS.2009.2038781

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

Radiation asymmetries during disruptions on DIII-D caused by massive gas injectiona)
journal, October 2014

  • Commaux, N.; Baylor, L. R.; Jernigan, T. C.
  • Physics of Plasmas, Vol. 21, Issue 10
  • DOI: 10.1063/1.4896721

Plasma radiometry with 30 chord resolution for fast transients in the DIII-D tokamak
journal, October 2004

  • Gray, D. S.; Hollmann, E. M.; Luckhardt, S. C.
  • Review of Scientific Instruments, Vol. 75, Issue 10
  • DOI: 10.1063/1.1787149

Modeling of stochastic magnetic flux loss from the edge of a poloidally diverted tokamak
journal, December 2002

  • Evans, T. E.; Moyer, R. A.; Monat, P.
  • Physics of Plasmas, Vol. 9, Issue 12
  • DOI: 10.1063/1.1521125

Imaging divertor strike point splitting in RMP ELM suppression experiments in the DIII-D tokamak
journal, October 2018

  • Moyer, R. A.; Bykov, I.; Orlov, D. M.
  • Review of Scientific Instruments, Vol. 89, Issue 10
  • DOI: 10.1063/1.5038350

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

Real‐time, vibration‐compensated CO 2 interferometer operation on the DIII‐D tokamak
journal, July 1988

  • Carlstrom, T. N.; Ahlgren, D. R.; Crosbie, J.
  • Review of Scientific Instruments, Vol. 59, Issue 7
  • DOI: 10.1063/1.1139726
    Sort by:
    [ × clear filter / sort ]

    Works referencing / citing this record:

    27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC
    journal, January 2020

      Sort by:
      [ × clear filter / sort ]

      Similar Records in DOE PAGES and OSTI.GOV collections: