Observation of non-thermal electron formation during the thermal quench of shattered pellet injection shutdowns in DIII-D

Hollmann, E. M.; Shiraki, D.; Baylor, L.; Bykov, I.; Eidietis, N. W.; Golovkin, I.; Herfindal, J. L.; Lvovskiy, A.; McLean, A.; Moyer, R. A.; O’Gorman, T.; Parks, P. B.; Popović, Ž.

doi:10.1088/1741-4326/abc409

Title: Observation of non-thermal electron formation during the thermal quench of shattered pellet injection shutdowns in DIII-D

Journal Article · Mon Nov 30 00:00:00 EST 2020 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/abc409· OSTI ID:1730928

^[1]; Shiraki, D. ^[2]; Baylor, L. ^[2]; Bykov, I. ^[1];

^[3]; Golovkin, I. ^[4];

^[2];

^[3]; McLean, A. ^[5]; Moyer, R. A. ^[1]; O’Gorman, T. ^[3]; Parks, P. B. ^[3]; Popović, Ž. ^[1]

Univ. of California, San Diego, La Jolla, CA (United States)
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
General Atomics, San Diego, CA (United States)
Prism Computational Sciences, Madison, WI (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Formation of non-thermal (hot) electrons is studied during the thermal quench of shattered pellet injection (SPI) discharge shutdowns in the DIII-D tokamak. Both pure neon and mixed neon/deuterium shutdowns are studied. High-energy radiation (SXR and EUV) brightness levels show indications of non-thermal electron formation during the TQ. The non-thermal densities are of order 10¹⁸ m^–3 and non-thermal temperatures are estimated to be of order 10 keV. The non-thermal electrons appear to be mostly lost during the subsequent current quench, as no signal of relativistic runaway electrons is typically seen at the end of the current quench. In conclusion, the non-thermals appear to have an effect on the deposition profile of the SPI pellets, especially at the end of the TQ, due to increased pellet ablation.

View Accepted Manuscript (DOE)

Cite

Export

Save

Research Organization:: General Atomics, San Diego, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: FC02-04ER54698; FG02-07ER54917; AC05-00OR22725; AC52-07NA27344; FG02-04ER54744; AC05-06OR23100

OSTI ID:: 1730928

Alternate ID(s):: OSTI ID: 2320366

Journal Information:: Nuclear Fusion, Vol. 61, Issue 1; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (32)

Comparison of He I line intensity ratio method and electrostatic probe for electron density and temperature measurements in NAGDIS-II Kajita, Shin; Ohno, Noriyasu; Takamura, Shuichi Physics of Plasmas, Vol. 13, Issue 1 https://doi.org/10.1063/1.2164461	journal	January 2006
Kinetic modelling of runaway electrons in dynamic scenarios Stahl, A.; Embréus, O.; Papp, G. Nuclear Fusion, Vol. 56, Issue 11 https://doi.org/10.1088/0029-5515/56/11/112009	journal	July 2016
The role of kinetic instabilities in formation of the runaway electron current after argon injection in DIII-D Lvovskiy, A.; Paz-Soldan, C.; Eidietis, N. W. Plasma Physics and Controlled Fusion, Vol. 60, Issue 12 https://doi.org/10.1088/1361-6587/aae95a	journal	November 2018
Shattered pellet penetration in low and high energy plasmas on DIII-D Raman, R.; Sweeney, R.; Moyer, R. A. Nuclear Fusion, Vol. 60, Issue 3 https://doi.org/10.1088/1741-4326/ab686f	journal	February 2020
Experimental tests of paleoclassical transport Callen, J. D.; Anderson, J. K.; Arlen, T. C. Nuclear Fusion, Vol. 47, Issue 11 https://doi.org/10.1088/0029-5515/47/11/006	journal	October 2007
Injection of multiple shattered pellets for disruption mitigation in DIII-D Herfindal, J. L.; Shiraki, D.; Baylor, L. R. Nuclear Fusion, Vol. 59, Issue 10 https://doi.org/10.1088/1741-4326/ab3693	journal	September 2019
A numerical investigation of the effects of impurity penetration depth on disruption mitigation by massive high-pressure gas jet Izzo, V. A. Nuclear Fusion, Vol. 46, Issue 5 https://doi.org/10.1088/0029-5515/46/5/006	journal	March 2006
Status of research toward the ITER disruption mitigation system Hollmann, E. M.; Aleynikov, P. B.; Fülöp, T. Physics of Plasmas, Vol. 22, Issue 2 https://doi.org/10.1063/1.4901251	journal	November 2014
Experimental Pellet Shatter Thresholds and Analysis of Shatter Tube Ejecta for Disruption Mitigation Cryogenic Pellets Gebhart, T. E.; Baylor, L. R.; Meitner, S. J. IEEE Transactions on Plasma Science, Vol. 48, Issue 6 https://doi.org/10.1109/tps.2019.2957968	journal	June 2020
A design retrospective of the DIII-D tokamak Luxon, J. L. Nuclear Fusion, Vol. 42, Issue 5 https://doi.org/10.1088/0029-5515/42/5/313	journal	May 2002
High fusion performance in Super H-mode experiments on Alcator C-Mod and DIII-D Snyder, P. B.; Hughes, J. W.; Osborne, T. H. Nuclear Fusion, Vol. 59, Issue 8 https://doi.org/10.1088/1741-4326/ab235b	journal	June 2019
Chapter 3: MHD stability, operational limits and disruptions Mhd, ITER Physics Expert Group on Disrup; Editors, ITER Physics Basis Nuclear Fusion, Vol. 39, Issue 12 https://doi.org/10.1088/0029-5515/39/12/303	journal	December 1999
0-D Modeling of Fast Radiative Shutdown of Tokamak Discharges Following Massive Gas Injection Hollmann, E. M.; Parks, P. B.; Scott, H. A. Contributions to Plasma Physics, Vol. 48, Issue 1-3 https://doi.org/10.1002/ctpp.200810045	journal	March 2008
Plasma–surface interactions during tokamak disruptions and rapid shutdowns Hollmann, E. M.; Arnoux, G.; Commaux, N. Journal of Nuclear Materials, Vol. 415, Issue 1 https://doi.org/10.1016/j.jnucmat.2010.10.009	journal	August 2011
Shattered pellet injection technology design and characterization for disruption mitigation experiments Baylor, L. R.; Meitner, S. J.; Gebhart, T. E. Nuclear Fusion, Vol. 59, Issue 6 https://doi.org/10.1088/1741-4326/ab136c	journal	April 2019
Hot tail runaway electron generation in tokamak disruptions Smith, H. M.; Verwichte, E. Physics of Plasmas, Vol. 15, Issue 7 https://doi.org/10.1063/1.2949692	journal	July 2008
Thermal quench mitigation and current quench control by injection of mixed species shattered pellets in DIII-D Shiraki, D.; Commaux, N.; Baylor, L. R. Physics of Plasmas, Vol. 23, Issue 6 https://doi.org/10.1063/1.4954389	journal	June 2016
Determination of the Electron Temperature by the Line-Ratio Method in SNF Plasma Separator Melnikov, A. D.; Usmanov, R. A.; Vorona, N. A. Physics of Atomic Nuclei, Vol. 81, Issue 11 https://doi.org/10.1134/s1063778818110145	journal	December 2018
Spectroscopic measurement of atomic and molecular deuterium fluxes in the DIII-D plasma edge Hollmann, E. M.; Brezinsek, S.; Brooks, N. H. Plasma Physics and Controlled Fusion, Vol. 48, Issue 8 https://doi.org/10.1088/0741-3335/48/8/009	journal	July 2006
Deployment of multiple shattered pellet injection systems in KSTAR Park, SooHwan; Lee, KunSu; Baylor, Larry R. Fusion Engineering and Design, Vol. 154 https://doi.org/10.1016/j.fusengdes.2020.111535	journal	May 2020
Calibrated simulations of $Z$ opacity experiments that reproduce the experimentally measured plasma conditions Nagayama, T.; Bailey, J. E.; Loisel, G. Physical Review E, Vol. 93, Issue 2 https://doi.org/10.1103/PhysRevE.93.023202	journal	February 2016
Disruptions in ITER and strategies for their control and mitigation Lehnen, M.; Aleynikova, K.; Aleynikov, P. B. Journal of Nuclear Materials, Vol. 463 https://doi.org/10.1016/j.jnucmat.2014.10.075	journal	August 2015
Shattered pellet injection simulations with NIMROD Kim, Charlson C.; Liu, Yueqiang; Parks, Paul B. Physics of Plasmas, Vol. 26, Issue 4 https://doi.org/10.1063/1.5088814	journal	April 2019
Design and Commissioning of a Three-Barrel Shattered Pellet Injector for DIII-D Disruption Mitigation Studies Meitner, S.; Baylor, L. R.; Commaux, N. Fusion Science and Technology https://doi.org/10.1080/15361055.2017.1333854	journal	June 2017
Bremsstrahlung photon emission rate from Maxwellian plasmas Halverson, W. Plasma Physics, Vol. 14, Issue 6 https://doi.org/10.1088/0032-1028/14/6/004	journal	June 1972
First demonstration of rapid shutdown using neon shattered pellet injection for thermal quench mitigation on DIII-D Commaux, N.; Shiraki, D.; Baylor, L. R. Nuclear Fusion, Vol. 56, Issue 4 https://doi.org/10.1088/0029-5515/56/4/046007	journal	March 2016
Theory of tokamak disruptions Boozer, Allen H. Physics of Plasmas, Vol. 19, Issue 5 https://doi.org/10.1063/1.3703327	journal	May 2012
Chapter 3: MHD stability, operational limits and disruptions Hender, T. C.; Wesley, J. C.; Bialek, J. Nuclear Fusion, Vol. 47, Issue 6 https://doi.org/10.1088/0029-5515/47/6/S03	journal	June 2007
Physics of runaway electrons in tokamaks Breizman, Boris N.; Aleynikov, Pavel; Hollmann, Eric M. Nuclear Fusion, Vol. 59, Issue 8 https://doi.org/10.1088/1741-4326/ab1822	journal	June 2019
3D non-linear MHD simulation of the MHD response and density increase as a result of shattered pellet injection Hu, D.; Nardon, E.; Lehnen, M. Nuclear Fusion, Vol. 58, Issue 12 https://doi.org/10.1088/1741-4326/aae614	journal	October 2018
Use of Ar pellet ablation rate to estimate initial runaway electron seed population in DIII-D rapid shutdown experiments Hollmann, E. M.; Commaux, N.; Moyer, R. A. Nuclear Fusion, Vol. 57, Issue 1 https://doi.org/10.1088/0029-5515/57/1/016008	journal	October 2016
Electron acceleration in a JET disruption simulation Sommariva, C.; Nardon, E.; Beyer, P. Nuclear Fusion, Vol. 58, Issue 10 https://doi.org/10.1088/1741-4326/aad47d	journal	August 2018

Similar Records

Estimate of pre-thermal quench non-thermal electron density profile during Ar pellet shutdowns of low-density target plasmas in DIII-D

Journal Article · Tue Jul 06 00:00:00 EDT 2021 · Physics of Plasmas · OSTI ID:1730928

Hollmann, E. M.; Austin, M.; Bykov, I.; +9 more

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

Journal Article · Wed Mar 02 00:00:00 EST 2016 · Nuclear Fusion · OSTI ID:1730928

Commaux, Nicolas J. C.; Shiraki, Daisuke; Baylor, Larry R.; +8 more

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

Journal Article · Wed Sep 04 00:00:00 EDT 2019 · Nuclear Fusion · OSTI ID:1730928

Herfindal, J. L.; Shiraki, D.; Baylor, L. R.; +4 more

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Tokamak
disruptions
shattered pellet injection
runaway electrons

Title: Observation of non-thermal electron formation during the thermal quench of shattered pellet injection shutdowns in DIII-D

Citation Formats

References (32)

Similar Records

Related Subjects