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Title: Impurity-induced divertor plasma oscillations

Two different oscillatory plasma regimes induced by seeding the plasma with high- and low-Z impurities are found for ITER-like divertor plasmas, using computer modeling with the DUSTT/UEDGE and SOLPS4.3 plasma-impurity transport codes. The oscillations are characterized by significant variations of the impurity-radiated power and of the peak heat load on the divertor targets. Qualitative analysis of the divertor plasma oscillations reveals different mechanisms driving the oscillations in the cases of high- and low-Z impurity seeding. The oscillations caused by the high-Z impurities are excited near the X-point by an impurity-related instability of the radiation-condensation type, accompanied by parallel impurity ion transport affected by the thermal and plasma friction forces. The driving mechanism of the oscillations induced by the low-Z impurities is related to the cross-field transport of the impurity atoms, causing alteration between the high and low plasma temperature regimes in the plasma recycling region near the divertor targets. As a result, the implications of the impurity-induced plasma oscillations for divertor operation in the next generation tokamaks are also discussed.
Authors:
ORCiD logo [1] ; ORCiD logo [2] ;  [1] ;  [1] ;  [3]
  1. Univ. of California, San Diego, La Jolla, CA (United States)
  2. NRC "Kurchatov Institute", Moscow (Russia); National Research Nuclear Univ. MEPhI, Moscow (Russia)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-678528
Journal ID: ISSN 1070-664X; PHPAEN; FG02-04ER54739, AC52-07NA27344
Grant/Contract Number:
FG02-06ER54852; AC52-07NA27344; FG02-04ER54739
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 1; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of California, San Diego, La Jolla, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; oscillations; plasma; impurity; radiation; divertors; plasma impuritites; plasma oscillations; plasma temperature; friction; 70 PLASMA PHYSICS AND FUSION
OSTI Identifier:
1234254
Alternate Identifier(s):
OSTI ID: 1234151; OSTI ID: 1343030

Smirnov, R. D., Kukushkin, A. S., Krasheninnikov, S. I., Pigarov, A. Yu., and Rognlien, T. D.. Impurity-induced divertor plasma oscillations. United States: N. p., Web. doi:10.1063/1.4939539.
Smirnov, R. D., Kukushkin, A. S., Krasheninnikov, S. I., Pigarov, A. Yu., & Rognlien, T. D.. Impurity-induced divertor plasma oscillations. United States. doi:10.1063/1.4939539.
Smirnov, R. D., Kukushkin, A. S., Krasheninnikov, S. I., Pigarov, A. Yu., and Rognlien, T. D.. 2016. "Impurity-induced divertor plasma oscillations". United States. doi:10.1063/1.4939539. https://www.osti.gov/servlets/purl/1234254.
@article{osti_1234254,
title = {Impurity-induced divertor plasma oscillations},
author = {Smirnov, R. D. and Kukushkin, A. S. and Krasheninnikov, S. I. and Pigarov, A. Yu. and Rognlien, T. D.},
abstractNote = {Two different oscillatory plasma regimes induced by seeding the plasma with high- and low-Z impurities are found for ITER-like divertor plasmas, using computer modeling with the DUSTT/UEDGE and SOLPS4.3 plasma-impurity transport codes. The oscillations are characterized by significant variations of the impurity-radiated power and of the peak heat load on the divertor targets. Qualitative analysis of the divertor plasma oscillations reveals different mechanisms driving the oscillations in the cases of high- and low-Z impurity seeding. The oscillations caused by the high-Z impurities are excited near the X-point by an impurity-related instability of the radiation-condensation type, accompanied by parallel impurity ion transport affected by the thermal and plasma friction forces. The driving mechanism of the oscillations induced by the low-Z impurities is related to the cross-field transport of the impurity atoms, causing alteration between the high and low plasma temperature regimes in the plasma recycling region near the divertor targets. As a result, the implications of the impurity-induced plasma oscillations for divertor operation in the next generation tokamaks are also discussed.},
doi = {10.1063/1.4939539},
journal = {Physics of Plasmas},
number = 1,
volume = 23,
place = {United States},
year = {2016},
month = {1}
}