Ablation of solid pellets induced by supra-thermal ions in the far scrape-off layer of DIII-D plasmas
Abstract
Injection of solid pellets is a key element in several aspects of the operation of a magnetic confinement plasma reactor for fusion applications, including plasma fueling, control and diagnosis. This letter reports observations demonstrating that pellet ablation can begin outside the plasma boundary, by effect of supra-thermal ions, whose orbits, under appropriate conditions, can extend well into the vacuum region. The phenomenon was recorded during plasma discharges in the DIII-D tokamak, combining pulsed modulation of heating neutral beams, with high-frequency injection of sub-millimeter lithium pellets, and it is ascribed to the large fraction of trapped beam ions associated with counter current neutral beam injection. The effect was quantitatively evaluated by means of Monte-Carlo simulations of supra-thermal ion orbits, finding that the heat-deposition was of the order of 50-100 W/mm2, in the region traversed by the lithium pellets before reaching the plasma boundary, which is consistent with the severe pellet deterioration observed for low velocity pellets.
- Authors:
-
[1];
[1];
[1];
[1];
[2];
[3];
[3];
[1]
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Univ. of California, San Diego, La Jolla, CA (United States)
- General Atomics, San Diego, CA (United States)
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Contributing Org.:
- the DIII-D team; DIII-D team
- OSTI Identifier:
- 1558757
- Alternate Identifier(s):
- OSTI ID: 1481003
- Grant/Contract Number:
- AC02-09CH114661; AC05-00OR227252; AC52-07NA273444; FC02-04ER54698; FC02-04ER546983; FG02-06ER54867; AC02-09CH11466; AC05-00OR22725; AC52-07NA27344
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 59; Journal Issue: 8; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; tokamak; pellet; fast-ion; ablation; scrape-off layer; lithium; DIII-D
Citation Formats
Bortolon, A., Kramer, G. J., Maingi, R., Mansfield, D. K., Nagy, A., Roquemore, A. L., Lunsford, R., Bykov, I., Moyer, R. A., Parks, P. B., Van Zeeland, M. A., and Nazikian, R. Ablation of solid pellets induced by supra-thermal ions in the far scrape-off layer of DIII-D plasmas. United States: N. p., 2019.
Web. doi:10.1088/1741-4326/ab267f.
Bortolon, A., Kramer, G. J., Maingi, R., Mansfield, D. K., Nagy, A., Roquemore, A. L., Lunsford, R., Bykov, I., Moyer, R. A., Parks, P. B., Van Zeeland, M. A., & Nazikian, R. Ablation of solid pellets induced by supra-thermal ions in the far scrape-off layer of DIII-D plasmas. United States. https://doi.org/10.1088/1741-4326/ab267f
Bortolon, A., Kramer, G. J., Maingi, R., Mansfield, D. K., Nagy, A., Roquemore, A. L., Lunsford, R., Bykov, I., Moyer, R. A., Parks, P. B., Van Zeeland, M. A., and Nazikian, R. Tue .
"Ablation of solid pellets induced by supra-thermal ions in the far scrape-off layer of DIII-D plasmas". United States. https://doi.org/10.1088/1741-4326/ab267f. https://www.osti.gov/servlets/purl/1558757.
@article{osti_1558757,
title = {Ablation of solid pellets induced by supra-thermal ions in the far scrape-off layer of DIII-D plasmas},
author = {Bortolon, A. and Kramer, G. J. and Maingi, R. and Mansfield, D. K. and Nagy, A. and Roquemore, A. L. and Lunsford, R. and Bykov, I. and Moyer, R. A. and Parks, P. B. and Van Zeeland, M. A. and Nazikian, R.},
abstractNote = {Injection of solid pellets is a key element in several aspects of the operation of a magnetic confinement plasma reactor for fusion applications, including plasma fueling, control and diagnosis. This letter reports observations demonstrating that pellet ablation can begin outside the plasma boundary, by effect of supra-thermal ions, whose orbits, under appropriate conditions, can extend well into the vacuum region. The phenomenon was recorded during plasma discharges in the DIII-D tokamak, combining pulsed modulation of heating neutral beams, with high-frequency injection of sub-millimeter lithium pellets, and it is ascribed to the large fraction of trapped beam ions associated with counter current neutral beam injection. The effect was quantitatively evaluated by means of Monte-Carlo simulations of supra-thermal ion orbits, finding that the heat-deposition was of the order of 50-100 W/mm2, in the region traversed by the lithium pellets before reaching the plasma boundary, which is consistent with the severe pellet deterioration observed for low velocity pellets.},
doi = {10.1088/1741-4326/ab267f},
journal = {Nuclear Fusion},
number = 8,
volume = 59,
place = {United States},
year = {Tue Jun 25 00:00:00 EDT 2019},
month = {Tue Jun 25 00:00:00 EDT 2019}
}
Free Publicly Available Full Text
Publisher's Version of Record
Other availability
Search WorldCat to find libraries that may hold this journal
Cited by: 4 works
Citation information provided by
Web of Science
Web of Science
Figures / Tables:
Figure 1: Fast imaging of two Li granule injections with same granule size (0.9 mm) and speed (60 m/s), displaying short (top) and long (bottom) ablation dynamics. In the camera frames, the pellet is moving into the page and the view is partially obstructed by a vertical tube near themore »
All figures and tables
(6 total)
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:
Over-ablation and deflection of hydrogen pellets injected into neutral beam injection heated plasmas in the Large Helical Device
journal, February 2012
- Matsuyama, A.; Pégourié, B.; Sakamoto, R.
- Plasma Physics and Controlled Fusion, Vol. 54, Issue 3
A description of the full-particle-orbit-following SPIRAL code for simulating fast-ion experiments in tokamaks
journal, January 2013
- Kramer, G. J.; Budny, R. V.; Bortolon, A.
- Plasma Physics and Controlled Fusion, Vol. 55, Issue 2
High frequency pacing of edge localized modes by injection of lithium granules in DIII-D H-mode discharges
journal, April 2016
- Bortolon, A.; Maingi, R.; Mansfield, D. K.
- Nuclear Fusion, Vol. 56, Issue 5
Effect of transonic flow in the ablation cloud on the lifetime of a solid hydrogen pellet in a plasma
journal, January 1978
- Parks, P. B.; Turnbull, R. J.
- Physics of Fluids, Vol. 21, Issue 10
A design retrospective of the DIII-D tokamak
journal, May 2002
- Luxon, J. L.
- Nuclear Fusion, Vol. 42, Issue 5
Hydrogen-Pellet Fueling Experiments on the ISX- Tokamak
journal, January 1979
- Milora, S. L.; Foster, C. A.; Edmonds, P. H.
- Physical Review Letters, Vol. 42, Issue 2
Non-linear MHD modelling of ELM triggering by pellet injection in DIII-D and implications for ITER
journal, April 2014
- Futatani, S.; Huijsmans, G.; Loarte, A.
- Nuclear Fusion, Vol. 54, Issue 7
Measurements of Fast Confined Alphas on TFTR
journal, July 1995
- Fisher, R. K.; McChesney, J. M.; Parks, P. B.
- Physical Review Letters, Vol. 75, Issue 5
Imaging spectroscopy diagnosis of internal electron temperature and density distributions of plasma cloud surrounding hydrogen pellet in the Large Helical Device
journal, September 2012
- Motojima, G.; Sakamoto, R.; Goto, M.
- Review of Scientific Instruments, Vol. 83, Issue 9
Investigation of Electron-Distribution Function and Dynamo Mechanisms in a Reversed-Field Pinch by Analysis of Hydrogen-Pellet Deflection
journal, June 2000
- Garzotti, L.; Pégourié, B.; Bartiromo, R.
- Physical Review Letters, Vol. 84, Issue 24
Reduction of Edge-Localized Mode Intensity Using High-Repetition-Rate Pellet Injection in Tokamak -Mode Plasmas
journal, June 2013
- Baylor, L. R.; Commaux, N.; Jernigan, T. C.
- Physical Review Letters, Vol. 110, Issue 24
High-Efficiency Plasma Refuelling by Pellet Injection from the Magnetic High-Field Side into ASDEX Upgrade
journal, August 1997
- Lang, P. T.; Büchl, K.; Kaufmann, M.
- Physical Review Letters, Vol. 79, Issue 8
On the fluctuation of line radiation emitted during aluminum micro-pellet ablation in magnetized plasmas
journal, January 1999
- Kocsis, G.; Bakos, J. S.; Burhenn, R.
- Plasma Physics and Controlled Fusion, Vol. 41, Issue 7
Pellet imaging techniques in the ASDEX tokamak
journal, November 1990
- Wurden, G. A.; Büchl, K.; Hofmann, J.
- Review of Scientific Instruments, Vol. 61, Issue 11
Rapid Inward Impurity Transport during Impurity Pellet Injection on the DIII-D Tokamak
journal, November 1998
- Whyte, D. G.; Evans, T. E.; Hyatt, A. W.
- Physical Review Letters, Vol. 81, Issue 20
Model of ablation flow near light-atom pellets with surface boundary conditions
journal, March 1994
- Parks, P. B.; Gerdin, G. A.; Vahala, L. L.
- Nuclear Fusion, Vol. 34, Issue 3
Neutral and plasma shielding model for pellet ablation
journal, April 1988
- Houlberg, W. A.; Milora, S. L.; Attenberger, S. E.
- Nuclear Fusion, Vol. 28, Issue 4
Cross sections for and H atoms colliding with Li in the low-keV-energy region
journal, July 2008
- Cabrera-Trujillo, R.; Sabin, John R.; Deumens, E.
- Physical Review A, Vol. 78, Issue 1
Observation of three-dimensional motion of the pellet ablatant in the Large Helical Device
journal, July 2011
- Mishra, J. S.; Sakamoto, R.; Matsuyama, A.
- Nuclear Fusion, Vol. 51, Issue 8
Recent Upgrades of the DIII-D Impurity Granule Injector
journal, July 2017
- Vorenkamp, M. S.; Nagy, A.; Bortolon, A.
- Fusion Science and Technology
Modelling of pellet ablation in additionally heated plasmas
journal, December 2004
- Pégourié, B.; Waller, V.; Dumont, R. J.
- Plasma Physics and Controlled Fusion, Vol. 47, Issue 1
Mitigation of divertor heat flux by high-frequency ELM pacing with non-fuel pellet injection in DIII-D
journal, August 2017
- Bortolon, A.; Maingi, R.; Mansfield, D. K.
- Nuclear Materials and Energy, Vol. 12
Figures / Tables found in this record:
Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.