This content will become publicly available on October 11, 2020
Divertor currents during type-I edge-localized modes on the DIII-D tokamak
Abstract
Measurements of divertor currents on DIII-D lead to new insights in nonlinear edge-localized mode (ELM) dynamics and a possible mechanism to explain their explosive growth. Rapidly oscillating currents flowing into the divertor before a significant increase in divertor heat flux occurs are measured with an array of shunted tiles and characterized. Extrapolation results in total n = 0 currents of 5–10 kA flowing into a concentric circle near the strike point. The detected Fourier harmonics appear consistent with a mix of low-n modes (n < 4) with currents up to 4 kA. A heuristic framework for ELM currents is developed based on thermoelectric origin of the tile currents with flow through regions inside of the nominal separatrix and found consistent with the current measurements. A current flow through the confined plasma leading to increased stochasticity and transport at the plasma edge could provide a mechanism for additional nonlinear growth as sought for in computational ELM simulations. Results also imply that ELM currents may open the possibility to manipulate the ELM character by perturbations through non-axisymmetric divertor bias or tile insulation.
- Authors:
- Univ. of California, San Diego, CA (United States)
- General Atomics, San Diego, CA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Max Planck Inst. for Plasma Physics, Garching (Germany)
- Publication Date:
- Research Org.:
- Dept. of Energy (DOE), Washington DC (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
- OSTI Identifier:
- 1571140
- Grant/Contract Number:
- FC02-04ER54698
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Fusion
- Additional Journal Information:
- Journal Volume: 59; Journal Issue: 12; Journal ID: ISSN 0029-5515
- Publisher:
- IOP Science
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ELM; divertor; current; nonlinear
Citation Formats
Knolker, M., Evans, T. E., Wingen, A., Bortolon, A., Laggner, F. M., Moyer, R. A., Nazikian, R., and Zohm, H. Divertor currents during type-I edge-localized modes on the DIII-D tokamak. United States: N. p., 2019.
Web. doi:10.1088/1741-4326/ab3e9a.
Knolker, M., Evans, T. E., Wingen, A., Bortolon, A., Laggner, F. M., Moyer, R. A., Nazikian, R., & Zohm, H. Divertor currents during type-I edge-localized modes on the DIII-D tokamak. United States. doi:10.1088/1741-4326/ab3e9a.
Knolker, M., Evans, T. E., Wingen, A., Bortolon, A., Laggner, F. M., Moyer, R. A., Nazikian, R., and Zohm, H. Fri .
"Divertor currents during type-I edge-localized modes on the DIII-D tokamak". United States. doi:10.1088/1741-4326/ab3e9a.
@article{osti_1571140,
title = {Divertor currents during type-I edge-localized modes on the DIII-D tokamak},
author = {Knolker, M. and Evans, T. E. and Wingen, A. and Bortolon, A. and Laggner, F. M. and Moyer, R. A. and Nazikian, R. and Zohm, H.},
abstractNote = {Measurements of divertor currents on DIII-D lead to new insights in nonlinear edge-localized mode (ELM) dynamics and a possible mechanism to explain their explosive growth. Rapidly oscillating currents flowing into the divertor before a significant increase in divertor heat flux occurs are measured with an array of shunted tiles and characterized. Extrapolation results in total n = 0 currents of 5–10 kA flowing into a concentric circle near the strike point. The detected Fourier harmonics appear consistent with a mix of low-n modes (n < 4) with currents up to 4 kA. A heuristic framework for ELM currents is developed based on thermoelectric origin of the tile currents with flow through regions inside of the nominal separatrix and found consistent with the current measurements. A current flow through the confined plasma leading to increased stochasticity and transport at the plasma edge could provide a mechanism for additional nonlinear growth as sought for in computational ELM simulations. Results also imply that ELM currents may open the possibility to manipulate the ELM character by perturbations through non-axisymmetric divertor bias or tile insulation.},
doi = {10.1088/1741-4326/ab3e9a},
journal = {Nuclear Fusion},
number = 12,
volume = 59,
place = {United States},
year = {2019},
month = {10}
}
Works referenced in this record:
Principal physics developments evaluated in the ITER design review
journal, May 2009
- Hawryluk, R. J.; Campbell, D. J.; Janeschitz, G.
- Nuclear Fusion, Vol. 49, Issue 6
Edge-localized-modes in tokamaks
journal, September 2014
- Leonard, A. W.
- Physics of Plasmas, Vol. 21, Issue 9
Characteristics of type I ELM energy and particle losses in existing devices and their extrapolation to ITER
journal, August 2003
- Loarte, A.; Saibene, G.; Sartori, R.
- Plasma Physics and Controlled Fusion, Vol. 45, Issue 9
Edge localized modes and the pedestal: A model based on coupled peeling–ballooning modes
journal, May 2002
- Snyder, P. B.; Wilson, H. R.; Ferron, J. R.
- Physics of Plasmas, Vol. 9, Issue 5
ELM divertor peak energy fluence scaling to ITER with data from JET, MAST and ASDEX upgrade
journal, August 2017
- Eich, T.; Sieglin, B.; Thornton, A. J.
- Nuclear Materials and Energy, Vol. 12
Submicrosecond laser-filament-assisted corona bursts near a high-voltage electrode
journal, April 2010
- Sugiyama, Kiyohiro; Fujii, Takashi; Miki, Megumu
- Physics of Plasmas, Vol. 17, Issue 4
A conceptual model of the magnetic topology and nonlinear dynamics of ELMs
journal, June 2009
- Evans, T. E.; Yu, J. H.; Jakubowski, M. W.
- Journal of Nuclear Materials, Vol. 390-391
Numerical Modeling of Edge-Localized-Mode Filaments on Divertor Plates Based on Thermoelectric Currents
journal, April 2010
- Wingen, A.; Evans, T. E.; Lasnier, C. J.
- Physical Review Letters, Vol. 104, Issue 17
The X-point scrape-off plasma in jet with L- and H-modes
journal, April 1989
- Harbour, P. J.; Summers, D. D. R.; Clement, S.
- Journal of Nuclear Materials, Vol. 162-164
ELM driven divertor target currents on TCV
journal, September 2003
- Pitts, R. A.; Alberti, S.; Blanchard, P.
- Nuclear Fusion, Vol. 43, Issue 10
Electric currents in the scrape-off layer in ASDEX Upgrade
journal, March 2001
- Kallenbach, A.; Carlson, A.; Pautasso, G.
- Journal of Nuclear Materials, Vol. 290-293
Observation of electric currents in diverted tokamak scrape-off layers
journal, September 1991
- Schaffer, M. J.; Leikind, B. J.
- Nuclear Fusion, Vol. 31, Issue 9
Measurements of non-axisymmetric effects in the DIII-D divertor
journal, April 1995
- Evans, T. E.; Lasnier, C. J.; Hill, D. N.
- Journal of Nuclear Materials, Vol. 220-222
Investigation of the role of pedestal pressure and collisionality on type-I ELM divertor heat loads in DIII-D
journal, July 2018
- Knolker, M.; Bortolon, A.; Canal, G. P.
- Nuclear Fusion, Vol. 58, Issue 9
ELM particle and energy transport in the SOL and divertor of DIII-D
journal, August 2003
- Fenstermacher, M. E.; Leonard, A. W.; Snyder, P. B.
- Plasma Physics and Controlled Fusion, Vol. 45, Issue 9
Power requirement for accessing the H-mode in ITER
journal, July 2008
- Martin, Y. R.; Takizuka, T.; Group, the ITPA CDBM H-mode Threshold Data
- Journal of Physics: Conference Series, Vol. 123
Pedestal performance dependence upon plasma shape in DIII-D
journal, June 2007
- Leonard, A. W.; Casper, T. A.; Groebner, R. J.
- Nuclear Fusion, Vol. 47, Issue 7
ELM pacing using modulated non-axisymmetric magnetic fields on DIII-D
journal, March 2012
- Solomon, W. M.; Burrell, K. H.; Garofalo, A. M.
- Nuclear Fusion, Vol. 52, Issue 3
Energy flux to the ASDEX-Upgrade diverter plates determined by thermography and calorimetry
journal, January 1995
- Herrmann, A.; Junker, W.; Gunther, K.
- Plasma Physics and Controlled Fusion, Vol. 37, Issue 1
Progress in the peeling-ballooning model of edge localized modes: Numerical studies of nonlinear dynamics
journal, May 2005
- Snyder, P. B.; Wilson, H. R.; Xu, X. Q.
- Physics of Plasmas, Vol. 12, Issue 5
Recent progress in understanding the processes underlying the triggering of and energy loss associated with type I ELMs
journal, November 2014
- Kirk, A.; Dunai, D.; Dunne, M.
- Nuclear Fusion, Vol. 54, Issue 11
Observation of SOL current correlated with MHD activity in NBI heated DIII-D tokamak discharges
journal, September 2004
- Takahashi, H.; Fredrickson, E. D.; Schaffer, M. J.
- Nuclear Fusion, Vol. 44, Issue 10
Scrape-Off-Layer Current Model for Filament Structure Observed during Edge-Localized Modes in the DIII-D Tokamak
journal, May 2008
- Takahashi, Hironori; Fredrickson, E. D.; Schaffer, M. J.
- Physical Review Letters, Vol. 100, Issue 20
Nonlinear excitation of low-n harmonics in reduced magnetohydrodynamic simulations of edge-localized modes
journal, August 2013
- Krebs, I.; Hölzl, M.; Lackner, K.
- Physics of Plasmas, Vol. 20, Issue 8
Intrinsic Rotation of a Magnetic Island with Finite Width
journal, January 2010
- Uzawa, Ken; Ishizawa, Akihiro; Nakajima, Noriyoshi
- Plasma and Fusion Research, Vol. 5
Solitary magnetic perturbations at the ELM onset
journal, October 2012
- Wenninger, R. P.; Zohm, H.; Boom, J. E.
- Nuclear Fusion, Vol. 52, Issue 11
Electromagnetic ELM and inter-ELM filaments detected in the COMPASS Scrape-Off Layer
journal, August 2017
- Spolaore, M.; Kovařík, K.; Stöckel, J.
- Nuclear Materials and Energy, Vol. 12
High resolution numerical studies of separatrix splitting due to non-axisymmetric perturbation in DIII-D
journal, April 2009
- Wingen, A.; Evans, T. E.; Spatschek, K. H.
- Nuclear Fusion, Vol. 49, Issue 5
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
Explicit calculations of homoclinic tangles in tokamaks
journal, September 2003
- Roeder, R. K. W.; Rapoport, B. I.; Evans, T. E.
- Physics of Plasmas, Vol. 10, Issue 9
Homoclinic tangles, bifurcations and edge stochasticity in diverted tokamaks
journal, April 2004
- Evans, T. E.; Roeder, R. K. W.; Carter, J. A.
- Contributions to Plasma Physics, Vol. 44, Issue 13
Experimental signatures of homoclinic tangles in poloidally diverted tokamaks
journal, January 2005
- Evans, T. E.; Roeder, R. K. W.; Carter, J. A.
- Journal of Physics: Conference Series, Vol. 7
Effect of thermoelectric current splitting on the magnetic topology in DIII-D
journal, April 2011
- Wingen, A.; Evans, T. E.; Spatschek, K. H.
- Physics of Plasmas, Vol. 18, Issue 4
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
Thermoelectric currents and their role during ELM formation in JET
journal, July 2012
- Rack, M.; Wingen, A.; Liang, Y.
- Nuclear Fusion, Vol. 52, Issue 7
Divertor heat load in ASDEX Upgrade L-mode in presence of external magnetic perturbation
journal, July 2017
- Faitsch, M.; Sieglin, B.; Eich, T.
- Plasma Physics and Controlled Fusion, Vol. 59, Issue 9
Currents in the scrape-off layer of diverted tokamaks
journal, October 1989
- Staebler, G. M.; Hinton, F. L.
- Nuclear Fusion, Vol. 29, Issue 10
ELM transport in the JET scrape-off layer
journal, October 2007
- Pitts, R. A.; Andrew, P.; Arnoux, G.
- Nuclear Fusion, Vol. 47, Issue 11
Divertor bias experiments
journal, April 1995
- Staebler, G. M.
- Journal of Nuclear Materials, Vol. 220-222
Impact of plasma response on plasma displacements in DIII-D during application of external 3D perturbations
journal, May 2014
- Wingen, A.; Ferraro, N. M.; Shafer, M. W.
- Nuclear Fusion, Vol. 54, Issue 6
Experimentally-based ExB drifts in the DIII-D divertor and SOL calculated from integration of Ohm's law using Thomson scattering measurements of Te and ne
journal, August 2017
- Stangeby, P. C.; Elder, J. D.; McLean, A. G.
- Nuclear Materials and Energy, Vol. 12
The critical point for the onset of divertor energy flux asymmetry in tokamaks
journal, November 1996
- Staebler, G. M.
- Nuclear Fusion, Vol. 36, Issue 11
The role of magnetic geometry on the poloidal distribution of ELM-induced peak particle flux at the divertor targets in DIII-D
journal, August 2003
- Petrie, T. W.; Watkins, J. G.; Lao, L. L.
- Nuclear Fusion, Vol. 43, Issue 9
Characterization of the density profile collapse of type I ELMs in ASDEX Upgrade with high temporal and spatial resolution reflectometry
journal, July 2004
- Nunes, I.; Conway, G. D.; Loarte, A.
- Nuclear Fusion, Vol. 44, Issue 8
Divertor power and particle fluxes between and during type-I ELMs in the ASDEX Upgrade
journal, July 2008
- Kallenbach, A.; Dux, R.; Eich, T.
- Nuclear Fusion, Vol. 48, Issue 8
Divertor power deposition and target current asymmetries during type-I ELMs in ASDEX Upgrade and JET
journal, June 2007
- Eich, T.; Kallenbach, A.; Pitts, R. A.
- Journal of Nuclear Materials, Vol. 363-365
Driving toroidally asymmetric current through the tokamak scrape-off layer. II. Magnetic field structure and spectrum
journal, May 2009
- Joseph, Ilon
- Physics of Plasmas, Vol. 16, Issue 5
Effect of divertor bias on plasma flow in the DIII-D scrape-off layer
journal, May 1992
- Schaffer, M. J.; Mahdavi, A.; Klepper, C. C.
- Nuclear Fusion, Vol. 32, Issue 5
Biased electrodes for SOL control in NSTX
journal, June 2009
- Zweben, S. J.; Maqueda, R. J.; Roquemore, A. L.
- Journal of Nuclear Materials, Vol. 390-391