Local measurements of the pedestal magnetic field profile throughout the ELM cycle on DIII-D
Abstract
New high speed localized measurements of the pedestal magnetic field during the edge localized mode (ELM) cycle of a DIII-D High confinement mode (H-mode) discharge indicate a temporally and spatial complex redistribution of the edge current density profile, jedge. The measurement technique extracts the magnetic field magnitude, B, via the spectral separation of Stark-split neutral beam radiation in the pedestal. Single spatial channel measurements from a novel spatial heterodyne spectrometer are validated in discharges with core current profile changes. The technique measures Stark-splitting changes that imply B changes as small as 1 mT with high time resolution (50 μs). At normalized poloidal flux ψn=1.0, B appears saturated in the inter-ELM period and then rapidly decreases in <200 μs by ∼1%, before edge recycling emission begins to increase. Radially inboard of jedge, B increases at the ELM crash. The behavior is consistent with a rapid collapse of jedge at the ELM crash and subsequent pedestal recovery. In some discharges, at ψn<0.96, changes in B are observed throughout the ELM cycle. In others, B recovers and is relatively stable until a few ms leading up to the next crash. Measurements of B during the H-mode transition show a large increase at ψn=1 with little changemore »
- Authors:
-
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of Wisconsin, Madison, WI (United States)
- General Atomics, San Diego, CA (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Publication Date:
- Research Org.:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE National Nuclear Security Administration (NNSA)
- OSTI Identifier:
- 1895046
- Alternate Identifier(s):
- OSTI ID: 1890770; OSTI ID: 1903619; OSTI ID: 2202922
- Report Number(s):
- DOE-GA-54698; LLNL-JRNL-836197
Journal ID: ISSN 1070-664X; TRN: US2310335
- Grant/Contract Number:
- FC02-04ER54698; FG02-89ER53296; FG02-08ER54999; AC52-07NA27344; AC02-09CH11466
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Physics of Plasmas
- Additional Journal Information:
- Journal Volume: 29; Journal Issue: 10; Conference: 63.Annual Meeting of the APS Division of Plasma Physics, Pittsburgh, PA (United States), 8-12 Nov, 2021; Journal ID: ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Plasma properties and parameters; Magnetohydrodynamics; Plasma confinement; Stark effect; High resolution spectroscopy; Tokamaks
Citation Formats
Burke, M. G., Fonck, R. J., McKee, G. R., Burrell, K. H., Haskey, S. R., Knolker, M., Laggner, F. M., Osborne, T. H., Victor, B. S., and Yan, Z. Local measurements of the pedestal magnetic field profile throughout the ELM cycle on DIII-D. United States: N. p., 2022.
Web. doi:10.1063/5.0102610.
Burke, M. G., Fonck, R. J., McKee, G. R., Burrell, K. H., Haskey, S. R., Knolker, M., Laggner, F. M., Osborne, T. H., Victor, B. S., & Yan, Z. Local measurements of the pedestal magnetic field profile throughout the ELM cycle on DIII-D. United States. https://doi.org/10.1063/5.0102610
Burke, M. G., Fonck, R. J., McKee, G. R., Burrell, K. H., Haskey, S. R., Knolker, M., Laggner, F. M., Osborne, T. H., Victor, B. S., and Yan, Z. Mon .
"Local measurements of the pedestal magnetic field profile throughout the ELM cycle on DIII-D". United States. https://doi.org/10.1063/5.0102610. https://www.osti.gov/servlets/purl/1895046.
@article{osti_1895046,
title = {Local measurements of the pedestal magnetic field profile throughout the ELM cycle on DIII-D},
author = {Burke, M. G. and Fonck, R. J. and McKee, G. R. and Burrell, K. H. and Haskey, S. R. and Knolker, M. and Laggner, F. M. and Osborne, T. H. and Victor, B. S. and Yan, Z.},
abstractNote = {New high speed localized measurements of the pedestal magnetic field during the edge localized mode (ELM) cycle of a DIII-D High confinement mode (H-mode) discharge indicate a temporally and spatial complex redistribution of the edge current density profile, jedge. The measurement technique extracts the magnetic field magnitude, B, via the spectral separation of Stark-split neutral beam radiation in the pedestal. Single spatial channel measurements from a novel spatial heterodyne spectrometer are validated in discharges with core current profile changes. The technique measures Stark-splitting changes that imply B changes as small as 1 mT with high time resolution (50 μs). At normalized poloidal flux ψn=1.0, B appears saturated in the inter-ELM period and then rapidly decreases in <200 μs by ∼1%, before edge recycling emission begins to increase. Radially inboard of jedge, B increases at the ELM crash. The behavior is consistent with a rapid collapse of jedge at the ELM crash and subsequent pedestal recovery. In some discharges, at ψn<0.96, changes in B are observed throughout the ELM cycle. In others, B recovers and is relatively stable until a few ms leading up to the next crash. Measurements of B during the H-mode transition show a large increase at ψn=1 with little change at ψn=0.9, consistent with the formation of the edge bootstrap current density peak. The ψn=0.9 spectrum is complicated by predicted changes to the Stark component intensities with density at the L–H transition.},
doi = {10.1063/5.0102610},
journal = {Physics of Plasmas},
number = 10,
volume = 29,
place = {United States},
year = {Mon Oct 03 00:00:00 EDT 2022},
month = {Mon Oct 03 00:00:00 EDT 2022}
}
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