Fast camera imaging of plasmas in Alcator C-Mod and W7-X
Abstract
In this work we present an analysis of fast-camera imaging of Alcator C-Mod's divertor region and of the plasma cross section in the W7-X stellarator. In C-Mod, the dynamics of intermittent edge plasma filaments are imaged at 397,100 frames per second in an oblique view. An automatic pipeline was developed to reconstruct the filament motion in the R, Z plane of the divertor using EFIT field line projections. Next, we added our fast-framing camera to W7-X's diagnostic suite for the 2017 run campaign, the first with a divertor. It has a tangential view of the machine cross section, including part of a divertor module. The view is coupled to the camera via a coherent fiber bundle. The spatial resolution is 2–4 cm and the typical plasma brightness limits the fastest usable frame rate to 30k frames/s. We observe filaments in the plasma boundary that rotate around the magnetic axis during radiative collapse; filaments were observed in steady state in the limiter configuration of W7-X by Kocsis et al. [1]. We also observe for the first time a 1–2 kHz quasi-coherent fluctuation in divertor target emissions in the W7-X “standard” magnetic configuration. Finally, a rough analysis of edge gas fueling efficiencymore »
- Authors:
-
[1];
[1];
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Max Planck Inst. for Plasma Physics, Greifswald (Germany)
- Forschungszentrum Juelich (Germany)
- Publication Date:
- Research Org.:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- Contributing Org.:
- W7-X Team
- OSTI Identifier:
- 1609306
- Grant/Contract Number:
- FC02-99ER54512; SC0014251; SC0014264
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Nuclear Materials and Energy
- Additional Journal Information:
- Journal Volume: 17; Journal Issue: C; Journal ID: ISSN 2352-1791
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; Nuclear Science & Technology
Citation Formats
Ballinger, S. B., Terry, J. L., Baek, S. G., Tang, K., von Stechow, A., Killer, C., Nicolai, D., Satheeswaran, G., Drews, P., and Grulke, O. Fast camera imaging of plasmas in Alcator C-Mod and W7-X. United States: N. p., 2018.
Web. doi:10.1016/j.nme.2018.11.015.
Ballinger, S. B., Terry, J. L., Baek, S. G., Tang, K., von Stechow, A., Killer, C., Nicolai, D., Satheeswaran, G., Drews, P., & Grulke, O. Fast camera imaging of plasmas in Alcator C-Mod and W7-X. United States. https://doi.org/10.1016/j.nme.2018.11.015
Ballinger, S. B., Terry, J. L., Baek, S. G., Tang, K., von Stechow, A., Killer, C., Nicolai, D., Satheeswaran, G., Drews, P., and Grulke, O. Fri .
"Fast camera imaging of plasmas in Alcator C-Mod and W7-X". United States. https://doi.org/10.1016/j.nme.2018.11.015. https://www.osti.gov/servlets/purl/1609306.
@article{osti_1609306,
title = {Fast camera imaging of plasmas in Alcator C-Mod and W7-X},
author = {Ballinger, S. B. and Terry, J. L. and Baek, S. G. and Tang, K. and von Stechow, A. and Killer, C. and Nicolai, D. and Satheeswaran, G. and Drews, P. and Grulke, O.},
abstractNote = {In this work we present an analysis of fast-camera imaging of Alcator C-Mod's divertor region and of the plasma cross section in the W7-X stellarator. In C-Mod, the dynamics of intermittent edge plasma filaments are imaged at 397,100 frames per second in an oblique view. An automatic pipeline was developed to reconstruct the filament motion in the R, Z plane of the divertor using EFIT field line projections. Next, we added our fast-framing camera to W7-X's diagnostic suite for the 2017 run campaign, the first with a divertor. It has a tangential view of the machine cross section, including part of a divertor module. The view is coupled to the camera via a coherent fiber bundle. The spatial resolution is 2–4 cm and the typical plasma brightness limits the fastest usable frame rate to 30k frames/s. We observe filaments in the plasma boundary that rotate around the magnetic axis during radiative collapse; filaments were observed in steady state in the limiter configuration of W7-X by Kocsis et al. [1]. We also observe for the first time a 1–2 kHz quasi-coherent fluctuation in divertor target emissions in the W7-X “standard” magnetic configuration. Finally, a rough analysis of edge gas fueling efficiency using fast camera data and S/XB coefficients finds that fueling is less efficient at densities higher than 4 × 1019 m-3.},
doi = {10.1016/j.nme.2018.11.015},
journal = {Nuclear Materials and Energy},
number = C,
volume = 17,
place = {United States},
year = {Fri Nov 23 00:00:00 EST 2018},
month = {Fri Nov 23 00:00:00 EST 2018}
}
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Works referenced in this record:
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Works referencing / citing this record:
Multi-diagnostic analysis of plasma filaments in the island divertor
journal, November 2019
- Zoletnik, S.; Anda, G.; Biedermann, C.
- Plasma Physics and Controlled Fusion, Vol. 62, Issue 1
Characterization of the W7-X scrape-off layer using reciprocating probes
journal, June 2019
- Killer, Carsten; Grulke, Olaf; Drews, Philipp
- Nuclear Fusion, Vol. 59, Issue 8