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Title: Exploration of non-resonant divertor features on the Compact Toroidal Hybrid

Abstract

Abstract Non-resonant divertors (NRDs) separate the confined plasma from the surrounding plasma facing components (PFCs). The resulting striking field line intersection pattern on these PFCs is insensitive to plasma equilibrium effects. However, a complex scrape-off layer (SOL), created by chaotic magnetic topology in the plasma edge, connects the core plasma to the PFCs through varying magnetic flux tubes. The Compact Toroidal Hybrid (CTH) serves as a test-bed to study this by scanning across its inductive current. Simulations observe a significant change of the chaotic edge structure and an effective distance between the confined plasma and the instrumented wall targets. The intersection pattern is observed to be a narrow helical band, which we claim is a resilient strike line pattern. However, signatures of finger-like structures, defined as heteroclinic tangles in chaotic domains, within the plasma edge connect the island chains to this resilient pattern. The dominant connection length field lines intersecting the targets are observed via heat flux modeling with EMC3-EIRENE. At low inductive current levels, the excursion of the field lines resembles a limited plasma wall scenario. At high currents, a private flux region is created in the area where the helical strike line pattern splits into two bands. Thesemore » bands are divertor legs with distinct SOL parallel particle flow channels. The results demonstrate the NRD strike line pattern resiliency within CTH, but also show the underlying chaotic edge structure determining if the configuration is diverted or limited. This work supports future design efforts for a mechanical structure for the NRD.« less

Authors:
ORCiD logo; ORCiD logo; ORCiD logo; ORCiD logo; ORCiD logo; ; ORCiD logo
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
2203576
Grant/Contract Number:  
FG02-00ER54610
Resource Type:
Published Article
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Name: Nuclear Fusion Journal Volume: 63 Journal Issue: 12; Journal ID: ISSN 0029-5515
Publisher:
IOP Publishing
Country of Publication:
IAEA
Language:
English

Citation Formats

Garcia, K. A., Bader, A., Frerichs, H., Hartwell, G. J., Schmitt, J. C., Allen, N., and Schmitz, O. Exploration of non-resonant divertor features on the Compact Toroidal Hybrid. IAEA: N. p., 2023. Web. doi:10.1088/1741-4326/ad0160.
Garcia, K. A., Bader, A., Frerichs, H., Hartwell, G. J., Schmitt, J. C., Allen, N., & Schmitz, O. Exploration of non-resonant divertor features on the Compact Toroidal Hybrid. IAEA. https://doi.org/10.1088/1741-4326/ad0160
Garcia, K. A., Bader, A., Frerichs, H., Hartwell, G. J., Schmitt, J. C., Allen, N., and Schmitz, O. Wed . "Exploration of non-resonant divertor features on the Compact Toroidal Hybrid". IAEA. https://doi.org/10.1088/1741-4326/ad0160.
@article{osti_2203576,
title = {Exploration of non-resonant divertor features on the Compact Toroidal Hybrid},
author = {Garcia, K. A. and Bader, A. and Frerichs, H. and Hartwell, G. J. and Schmitt, J. C. and Allen, N. and Schmitz, O.},
abstractNote = {Abstract Non-resonant divertors (NRDs) separate the confined plasma from the surrounding plasma facing components (PFCs). The resulting striking field line intersection pattern on these PFCs is insensitive to plasma equilibrium effects. However, a complex scrape-off layer (SOL), created by chaotic magnetic topology in the plasma edge, connects the core plasma to the PFCs through varying magnetic flux tubes. The Compact Toroidal Hybrid (CTH) serves as a test-bed to study this by scanning across its inductive current. Simulations observe a significant change of the chaotic edge structure and an effective distance between the confined plasma and the instrumented wall targets. The intersection pattern is observed to be a narrow helical band, which we claim is a resilient strike line pattern. However, signatures of finger-like structures, defined as heteroclinic tangles in chaotic domains, within the plasma edge connect the island chains to this resilient pattern. The dominant connection length field lines intersecting the targets are observed via heat flux modeling with EMC3-EIRENE. At low inductive current levels, the excursion of the field lines resembles a limited plasma wall scenario. At high currents, a private flux region is created in the area where the helical strike line pattern splits into two bands. These bands are divertor legs with distinct SOL parallel particle flow channels. The results demonstrate the NRD strike line pattern resiliency within CTH, but also show the underlying chaotic edge structure determining if the configuration is diverted or limited. This work supports future design efforts for a mechanical structure for the NRD.},
doi = {10.1088/1741-4326/ad0160},
journal = {Nuclear Fusion},
number = 12,
volume = 63,
place = {IAEA},
year = {Wed Oct 25 00:00:00 EDT 2023},
month = {Wed Oct 25 00:00:00 EDT 2023}
}

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https://doi.org/10.1088/1741-4326/ad0160

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