Title: Toroidal modeling of runaway electron loss due to 3-D fields in DIII-D and COMPASS

Abstract

The 3-D field induced relativistic runaway electron (RE) loss has been simulated for DIII-D, COMPASS and ITER plasmas, utilizing the MARS-F code incorporated with the recently developed and updated RE orbit module (REORBIT). Modeling shows effectively 100% loss of a post-disruption, high-current runaway beam in DIII-D, due to the 1 kG level of magnetic field perturbation produced by a fast growing n = 1 resistive kink instability. The RE loss is shown to be independent of the particle energy or the initial location of particles in the configuration space. Applied resonant magnetic perturbation (RMP) fields from in-vessel coils are not effective for RE beam mitigation in DIII-D, but do produce finite (>10%) RE loss in COMPASS, consistent with experimental observations in above two devices. The major reasons for this difference in RE control by RMP between these two devices are (i) the coil proximity to the RE beam and (ii) the effective coil current scaling versus the machine size and the toroidal magnetic field. About 10% RE loss fraction is also predicted for an ITER 15 MA scenario with pre-disruption plasma, highlighting the role of the plasma response. Up to 30% loss is computed, however, by artificially scaling the equilibriummore » pressure to zero. This is due to the more resistive plasma response and stronger resulting field line stochasticity. Distributions of the lost REs to the limiting surface show poloidally peaked profile near the high-field-side in both DIII-D and COMPASS, covering about 100o poloidal angle. Higher perturbation field level and/or higher particle energy also result in REs being lost to the low-field-side of the limiting surface of these two devices, increasing the effective wetted area. Finally, for the modeled ITER plasmas, the applied RMP field, with optimal poloidal spectrum that maximizes the edge localized mode control, leads to REs being lost to the lower divertor region of the limiting surface within a narrow poloidal band.« less

Authors:

Liu, Yueqiang  ^[1];

• Search DOE PAGES for author "Liu, Yueqiang"
• Search DOE PAGES for ORCID "0000-0002-8192-8411"

Paz-Soldan, C.  ^[1];

• Search DOE PAGES for author "Paz-Soldan, C."
• Search DOE PAGES for ORCID "0000-0001-5069-4934"

Macusova, E.  ^[2];

• Search DOE PAGES for author "Macusova, E."
• Search DOE PAGES for ORCID "0000-0002-0381-9244"

Markovic, T. ^[3]; Ficker, O. ^[4]; Parks, P. B.  ^[1];

• Search DOE PAGES for author "Parks, P. B."
• Search DOE PAGES for ORCID "0000-0001-5539-1297"

Kim, C. C. ^[5]; Lao, L. L.  ^[1];

• Search DOE PAGES for author "Lao, L. L."
• Search DOE PAGES for ORCID "0000-0003-1937-2675"

Li, L. ^[6]

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+ Show Author Affiliations

1. General Atomics, San Diego, CA (United States)
2. Institute of Plasma Physics of the CAS, Prague (Czechia); Charles Univ., Prague (Czech Republic)
3. Institute of Plasma Physics of the CAS, Prague (Czechia)
4. Institute of Plasma Physics of the CAS, Prague (Czechia); Czech Technical Univ., Prague (Czech Republic)
5. 2SLS2 Consulting, San Diego, CA (United States)
6. Donghua University, Shanghai (China)

Publication Date:

Thu Oct 08 00:00:00 EDT 2020

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1673624

Alternate Identifier(s):

OSTI ID: 1671157

Grant/Contract Number:  

FG02-95ER54309; SC0016452; FC02-04ER54698; 633053

Resource Type:

Accepted Manuscript

Journal Name:

Physics of Plasmas

Additional Journal Information:

Journal Volume: 27; Journal Issue: 10; 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; runaway current; 3-D field; RE loss