Title: Impact of β _n and spectrum of n = 1 applied fields on fast ion losses in DIII-D

Abstract

Abstract The effect of n = 1 magnetic perturbations (MPs) on prompt fast ion losses in DIII-D has been investigated using the light ion beam probe technique. The effect of normalized beta, β _n , and the plasma response to the MPs is studied for several MP spectra. Magnetics data show a strong dependence of plasma response to β _n that depends on the phase difference in perturbation coils, $\mathrm{\Delta }{\varphi }_{\mathrm{U}\mathrm{L}}$ . For most phases, the response increases with β _n , however, the response is suppressed for phases between 180 ^∘ and 240 ^∘ . Experimental data from scintillator based fast ion loss detectors shows that relative fluctuation of lost ions (20%–30% of the steady signal) does not diminish across the L- to H-mode transition for $\mathrm{\Delta }{\varphi }_{\mathrm{U}\mathrm{L}}={240}^{\circ }$ , despite the 34% decrease in radial response field and 50% decrease in poloidal response field. Simulations of the DIII-D discharges using M3D-C1 and ASCOT5 find that prompt losses from neutral beam injection in each investigated case hit the first wall at several concentrated locations: the vessel floor, midplane diagnostic ports, vessel ceiling, and inner wall. Simulated losses from co-injection neutral beams are born outside the last closed flux surface, corresponding to radial orbit displacements of 3–6 cm due to the MPs.

Authors:

Gage, K. R. ;

• Search DOE PAGES for author "Gage, K. R."
• Search DOE PAGES for ORCID "0000-0003-0262-416X"

Chen, X. ;

• Search DOE PAGES for author "Chen, X."
• Search DOE PAGES for ORCID "0000-0002-8718-6877"

Van Zeeland, M. ;

• Search DOE PAGES for author "Van Zeeland, M."
• Search DOE PAGES for ORCID "0000-0002-7911-2739"

Heidbrink, W. W. ;

• Search DOE PAGES for author "Heidbrink, W. W."
• Search DOE PAGES for ORCID "0000-0002-6942-8043"

Hanson, J. ;

• Search DOE PAGES for author "Hanson, J."
• Search DOE PAGES for ORCID "0000-0003-2432-4870"

Lyons, B. ;

• Search DOE PAGES for author "Lyons, B."
• Search DOE PAGES for ORCID "0000-0003-3232-1581"

Pace, D. C.; Galdon-Quiroga, J. ;

• Search DOE PAGES for author "Galdon-Quiroga, J."
• Search DOE PAGES for ORCID "0000-0002-7415-1894"

Garcia-Munoz, M.

• Search DOE PAGES for author "Garcia-Munoz, M."
• Search DOE PAGES for ORCID "0000-0002-3241-502X"

Publication Date:

Wed Jan 25 00:00:00 EST 2023

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Fusion Energy Sciences (FES)

OSTI Identifier:

1922129

Alternate Identifier(s):

OSTI ID: 1908862; OSTI ID: 1923690

Grant/Contract Number:  

SC002033; FC02-04ER54698; SC0020337

Resource Type:

Published Article

Journal Name:

Nuclear Fusion

Additional Journal Information:

Journal Name: Nuclear Fusion Journal Volume: 63 Journal Issue: 3; Journal ID: ISSN 0029-5515

Publisher:

IOP Publishing

Country of Publication:

IAEA

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; energetic particles; tokamaks; fast ion losses; magnetic perturbations