Title: Isotope impact on Alfvén eigenmodes and fast ion transport in DIII-D

Abstract

Abstract Measurements of beam driven Alfvén Eigenmode (AE) activity in matched deuterium (D) and hydrogen (H) DIII-D plasmas show a dramatic difference in unstable mode activity and fast ion transport for a given injected beam power. The dependence of the unstable AE spectrum in reversed magnetic shear plasmas on beam and thermal species is investigated in the current ramp by varying beam power in a sequence of discharges for fixed thermal and beam species at fixed density. In general, a spectrum of Reversed Shear Alfvén Eigenmodes (RSAEs) and Toroidal Alfvén Eigenmodes (TAEs) are driven unstable with sub-Alfvénic D beam injection while primarily only RSAEs are driven unstable for the H beam cases investigated. Further, for a given beam power, the driven AE amplitude is always reduced with H beams relative to D and for H thermal plasma relative to pure D or mixed D/H plasmas. Estimates of the fast ion stored energy combined with modeling using the hybrid kinetic-MHD code MEGA indicate that the dominant mechanism contributing to the difference between H and D beam drive is the faster classical slowing down of H beam ions relative to D and the resultant lower beam ion pressure. Calculations of the AEmore » induced stored energy deficits using the reduced critical gradient model TGLFEP show quantitative agreement with the observed dependencies on injected power, isotope and minimum safety factor.« less

Authors:

Van Zeeland, M. A. ;

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

Bass, E.; Du, X. D. ;

• Search DOE PAGES for author "Du, X. D."
• Search DOE PAGES for ORCID "0000-0001-6127-2825"

Heidbrink, W. W. ;

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

Chrystal, C. ;

• Search DOE PAGES for author "Chrystal, C."
• Search DOE PAGES for ORCID "0000-0003-3049-8658"

Crocker, C. ;

• Search DOE PAGES for author "Crocker, C."
• Search DOE PAGES for ORCID "0000-0003-2379-5814"

DeGrandchamp, G. ;

• Search DOE PAGES for author "DeGrandchamp, G."
• Search DOE PAGES for ORCID "0000-0002-1363-9570"

Haskey, S. ;

• Search DOE PAGES for author "Haskey, S."
• Search DOE PAGES for ORCID "0000-0002-9978-6597"

Liu, D.; Gonzalez-Martin, J. ;

• Search DOE PAGES for author "Gonzalez-Martin, J."
• Search DOE PAGES for ORCID "0000-0002-3237-5195"

Thome, K. E. ;

• Search DOE PAGES for author "Thome, K. E."
• Search DOE PAGES for ORCID "0000-0002-4801-3922"

Yu, G. ;

• Search DOE PAGES for author "Yu, G."
• Search DOE PAGES for ORCID "0000-0002-0002-5342"

Zhu, Y.

Publication Date:

Wed Apr 10 00:00:00 EDT 2024

Research Org.:

General Atomics, San Diego, CA (United States)

Sponsoring Org.:

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

OSTI Identifier:

2335945

Alternate Identifier(s):

OSTI ID: 2329548; OSTI ID: 2339633

Grant/Contract Number:  

AC02- 09CH11466; FC02-04ER54698; AC02-09CH11466; FG02-99ER54531; SC0023500; SC0018108; SC0020337

Resource Type:

Published Article

Journal Name:

Nuclear Fusion

Additional Journal Information:

Journal Name: Nuclear Fusion Journal Volume: 64 Journal Issue: 5; Journal ID: ISSN 0029-5515

Publisher:

IOP Publishing

Country of Publication:

IAEA

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY; fast ions; Alfven eigenmodes; energetic particles; tokamaks; DIII-D tokamak; isotopes; neutral beam heating