The effect of ELMs on HHFW heating of NBI generated H-modes

J. C. Hosea, J. W. Ahn, R. E. Bell, S. Gerhardt, T. K. Gray, D. L. Green, E. F. Jaeger, B. P. Leblanc, R. Maingi, A. McLean, C. K. Phillips, L. Roquemore, P. M. Ryan, S. Sabbagh, G. Taylor, K. Tritz, J. Wilgen, J. R. Wilson

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

ELMs reduce the stored energy achieved with HHFW heating compared with the ELM free case as also occurs for NBI heating alone. This reduction can be attributed both to direct ELM ejection of stored energy and to an increase in edge density with ELMs that exceeds the onset density for perpendicular wave propagation near the antenna [1,2], and leads to significantly more edge RF power deposition. This latter effect causes a more intense RF "hot" zone in the lower divertor scrape off region due to an increase in edge RF power propagating to the divertor from the antenna region along the magnetic field lines. Fast IR measurements of the direct ELM heat deposition at the lower divertor shows it to be peaked in the vicinity of the outer strike radius and to fall off strongly as the "hot" zone is approached, indicating little direct ELM effect on the "hot" zone heating. Physics studies of the "hot" zone have begun with sweeping the RF "hot" zone spiral over Rogowski instrumented divertor region tiles to show that the tile currents track the location of the zone. The relation of the results here to the AORSA RF code simulations including the SOL region is pointed out.

Original languageEnglish
Title of host publicationRadio Frequency Power in Plasmas - Proceedings of the 19th Topical Conference
Pages333-336
Number of pages4
DOIs
StatePublished - 2011
Event19th Topical Conference on Radio Frequency Power in Plasmas - Newport, RI, United States
Duration: Jun 1 2011Jul 3 2011

Publication series

NameAIP Conference Proceedings
Volume1406
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference19th Topical Conference on Radio Frequency Power in Plasmas
Country/TerritoryUnited States
CityNewport, RI
Period06/1/1107/3/11

Keywords

  • ELM effects on RF power deposition
  • RF Heating
  • Spherical Torus

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