Archivio Istituzionale della RicercaFast Waves (FWs) at 60 MHz and 90 MHz are used in DIII‐D for central electron heating and current drive. Coupling of FWs to high‐performance discharges is limited by low antenna loading in these regimes. To extend the application of high‐power FWs to such regimes, methods of increasing the antenna loading in these regimes are needed. A systematic study of loading enhancement techniques has been carried out in DIII‐D, including reduction of the antenna∕plasma distance, gas puffing into the far scrape‐off layer (SOL), and control of other parameters that affect the particle balance in the far SOL. Quantitative understanding of the physics of the loading resistance and its dependence on edge density profiles is demonstrated. The core FW heating efficiency appeared to be ∼100% in the Advanced Inductive regime, consistent with the high first‐pass direct electron absorption of ∼75% that is predicted by the ray‐tracing code GENRAY in this high electron beta regime.
Recent Results on Coupling Fast Waves to High Performance Plasmas on DIII-D / Pinsker, R. I.; Luce, T. C.; Politzer, P. A.; Porkolab, M.; Goulding, R. H.; Hanson, G. R.; Ryan, P. M.; Hosea, J. C.; Nagy, A.; Wilson, J. R.; Maggiora, Riccardo; Milanesio, Daniele; Zeng, L.. - In: AIP CONFERENCE PROCEEDINGS. - ISSN 0094-243X. - STAMPA. - 1406:(2011), pp. 313-320. (Intervento presentato al convegno 19th Topical Conference on Radio Frequency Power in Plasmas tenutosi a Newport, Rhose Island, USA nel 1-3 June 2011) [10.1063/1.3664983].
Recent Results on Coupling Fast Waves to High Performance Plasmas on DIII-D
MAGGIORA, Riccardo;MILANESIO, DANIELE;
2011
Abstract
Fast Waves (FWs) at 60 MHz and 90 MHz are used in DIII‐D for central electron heating and current drive. Coupling of FWs to high‐performance discharges is limited by low antenna loading in these regimes. To extend the application of high‐power FWs to such regimes, methods of increasing the antenna loading in these regimes are needed. A systematic study of loading enhancement techniques has been carried out in DIII‐D, including reduction of the antenna∕plasma distance, gas puffing into the far scrape‐off layer (SOL), and control of other parameters that affect the particle balance in the far SOL. Quantitative understanding of the physics of the loading resistance and its dependence on edge density profiles is demonstrated. The core FW heating efficiency appeared to be ∼100% in the Advanced Inductive regime, consistent with the high first‐pass direct electron absorption of ∼75% that is predicted by the ray‐tracing code GENRAY in this high electron beta regime.
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https://hdl.handle.net/11583/2495875
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