ICRF heating experiments on Alcator C-Mod

Journal Article · Tue Apr 01 04:00:00 EST 1997 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.53390· OSTI ID:587031

Takase, Y; Bonoli, P T; Hubbard, A; Mazurenko, A; OShea, P J; Porkolab, M; Reardon, J; Wukitch, S; Boivin, R ^[1]; Bombarda, F ^[2]; Fiore, C; Garnier, D; Goetz, J A; Granetz, R; Greenwald, M ^[1]; Hartmann, D ^[3]; Hutchinson, I H; Irby, J; LaBombard, B; Lipschultz, B ; Marmar, E ^[1]; May, M ^[4]; Rice, J; Rost, J C; Schachter, J; Snipes, J A; Stek, P; Terry, J ^[1]; Welch, B ^[5]; Wolfe, S ^[1]

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1. MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)
2. Associazione EURATOM-ENEA sulla Fusione, Frascati 00044 (Italy)
3. Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany)
4. Department of Physics, The John Hopkins University, Baltimore, Maryland 21218 (United States)
5. Institute for Plasma Research, University of Maryland, College Park, Maryland 20742 (United States)

Routine high power operation of the ICRF heating system (up to 3.5 MW at 80 MHz) has enabled studies of enhanced confinement modes as well as high heat flux divertor experiments in the Alcator C-Mod tokamak with toroidal magnetic fields of up to 8 T. H-mode was routinely observed when the edge temperature exceeded a threshold value. Boronization has reduced the radiated power to approximately 30{percent} of the input power, which had little effect on confinement of L-mode plasmas, but had a large impact on the performance of H-mode plasmas. It has become possible to achieve quasi-steady-state H-modes with H{approx_equal}2 and {beta}{sub N}{approx_equal}1.5 simultaneously with P{sub rad}/P{sub in}{approx_equal}0.3 and Z{sub eff}{approx_equal}1.5. PEP mode can be obtained with central ICRF heating combined with core fuelling by pellet injection. Because of the high central density, ion heating becomes the dominant heating channel during PEP mode. For direct electron heating schemes, such as heating by the mode converted ion Bernstein wave, the electron heating profile can be measured using the break-in-slope analysis of the electron temperature at rf power transitions. Mode conversion heating produced highly localized electron heating profiles, both on-axis and off-axis. Recent developments in full-wave codes have improved the agreement between the observed experimental results and the theoretically calculated power absorption profiles and power partition between ions and electrons. {copyright} {ital 1997 American Institute of Physics.}

• Research Organization: Massachusetts Institute of Technology
• DOE Contract Number: AC02-78ET51013
• OSTI ID: 587031
• Report Number(s): CONF-9704102--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 403; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
EXPERIMENT PLANNING
ICR HEATING
MODE CONVERSION
PELLET INJECTION
PLASMA CONFINEMENT
POWER RANGE 01-10 MW
TOKAMAK DEVICES