JET Radiative Mantle Experiments in ELMy H-Mode

Conference · Tue Sep 28 04:00:00 EDT 1999

OSTI ID:12131

Budny, R ^[1]; Coffey, I; Dumortier, P; Grisolia, C; Strachan, J D

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1. Princeton Plasma Physics Laboratory

Radiative mantle experiments were performed on JET ELMy H-mode plasmas. The Septum configuration was used where the X-point is embedded into the top of the Septum. Argon radiated 50% of the input power from the bulk plasma while Z{sub eff} rose from an intrinsic level of 1.5 to about 1.7 due to the injected Argon. The total energy content and global energy confinement time decreased 15% when the impurities were introduced. In contrast, the effective thermal diffusivity in the core confinement region (r/a = .4--.8) decreased by 30%. Usually, JET ELMy H-mode plasmas have confinement that is correlated to the edge pedestal pressure. The radiation lowered the edge pedestal and consequently lowered the global confinement. Thus the confinement was changed by a competition between the edge pedestal reduction lowering the confinement and the weaker RI effect upon the core transport coefficients raising the confinement. The ELM frequency increased from 10 Hz Type I ELMs, to 200 Hz type III ELMs. The energy lost by each ELM reduced to 0.5% of the plasma energy content.

• Research Organization: Princeton Plasma Physics Lab., NJ (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 12131
• Report Number(s): Cfpaper-4057
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
CONFIGURATION
CONFINEMENT TIME
H-MODE PLASMA CONFINEMENT
IMPURITIES
THERMAL DIFFUSIVITY