METHANE PENTRATION IN DIII-D ELMing H-MODE PLASMAS

Conference · Sat Jun 01 04:00:00 EDT 2002

OSTI ID:804697

WEST, W P ^[1]; LASNIER, C J; WHYTE, D G; ISLER, R C; EVANS, T E; JACKSON, G L; RUDAKOV, D L; WADE, M R; STRACHAN, J

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1. General Atomics

Carbon penetration into the core plasma during midplane and divertor methane puffing has been measured for DIII-D ELMing H-mode plasmas. The methane puffs are adjusted to a measurable signal, but global plasma parameters are only weakly affected (line average density, <n{sub e}> increases by < 10%, energy confinement time, {tau}{sub E} drops by < 10%). The total carbon content is derived from C{sup +6} density profiles in the core measured as a function of time using charge exchange recombination spectroscopy. The methane penetration factor is defined as the difference in the core content with the puff on and puff off, divided by the carbon confinement time and the methane puffing rate. In ELMing H-mode discharges with ion {del}B drift direction into the X-point, increasing the line averaged density from 5 to 8 x 10{sup 19} m{sup -3} dropped the penetration factor from 6.6% to 4.6% for main chamber puffing. The penetration factor for divertor puffing was below the detection limit (<1%). Changing the ion {del}B drift direction to away from the X-point decreased the penetration factor by more than a factor of five for main chamber puffing.

• Research Organization: GENERAL ATOMICS (US)
• Sponsoring Organization: (US)
• DOE Contract Number: AC03-99ER54463
• OSTI ID: 804697
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
CARBON
CHARGE EXCHANGE
CONFINEMENT TIME
DIVERTORS
DOUBLET-3 DEVICE
METHANE
PLASMA
RECOMBINATION
SENSITIVITY
SPECTROSCOPY