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XP 521 Ip Rampup with HHFW. C. Kessel. 8/16/05. Goal: Use HHFW heating and/or CD to sustain or rampup Ip from low Te and low Ip ----> necessary part of non-solenoidal Ip startup in an ST Examined Ip = 300, 275, and 250 kA HHFW 14 m -1 heating (2 shots with 7 m -1 co-CD)
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XP 521 Ip Rampup with HHFW C. Kessel 8/16/05 • Goal: Use HHFW heating and/or CD to sustain or rampup Ip from low Te and low Ip ----> necessary part of non-solenoidal Ip startup in an ST • Examined Ip = 300, 275, and 250 kA • HHFW 14 m-1 heating (2 shots with 7 m-1 co-CD) • PHHFW up to 3+ MW, on for as long as 650 ms • Started using CS gas, which helped H-mode access • Used new equlibrium/outer gap control developed in XP527 • Performed 2 shots with OH clamping • Strong H-modes produced, RF trips cause loss of H-mode • Te(0) as high as 2.8 keV, p as high as 1.9 (250 kA) • Negative Vsurf, flat and reversed IOH observed
RF trip 300 kA cases showed entry into H-mode, but dropped out and stayed out after RF trip, even if RF recovers, this is same as previous run day 250 kA cases showed entry and drop out of H-mode, but continues to go into H-mode each time the RF recovers, may be a threshold in PHHFW for this effect OH clamp case mimics best Ip controlled case at 250 kA Vs Wth RF trips for 117605) Vs Wth Ip Wth