| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Steve Wolfe |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Sam Pierson |
| Engineering Operator Run Comment |
| MP#580 Comparison of Type I ELM access and characteristics in He4 and D |
| Session Leader Plans |
| Entered: Dec 15 2009 03:37:23:313PM |
| Author: Steve Wolfe |
| Session Leader Plan for Friday, Dec 18, 2009
MP#580 Comparison of Type I ELM access and characteristics in He4 and D plasmas in C-Mod SL: wolfe PO: Marmar The goal of this experiment is to produce type I ELMy H-mode discharges in helium plasmas and, if successful, compare ELM behavior with similar discharges in D2. We will be operating in the modified JFT2-M shape as on 1090914016 (900kA, nl04=4e19), which exhibited strong ELM behavior in D. This will be the first attempt at producing Helium ELMy H-modes in C-Mod. I'll be happy if we just get an existence proof, but if possible we'll document some scalings. Note that this experiment would probably benefit from a more recent boronization (last was before 1091210), but there will have been mostly ohmic runs since then, so it may be ok. Step 6 will help evaluate the suitability of the wall conditions by comparison with 1090914016. -------------- Preparation: -------------- Overnight ECDC in He4, P=5e-5 Torr. sweep: 44/45/103 cm scan: 20/120 s ----------------- Engineering Setup ----------------- Run begins at 09:00 and ends at 17:00 Power systems as on: 1090914016 Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled Gas setup: NOTE non-standard setup! Fill B-Top with 6 psi He4 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill B-main (C-side) with 40 psi He4 Hybrid enabled (PG3) fill H-bot with 2psi Ne, Hybrid DISABLED fill NINJA with 10 psi He4 DISABLED Enable gatevalves and shutters: ECE, VUV, B-spectrometer, HiREX Sr, Z-bolo Torvac gatevalve toggle (yes/no):NO Boronization(yes/no): no Overnight ECDC (yes/no): Yes ICRF(yes/no): Yes D,E, J LH(yes/no): no Cryopump (yes/no): no Vessel temperature: 35/35/35 Session Leader Plan: -------------------- 1. Establish shot based on 1090914016 (900kA, nl04=4e19,"JFT2-M shape" in helium. Bring up RF power, de-deuterize antenna and walls. [4-6 shots] 2. Look for ELMs. Vary power, density, shaping (esp. lower triangularity, elongation), current, in order to provoke ELMs in helium. If Prad seems to be a problem, try neon puffing from H-bottom. If unsuccessful after sufficient effort, skip to step 6 to verify presence of ELMs in D plasmas [1-15 shots] 3. If ELMs are obtained, determine power threshold, frequency vs power scaling, using staircase RF waveform. Also bracket L-H threshold in ELMy shape. Turn on argon for HIREX, evaluate effect on ELMs, if acceptable leave on for Ti, rotation documentation. Allow NINJA He puff for GPI camera.[4 shots] 4. If not already done during step 2, scan density (collisionality) [5 shots] 5. If not already done, and time permits, scan current (q95), e.g. down to 650kA up to 1.1MA [3 shots] 6. Beginning no later than 15:00, changeover to D plasma, monitoring change (or appearance of) ELM behavior. Monitor changeover watching HeII signal, neutrons. (4-10shots) 7. Document comparison of "best" ELM conditions from helium (if any) and similar configuration in D. If no pure He example was produced in step 2, then verify existence in D. [1-4 shots] |
| Physics Operators Plans |
| Entered: Dec 18 2009 12:23:48:557PM |
| Author: Earl Marmar |
| load from 1090914016
zero segments 3 and 4 recalculate all magnetics predictors in segment 2 import segment 1 from 1091217021 into segment 1 reduce prefill puff to 25 msec (He startup) The alternator has a problem and will not operate today, so the run has been scrubbed. |
| Entered: Dec 18 2009 12:25:00:823PM |
| Author: Earl Marmar |
| see session leader plan
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| Session Leader Summaries |
| Entered: Dec 18 2009 10:16:49:543AM |
| Author: Steve Wolfe |
Run 1091218 has been cancelled due to required repair on the alternator drive system. THIS CONCLUDES OPERATION FOR CALENDAR YEAR 2009 See you next year, folks. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| Dec 18 2009 09:01:18:230AM | 1091218001 | Steve Wolfe | We are experiencing a delay in starting run 1091218 because of an alternator problem transferring to speed 3. Delay will probably be at least an hour. |
| Dec 18 2009 09:29:36:760AM | 1091218001 | Steve Wolfe | Run 1091218 has been cancelled due to required repair on the alternator drive system. THIS CONCLUDES OPERATION FOR CALENDAR YEAR 2009 See you next year, folks. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
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