| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Steve Golovato |
| Physics operator(s): | Yuichi Takase |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| RF |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:09:507PM |
| Author: To Be Determined |
| Run Summary - 931027 - ICRF Heating ----------------------------------- Run Goals: We will first establish our previous conditions, then we will start lithiumization in hopes of reducing radiation losses so we can see heating. We also want to lower density and puff H2 to get stronger CX signal to look for a minority hydrogen tail. Antenna at 94cm, limiter at 93cm. Tuning from shot 931027026, ST at 353, PS at 642. ICRF at low level throughout shot, level high at start to assist breakdown and from 450-750ms. At 450 it ramps to full power for 50ms and it ramps down at 700 for 50ms. Started with shot 931020026, a good shot from our last run. 001 - fizzle. rf off. 002 - Good plasma. rf on. 400kw on first try. no density rise, no dip in Te, maybe evn a slight rise if you're a believer. 003 - power raised to aboput 500kw, disrupted at 670ms. lithium pellet at 400ms. density goes to 1.7e20 with pellet. disrupted after density recovered. 004 - two lithium pellets this time at 400,500ms. a little lower power. disrupted at 520ms, as rf power peaks and second pellet density rise occurs. 005 - three lithium pellets at 350,420,490ms, rf starting up at 500ms, peaking at 550ms. another early disruption, at 425ms. caused by second pellet, rf not on yet. 006 - two pellets, large at 350, small at 420ms. rf at two levels. disrupted at 495, before rf. 007 - one pellet at 400ms. adding back late gas puff. Good shot. Disrupted at 850ms. Evidence of tail on CX with density kept low. 008 - puff H2 at 400ms for 50ms. more power in second level. Fizzle, late breakdown. 009 - lower fill. dud. 010 - try again. Good shot, no disruption. rf power lower, 400-500kw. 011 - fizzle. 012 - higher power, more H2, less D2 puff to reduce density. adding second pellet after rf at 800ms. adjusting Bz at breakdown. good shot but disrupted at 625ms when rf power is at highest value. 013 - ran but disrupted again at 615ms. 014 - rf power varies as loading variations change match to transmitter. changing pulse shape a little to try to compensate for this. dsirupted at 645ms this time. 015 - keep power around 500kw, trying to avoid disruptions. density dropping during rf, may lead to disruptions. disrupted at end of rf pulse. 600kw power. 016 - rf in two pulses, lower power. good shot, no disruptions. no pellet 017 - lower power rf and three pellets. disrupted at 680ms, after third pellet change match, rf power shot up to 300kw. 018 - no pellets. rf power up. disrupted early, at 670ms, 600kw. 019 - trying for about 500kw. disrupted at 715ms, at end of second rf pulse. second pulse higher power because of better match at lower density. evidence of H tail out to 20kev during second pulse. 020 - shorten second pulse and lower power slightly to try to avoid disruption. disrupted after rf, 820ms. 021 - repeat with CX set to Deuterium. good shot, disrupted after 1 sec. somewhat ragged shot. 022 - no H2 puff. CX back to H. another late disruption. 023 - adding third rf pulse at lower power. good shot, no disruptions. moly event at 400ms, just before first rf pulse. 024 - early disruption at 500ms, end of first rf pulse. 025 - good shot. density rises, Te dips at each rf pulse. density rise typical at lower density. 026 - disrupted at end of second rf pulse. H2 puff back. 027 - power scan for cx data. p=200kw (-2v). dud. 028 - try again after raising fill, tweaking Bz down at breakdown. fizzle. tf fault. 029 - good shot. problem with tf supply, may need correctig. 030 - good shot. p=300kw (-2.1v) 031 - p=400kw (-2.2v) fizzle. 032 - fizzle. 033 - fizzle. 034 - Br problems. reloaded shot 29 and changed Br offset back to previous value. also halved H2 puff length, lower H concentration. Plasma, disrupted at 550ms. 035 - good shot. disrupted after 1 sec. 036 - No rf shot. lithum pellet at 800 ms. longer H2 puff, as before shot 34. Post-run Comments: Basically a pretty good run. We went immediately to high power on the first rf shot (002) and had reliable transmitter operation throughout. We did cause disruptions with rf either when the power approached 600kw or when the density was low (nl<4.e19). We ran with lithium pellets but saw no obvious improvement in rf performance, although the wall recycling did seem to be effected, as evidenced by lower density operation without reduced puffing. Trying to get three pellets and a reasonably long rf pulse into the 400-850ms usable flattop proved difficult without disrupting. Though we had numerous disruptions, there was little problem recoverong from them without the need for adjustments in gas. The biggest result of the run was the evidence of absorption of rf by the minority hydrogen, as seen in the charge exchange data out to 20 kev. We could see the H2 puff in the CX signal without rf and saw the signal rise particularly in the high energy channels with rf. We did rough power and H2 puff scans. The scans are made difficult because the density was not very reproducible and the cx signal is very density dependent. There is still no evidence of increased energy content or electron heating. Typically there is a density rise and corresponding Te decrease during rf. The rf effects on density and impurity radiation do not always seem linear in power but seem to depend on when in the shot the rf is applied. The first rf pulse always has the biggest impact, even if it is not at the highest power. Another important result was the observation on H-mode at the end of several shots, after the rf pulses. Shot 29 showed all of the symptoms of our previous ohmic H-modes at 5T. This data point did not appear to fit the ASDEX scaling. The last shot had an elming H-mode into which we fired a lithium pellet. We had plasma on 27 of 36 shots, with several lost to power supply problems. We had rf assist on all but the first and last shots. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:50:600PM |
| Author: To Be Determined |
| Physics Operator's Summary RF Heating Run (mostly Li pellet and Charge Exchange) SL: Golovato PO: Takase EO: Bertolino 2 hrs of D2 ECDC prior to run D2 fill and puff from A-side H puff from B-side-upper shot 001 fizzle loaded 931020026, D only, fill=1.4e-5 002 plasma fill=1.3e-5, rf on, nice shot 003 plasma lowered A-side puff 1 Li pellet @ .4, disrupt @ .67 004 plasma 2 Li pellets @ .4 and .5, disrupt @.51 005 plasma lowered A-side puff 3 pellets @ .35, .42, .49, disrupt @ .44 006 plasma 2 pellets @ .35, .42(small), disrupt @ .5 (before rf) 007 plasma raised late D puff, 1 pellet @.4, sign of H tail? 008 fizzle H puff from B-side-upper on (60V for .05) 009 dud fill=1.2e-5 010 plasma fill=1.3e-5, 1 pellet @ .4, good shot, nel_05 = 7 - 8 during rf, very little H flux 011 fizzle increased H puff (70V for .05), lowered later D puff to 30V 012 plasma changed EF4 from -1030 to -1040A nel_05 = 6 - 4 during rf, more H flux saw a projectile after disruption 013 plasma move H puff earlier to .35s (was @ .4), disrupted @ .62 014 plasma raised later D puff to 35V, disrupted @ .65 015 plasma raised later D puff some more, got flat density disrupted @ .71 (end of rf) 016 plasma move H puff earlier to .3s, good shot, no Li pellet 017 plasma 3 Li pellets, disrupt @ 3rd pellet .67s 018 plasma no pellet, disrupt @ .67 019 plasma no pellet, CX tail up to 20kV, disrupt @ .72 020 plasma good shot, rising density, large sawteeth, lasted till .83 021 plasma good shot, steady density, CX looking at D. lasted till 1.04 022 plasma H puff off, rising density 023 plasma H puff off, decreased D puff, density still rising 024 plasma H puff off, decreased D puff to 30V (too low?), disrupt @ .51 025 plasma H puff off, increased D puff, density rising 026 plasma H puff on, decreased D puff, disrupt @ .67 027 dud H puff on, Bz too positive 028 fizzle changed EF4 to -1050A, raised fill to 1.4e-5 029 plasma raised B_R by 1mT, lowered fill to 1.3e-5, H-mode after rf having TF power supply problems (since shot 027) 030 plasma lowered D puff again 031 fizzle back to 029 D puff programming 032 fizzle lowered B_R by .5mT (got -2mT!?) 033 fizzle raised B_R by 1mT B_R going wild (+7mT @ .03 then -5mT @ .05) 034 plasma loaded shot 029, but with B_R offset -2.5mT (from shot 002) H puff 70V for .02, disrupted @ .55 035 plasma repeat, good shot, H-mode 036 plasma H puff 70V for .05, no rf, Li pellet at the end, H-mode Loaded 931020026 (last rf shot on last rf run) RF on from shot 002 (no rf on 001 and 036) Li pellet on from shot 003 to shot 017 H puff started on shot 008 (no H puff 001 to 007 and 022 to 025) "H-mode" on shots 029, 035, 036 We had some unpredictable irreproducibility in B_z and B_R by about 2mT, which resulted in a number of fizzles and duds (I don't think they were caused by inappropriate fill pressures). RF was on for start-up assist on all shots except 001 and 036 (one of which was a fizzle). While it is certainly not perfect and cannot guarantee success, and is not needed when things are going well, I do believe that RF helps when the plasma initiation condition is marginal. If you do a statistical analysis of rf-assisted vs. non-rf-assisted shots, I think you will agree. dud 2 fizzle 7 plasma 27 ---------- total 36 |
| Session Leader Comments |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:01:17:050AM | Plasma | Ok | no faults |
| 2 | 09:16:40:660AM | Plasma | Ok | no faults |
| 3 | 09:33:45:460AM | Plasma | Ok | no faults |
| 4 | 09:49:44:610AM | Plasma | Ok | no faults |
| 5 | 10:08:51:430AM | Plasma | Ok | no faults |
| 6 | 10:27:34:530AM | Plasma | Ok | no faults |
| 7 | 10:41:46:170AM | Plasma | Ok | no faults |
| 8 | 11:00:22:570AM | Plasma | Ok | no faults |
| 9 | 11:13:09:350AM | Plasma | Ok | no faults |
| 10 | 11:34:10:420AM | Plasma | Ok | no faults |
| 11 | 11:51:23:640AM | Plasma | Ok | no faults |
| 12 | 12:06:58:690PM | Plasma | Ok | no faults |
| 13 | 12:24:57:680PM | Plasma | Ok | ps,s ok plasma |
| 14 | 12:39:54:780PM | Plasma | Ok | no faults |
| 15 | 12:54:35:870PM | Plasma | Ok | no faults |
| 16 | 01:12:37:700PM | Plasma | Ok | no faults |
| 17 | 01:28:01:870PM | Plasma | Ok | no faults |
| 18 | 01:43:06:910PM | Plasma | Ok | no faults |
| 19 | 01:59:30:980PM | Plasma | Ok | no faults |
| 20 | 02:14:34:300PM | Plasma | Ok | no faults |
| 21 | 02:30:54:640PM | Plasma | Ok | no faults |
| 22 | 02:52:10:020PM | Plasma | Ok | no faults |
| 23 | 03:07:44:010PM | Plasma | Ok | no faults |
| 24 | 03:23:12:410PM | Plasma | Ok | no faults |
| 25 | 03:38:15:930PM | Plasma | Ok | no faults |
| 26 | 03:54:46:780PM | Plasma | Ok | no faults |
| 27 | 04:16:33:280PM | Plasma | Ok | tf comm fail very late in the shot -- after plasma |
| 28 | 04:48:46:760PM | Plasma | Bad | tf comm fault -- only one fault board indicated, suspect bad board |
| 29 | 05:05:08:900PM | Plasma | Ok | tf still shows signs of a problem but highpots ok |
| 30 | 05:31:25:200PM | Plasma | Ok | no faults -- tf ok this shot |
| 31 | 05:46:04:460PM | Plasma | Ok | no faults |
| 32 | 05:58:59:370PM | Plasma | Ok | no faults |
| 33 | 06:14:12:060PM | Plasma | Ok | no faults |
| 34 | 06:31:47:320PM | Plasma | Ok | no faults |
| 35 | 06:45:34:550PM | Plasma | Ok | comm faults pf supplies due to disruption |
| 36 | 07:02:18:880PM | Test | Bad | |