| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Dmitri Mossessian |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Gary Dekow |
| Engineering Operator Run Comment |
| MP271 Pedestal Scalings |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:23:757PM |
| Author: To Be Determined |
| Run Summary for Thurs. May 25, 2000 MP# 271 Scaling of Pedestal Parameters SL: Mossessian PO: wolfe EO: Dekow Run Plan: --------- The plan is to carry out the first part of MP271 - scaling of pedestal parameters with plasma current and input power. We'll start with 0.8 MA, 1.0e20 nl01, Bt=5.3T. (shot 1000523008 with ip lowered to 0.8) RF should start at .6 sec with max power (2.5-3 MW) and continue for 0.8 sec, stepping down 0.5MW at 1. sec. We will have 3 shots at 0.8MA with RF varying from 3 MW to 0.5MW. Then repeat the power scan at 0.6 MA, 1MA, 1.2MA and 1.4MA Results: -------- The run started well, but only about 20% of the plan was accomplished. We had 3 shots at 0.8 MA, with nice RF power scan. Going to 0.6MA turned out to be harder then expected. Eventually, we had only one H-mode shot at this current, and it was not very good. Then we decided to go to higher Ip, but an attempt to go to 1.4MA lead to a very dramatic disruption and no plasma shots after that to the end of the day. The net results - good power scan at Ip=0.8MA, showing clearly increase of Te and Pe pedestal height and gradient with input power. Good shots - 2, 4, 6, 13, 14 |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:11:020PM |
| Author: To Be Determined |
| Physics Operator Summary for Thurs. May 25, 2000 MP# 271 Scaling of Pedestal Parameters SL: Mossessian PO: wolfe EO: Dekow Run Plan: --------- Engineering setup: Overnight ECDC stopping at 7:30am. Power system setup as on 1000523006. Gas setup - fill B-top 6 psi of D2 Hybrid enabled fill B-side lower 1 psi of Ar Hybrid DISABLED leave B-side upper as is Hybrid DISABLED fill C-side 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming there are no vacuum problems: VUV ECE DNB disabled We'll start with 0.8 MA, 1.0e20 nl01, Bt=5.3T. (shot 1000523008 with ip lowered to 0.8) RF should start at .6 sec with max power (2.5-3 MW) and continue for 0.8 sec, stepping down 0.5MW at 1. sec. Then we'll proceed as described in MP271 (current and RF power scan) Enabled argon 35ms puff for all shots. Results: -------- Not a good run, although it started off well. We basically only got good data at one current. We had a bad disruption on shot 15 (at 1.4MA) and never got another plasma. RF succeeded in providing 2.8MW top power from D and E antennas We ran with two RF powers per shot, stepping down by 0.5MW at 1sec The first sequence, at 800kA, went pretty well, although we did lose one shot to a runaway density when the TCI dropped out. 600kA gave a lot of problems due to vertical instability at the lower current. We finally succeeded in getting two non-disruptive shots, but the second did not go into H-mode at 1.5MW. The first attempt at 1.4MA resulted in a hard disruption, followed by a series of fizzles. We went back to 1.0MA, so as not to risk more disruptions, but we never got another plasma. The F29 decant flux loop broke on the disruption (big baseline offset, volts of spurious signal during shot). Bob disconnected it from the magnetics patch panel after the run. Ricky's camera showed a remarkable starburst on the disruption. Part of the problem in changing currents was that the CLEARIN needs to be adjusted at each current. For 600ka, it was necessary to make CLEARIN more negative by over 4mm, and using the 1MA settings at 1.4MA resulted in touching the outer limiter. While fighting the fizzles, I set up a zero gain CLEARIN wire in segment 1, and found that an offset value of +12700(a-m) will zero the CLEARIN error. This corresponds to 1.27cm at 1MA, and about 5mm/400Ka, consistent with today's observations. So, my recommendation for future operation is: 1) Put CLEARIN offset to +12700 2) Adjust programmed waveform by new=old+(12700/|Ip|) 3) Tweak to taste It may be safer to do this in small steps, say by starting with a +1000 offset and adjusting the waveform by (1000/|Ip|), and proceeding slowly; it would be bad if I got the sign wrong in a 12mm adjustment. Note that the above expression is in terms of the magnitude of Ip. Lessons learned: ---------------- It is a bad idea to jump to 1.4MA in one go, instead of sneaking up on it. 600kA is trickier than it looks. The problem is that normal elongation gives n/nc very close to the limit and OH1 crossover is delayed to about .5sec, and the resulting thrash in position can make it go vertically unstable. The CLEARIN offset problem noted above is a contributing factor. The CLEARIN offset is large (much larger than it used to be) and seems to be consistent with the current dependence of the gap control. It should be fixed (prescription given above). Shot summary: ------------- Shots#1-6: Ip=800kA (good shots #2,4,6) Shots#7-14:Ip=600kA (good shots #13,14) Shots#15: Ip=1.4MA, disrupted at .63sec Shots#16-23: fizzles Scorecard: ---------- Tests 0 Duds 0 Fizzles 8 Plasmas 15 ------- -- Shots 23 |
| Session Leader Comments | |||
| May 25 2000 09:17:30:547AM | 1000525001 | Dmitri Mossessian | Problems with edge TS (no bias voltages) -> no edge TS. Nice EDA, RF =2 MW, nl01=0.9e20, ip=0.8 MA |
| May 25 2000 09:43:55:827AM | 1000525002 | Dmitri Mossessian | Good shot. RF 2.8 - 2.1 MW, nice edge TS data. Continue RF scan at 0.8 MA, next shot should have RF 1.5 - 1 MW |
| May 25 2000 09:45:35:030AM | 1000525003 | Dmitri Mossessian | Disrupted at .7 sec |
| May 25 2000 10:18:13:297AM | 1000525004 | Dmitri Mossessian | Good shot, RF 1.5 - 1 MW, EDA changes to something like ELM-free after 1 sec, but radiated power does not rise and nl04 stays flat. |
| May 25 2000 10:39:13:200AM | 1000525005 | Dmitri Mossessian | Disrupted - nl04 gone bad. |
| May 25 2000 12:24:57:670PM | 1000525006 | Dmitri Mossessian | Good shot. RF 1 - 0.5 MW. Last shot at 0.8 MA. Thry to go to 0.6 MA now |
| May 25 2000 01:55:10:107PM | 1000525012 | Dmitri Mossessian | Too much RF power - plasma killed by injections. There are a few TS points in short H-mode. Lower RF power for next shot to 2 - 1.5 MW |
| May 25 2000 01:55:41:263PM | 1000525013 | Dmitri Mossessian | Better, but still very lousy H-mode. Lower RF to 1.5 - 1 MW for next shot |
| May 25 2000 02:07:06:827PM | 1000525014 | Dmitri Mossessian | No H-mode. Go to 1.4 MA next |
| Physics Operator Comments | |||
| May 25 2000 07:48:25:810AM | Steve Wolfe | coldstart at 07:45. Matrices respond ok. Note: logbook still thinks current run is 1000524. | |
| May 25 2000 08:15:10:437AM | Steve Wolfe | Setup for shot#1: IMport seg2 from 1000523008 change Ip from 1MA to 800kA, IC_EF4 from 3000A to 2500A Change seg1 TF curr from -150800 to -150000 Change seg2 TF curr from -148000 to -150000, add waggles to -158000 at 0.8,1.0 and 1.2->1.4 shorten Ar puff to 35msec, like yesterday seg 1 pg4 puff to 26msec Load at 25-May-2000 08:14:38.00 | |
| May 25 2000 09:31:32:373AM | 1000525001 | Steve Wolfe | shot#1: enable argon puff. plasma, h-mode looks good. vertical thrash around 0.25, got only 2MW of RF from .6 to 1.3 Wnhd=100kJ. neut=7.5e12 Hesitation in startup, current rise a little slow. next shot: decrease pg4 to 23msec |
| May 25 2000 09:31:19:077AM | 1000525002 | Steve Wolfe | shot#2: decrease pg4 to 23msec. Otherwsise a repeat with more RF Note that Nl4 is set to 0.9e20 instead of 1.0; SL says it's ok. plasma, still has a big thrash at .24-.3 sec, associated with injections. faster current rise in startup. h-mode, eda, big halpha neuts 1e13, wmhd=114 in first part. RF=2.8,2.1 next shot: repeat with lower RF power |
| May 25 2000 10:07:56:623AM | 1000525004 | Steve Wolfe | shot#4: increase ip at 0.1 to 500000 from 450000. decrease zcur3 pgain at .116 from 8 to 6 change first tf waggle from 0.7-0.8 (earlier and shorter); second unchanged (1.2:1.4) plasma No more early thrash. good h-mode, small injection at 1.06s. second h-mode is going elm-free after injection. wmhd=85,65kJ |
| May 25 2000 10:30:18:637AM | 1000525005 | Steve Wolfe | shot#5: increase first tf waggle to 150msec. RF to lower power. disrupted at 1.38- runaway density ? Interferometer died at .345sec. only .35MW of rf, didn't like the high target density. cell access to fix CO2. |
| May 25 2000 11:07:08:780AM | 1000525006 | Steve Wolfe | shot#6: try again for the low rf power point. plasma, h-modes (multiple in second RF step) small thrash at ~.3s, and early injections again. rf=1.0,.6, wmhd=77,55kJ Next shot: go to 600kA. |
| May 25 2000 11:44:06:250AM | 1000525007 | Steve Wolfe | shot#7: go to 600kA; EF4 from 2500 to 1600A rf trying for max power. early disruption. 300msec next shot: slow down zcur ramp (seems to overshoot) start rcur ramp out earlier |
| May 25 2000 11:56:09:000AM | 1000525008 | Steve Wolfe | shot#8: slow down zcur ramp (seems to overshoot) start rcur ramp out earlier still an early disruption. Looks the same. Go back to 800kA and ramp Ip down to 600ka. EF4 to 2000A |
| May 25 2000 12:22:21:810PM | 1000525009 | Steve Wolfe | shot#9: Go back to 800kA shot and ramp Ip down to 600ka, starting at 0.367s. EF4 to 2000A. Shot is identical to #6 until .367sec. Another short disruption! This one made it to .53, still has a vertical problem. Disrupts in crossover, but it seems to be high n/nc that does it. Gaps are bigger, could be a CLEARIN offset problem? Next shot: clearin from -.00975 to -.014, slow down ip rampback |
| May 25 2000 12:55:18:217PM | 1000525011 | Steve Wolfe | shot#10: clearin from -.00975 to -.014, slow down ip rampback Another one! Almost the same. It's getting narrow in crossover. Delay the ip ramp back to 0.4-0.6, slow down the nl4 rise, |
| May 25 2000 01:04:18:090PM | 1000525011 | Steve Wolfe | shot#11: Delay the ip ramp back to 0.4-0.6, slow down the nl4 rise, disrupts at 0.8sec, after an h-mode. looks like an injection this time, maybe from the antenna. outer gap is around 1.9cm, could move it out next shot: rcur from .667 to .669 |
| May 25 2000 01:26:40:780PM | 1000525012 | Steve Wolfe | shot#12: rcur from .667 to .669, try again at 0.6MA disrupted at .82sec again. More bricks. right gap around 1.3cm. It makes it to 80kJ, while it lasts. Try backing down on the power to see if it helps the injections. |
| May 25 2000 01:46:23:140PM | 1000525013 | Steve Wolfe | shot#13: Try backing down on the power to see if it helps the injections. plasma full length. long h-mode with a few injections. RF 2.2,1.5MW Wmhd=70,50kJ Next shot: repeat at lower power |
| May 25 2000 02:05:25:653PM | 1000525014 | Steve Wolfe | shot#14:repeat at lower power plasma, no h-mode with injections. RF=1.4,1.0 Wmhd=40kJ. Next shot: 1.4MA |
| May 25 2000 02:55:39:263PM | 1000525015 | Steve Wolfe | shot#15: 1.4MA, load clearin and rcur from 1000523008, ef4 to 3000A q95 should be around 2.8 if we make it. disruption at .6sec, 1.38MA Looks like the right gap is at zero, I'm getting a coil stress warning on EFCU! Current gain takes a big jump at .5sec, just when I get to full current Next shot: max IP gain delayed from ,5 to .7, drop from 9 to 6 delay max current from .5 to .55 clearin increase by +.004 to -.00575 rcur in by 1mm to .666 |
| May 25 2000 03:03:37:670PM | 1000525016 | Steve Wolfe | shot#16: 1.4MA, max IP gain delayed from ,5 to .7, drop from 9 to 6 delay max current from .5 to .55 clearin increase by +.004 to -.00575 rcur in by 1mm to .666 fizzle. slow current rise, lots of CII .008 zmeter never burns out. Next shot: raise seg 2 ef4 to 3.3kA and try again |
| May 25 2000 03:23:10:937PM | 1000525017 | Steve Wolfe | shot#17: 1.4MA, max IP gain delayed from ,5 to .7, drop from 9 to 6 delay max current from .5 to .55 clearin increase by +.004 to -.00575 rcur in by 1mm to .666 raise seg 2 ef4 to 3.3kA and try again another fizzle CII=.006, bd ~7msec, Bz may be a little positive next shot: pg4 to 21msec; ef4 from -1260-> -1270 |
| May 25 2000 03:43:57:607PM | 1000525018 | Steve Wolfe | shot#18: Still trying 1.4MA, pg4 to 21msec; ef4 from -1260-> -1270 max IP gain delayed from .5 to .7, drop from 9 to 6 delay max current from .5 to .55 clearin increase by +.004 to -.00575 rcur in by 1mm to .666 raise seg 2 ef4 to 3.3kA and try again pg4 to 21msec; ef4 from -1260-> -1270 fizzle. bd at 5.8msec, CII=.004, Ip gets to 44kA at 13msec. Next shot: put pg4 back to 23msec. Go back to 1MA |
| May 25 2000 03:59:09:030PM | 1000525019 | Steve Wolfe | shot#19: punt 1.4MA, go to 1MA and try to get a dataset there; import seg 2 from 1000523008, copy tf and Ar program from today (1.4MA seg is now in segment 3) put pg4 back to 23msec. Still fizzles. CII at .004 and doesn't burn out ICef4 back to -1260. |
| May 25 2000 04:19:19:390PM | 1000525020 | Steve Wolfe | shot#20: ICef4 back to -1260. fizzle drop pg4 to 20msec |
| May 25 2000 04:37:22:937PM | 1000525021 | Steve Wolfe | shot#21: drop pg4 to 20msec PUt zero gain clearin on seg1 wire 4 to check offset Fizzle #7, 47ka and a bounce at 20ms. CII down to .0035, bd at 6msec CLEARIN offset is -12700 |
| May 25 2000 04:52:44:200PM | 1000525022 | Steve Wolfe | shot#22: fields look fine, just try again. Set CLEARIN offset in seg 1 to +12700 (testing sign) fizzle#8, CII down to .003, still bounces The clearin offset should be set to +12700 to avoid current-dependant changes. However, that means the program level needs to be adjusted accordingly. One more try to get back to plasma. |
| May 25 2000 04:54:18:263PM | 1000525022 | Steve Wolfe | shot#23: fields look fine, just try again. Set CLEARIN offset in seg 1 to +12700 (testing sign) fizzle#8, CII down to .003, still bounces The clearin offset should be set to +12700 to avoid current-dependant changes. However, that means the program level needs to be adjusted accordingly. One more try to get back to plasma. |
| May 25 2000 05:16:31:217PM | 1000525023 | Steve Wolfe | shot#23: ef4 from -1260 to -1270. Last try one last fizzle. I hope nothing is broken. CII levels are still slightly elevated, but not that bad. This one bounced little earlier, so maybe the Bz went the wrong way. F29 started having a baseline offset on the disruptive shot; of course, we aren't using it. It has up to 9volts of "signal" on it, so it is definitely broken. Bob will disconnect it from the patch panel so it doesn't put bad signals into the hybrid; it doesn't seem to be saturating. Hopefully, it isn't flying loose. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:55:05:750AM | Plasma | Ok | |
| 2 | 09:19:35:687AM | Plasma | Ok | |
| 3 | 09:41:52:013AM | Plasma | Ok | |
| 4 | 10:01:48:000AM | Plasma | Ok | |
| 5 | 10:22:47:140AM | Plasma | Ok | |
| 6 | 11:01:04:797AM | Plasma | Ok | |
| 7 | 11:22:58:000AM | Plasma | Ok | |
| 8 | 11:46:09:530AM | Plasma | Ok | |
| 9 | 12:09:52:560PM | Plasma | Bad | OH1 Fault |
| 10 | 12:32:53:013PM | Plasma | Ok | OH1 fault |
| 11 | 12:53:50:060PM | Plasma | Ok | |
| 12 | 01:18:43:060PM | Plasma | Ok | |
| 13 | 01:39:18:560PM | Plasma | Ok | |
| 14 | 01:59:45:077PM | Plasma | Ok | |
| 15 | 02:25:19:403PM | Plasma | Ok | |
| 16 | 02:57:40:687PM | Plasma | Ok | |
| 17 | 03:14:53:950PM | Plasma | Ok | |
| 18 | 03:31:54:530PM | Plasma | Ok | |
| 19 | 03:48:50:513PM | Plasma | Ok | |
| 20 | 04:11:53:670PM | Plasma | Ok | |
| 21 | 04:28:04:920PM | Plasma | Ok | |
| 22 | 04:43:19:607PM | Plasma | Ok | |
| 23 | 05:03:41:153PM | Plasma | Ok | |