| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Spencer Pitcher |
| Physics operator(s): | Ron Parker |
| Engineering operator(s): | Bill Cochran |
| Engineering Operator Run Comment |
| MP #262 (CONT'D) The Effect of Main Chamber Recycling on H-Mode Confinem |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:24:553PM |
| Author: To Be Determined |
| MP 262 The Effect of Main Chamber Recycling on H-mode Confinement SL S Pitcher PO R Parker This run follows from 1000511, where we performed a left gap scan with fixed right gap. Initial Discharges: Left gap scan, 800 kA, nl04 = 1.0, 5.4 T, D and E antenna power ramps, right gap fixed at approx 15 mm, fixed Xpt geometry. We will first touch base with the results from 1000511 (i.e. left gaps, 2.0, 1.0, 0.3 cm). Determine the threshold powers. Following this will will run discharges on the inner wall and shot by shot push the effective left gap to negative values looking for the effect of threshold power. If time permits we will explore the effect of varying the right-gap on threshold power. Results: A very frustrating day! Slow to get started, problems with arcing on D antenna, general power failure, etc. The thresholds we found more or less fell on top of the data from 1000511. The discharges with lgap = 0.0 and negative did not show a convincing H-mode transition. We were hampered by problems with the RF traces, which were not always accurate. They need to be double checked. Conclusion: Unfortunately, we still cannot say what the H-mode threshold power is in a inner wall limited discharge. -------------------------------------------------------------- Shot by shot notes: ******** shot 3 right gap too large >>>> reduce next shot no H-mode ******** shot 4 gaps are reasonable RF problem....no H-mode ******** shot 5 RF a little ratty H-mode lgap = 1.4 cm ******** shot 6 RF problem no H-mode lgap = 1.4 cm ******** shot 7 no plasma ******** shot 8 no H-mode ******** shot 9 no H-mode ******** shot 10 no H-mode ******** shot 11 no H-mode ******** shot 12 increase right gap to rgap = 1.5 cm H-mode!...faults stopped on D antenna! clearly we should not have reduced the right gap before! ******** shot 13 no plasma ******** shot 14 H-mode! problem with RF signals ******** shot 15 reduce lgap....lgap = 0.5 cm (actually, it looks like we attempted to increase lgap) disrupt t = 0.45 s ******** shot 16 reduce lgap....lgap = 0.5 cm good shot H-mode problem with RF signals ******** shot 17 reduce lgap....lgap = 0.0 cm no H-mode problem with RF signals estimated max RF power was 2.0 MW ******** shot 18 reduce lgap....lgap = 0.0 cm no plasma RF signals for shots 14-17 now look fixed ******** shot 19 reduce lgap....lgap = 0.0 cm H-mode! RF signals suspect! ******** shot 20 reduce lgap....lgap = -0.5 cm no H-mode! RF signals suspect! ******** shot 21 lgap = -0.5 cm no H-mode! RF signals suspect! |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:11:520PM |
| Author: To Be Determined |
| Run Plan and Engineering Setup for 1000627 MP262 (CONT'D) The Effect of Main Chamber Recycling on H-Mode Confinement Session Leader: S. Pitcher Physics Operator: R. Parker Engineering Operators: B. Cochran Engineering Setup: Overnight ECDC in D2, stopping 2 hours before run. Run begins at *** 8:00 *** NOTE!!! and ends at 16:00. Power system setup: Same as for 1000511001 Set OH1, OH2U and OH2L fizzle delays at 300ms Set TF fizzle delay at 400 ms Gas setup: B-Top 6 psi D2 Hybrid Enabled B-side lower 1 psi Argon Hybrid DISABLED B-side upper leave as is Hybrid DISABLED C-side 30 psi D2 Hybrid Enabled J-bottom leave as is Hybrid DISABLED The following Gate Valves should be ENABLED, assuming no vacuum problems: ECE, VUV DNB gate valve should be DISABLED RF Setup: RF should ramp from 0.4 MW @ t=0.55 s to 2.0 MW @ t=1.1 s Higher total power at same ramp rate will be requested as run proceeds. Only D&E antennas will be required. Run Plan: This run continues the program initiated on 1000511, where a left gap scan with fixed right gap was performed and the effect on H-Mode confinement properties was investigated. Initial discharges will be setup for a left gap scan @ 800 kA, n104=1.0, B=5.4 T, RF setup as described above, and right gap fixed at approximately 15 mm, with fixed X-point geometry. We will first touch base with results from 1000511 run (left gap scan: 2.0, 1.0, 0.3 cm). The threshold powers will be determined. Then, we'll run discharge on the inner wall and effectively push the left gap to negative values, again looking for the effect on threshold power. If time permits, we will explore the effect of varying the right gap on the threshold power. Run Summary The run started auspiciously with two duds on the first two shots. These were mainly due to a low fill pressure (0.045 - 0.05 mT), even though the pulse length was 20-22 msec. After increasing up to 26 msec, the fill pressure rose to about 0.065 mT and normal breakdown and startup were obtained. Thereafter, there was no further problem with breakdown, although two fizzles were encountered. These fizzles seem to have more to do with the EF4 current than fill pressure, although the fill pressure can be used to control the rate of ramp of the current relative to that of the EF field. Unfortunately the RF did not perform reliably today, which gave difficulty in reaching the goals of the run plan. Thus shots 4-11 were programmed identically but failed to produce good data because of RF trips. In retrospect at least part of the RF problem was due to setting the right gap to 1 cm, which has presented coupling problems in the past. In shot 12, the right gap was increased by 0.5 cm, and the RF responded favorably, although the plasma remained disruptive. After shot 12, there was a brief power interruption which caused the UPS to cut in. The delay caused by this event lasted over 1 hour. Shot 13 was then a no-power shot, and plasma operation resumed with shot 14, which ran normally except without the magnetics data. For shot 15, the inner gap was supposed to be reduced from 1.5 to 0.5 cm, but the PO blundered and actually increased the gap by 1 cm instead. This error was corrected by S. Wolfe, who took over for R. Parker for the remainder of the run. Shot 16 ran with the desired inner gap and shot 17 was setup for the inner gap =0. The discharge ran, but disrupted. The settings for shot 18 were tweaked in an effort to improve startup and limited operation, but alas shot 18 was a fizzle. On further inspection, Steve noticed that EF1U was not following its demand, a pathology that was also observed yesterday. Trying to compensate for this with EF4 probably led to the fizzle. After engineering inspection and some tweaking of a pot, EF1U behaved and the rest of the shots (19-21) at least started up normally. Shot 20 was full length, but without H-mode, and shots 19 and 21 disrupted. A small bug was found in the clearin program waveform, namely setting a point at -0.00000 causes it to disappear. This is easily avoided by adding a nonzero digit after several zeros, but should be fixed. Overall a disappointing run: 21 shots, 2 duds, 2 fizzles, 1 no power, and 8 disruptions. |
| Session Leader Comments | |||
| Jun 27 2000 09:00:09:780AM | 1000627003 | Spencer Pitcher | right gap too large >>>>>> reduce next shot no H-mode |
| Jun 27 2000 09:33:39:670AM | 1000627004 | Spencer Pitcher | gaps are reasonable RF problem....no H-mode |
| Jun 27 2000 09:34:03:937AM | 1000627005 | Spencer Pitcher | RF a little ratty H-mode lgap = 1.4 cm |
| Jun 27 2000 10:52:28:607AM | 1000627006 | Spencer Pitcher | RF problem no H-mode lgap = 1.4 cm |
| Jun 27 2000 10:52:46:547AM | 1000627007 | Spencer Pitcher | no plasma |
| Jun 27 2000 10:53:01:840AM | 1000627008 | Spencer Pitcher | no H-mode |
| Jun 27 2000 10:53:17:153AM | 1000627009 | Spencer Pitcher | no H-mode |
| Jun 27 2000 01:53:19:467PM | 1000627010 | Spencer Pitcher | no H-mode |
| Jun 27 2000 01:53:29:310PM | 1000627011 | Spencer Pitcher | no H-mode |
| Jun 27 2000 01:53:51:747PM | 1000627012 | Spencer Pitcher | increase right gap to rgap = 1.5 cm H-mode!...faults stopped on D antenna! clearly we should not have reduced the right gap before! |
| Jun 27 2000 02:00:31:983PM | 1000627013 | Spencer Pitcher | no plasma |
| Jun 27 2000 01:54:41:390PM | 1000627014 | Spencer Pitcher | H-mode! problem with RF power signals |
| Jun 27 2000 01:55:38:263PM | 1000627015 | Spencer Pitcher | reduce lgap....lgap = 0.5 cm (actually, it looks like we attempted to increase lgap) disrupt t = 0.45 s |
| Jun 27 2000 02:44:27:000PM | 1000627016 | Spencer Pitcher | reduce lgap....lgap = 0.5 cm good shot H-mode problem with RF signals |
| Jun 27 2000 02:44:51:827PM | 1000627017 | Spencer Pitcher | reduce lgap....lgap = 0.0 cm no H-mode problem with RF signals estimated max RF power was 2.0 MW |
| Jun 27 2000 04:05:21:403PM | 1000627018 | Spencer Pitcher | reduce lgap....lgap = 0.0 cm no plasma RF signals for shots 14-17 now look fixed |
| Jun 27 2000 04:05:34:420PM | 1000627019 | Spencer Pitcher | reduce lgap....lgap = 0.0 cm H-mode! RF signals suspect! |
| Jun 27 2000 04:05:53:000PM | 1000627020 | Spencer Pitcher | reduce lgap....lgap = -0.5 cm no H-mode! RF signals suspect! |
| Jun 27 2000 04:06:17:827PM | 1000627021 | Spencer Pitcher | lgap = -0.5 cm no H-mode! RF signals suspect! |
| Physics Operator Comments | |||
| Jun 27 2000 08:18:36:140AM | 1000627001 | Ron Parker | Shot 1 was a dud. Startup settings were the same as 100062601. The gas pressure was a little low (~.045 mT) and will be increased for the next shot. |
| Jun 27 2000 08:33:58:607AM | 1000627002 | Ron Parker | Shot 2 was also a dud -- pressure may be still too low, although it was increased to 0.05 mT. The pulse gas duration will be increased by 4 ms on the next shot. Also BR offset (-.0002 T) will be eliminated. |
| Jun 27 2000 08:57:35:750AM | 1000627003 | Ron Parker | Shot 3 finally ran, with initial fill ~0.06 mT. However, it disrupted at ~ 1.15 s. In the next shot, the right gap, which was 2.2 cm, will be reduced toward 1 cm. This will be done by holding the inner gap constant at ~ 1.5 cm and increasing RCUR by 7 mm. Pulsed gas width decreased for next shot from 27 to 25 ms. |
| Jun 27 2000 09:14:34:937AM | 1000627004 | Ron Parker | Shot 4 ran as programmed. The initial fill pressure is drifting up and was ~ 0.07 mT for this shot. The fill pulse width will be reduced by 2 more msec for the next shot. Also there was a 3-4 mm drift in the right gap, which we will try to compensate for on next shot. There was a pretty strong Marfe during current rise, which we'll try to mitigate by reducing rate of density rise. Next Shot: repeat with above changes. |
| Jun 27 2000 09:33:08:750AM | 1000627005 | Ron Parker | Shot 5 ran well, with the early Marfe mitigated and right gap stabilized. No change for next shot (except -1 msec on gas pulse width) so RF can tune. E port seems to be OK but D is tripping out. |
| Jun 27 2000 10:03:34:717AM | 1000627006 | Ron Parker | Shot 6 ran well, no changes for next shot. |
| Jun 27 2000 10:11:19:340AM | 1000627007 | Ron Parker | Shot 7 was a fizzle due to late ( 8 msec) breakdown. Next shot: same thing, but increase pressure (2 ms on width) and go to 1290 on EF4 (from 1280) |
| Jun 27 2000 10:26:43:340AM | 1000627008 | Ron Parker | Shot 8 came back. Today, the pressure seems to want to be > 0.06 mT. RF (D port) still having problems and there will be no changes for next shot. |
| Jun 27 2000 10:59:38:483AM | 1000627009 | Ron Parker | Shot 9 ran well, but breakdown became late (no apparent reason). Slightly less (-1295 to -1290 A) on EF4, otherwise no changes for next shot. |
| Jun 27 2000 11:35:49:340AM | 1000627010 | Ron Parker | Shot 10 ran well, except it disrupted. Still problems with RF. No changes for next shot. |
| Jun 27 2000 11:33:24:607AM | 1000627011 | Ron Parker | Shot 11 ran well, except it disrupted again. For next shot, right gap will be increased by ~ 5mm. |
| Jun 27 2000 11:54:36:107AM | 1000627012 | Ron Parker | Shot 12 ran as programmed, but again disrupted. Shortly after the shot, there was a brief interuption of power with transfer to the UPS (at ~ 11:45). |
| Jun 27 2000 01:03:02:577PM | 1000627013 | Ron Parker | Delay lasted ~ 1hour. We will rerun last shot to reestablish plasmas. This was a no power shot. Repeat shot on shot 14. |
| Jun 27 2000 01:37:01:653PM | 1000627014 | Ron Parker | Shot 14 ran well, even after the long delay, but no magnetics. For next shot, the inner gap will be reduced by 1 cm (from 1.5 to 0.5 cm). The right gap will be held at the same value (RCUR decreased by 0.5 cm). |
| Jun 27 2000 03:58:58:700PM | 1000627015 | Ron Parker | For this shot, the inner gap was reduced by 1 cm and RCUR was reduced by 5 mm, thus the outer gap should have stayed constant. Steve Wolfe takes over as PO. |
| Jun 27 2000 02:04:13:000PM | 1000627016 | Steve Wolfe | wolfe taking over for parker. Thanks for the disruption Ron! Looks like the previous adjustment went the wrong way. Clearin to -.022, rcur to .661 drop pre-puff by 1msec plasma, full length, but rf faulted. got an h-mode at 0.8sec left gap~ 6-7mm, right gap~1.8cm |
| Jun 27 2000 02:29:20:013PM | 1000627017 | Steve Wolfe | shot 17: go for zero left gap clearin more negative by 7mm, reduce early times by 8mm rcur more negative by 3mm breakdown was a little late on 16, but leave it for now disruption at 1.17sec, no h-mode. looks like an injection 1.098sec left gap between .4 and 0cm, right gap around 2cm next shot, try for better limited before .8 sec, a little smaller outer gao. |
| Jun 27 2000 02:58:30:390PM | 1000627018 | Steve Wolfe | shot 18: 2mm more negative on clearin before .8sec, 1mm more POSITIVE on rcur icef4 from -1297->-1305; 1msec less pre-puff. I'm tempted to make Br0 more positive, but leave it for now fizzle. Did I tweak too soon? early bd 5.3ms, faster current rise 45kA@15msec. Bz may now be too negative. Raise the fill 2msec and repeat Wait, EF1U is not following its demand again. Less bad than yesterday, maybe 50V of lossage, but it isn't quite making it to current |
| Jun 27 2000 03:19:18:797PM | 1000627019 | Steve Wolfe | shot 19:It looks like the EF1U problem was worse on 17 than on 18. I'm going to assume they have fixed it, and put the ef4 back to -1297. leave increase in gas by 2ms. disrupted, 0.8sec h-mode at .77sec, lgap and dsep ~0.00 next shot, try for -1cm |
| Jun 27 2000 04:06:05:577PM | 1000627019 | Steve Wolfe | There seems to be a corrupted point in the clearin trace in segment 2 on shot #19. The plasma ran ok, but I was unable to edit the clearin trace for the next shot. The symptom is a gap in the trace when displayed in all-p's or edit_wire. I also see invalid arithmetic op in the decterm output, so it may have a NaN in it. |
| Jun 27 2000 04:39:34:903PM | 1000627019 | Steve Wolfe | On shot 19, I accidentally put in a spurious point at time .792 of "-0.0" in the CLEARIN trace. This seems to have been interpreted 'correctly' by the waveform generator, and caused the plasma to come off the wall, which was observed just before the disruption. The RF power and other signals also responded, as noted by CSP, before the putative H-mode transition on this shot. Apparently the -0 bug that Josh thought he had fixed is still there in PCS, and this is why I subsequently had a gap in the waveform. |
| Jun 27 2000 03:47:59:483PM | 1000627020 | Steve Wolfe | shot 20: Something wrong in the PCS CLEARIN trace. Can't change values with add. Reload from 1000627019. Same problem, it shows up as a gap in the waveform. quit pcs and start again. Still there, something is corrupted. reload from shot 17 and try to fix up clearin to -.041, rcur from .659(on 19) to .657 dnb will fire, reduce puff to 18msec plasma, (it's a miracle!). Full length, no h-mode dsep =-1, right gap ~2.3cm |
| Jun 27 2000 04:03:30:500PM | 1000627021 | Steve Wolfe | shot 21: Move rcur out 2mm to .659, zxu from .058 to .04 I don't see the dnb puff, set pre-puff back to 21msec disrupted, 1.3sec. no h-mode. right gap at 1.9cm, may have still been too big. D faulted, max power of 1.5MW. Elongation did not increase, dsep around -0.8cm |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:03:10:670AM | Plasma | Ok | |
| 2 | 08:21:53:390AM | Plasma | Ok | |
| 3 | 08:38:24:607AM | Plasma | Ok | |
| 4 | 08:57:36:170AM | Plasma | Ok | |
| 5 | 09:17:32:903AM | Plasma | Ok | |
| 6 | 09:37:53:340AM | Plasma | Ok | |
| 7 | 10:00:00:810AM | Plasma | Ok | |
| 8 | 10:16:28:903AM | Plasma | Ok | |
| 9 | 10:37:19:077AM | Plasma | Ok | |
| 10 | 10:58:47:090AM | Plasma | Ok | |
| 11 | 11:19:47:123AM | Plasma | Ok | |
| 12 | 11:40:23:327AM | Plasma | Ok | |
| 13 | 12:53:10:077PM | Plasma | Bad | Igor failure during Init, shot cont'd without power |
| 14 | 01:14:51:623PM | Plasma | Ok | |
| 15 | 01:41:58:543PM | Plasma | Bad | OH1 Self Powered Circuit Fired |
| 16 | 01:58:37:310PM | Plasma | Ok | |
| 17 | 02:21:33:590PM | Plasma | Ok | |
| 18 | 02:44:23:750PM | Plasma | Ok | |
| 19 | 03:13:09:780PM | Plasma | Ok | |
| 20 | 03:36:18:030PM | Plasma | Ok | |
| 21 | 03:55:39:107PM | Plasma | Ok | |