| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Earl Marmar |
| Physics operator(s): | Ron Parker |
| Engineering operator(s): | Andy Pfeiffer,Gary Dekow |
| Engineering Operator Run Comment |
| MP430 Localization of Effects of Boronization Session Leader: E. Marmar |
| Session Leader Plans |
| Entered: Aug 31 2005 07:58:29:253AM |
| Author: Earl Marmar |
| Session leader plan for 1050831
MP430 Localization of Effects of Boronization Overnight bake at 60 C; no ECDC Be set up for between-shot glow boronization during the run ICRF: E and J-4 will be needed Shot plan: Start from a shot like 1050822011 (1 MA, LSN, 1 cm outer gap), ~2.7 MW ICRF (E + J4) 1) Take ~2 shots to evaluate plasma conditions, and make sure plasma and RF are tuned up [~30 minutes] 2) open the diborane bottle, establish the glow in pure helium and then switch over to diborane/helium after a few minutes. glow discharge boronize for 10 minutes [~45 minutes] 3) take 2 plasma shots to evaluate boronization (go to init on first shot when torus pressure is 4e-6 or below) [~30 minutes] 3a) If boron effects have not worn off after 2 shots, continue until boronization no longer effective (SL judgement) 4) unless there is a dramatic plasma improvement, glow boronize again, for 20 minutes [~40 minutes] 4a) in the event that a single 10 minute glow makes a dramatic improvement, go to 5 minute glow boronization 5) 2 plasma shots to evaluate [30 minutes] 6) Assess results, and either go to 30 minute or 5 minute glow boronization 7) 2 plasma shots At this point, if results are clear and positive, switch to ECDC boronization, for comparison with glow boronization: 30 minute ECDC boronization, scan 50,70,103 2 shots to evaluate If 30 minute glow results are marginal, consider 1 hour glow boronization. All glow boronizations should be carried out with average pressure of ~6.5 mT on TC3 and about 100 mTorr on TC6, GV1 closed, GV2 open, and the bypass open 171 clicks. We are using an MIT diborane bottle (10% deuterated diborane/90% helium). The RGA can be on for the boronizations, but should be turned off prior to plasma shots. Both GV1 and GV2 should be open during plasma shots. We might try a few post boron shots with GV1 closed, bypass open and RGA on, but this will be decided during the run. |
| Physics Operators Plans |
| Entered: Aug 30 2005 05:05:09:140PM |
| Author: Ron Parker |
| Engineering Setup for 1050831
MP 430 Effects of Between Shot Boronization (Glow Discharge) Session Leader: E. Marmar Physics Operator: R. Parker Overnight bake bake at 60 C **********NO ECDC************** Setup for between shot boronization with glow discharge. Keep diborane bottle CLOSED until after a few shots. Normal cell lockup. Be prepared for SCBA access after run begins. Use diborane bottle currently installed (10%) Run Begins at 9:00 and ends at 5:00 Power Systems as on 1050822005 RF in run on by 8:30 (E and J-4 sources) A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled. Gas Setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) leave B-side lower as is, Hybrid DISABLED (PG1) leave B-side upper as is, Hybrid DISABLED (PG2) fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3) Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters |
| Session Leader Summaries |
| Entered: Aug 31 2005 06:18:16:280PM |
| Author: Earl Marmar |
| This was an interesting day. We managed to get decent comparisons of various glow boronizations (pressure, current and time) with 2 ECDC boronizations (20 minutes, 1 with modulated RF, the other with 100% duty factor).
Tentative conclusions: Glow boronization has very little effect on subsequent plasmas, at least for the conditions tried today. An example comparison is shot 6 (post glow boronization) with shots 1 and 2 (prior to first boronization). In addition to not decreasing Prad in h-mode, glow boronization has a much smaller effect than ECDC boronization on gas evolution from the walls at breakdown, with little adjustment of prefill puff required to avoid fizzles with the glow boronization. The comparison of ECDC boronization with and without 1 hertz magnetron modulation, seems to indicate that no modulation (shot 8) is better than modulation (shot 18). One problem encountered early in the run resulted from some residual xenon apparently being left in the B-side lower plenum from yesterday's run (in spite of having been pumped and purged at least once). This valve was used for the He-4 glow which was initiated before the first diborane glow. The subsequent plasma (shot 4) showed dramatic increases in xenon seen spectroscopically on the VUV (mcpherson) and soft-xray (nesoxs) spectroscopy. This valve was not used during the rest of the run. |
| Physics Operator Summaries |
| Entered: Aug 31 2005 05:53:57:843PM |
| Author: Ron Parker |
| The purpose of the run was to compare the efficacy of glow boronization compared with ECDC boronization. Various glow conditions were used during between shots boronizations. Noticeable was the difference in take-up by the wall compared with ECDC, both from the speed at which the pressure came down after terminating the boronization, and the fact it was not necessary to adjust the fill pressure to control the breakdown. The general conclusion was that glow boronization was marginally effective in affecting the radiated power and performance and not as effective as when the boronization was appplied with ECDC.
The machine ran well, with the exception of an RF power supply crowbar (J-4) that required 2 SCBA entries to reset and a ~40 minute delay. There were relatively few shots (17) due to the time required to do the boronization between shots. Early on,there was an unexpectedly high level of xenon in the discharges, presumably due to inadequate purging of the gas line used for He glow discharge cleaning prior to shot 2. Scorecard: 18 shots, 16 full length, 2 fizzles, 1 dud. |
| Session Leader Comments | |||
| Aug 31 2005 02:12:02:653PM | 1050831001 | Earl Marmar | decent first shot
looks completely unboronized multiple h-modes, h89 ~ 1 dPrad/dt (initial H-mode) = 22 MW/s (2*\prad_2pi) Prf = 2.7MW |
| Aug 31 2005 02:11:46:280PM | 1050831002 | Earl Marmar | another good baseline shot
dithery, small ELMish h-mode Prf = 2.7 MW h89~1 dPrad/dt (initial h-mode) ~ 25 MW/s |
| Aug 31 2005 02:11:33:187PM | 1050831003 | Earl Marmar | glow boronize prior to this shot
start the glow in pure helium, then switch to 10% deuterated diborane/90% helium intended to glow for 10 minutes after the switch to diborane, 1 amp total current (2 glow paddles), 6.5 mTorr on TC3, 100 mTorr on TC6 However, actually had about 15 minutes of diborane glow, with TC3 pressure mostly between 50 and 100 mTorr dud |
| Aug 31 2005 02:11:13:403PM | 1050831004 | Earl Marmar | plasma
somewhat strange looking shot Matt and Alex I-C report xenon is increased by 1 order of magnitude compared to last shot from yesterday. Ultimate h-mode performance looks very similar to shots 1 and 2 |
| Aug 31 2005 02:10:48:107PM | 1050831005 | Earl Marmar | no additional glow boronization before this shot
plasma looks very much like shot 2, but there is still significant xenon emission h89~1 dPrad/dt (initial h-mode) ~ 30 MW/s |
| Aug 31 2005 02:09:59:717PM | 1050831006 | Earl Marmar | 20 minute glow boronization prior to this shot
pressures were better controlled this time, and the target pressures were reached for about the last 15 minutes of the boronization plasma looks very much like shot 1 dPrad/dt (initial h-mode) ~ 20 MW/s h89 ~ 1 less xenon in this shot (factor ~5 decrease) |
| Aug 31 2005 12:39:56:390PM | 1050831008 | Earl Marmar | prior to this shot, 20 minutes of ECDC boronization, scan 50,70,103, 100% duty factor (no flashing)
plasma definite improvements Prad 1.5 MW instead of 2.0 during h-mode dPrad/dt (initial h-mode) ~ 10 MW/s h89 ~ 1.4 |
| Aug 31 2005 12:51:06:857PM | 1050831009 | Earl Marmar | no additional boronization prior to this shot
plasma boronization clearly wearing off dPrad/dt (initial H-mode) = 16 MW/s |
| Aug 31 2005 01:33:32:233PM | 1050831010 | Earl Marmar | Prior to this shot, 20 minutes glow boronization, aiming for lower pressure (~4 mT on TC3 for most of the time)
plasma seems slightly better than previous glow boronizations, not as good as ECDC boronization (shot 8) multiple ELM-free h-modes dPrad/dt (initial H-mode) = 10 MW/s H89 ~ 1.3 and drooping quickly |
| Aug 31 2005 02:02:03:873PM | 1050831011 | Earl Marmar | no additional boronization prior to this shot
plasma H-modes more like earlier post glow shots (dithery, small ELMs) Prad rising to 2 MW h89 ~ 1.1 and lower |
| Aug 31 2005 02:40:22:593PM | 1050831012 | Earl Marmar | prior to this shot, 20 minutes glow boronization
pressure was not well controlled, but mostly between 10 and 15 mTorr (TC3) plasma looks much like the previous post glow boronization shots dithery/small ELM H-modes H89 ~ 1.25 and then drooping dPrad/dt (initial H-mode) ~ 15 MW/s |
| Aug 31 2005 02:58:53:717PM | 1050831013 | Earl Marmar | prior to this shot, 20 minutes glow boronization
TC3 = 25. mTorr, well controlled fizzle |
| Aug 31 2005 03:47:48:763PM | 1050831014 | Earl Marmar | no additional boronization prior to this shot.
plasma similar to previous dithery/small ELM h-modes h89 ~ 1.38 and drooping dPrad/dt (initial h-mode) = 15 MW/s |
| Aug 31 2005 04:31:21:623PM | 1050831015 | Earl Marmar | prior to this shot, glow boronization, 25 mT on TC3, 3.75 amp total electrode current (2 electrodes).
All previous glow boronizations today were done with 1. amp total electrode current. plasma ELM-free H-modes target density is low (TCI fringe jump) |
| Aug 31 2005 04:42:56:857PM | 1050831016 | Earl Marmar | no additional boronization prior to this shot.
similar to previous got the right target density several h-modes h89 = 1.26 and drooping dPrad/dt (initial h-mode) = 14 MW/s |
| Aug 31 2005 05:18:30:700PM | 1050831017 | Earl Marmar | prior to this shot, ECDC boronization 20 minutes
scan 50, 70, 103 magnetron modulated at 1 Hz (should give a direct comparison with the 100% duty factor ECDC boronization done before shot 8) fizzle |
| Aug 31 2005 05:57:25:670PM | 1050831018 | Earl Marmar | no additional boronization before this shot
plasma not as good as shot 8 Prad reaches 1.5 MW nice RF pulse dPrad/dt (initial h-mode) = 10 MW/s h89 ~ 1.35 |
| Physics Operator Comments | |||
| Aug 31 2005 09:27:37:003AM | 1050831001 | Ron Parker | A short delay getting underway due to minor problems.
After a 15 minute dely, first shot ram well except for intermittent RF. Net: Repeat, hopefully with sustained RF |
| Aug 31 2005 09:46:44:613AM | 1050831002 | Ron Parker | Shot 2 ran OK. Now we'll set up for boronization, first He glow,
then diborane. There will be a ~ 20 minute delay. For the nest shot, pulsed gas voltage duration will be reduced from 31 ms to 8 ms. |
| Aug 31 2005 10:29:42:607AM | 1050831003 | Ron Parker | Shot 3, after the "random" glow boronization, was a dud possibly due to
the fill pressure being too low -- ~ 2.7e-4. We'll increase the valve duration to 18 ms for the next shot. |
| Aug 31 2005 10:48:50:653AM | 1050831004 | Ron Parker | Shot 4 ran, some hards at beginning and disruption on way down.
No clear (good) effect due to boronization. Matt Reinke reports high level of Xenon in discharge, presumably from the line used for helium glow before this shot. Next: repeat, increase pulse gas to 22 ms from 18. |
| Aug 31 2005 11:08:44:890AM | 1050831005 | Ron Parker | Shot 5 looked a little better, somewhat less xenon.
Next: glow boronization for 20 minutes. Set pulse gas width to 18 ms. |
| Aug 31 2005 11:39:44:140AM | 1050831006 | Ron Parker | Shot 6 ran well, insignificant improvement over non-boronized shots.
Noticeable is that the initial fill does not seem to be affected by the glow boronization, contrary to the case with ECDC. Next: Repeat to check xenon level. |
| Aug 31 2005 11:52:52:593AM | 1050831007 | Ron Parker | Shot 7 ran OK, but no improvement over non-boronized shots.
Next: Shut down for 20 minutes for ECDC boronization, 50,70,103 . Pulse gas width reduced to 8 ms for next shot. |
| Aug 31 2005 12:33:51:577PM | 1050831008 | Ron Parker | Shot ran well, stored energy up to 150 kJ, clearly improved over glow.
Next: Repeat, pulse gas at 18 ms. |
| Aug 31 2005 12:50:29:403PM | 1050831009 | Ron Parker | Shot 9 ran well, but effect of boronization was reduced (as seen before).
Next: repeat glow boronization, 20 minutes and lower pressure. |
| Aug 31 2005 01:32:22:560PM | 1050831010 | Ron Parker | Shot 10 ran OK, and the stored energy was somewhat higher than in previous
glow boronization shots. Next: repeat. |
| Aug 31 2005 02:08:50:920PM | 1050831011 | Ron Parker | Shot 11 ran OK, stored energy ~ 120 kJ.
Next: Glow for 20 minutes, try for slightly lower pressure. Glow pressure was actually higher than in last glow boronization. |
| Aug 31 2005 02:22:39:233PM | 1050831012 | Ron Parker | Shot ran, no improvement.
Nest: change glow pressure to 20-25 mT. |
| Aug 31 2005 03:03:18:200PM | 1050831013 | Ron Parker | Shot 13 fizzled, slightly longer H-alpha burnout.
Repeat, no change -- should go this time. |
| Aug 31 2005 03:16:32:107PM | 1050831014 | Ron Parker | Shot 14 ran, not much improvement.
Next: Glow again, this time at higher current from glow power supply. Anticipating a bit more wall adsorption, shorten the fill pulse by a few ms. |
| Aug 31 2005 04:31:27:890PM | 1050831015 | Ron Parker | Shot 15 went off, no improvement. Interferometer missed some fringes.
J-port RF power supply crowbarred after shot and will require an SCBA entry into power room. After reset, voltage did not reset and run may be scrubbed -- stay tuned. After a second power room entry, the power supply was successfully reset and the run can be continued. Next shot: repeat shot 15, with interferometer working. |
| Aug 31 2005 04:42:51:857PM | 1050831016 | Ron Parker | Shot 16 ran well, W ~ 120 kJ.
Next: ECDC boronization for 20 minutes, "flashing". |
| Aug 31 2005 05:20:49:280PM | 1050831017 | Ron Parker | Shot 17 fizzled, fill pressure too low -- evidently the flashing ECDC
does not load the walls as much as the steady ECDC. Now we need a cell access to fix interferometer, then we'll repeat shot with 18 ms of pulse gas instead of 8 as in previous shot. |
| Aug 31 2005 05:57:54:717PM | 1050831018 | Ron Parker | Shot 18 ran well, after a 45 minute delay to enter cell for fixing interferometer.
This shot again demonstrated that boronization is more effective with ECDC than glow discharge. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:15:34:207AM | Plasma | Ok | |
| 2 | 09:28:04:770AM | Plasma | Ok | |
| 3 | 10:25:27:810AM | Plasma | Ok | |
| 4 | 10:38:03:983AM | Plasma | Ok | |
| 5 | 10:50:47:733AM | Plasma | Ok | |
| 6 | 11:30:25:810AM | Plasma | Ok | |
| 7 | 11:43:08:187AM | Plasma | Ok | |
| 8 | 12:26:05:733PM | Plasma | Ok | |
| 9 | 12:38:37:623PM | Plasma | Ok | |
| 10 | 01:21:01:263PM | Plasma | Ok | |
| 11 | 01:34:00:827PM | Plasma | Ok | |
| 12 | 02:14:58:700PM | Plasma | Ok | |
| 13 | 02:55:24:857PM | Plasma | Ok | |
| 14 | 03:07:59:750PM | Plasma | Ok | |
| 15 | 03:48:37:920PM | Plasma | Ok | |
| 16 | 04:31:36:983PM | Plasma | Ok | |
| 17 | 05:13:14:077PM | Plasma | Ok | |
| 18 | 05:51:48:200PM | Plasma | Ok | |