| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Robert Granetz,Brian Labombard |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Frank Silva |
| Engineering Operator Run Comment |
| MP#236/Granetz, Silva |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:22:273PM |
| Author: To Be Determined |
| Run summary for run 991103A MP 236 -- H-mode pedestals in reversed field with lower X-pt. SL: R. Granetz PO: S. Wolfe EO: F. Silva Goal: Get H-modes (w/ICRF) in reversed field plasmas and look for poloidal asymmetries in the x-ray edge pedestals. Because the arrays are mechanically aligned to look at lower single null plasmas, this is what we have to run. This means that the grad-B drift, which is now upward, is away from the x-point, and therefore we'll probably need multi- megawatts of RF power to get an H-mode. Other options to enhance our chances are: raise Ip to 1.2 MA, lower Bt a bit (5.0-5.1 T), and keep the density low. Summary: Transmitter #2 died after the first plasma shot, and is unavailable until sometime next week at the earliest. Since we therefore had no chance of getting an H-mode with the lower X-point plasma, I turned the run over the Brian Labombard for his miniproposal after shot 5. On shot 5, we had a neon puff during the ohmic phase (at t=0.5 s). The neon stayed in the machine, and therefore also showed up in the ICRF L-mode phase as well. Although the signal levels were low (since there wasn't an H-mode), the indications are that top profile was shifted radially inward ever so slightly compared to similar neon puffing into plasmas with the usual B-field direction. We need to re-schedule this run when the ICRF is capable of sustained high power. ------------------------------------------------------------------------------ Shot 01 -- Dud. No EF2's, EF3. Engineering operator error. Delay for cell access to check density interferometer. Shot 02 -- Plasma. Ip=0.8 MA, Bt=5.4 T, nl_04=1.0e20 m-2. Prf=1 MW. Heating, no H-mode. There's a problem with transmitter #2. Shot 03 -- Fizzle. Shot 04 -- Fizzle. Shot 05 -- Plasma. Good shot. 1.3 MW of RF (D-port only) from t=0.75 to 1.1 s. L-Mode. This shot had a 50 ms neon puff at t=0.5 s (and argon is enabled as well). There's just barely enough x-ray signal to do the reconstructions. It seems that the top profiles are shifted a tiny amount inward (radially) compared to the normal field case. Due to the failure of transmitter 2, there is no hope of getting H-modes with these lower X-point plasmas. Therefore, I'm turning the run over to Brian Labombard for his miniproposal. |
| Entered: Jul 7 2004 03:49:22:290PM |
| Author: To Be Determined |
| Session Leader's summary of second part of run 991103 MP#228 - SOL Transport with reversed Bt Physics Operator: Wolfe Session Leader: LaBombard Background: Previous operation with reversed Bt has yielded some interesting phenomena in the edge plasma/divertor: reversed in/out density and temperature asymmetries on the divertor plates, reversed direction of parallel flows in the scrape-off layer, and reversed direction of thermoelectric currents in the scrape-off layer. Also associated with reversed Bt is the observation that the H-mode power threshold is much higher. It has been speculated that the change in power threshold may be caused by one or more the changes in boundary phenomena. New diagnostics are now available to study changes in scrape-off layer phenomena caused by Bt reversal including: A new scanning Mach probe at the outer midplane (ASP), tomographic reconstruction of CIII and CII dispersal "plumes" in the SOL, the capability of recording fluctuations and transport on scanning probes and divertor plate probes, new edge thomson system, and a new Lyman-alpha emission diagnostic to infer ionization profiles across the separatrix. By comparing discharges which are identical except for Bt reversal, it is hoped that the underlying mechanism(s) for the observed differences can be uncovered. At this time, the best data from the probe diagnostics is obtained in non-rf heated discharges. For this reason, the focus here is on ohmic-only discharges. Also, there already exists a number of well diagnosed normal Bt ohmic discharges in the database with Ip=0.8 and 1.0 MA and Bt=5.3 tesla at a variety of densities. Therefore we would like to fill this parameter space with corresponding reversed Bt discharges. Goal: Record cross-field SOL profiles of density, Te, parallel flow, and fluctuations, in ohmic ohmic L-mode reversed Bt discharges with various core densities and plasma currents. Also, monitor local impurity transport in the SOL by recording camera images of CIII and CII 'plumes' generated by puffing C2H4 from the F-scanning probe. Target conditions are: NL04 = 0.7, 1.0, 1.3x10^20 with Ip=0.8 and 1.0 MA Setup: FSP: - Operate in two bias modes: (a) West/East-sweep, North/South-float mode (b) West/South-sweep, North/East-float mode - Enable gas (C2H4) for optional plumes - Set up for a "deep" scan to the separatrix ASP: - Operate in two bias modes: (South probe is dead) (a) West/East-sweep, North-float mode (b) West-sweep, North/East-float mode - Set up for a "deep" scan to the separatrix FMP: - Operate in two bias modes: (a) Divertor probes in sweep and Vf mode with gated fast sampling (b) Divertor probes in Isat and Vf mode with continuous fast sampling ________________________________________________________________________________ Result: We managed to get only 9 plasma shots for this MP today. We got the coarse density scan for Ip=0.8 MA except that we did not get the fluctuation data for the NL04=1.3 setup. Perhaps we can get this on friday. CIII plumes indicate that the ExB flows in the scrape-off layer reverse, as expected. Similar to the FSP probe, the ASP recorded parallel flows in the opposite direction to that obtained in normal Bt discharges. SOL particle transport analysis and fluctuation analysis needs to be done on these data. We also did some basic flapper tests today. Spencer flapped the B and C flappers (and other combinations) while JT looked for H-alpha increases on his reticon array. We also did a heavy gas puff (12 torr-liters) of D2 through capillary C32-020 on shot#9 in order to see it on JT's reticon array and compare it to the flapper gas release. But the reticon saw neither puff! The C-side H-alpha survey view did see some increases and Spencer is using these data to estimate the flow rate through the flapper. Quick Shot Log: Execution of this miniproposal started from shot#6 today: shot Ip NL04 Probe Bias Plume Comment 6 0.8 1 Mach CIII C Flapper at .65 sec, Plume drifts up now (reversed B) 7 no plasma 8 no plasma 9 0.8 1 Mach CIII C Flapper at .75 sec, D2 puff from C32-020, Good plume data 10 no plasma 11 0.8 1 Mach CIII all flaps at .75 sec, good plumes 12 0.8 1 Fluctuation no C2H4 13 no plasma 14 0.8 0.7 Mach CIII good plumes 15 no plasma 16 0.8 0.7 Fluctuation no C2H4 17 0.8 0.7 Mach no C2H4 18 0.8 1.3 Mach CIII good plume 19 no plasma 20 no plasma 21 0.8 1.3 Mach no C2H4 __________________________________________________________________________________________ NOTE: Te on outer divertor probes #8, #3 (maybe #7) are indicating way too high today which suggests a problem with fitting parameters in LP_ANAL. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:09:927PM |
| Author: To Be Determined |
| Physop Summary for Wednesday, 991103 MP #236 (+Bt) pedestal meas SL: Granetz PO: wolfe Experiment changed after a few shots to: MP#228 Reverse-field SOL, SL=LaBombard This was a difficult run from many standpoints. We lost transmitter #2 to a cavity arc on the first shot, forcing a re-direction of the remainder of the run. We did get one shot (#5) with neon puffing and 1.3MW from D-port for Thomas/Bob to evaluate the impurity transport in reverse field. Brian's experiment MP228 wanted ohmic discharges, so the RF team was given the rest of the day off once we switched over at shot#6. Startups continued to be problematic. All of the successful plasmas had bad hesitations, and most seemed to turn back inside in RCUR before taking off. The fizzles looked like they were inside and crunched on the inner wall. I tried several tweaks of IC_EF4, oh voltages, and RCUR offset, and fill pressure but nothing made an obvious improvement. The main problem seems to be that the current rise is very slow. Aside from the ~50% startup rate, there were no particular operational issues today. The plasmas were all long, although at the high density we only got to about 1.7 sec instead of 2.0 in rampdown. Toward the end of the day we started getting early runaways, but that seems to be part of the startup problem. There was a recurrence of the OH2l pre-charge fault on shot 10 that looked just like yesterday's: crowbar at -0.7sec with no fuse loss found. Shot 13 had an alternator inhibit fault in CHECK, and was run through with the breakers open. Summary: -------- Shot 1 was a dud due to lack of EF2's Shots 2-5 were for the Granetz/Pedersen experiment. Two plasmas, two fizzles. #5 had the neon puff. Shots 6-12 were 1e20 ohmic shots for Brian; 4 plasmas, 2 fizzles, 1dud Shot 13 was a non-power cycle Shot 14-17 were at 0.7e20. 3 plasmas, 1 fizzle Shots 18-23 were supposed to be at 1.3e20. 2 plasmas, 4 fizzles. Scorecard: ------------ Duds 3 (all due to power supply/alternator lossage) Fizzles 9 Plasmas 11 ------- -- Total 23 |
| Session Leader Comments | |||
| Nov 3 1999 10:17:30:763AM | Robert Granetz | MP 236 -- H-mode pedestals in reversed field with lower X-pt. SL: R. Granetz PO: S. Wolfe EO: F. Silva Goal: Get H-modes (w/ICRF) in reversed field plasmas and look for poloidal asymmetries in the x-ray edge pedestals. Because the arrays are mechanically aligned to look at lower single null plasmas, this is what we have to run. This means that the grad-B drift, which is now upward, is away from the x-point, and therefore we'll probably need multi- megawatts of RF power to get an H-mode. Other options to enhance our chances are: raise Ip to 1.2 MA, lower Bt a bit (5.0-5.1 T), and keep the density low. | |
| Nov 3 1999 12:29:15:420PM | 991103006 | Brian Labombard | C Flapper at .65 sec. ASP, FSP firing. Puffing C2H4 from FSP. CIII FIlter Plume drifts up now (reversed B) Next shot: increase outer gap, change probe timing |
| Nov 3 1999 01:24:47:093PM | 991103009 | Brian Labombard | C Flapper at .75 sec. ASP, FSP firing. Puffing C2H4 from FSP. CIII FIlter D2 puff from C32-20 fill: 700 torr, trigger: 0.75, duration: 0.5 Next shot: Repeat with deeper FSP/ASP insertion |
| Nov 3 1999 02:13:23:247PM | 991103011 | Brian Labombard | all Flaps at .75 sec. ASP, FSP firing. Puffing C2H4 from FSP. CIII FIlter Next shot: Repeat with FSP/ASP in fluctuation mode. |
| Nov 3 1999 02:28:43:967PM | 991103012 | Brian Labombard | ASP, FSP firing. No C2H4 puff fluctuation mode. Next shot: lower density to NL04 = 0.7 |
| Nov 3 1999 03:05:38:467PM | 991103014 | Brian Labombard | ASP, FSP firing. C2H4 puff, CIII filter Mach mode. Next shot: repeat in fluctuation mode |
| Nov 3 1999 03:57:01:090PM | 991103016 | Brian Labombard | ASP, FSP firing. No C2H4 puff. Fluctuation mode. Next shot: repeat in Mach mode with no C2H4 puff |
| Nov 3 1999 04:19:27:280PM | 991103017 | Brian Labombard | ASP, FSP firing. With no C2H4 puff Mach mode. Next shot: Go to NL04 = 1.3 |
| Nov 3 1999 04:38:18:107PM | 991103018 | Brian Labombard | ASP, FSP firing. C2H4 puff, CIII filters Mach mode. Next shot: Repeat without C2H4, deeper ASP insertion |
| Nov 3 1999 05:26:43:780PM | 991103021 | Brian Labombard | ASP, FSP firing. No C2H4 Mach mode. Next shot: Repeat in fluctuation mode |
| Physics Operator Comments | |||
| Nov 3 1999 08:00:26:577AM | Steve Wolfe | Load from 991102030 Coldstart @06:58 Log file ok. Do a LOAD/CLEAN (forgot to load before coldstart) Get some coffee | |
| Nov 3 1999 10:26:43:263AM | 991103001 | Steve Wolfe | Shot 1: Loaded from 991102030. They did some ECDC in helium for about 5 minutes, and had some gas problems DUD: No EF2's - Frank says "Operator Error". Irby didn't get a trigger. It works on test shots? Ratiomatic was turned off; turn on for next shot. |
| Nov 3 1999 11:00:32:343AM | 991103002 | Steve Wolfe | Shot 2: Irby couldn't find anything wrong with TCI - try a repeat, with EF2s. plasma - full length The hesitation is still there. RF is there, E faults early, D ramps to 1MW right gap is pretty solid at 0.7cm, except for crossover, when it gets very small left gap drops from 1.2 to .7 Next shot: Change CLEARIN from -.05 to -.03 at t=.1 and earlier. Turn on the argon BR0 form -.001 to 0. |
| Nov 3 1999 11:20:30:437AM | 991103003 | Steve Wolfe | Shot 3: Change CLEARIN from -.05 to -.03 at t=.1 and earlier. Turn on the argon BR0 form -.001 to 0. Brian will puff ethylene this shot RF has a problem with #2 fizzle. Next shot: Enable 50msec Neon puff at .5 sec BR0 back to -.001 |
| Nov 3 1999 11:36:25:717AM | 991103004 | Steve Wolfe | Shot 4: Change CLEARIN from -.05 to -.03 at t=.1 and earlier. Turn on the argon Enable 50msec Neon puff at .5 sec BR0 back to -.001 Brian will also puff ethylene this shot RF has a problem with #2; they will try to fire #1 only, then see if #2 is fixable. Fizzle. Forgot to change BR0! Next Shot: Actually change BR0! |
| Nov 3 1999 12:07:05:733PM | 991103005 | Steve Wolfe | Shot 5: Change CLEARIN from -.05 to -.03 at t=.1 and earlier. Turn on the argon Enable 50msec Neon puff at .5 sec BR0 back to -.001 (really, this time) Brian will also puff ethylene this shot RF has a serious problem with #2. Probably not fixable this week. plasma - No tv at front of room, but the plasma is full length. looks like some runaways early. RF gets 1.3MW. Next shot: Double the neon puff |
| Nov 3 1999 12:27:39:920PM | 991103006 | Steve Wolfe | Shot 6: Change of plan. No more neon, or RF. Brian is now in charge, increas gaps to 1.5cm on outside and similar inside INcrease CLEARIN to .02 No change to startup; see if it will repeat plasma: hesitation is still there, but I won't touch it until we lose the plasma. Sanjay reports the plumes go the other way. |
| Nov 3 1999 12:44:22:670PM | 991103007 | Steve Wolfe | Shot 7: Delay RCUR flattop to .62sec, decrease to .671 from .673 to increase outer gap. fizzle. Bz was less negative this time. Next shot: EF4 from 1425 to 1410 |
| Nov 3 1999 01:03:30:013PM | 991103008 | Steve Wolfe | Shot 8: EF4 from 1425 to 1410 Delay RCUR flattop to .62sec, decrease to .671 from .673 to increase outer gap. fizzle. |
| Nov 3 1999 01:22:53:653PM | 991103009 | Steve Wolfe | Shot 9: EF4 fro 1410 to 1390. plasma. I don't know why, but plasma. Bad hesitation (turns around), and the Bz looks too high (negative). Gap looks ok to me, although it didn't grow as much as I expected. |
| Nov 3 1999 01:36:12:310PM | 991103010 | Steve Wolfe | Shot 10: Change initial RCUR point from .61 to .62 (make program waveform flat for first 50msec.) NO seg 2 changes. Dud - PF breaker pulled out. OH2L, just like yesterday |
| Nov 3 1999 02:14:24:590PM | 991103011 | Steve Wolfe | Shot 11: Change initial RCUR point from .61 to .62 (make program waveform flat for first 50msec.) NO seg 2 changes. plasma. TV started working again. long hesitation, but no dip. Maybe a little more sensible RCUR, but still moves in a little a couple of times. |
| Nov 3 1999 02:28:26:233PM | 991103012 | Steve Wolfe | Shot 12: repeat And it did - plasma A little dicier on the startup, but it made it. Next shot: lower density to 0.7 |
| Nov 3 1999 02:48:20:827PM | 991103013 | Steve Wolfe | Shot 13: lower density to 0.7 and reduce PG3 voltage after .12sec No power shot - alternator inhibit fault. Ran through the sequence anyway to avoid the usual back-out problem |
| Nov 3 1999 03:19:14:513PM | 991103014 | Steve Wolfe | Shot 14: lower density to 0.7 and reduce PG3 voltage after .12sec plasma - tv is gone again. Another long hesitation, no dip. nl4 = 7e19. got some injections early |
| Nov 3 1999 03:26:50:170PM | 991103015 | Steve Wolfe | Shot 15: Repeat. fizzle - now I can play with startup some more; |
| Nov 3 1999 04:00:28:590PM | 991103016 | Steve Wolfe | Shot 16: Add -50V to V_OH1 at .007,.008,.015sec; add -10V to the OH2's at the same times plasma Still has a long hesitation, maybe worse! rcur turns back at 20-25msec now. Some hards on this one. |
| Nov 3 1999 04:05:19:733PM | 991103017 | Steve Wolfe | Shot 17: Change RCUR offset from -8000 to -7000 plasma still has some hards. still hesitates, less of an rcur turnaround, but still does it. Next shot: 1.3e20 |
| Nov 3 1999 04:31:58:360PM | 991103018 | Steve Wolfe | Shot 18: Increase nl4 to 1.3e20, raise pg3 maint level to ~35V In seg 1 - raise V_oh1/oh2 by -50/-10V at 15, 20msec plasma to 1.8sec; hards still there. lost it to vertical problem in rampdown, after ef2's go to zero. Still hesitates. Has an injection at crossover, density at 1.3-1.4, sagging slightly |
| Nov 3 1999 04:46:59:497PM | 991103019 | Steve Wolfe | Shot 19: lower seg2 pg3 maintenance level to 20V later in discharge leave startup alone this time. fizzle. That's what I get for leaving it alone! |
| Nov 3 1999 05:06:19:860PM | 991103020 | Steve Wolfe | Shot 20:rcur offset from -7000 to -9000 (maybe I was going the wrong way?) another fizzle. Bz is higher at 15msec, which is consistent. |
| Nov 3 1999 05:30:08:950PM | 991103021 | Steve Wolfe | Shot 21: RCUR offset back to -7000. reduce gas puff from 22msec to 19msec plasma - it came back. so did the hards, not quite as bad this time hesitation is horrid, current turns around and then survives |
| Nov 3 1999 05:43:38:000PM | 991103022 | Steve Wolfe | Shot 22: Increase the seg1 pg3 puff (after 30ms) to help with runaways, maybe No other changes. fizzle. bz is more positive, but the current turns over sooner? |
| Nov 3 1999 06:07:40:547PM | 991103023 | Steve Wolfe | Shot 23: EF4 from 1390 to 1370 Daigle rebooted before we could get a shot off. Gary restarted cycle; only time for the one shot. fizzle. That's all for today. Bz came up (more negative), as expected, current rise too slow, turns around and dies. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 10:10:07:827AM | Plasma | Bad | EF2 u-l in plc control |
| 2 | 10:41:53:950AM | Plasma | Ok | no faults/plasma |
| 3 | 11:11:42:827AM | Plasma | Ok | no faults/fizzel |
| 4 | 11:31:52:950AM | Plasma | Ok | no faults/fizzel |
| 5 | 11:57:35:543AM | Plasma | Ok | no faults/plasma |
| 6 | 12:17:35:140PM | Plasma | Ok | no faults/plasma |
| 7 | 12:39:17:640PM | Plasma | Ok | no faults/fizzel |
| 8 | 12:57:28:437PM | Plasma | Ok | no faults/fizzel |
| 9 | 01:11:47:030PM | Plasma | Ok | no faults/plasma |
| 10 | 01:34:03:077PM | Plasma | Ok | Comm. Fail on supplies fuse check ok |
| 11 | 02:06:04:467PM | Plasma | Ok | no faults/plasma |
| 12 | 02:23:09:200PM | Plasma | Ok | no faults/plasma |
| 13 | 02:43:53:327PM | Plasma | Bad | alternator inhibit fault , no pulse |
| 14 | 02:56:59:390PM | Plasma | Ok | plasma |
| 15 | 03:22:03:983PM | Plasma | Ok | fizzle |
| 16 | 03:37:29:920PM | Plasma | Ok | (null) |
| 17 | 04:01:16:750PM | Plasma | Ok | (null) |
| 18 | 04:24:18:590PM | Plasma | Ok | (null) |
| 19 | 04:45:21:310PM | Plasma | Ok | (null) |
| 20 | 05:01:22:497PM | Plasma | Ok | (null) |
| 21 | 05:17:00:340PM | Plasma | Ok | (null) |
| 22 | 05:39:36:623PM | Plasma | Ok | (null) |
| 23 | 06:00:16:840PM | Plasma | Ok | (null) |