| Miniproposals | ||||||||||||
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| Operators | |
| Session leader(s): | David Mikkelsen,Amanda Hubbard |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Gary Dekow,Bill Parkin,Ed Fitzgerald |
| Engineering Operator Run Comment |
| MP#314 Evaluate BT sweep method of LT; SL: Hubbard/Mikkelsen; PO: Wolfe |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:30:507PM |
| Author: To Be Determined |
| Run summary for 1020918 MP 314: Evaluate BT sweep method of LTe Session Leaders: Amanda Hubbard, Dave Mikkelsen (from PPPL) Physics Operator: Steve Wolfe Plan: This run will be a continuation of 1020910, which set up the required discharge and TF waveforms but was impeded by post-vent plasma reproducibility. We there fore want to return to those conditions, and then start the current and density scans outlined in the MP. 1) Start by reloading 1020910020 (1 MA, 5.4 T, nebar 2.e20 m-3), no Bt ramps. Check that discharge conditions are correct, and steady. 2) Load Bt waveform from 1020910027 (slow ramps, 5.4-5.6 T). (Or, even better, the one Bob programmed for 1020910028, which fizzled but should have given a longer flat period at the end). Assuming sweep acceptable to Dave, repeat this shot 3 times. 3) Lower Ip to 500 kA, and repeat 4 discharges. May want one of these to not have sweeps, so as to check steadiness. 4) Repeat at 1.3 MA. If Physop deems prudent, step up current over 2-3 shots (1.1, 1.2 MA?) to avoid disruptions. 3 reproducible discharges. 5) Return to 1 MA and reduce nebar to 1.e20 (nel ~ 5 x 10^19 m-2). 3-4 shots. 6) 500 kA, nebar 6e19 m-3. ditto 7) 1.3 MA, nebar 6e19 m-3. (I'm a little unclear on the reason for this step, and anticipate it may be hard to get given 'natural' n, I are correlated. The low I, high n shot (3) may be tricky for the same reason) ---------------------------------------------------------------------------- Results: This run, a continuation of that on 1020910, was quite successful in accomplishing most of its scientific objectives. Small sweeps of Bt were used to determine the local gradient of Te, and its spatial scale length LTe, to unusually high accuracy. Plasma current and density were varied substantially, so that LTe was varied by more than its uncertainty. The first, and best documented, condition was 1 MA, nebar=2.e20 m-3. Shots 2-9 were used to vary the Bt waveform and achieve the most steady density and Ip levels possible. The measured profiles and gradients were found to be highly reproducible, and independent of the programmed sweep waveform. We then went to lower current, 500 kA, to vary q while keeping Ti~Te. It proved problematic to maintain stedy conditions at high densities; there was a spontaneous increase of density, and change in recycling (eg, shots 10,11,13,14,16). The threshold density proved to increase with Ip. We therefore compromised at 650 kA, nebar=1.6m-3.(shots 15, 17-19). Shot 20 was a large Bt ramp, 5.4-4.5 T, which was used to obtain a more accurate cross-calibration of the edge ECE channels for the day (by moving them to hotter regions.) Initial analysis shows that while the d/dR of Te is not much different between 1 and 0.65 MA (shots 7,8,9 vs. 17,18,19), the temperatures are quite different, so there is a big increase in R/L_Te at the lower current. This is qualitatively what theory predicts in the higher q(a) discharge. Lower density (nebar 6-7x 10^19 m-3) was then explored, to see the effect on Te of decoupling electrons and ions. As is typical of low density discharges, conditions were less steady; on several shots (eg 22, 24) there was a change in sawtooth character and reduction in edge Te late in the discharge. Densities ~ 8e19 were better, eg. 25-27 The final condition explored was 1 MA, nebar ~10^20 m-3. Again, there were often changes in confinement late in the shot. For shots 28 and 29, the first sweep may give useful gradient data. Due to concerns about tiles, we deferred exploration of 1.3 MA discharges to a future run. Summary of best shots for further analysis: Ip ne-bar better shots MA xE20 1.0 1.9 1020918007, '008, '009 0.65 ~1.6 '017, '018, '019 0.65 0.8 '021, '025, '026 Detailed analysis of measurements in this run will be started next week during David Mikkelsen's visit. John Rice has obtained core Ti profiles which will help assess under which conditions Te=Ti. Mikkelsen will later run turbulence simulations of the discharges to predict LTe for comparison with our measured values. As a note, having Dave participate actively as 'remote session leader' from PPPL worked well and ensured that we carried out his MP as well as possible. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:16:177PM |
| Author: To Be Determined |
| Physics Operator Summary for Wed. 9/18/2002 MP#314 Evaluate Bt sweeps for L_Te measurement SL: Hubbard/Mikkelsen PO: Wolfe EO: Fitzgerald, Dekow, Parkin Engineering Setup Power Systems as on 1020910027 except fizzle detector off time to 2.0sec Overnight ECDC in D2 at 2e-4 torr off by 7:00AM Run to begin at 9:00 AM Gas setup: B-Top 6 psi D2 Hybrid Enabled (PG4) B-side lower 1 psi Ar Hybrid Enabled (PG1) B-side upper 10 psi D2 Hybrid DISABLED (PG2, for ECDC) C-Side 30 psi D2 Hybrid Enabled (PG3) J-Bottom as is, Hybrid DISABLED Enable the following gate valves, assuming no vacuum problems: ECE,VUV,DNB RF Setup: None, this will be an all-ohmic run Run Plan: This run will be a continuation of 1020910, which set up the required discharge and TF waveforms but was impeded by post-vent plasma reproducibility. We therefore want to return to those conditions, and then start the current and density scans outlined in the MP. 1) Start by reloading 1020910020 (1 MA, 5.4 T, nebar 2.e20 m-3), no Bt ramps. Check that discharge conditions are correct, and steady. 2) Load Bt waveform from 1020910027 (slow ramps, 5.4-5.6 T). (Or, even better, the one Bob programmed for 1020910028, which fizzled but should have given a longer flat period at the end). Assuming sweep acceptable to Dave, repeat this shot 3 times. 3) Lower Ip to 500 kA, and repeat 4 discharges. May want one of these to not have sweeps, so as to check steadiness. 4) Repeat at 1.3 MA. If Physop deems prudent, step up current over 2-3 shots (1.1, 1.2 MA?) to avoid disruptions. 3 reproducible discharges. 5) Return to 1 MA and reduce nebar to 1.e20 (nel ~ 5 x 10^19 m-2). 3-4 shots. 6) 500 kA, nebar 6e19 m-3. ditto 7) 1.3 MA, nebar 6e19 m-3. (I'm a little unclear on the reason for this step, and anticipate it may be hard to get given 'natural' n, I are correlated. The low I, high n shot (3) may be tricky for the same reason) Results: -------- The 1MA nebar=1e20/m3 case was done ok. We ended up taking only one tf sweep up and down per shot, starting at .9 sec, and found that we could increase the upsweep rate to a step and the down-rate to .2T/150msec with no noises reported from the alternator; we did not attempt to go faster than this. The characteristic droop in Ip was counteracted by programming a positive ramp of 25kA during the pulse. The 0.5MA case was not successful, because we encountered a very strange mode that may have been poloidal detachment but was also reminiscent of H-mode. Density, prad, neutrons and Wmhd went up, and H-alpha and Te went down. The Halpha trace looked very much like an ELM-free H-mode, but the recycling as seen on the video view moved from the divertor to the top of the machine. These events were preceded by strong recycling from the BN tile, which by this time had fallen into the divertor slot. Examples are shots #10,11,13, and 14. Lowering the density (#12, seemed to eliminate the behavior, but the MP required higher density. The effect seemed to be somehow triggered by crossover of OH1. Putting a notch in the Ip gain around the crossover time did not fix it, but reduced the big gap change. It was decided to take 650kA as the lower current point. Shots #15,17,18,19 were good examples at 8e19 nl4; shot #16 did the detachment/H? thing at programmed nl4=1e20. Shot #20 was a slow Bt sweep down to 4.5T for cross-calibration purposes. Shots#21-27 were 650KA, low density. We actually took several densities, down to nl4 of 2.7e19, then worked back up to try to avoid the transition to sawtooth-less "VL" mode. This seemed to require nl4~5e19. Shot #27 was run with no waggle, to see how much conditions were changing over the pulse. Shots#28-31 were attempts to get the 1MA, nebar~1e20 case. These again suffered from the "VL" mode behavior. Only #28, which was at higher density than desired, made it through the TF sweeps without losing the sawteeth. Shots#28 and 29 lost sawteeth around 1.2-1.3 sec and then disrupted in early rampdown. Shot #30 fizzled. For Shot #31 we turned off the waggle, and extended the pg3 programmed pulse in seg2 to 2sec, for no better reason than it was the only waveform doing anything around the time of the "VL" transition. The shot ran full length, but lost sawteeth even earlier, at around .9sec. It also had a lot of early runaways, as I hadn't raised the pre-puff enough and the startup was bouncy. Startup reliability was good, with only 2 fizzles and 1 dud. Only the last shot had significant early runaways, and I made only one Br tweak and a few small gas tweaks all day. There were no power system problems. We had some data system problems late in the run, possibly caused by a new unix_submit task for the logbook admin things. TCI is now running with the array detector again. Feedback worked all day, except for shot #4, which was a dud anyway. Irby did have to make a couple of cell entries in the morning to keep things alive. Brian started exercising his probes after shot 22, until shot 25 when we noticed that small injections were following his pokes. It may have been launching some debris. He turned the probes off for #26-31 and the injections went away, except for the one associated with crossover. The BN tile which began the day on the outer shelf moved into the divertor after shot#2, and moved around some after that. For several shots it was clearly visible around the outer nose, but by the end of the run I lost sight of it in the videos. Maybe someone else can figure out where it is. The run plan called for shots at 1.3MA, but Irby requested that this not be done for fear of breaking off more tiles from the antenna. As far as we can tell, the near 1MA disruptions on 28 and 29 did not do any more breakage. Scorecard --------- duds 1 fizzles 2 plasmas 28 ------- -- shots 31 |
| Session Leader Comments | |||
| Sep 18 2002 10:05:28:423AM | 1020918001 | Amanda Hubbard | Start with steady Bt, 0.98 MA, 5.37 T. Te0 nice and steady at 1.3 keV, but outer channels are drooping slightly which is not ideal. For next shot, start sweeps of Bt. |
| Sep 18 2002 10:25:22:613AM | 1020918002 | Amanda Hubbard | Got a Bt sweep, 5.37 - 5.58 - 5.39 - 5.59 T. GPC, GPC2 look fine (changed angles for this shot). Didn't quite get the full sweep on the first one; steepen for next shot. Ne creeping up, Ip down ~ 20 kA, Dave reports 1st sweep has different grad Te than others, indicating Te not yet steady. |
| Sep 18 2002 10:26:18:813AM | 1020918003 | Amanda Hubbard | Got a Bt sweep, 5.37 - 5.58 - 5.4 - 5.59 T. Sweeps look good, but still indications Te not quite steady. |
| Sep 18 2002 11:37:46:877AM | 1020918007 | Amanda Hubbard | Only one Bt sweep (up and down). Looks good. Dave says we now have grad Te to at least 5% Repeat, try for faster sweeps. |
| Sep 18 2002 11:20:16:720AM | 1020918008 | Amanda Hubbard | Looks good. Take one more at this Ip, with slightly steeper down-ramp. |
| Sep 18 2002 11:46:55:583AM | 1020918009 | Amanda Hubbard | Looks good. Faster down-sweep. Next shot, keep Bt waveform same, go to 500 kA - |
| Sep 18 2002 11:33:17:213AM | 1020918010 | Amanda Hubbard | Went to 500 kA. Density went to 4e20 m-3; needs some work! Plasma discharge cleaning?? |
| Sep 18 2002 12:01:04:157PM | 1020918011 | Amanda Hubbard | Disturbingly similar. Big leap in nel ~ 0.67 secs, Te0 to 570 eV. Disrupts 0.95 secs. |
| Sep 18 2002 12:18:44:253PM | 1020918012 | Amanda Hubbard | Much better. Lowering density enabled shot to go through. Unfortunately, this is not the target we wanted. Try gradually raising the ne target to see where we get problems. |
| Sep 18 2002 12:49:57:923PM | 1020918014 | Amanda Hubbard | Still detaches (or whatever we call this!). Change of Plan: Raise Ip to 650 kA, hoping we can get higher density. |
| Sep 18 2002 01:00:05:550PM | 1020918015 | Amanda Hubbard | 650 kA seems much happier. No detachment Got fairly (though not perfectly) steady nel ~9e19, nebar 1.67e20. Try raising target to nel 1.e20 for next shot. |
| Sep 18 2002 01:28:08:143PM | 1020918017 | Amanda Hubbard | Pretty steady. Nebar 1.55-1.62 in sweeps. Ip 650 kA, very steady. A keeper. Repeat. |
| Sep 18 2002 01:42:36:267PM | 1020918018 | Amanda Hubbard | Very similar. Repeat once more. |
| Sep 18 2002 01:55:12:633PM | 1020918019 | Amanda Hubbard | Another good one. For our next shot, program a big Bt ramp down to 4.5 T, just to get really solid xcals on all the ECE instruments. |
| Sep 18 2002 02:09:58:927PM | 1020918020 | Amanda Hubbard | Good shot. Big Bt ramp to 4.5 T, moves edge ECE channels to center for more solid calibrations. Next, go to low density, low current series, with small Bt ramps again. |
| Sep 18 2002 02:32:52:173PM | 1020918021 | Amanda Hubbard | Got nebar 7.7e19, a bit higher than programmed, or desired. Quite steady during sweeps, though, and Dave says good overlap so a nice intermediate point. L/Te not very different. Next shot should be lower ne. (aiming for nebar=6e19) |
| Sep 18 2002 03:04:19:060PM | 1020918022 | Amanda Hubbard | Got nebar 5.3e20. Getting the change to mini-sawteeth ~ 1.27 secs, plus some small injections. Fairly decent sweeps, but not great. |
| Sep 18 2002 03:05:23:377PM | 1020918023 | Amanda Hubbard | Got nebar 4.7e20. Getting the change to mini-sawteeth ~ 1.1 secs. Injection lowers all Te's just before sweep; reprocdubility not good. |
| Sep 18 2002 03:16:57:057PM | 1020918024 | Amanda Hubbard | Got nebar 6-7e219 Getting the change to mini-sawteeth ~ 1.31 secs. Small Injection lowers edge Te's just before sweep (0.89 s) ; |
| Sep 18 2002 03:47:09:770PM | 1020918025 | Amanda Hubbard | Got nebar 8.7e20. Much better shot. But, GPC 6-9 don't have signal! Repeat |
| Sep 18 2002 03:48:17:913PM | 1020918026 | Amanda Hubbard | Repeat. Got nebar 8e20. GPC OK again. Also, no more injections. (note, probe no longer scanning) |
| Sep 18 2002 03:59:17:357PM | 1020918027 | Amanda Hubbard | Repeat, without Bt sweep to test constancy of Te(t). Looks good, nel 4e19. For rest of run, I'm handing over to Dave Mikkelsen as official session leader. Will go to 1 MA, nebar ~ 8e19. Dave has in fact been actively calling, and analysing, the shots all day. |
| Sep 19 2002 09:55:04:500AM | 1020918028 | Amanda Hubbard | Back to 1 MA, try for low ne point. Got nebar 1.2e20 m-3. Transitions to 'mini-sawteeth' ~ 1.3 secs (after sweeps) |
| Sep 19 2002 11:43:01:150AM | 1020918029 | Amanda Hubbard | Got nebar 1.0e20 m-3. Transitions to 'mini-sawteeth' ~ 1.12 secs Positive Bt sweep may be useable |
| Sep 19 2002 11:48:17:413AM | 1020918031 | Amanda Hubbard | Repeat, with no Bt sweep so we can see how steady it is. It isn't! Dramatic change in confinement (and sawteeth) ~ 0.85 secs. For example, Te6 drops from 940 to 500 eV! |
| Physics Operator Comments | |||
| Sep 18 2002 07:35:26:170AM | Steve Wolfe | Start from last shot from yesterday, which was loaded from 1020910020 seg2. coldstart All matrices respond NO errors in hloader log Total of 720640 words loaded to DAC cards | |
| Sep 18 2002 07:36:42:673AM | Steve Wolfe | Run Plan and Engineering Setup for Wed. 9/18/2002 MP#314 Evaluate BT sweep method of LTe SL: Hubbard/Mikkelsen PO: Wolfe Engineering Setup Power Systems as on 1020910027 except fizzle detector off time to 2.0sec (Note TF invert time should be 1.7sec) Overnight ECDC in D2 at 2e-4 torr off by 7:00AM Run to begin at 9:00 AM Gas setup: B-Top 6 psi D2 Hybrid Enabled (PG4) B-side lower 1 psi Ar Hybrid Enabled (PG1) B-side upper 10 psi D2 Hybrid DISABLED (PG2, for ECDC) C-Side 30 psi D2 Hybrid Enabled (PG3) J-Bottom as is, Hybrid DISABLED Enable the following gate valves, assuming no vacuum problems: ECE,VUV,DNB RF Setup: None, this will be an all-ohmic run Run Plan: This run will be a continuation of 1020910, which set up the required discharge and TF waveforms but was impeded by post-vent plasma reproducibility. We therefore want to return to those conditions, and then start the current and density scans outlined in the MP. 1) Start by reloading 1020910020 (1 MA, 5.4 T, nebar 2.e20 m-3), no Bt ramps. Check that discharge conditions are correct, and steady. 2) Load Bt waveform from 1020910027 (slow ramps, 5.4-5.6 T). (Or, even better, the one Bob programmed for 1020910028, which fizzled but should have given a longer flat period at the end). Assuming sweep acceptable to Dave, repeat this shot 3 times. 3) Lower Ip to 500 kA, and repeat 4 discharges. May want one of these to not have sweeps, so as to check steadiness. 4) Repeat at 1.3 MA. If Physop deems prudent, step up current over 2-3 shots (1.1, 1.2 MA?) to avoid disruptions. 3 reproducible discharges. 5) Return to 1 MA and reduce nebar to 1.e20 (nel ~ 5 x 10^19 m-2). 3-4 shots. 6) 500 kA, nebar 6e19 m-3. ditto 7) 1.3 MA, nebar 6e19 m-3. (I'm a little unclear on the reason for this step, and anticipate it may be hard to get given 'natural' n, I are correlated. The low I, high n shot (3) may be tricky for the same reason) | |
| Sep 18 2002 07:39:56:077AM | Steve Wolfe | Irby has installed the repaired multi-channel TCI detector. He and Rick Murray are doing the alignment now, and will put up the new chord locations in the tree when they are done. Channel nl_04 has been reconnected to the hybrid. It's location will presumably NOT be the same as the single detector in use on 1020910, so we may need some minor tweaks on the density programing. | |
| Sep 18 2002 08:13:48:080AM | Steve Wolfe | Minor program changes for shot#1 Ip point at .1 sec from .45 to .55MA to better match actual Ip point at .2 sec from .70 to .75MA Final Ip gain step (to 9) from .65 to .55 On shot 1020917023 there was a big gap change (touched) at OH1 crossover at .42 sec. I'll need to see if this recurs, and perhaps deal with it. | |
| Sep 18 2002 08:50:38:200AM | Steve Wolfe | Import seg2 of 1020910028 into seg 3. Note that this was never run, but was based on a shift of 27, which was acceptable except for the final flattop duration. sweep points are: 0.600,-152100 0.850,-158750 24.3kA/sec == .9T/sec drawn 1.100,-152100 -24.3kA/sec == -.9T/sec drawn 1.150,-152100 50msec dwell if we could get it. 1.400,-158750 24.3kA/sec 1.700,-158750 300msec dwell 1.769,-152100 would be 88kA/sec, but it inverts at 1.7sec anyway These are calling for sweeps about a third as fast as the old limit of 75kA/sec, and we are undoubtedly going to get slower than that. Jim's memo allows 1.1T/sec, which is slightly faster than this, around 30kA/sec actual, but is based on 1020910022, which had smaller amplitude shorter wiggles. Since we do need the amplitude of .2T, we can try slightly shorter drawn waveforms with increased dwells. | |
| Sep 18 2002 09:21:10:507AM | 1020918001 | Steve Wolfe | Shot#1 : constant tf of -152100kA, 1MA based on 1020910020, with mods as noted above. plasma, full length. Still seems to have a glitch at crossover. rco2v appears to be 55.5cm, so the nl_04 of 1.07e20/m2 comes out to 1.93e20/m3 It should be close enough, or I can tweak it up. Te(0) seems to be pretty flat. Amanda needs to reset her grating. Jim needs a cell access to tweak tci next shot: sweeps. |
| Sep 18 2002 09:37:14:107AM | 1020918002 | Steve Wolfe | Shot#2: modify seg3 Ip as on shot 1 seg2 import seg2 from seg3 import seg3 from seg2 of shot 1 (for future reference) plasma almost full length 1.9sec First wiggle only made it to 5.56, second to 5.59T Need to overshoot or else put in a dwell in the drawn waveform to make sure it gets there. next shot: increase the first upward sweep rate. |
| Sep 18 2002 09:50:46:783AM | 1020918003 | Steve Wolfe | Shot#3: increase the first upward sweep rate. add a point at .750, -158750, remove point at 1.769 plasma to 1.9sec, no noises reported from the alternator. sweep looks ok (not great, just ok). next shot: extend rxl, zxl waveforms to 1.7sec |
| Sep 18 2002 09:54:52:153AM | 1020918003 | Steve Wolfe | Shot#3: increase the first upward sweep rate. add a point at .750, -158750, remove point at 1.769 plasma to 1.9sec, no noises reported from the alternator. sweep looks ok (not great, just ok). next shot: extend rxl, zxl, nl04 waveforms to 1.7sec, and increase seg2 gas puff |
| Sep 18 2002 10:04:22:197AM | 1020918004 | Steve Wolfe | Shot#4: extend rxl, zxl, nl04 waveforms to 1.7sec, and increase seg2 gas puff dud. Irby jinxed it. Br looks negative, but it did earlier too. next shot: increase br0 from .0012 to .0017 |
| Sep 18 2002 10:24:22:417AM | 1020918005 | Steve Wolfe | Shot#5: extend rxl, zxl, nl04 waveforms to 1.7sec, and increase seg2 gas puff increase br0 from .0012 to .0017, increase pg4 from 23 to 25msec also, fix early seg2 tf point at 150000 instead of 152000. Earl reports that the BN tile was no longer visible on shot #3. plasma, past 2sec, all the way down. the crrent is dropping by 15kA during the "flattop" density jumps up at 1.6sec or so. Next shot: try putting in a 15kA ramp on Ip 1sweep starting at 0.9sec, |
| Sep 18 2002 10:35:36:670AM | 1020918006 | Steve Wolfe | Shot#6: Go to one sweep 0.900 -152100 1.000 -158750 1.100 -158750 1.350 -152100 1.700 -152100 Also put a 15kA ramp on Ip. fizzle next shot: drop pg4 back to 23msec |
| Sep 18 2002 10:49:51:607AM | 1020918007 | Steve Wolfe | Shot#7: drop pg4 back to 23msec Go to one sweep 0.900 -152100 1.000 -158750 1.100 -158750 1.350 -152100 1.700 -152100 Also put a 15kA ramp on Ip. plasma full length, current a little flatter, still some sag density increases after 1.5sec Amanda says it's a good Bt ramp |
| Sep 18 2002 11:08:28:617AM | 1020918008 | Steve Wolfe | Shot#8: try to increase the upsweep 0.900 -152100 0.910 -158750 1.100 -158750 1.350 -152100 1.700 -152100 Also put a 25kA ramp on Ip. plasma, full length. ip looks pretty flat now. Not a whole lot faster on the up-sweep. next shot: sweep down a little faster. |
| Sep 18 2002 11:16:10:930AM | 1020918009 | Steve Wolfe | Shot#9: try to increase the down-sweep a bit 0.900 -152100 0.910 -158750 1.100 -158750 1.250 -152100 1.700 -152100 plasma, full length. Alternator reports no noises. next shot: drop Ip to 500kA |
| Sep 18 2002 11:38:02:033AM | 1020918010 | Steve Wolfe | Shot#10: drop Ip to 500kA, same sweep. 0.900 -152100 0.910 -158750 1.100 -158750 1.250 -152100 1.700 -152100 plasma, disrupted at 1.6sec, but it looked double null. EF1's railed. density went way up. EF1's rail at 1.24sec, but before that it goes limited from .67 to .74 could be crossover. Startup had runaways too. |
| Sep 18 2002 12:06:23:933PM | 1020918011 | Steve Wolfe | Shot#11: move Ip gain switch out to .8 to avoid crossover Drop max current at .2 to 650kA, nl4 ramp to end at .6sec reduce seg2 gas puff. change flattop ip to -550000 No startup changes. It probably needs one, but which way? disrupted at .9sec. Stayed diverted, but still spews at about the time the strike gets onto the outer plate. It looks an awful lot like an H-mode, density and Prad and W go up Halpha and Te go down. Next shot: drop density demand to 6e19 |
| Sep 18 2002 12:16:09:170PM | 1020918012 | Steve Wolfe | Shot#12: drop density demand to 6e19, ip to 550kA straight across. plasma ran through. It got 550kA this time, so I should probably program 500 again. Density flat around 6e19 nl04. |
| Sep 18 2002 12:35:24:347PM | 1020918013 | Steve Wolfe | Shot#13: program current flat at 500kA put Ip gain up to 8 at .3, notch to 2 from .65 to .8 nl4 up to 8e19 Did it again, survives almost to the end, but the marfe/detachment/whatever happens at .73sec next shot: nl4 to 7e19, try dropping zxl by 1cm |
| Sep 18 2002 12:42:29:893PM | 1020918014 | Steve Wolfe | Shot#14: nl4 to 7e19, try dropping zxl by 1cm plasma, still detaching/marfing/ whatever. I don't think we're going to get any higher in density than shot 12. next shot: back to shot12. |
| Sep 18 2002 12:57:22:047PM | 1020918015 | Steve Wolfe | Shot#15: change of plan, try 650kA, 8e19 nl4 leave gain notch as before. plasma full ,length, no detachment. next shot: try going back to nl4=1 |
| Sep 18 2002 01:12:46:170PM | 1020918016 | Steve Wolfe | Shot#16: try going back to nl4=1e20, move Ip gain notch to .55 to .70 increase pg3 puff in seg2. Put a ramp up on the current to try to prevent the sag Back to detaching. Try keeping nl4 at 8e19 until .65, then increasing. |
| Sep 18 2002 01:26:30:140PM | 1020918017 | Steve Wolfe | Shot#17: Go back to 8e19 like shot 15 extend zxu to 1.7sec plasma, full length, Ip looks pretty flat; nl4 around 9e19. next shot: repeat. We're going to call this condition 3 of the plan |
| Sep 18 2002 01:36:34:333PM | 1020918018 | Steve Wolfe | Shot#18: repeat. plasma, looks the same. next shot: repeat once more |
| Sep 18 2002 01:53:08:690PM | 1020918019 | Steve Wolfe | Shot#19: repeat. plasma full length looks ok to me. next shot: change to a long Bt sweep for cross calibration. |
| Sep 18 2002 02:04:14:900PM | 1020918020 | Steve Wolfe | Shot#20: Ramp tf down from 0.800 -152100 1.350 -123000 1.700 -123000 plasma, full length. looks ok next shot: drop the density and put the waggles back |
| Sep 18 2002 02:21:23:043PM | 1020918021 | Steve Wolfe | Shot#21: re-import seg 20 from 1020918019 decrease nl4 to 3e19; decrease seg2 pg3 puff to zero plasma, full length, nl4 4.3e19 and falling. crossover is now out to .63 to .72sec, so I should move the notch gas is off after 0.1sec next shot: move the Ip gain notch to .6 to .75, wait for the density to drop |
| Sep 18 2002 02:40:59:143PM | 1020918022 | Steve Wolfe | Shot#22: move the Ip gain notch to .6 to .75, wait for the density to drop Brian gets a cell access to check out the probe. plasma, full length. nl4 is at 2.7e19, pretty flat. We're beginning to puff a little. plasma runs outside a little in startup. Some buildup of hards through the shot. next shot: raise pre-puff to 25msec |
| Sep 18 2002 02:56:17:360PM | 1020918023 | Steve Wolfe | Shot#23: raise pre-puff to 25msec plasma, full length. startup still moving outside. nl4 looks similar to 22; small gas level throughout. sawtooth change comes earlier on this one, around 1.1sec |
| Sep 18 2002 03:09:57:057PM | 1020918024 | Steve Wolfe | Shot#24: raise nl4 to 4e19 to try to get things more steady. plasma, full length, nl4 = 4e19 with small oscillation; probably too much gain in the feedback. next shot: drop the nl4 gain from 8 to 4 |
| Sep 18 2002 03:29:05:940PM | 1020918025 | Steve Wolfe | Shot#25: drop the nl4 gain from 8 to 4, raise pre-puff to 26msec raise nl4 to 5e19 plasma, full length nl4 about 4.7e19 (lower gain, no pg3 program). next shot: repeat, Dave wants another one and Amanda didn't get signal on four gpc channels |
| Sep 18 2002 03:41:40:807PM | 1020918026 | Steve Wolfe | Shot#26: repeat plasma, full length. density looks good. gpc channels are back, after a power cycle on the pre-amps. and the injections are gone; Brian was probing, may have been launching a little debris next shot: repeat without tf waggles |
| Sep 18 2002 03:59:53:077PM | 1020918027 | Steve Wolfe | Shot#27: repeat without tf waggles 8 minute delay for IGOR; Tom had to clear a cmodws01 server. plasma, full length. Next shot: back to 1MA, lower density. |
| Sep 18 2002 04:22:52:790PM | 1020918028 | Steve Wolfe | Shot#28: back to 1MA, lower density. Reload seg2 from 1020918009 and reduce nl4 to 6e19. Also, extend the zxu waveform to 1.7 sec, as on the lower current shots and slight decrease in pg3 waveform. Another delay for IGOR plasma disrupts at 1.73sec loses sawteeth at 1.3 or so next shot: decrease density to 5e19, decrease inner gap by 2mm |
| Sep 18 2002 04:39:03:230PM | 1020918029 | Steve Wolfe | Shot#29: decrease density to 5e19, decrease clearin by 2mm plasma disrupts at 1.77sec, similar. Something is changing at around 1.2sec. Lose the sawteeth again then. This looks like the low density thing, but this is pretty high nl to see it. Next shot: extend pg3 pulse in seg2 past 1.2sec, and take out the waggle. |
| Sep 18 2002 04:44:01:677PM | 1020918030 | Steve Wolfe | Shot#30: extend pg3 pulse in seg2 past 1.2sec, and take out the waggle. fizzle. The disruption probably did us in ran outside. next shot: raise pg4 by 2msec. |
| Sep 18 2002 05:02:26:477PM | 1020918031 | Steve Wolfe | Shot#31: raise pg4 by 2msec to 28msec plasma, full length but lots of early hards. Looks like the bad mode starts at around .88sec on this one, which had no waggle. I don't know what's causing it. End of run. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:57:01:213AM | Plasma | Ok | |
| 2 | 09:26:46:257AM | Plasma | Ok | |
| 3 | 09:41:54:987AM | Plasma | Ok | |
| 4 | 09:56:50:737AM | Plasma | Ok | |
| 5 | 10:14:54:810AM | Plasma | Ok | |
| 6 | 10:30:49:680AM | Plasma | Ok | |
| 7 | 10:43:41:780AM | Plasma | Ok | |
| 8 | 10:57:11:757AM | Plasma | Ok | |
| 9 | 11:11:56:827AM | Plasma | Ok | |
| 10 | 11:24:47:913AM | Plasma | Ok | |
| 11 | 11:51:47:107AM | Plasma | Ok | |
| 12 | 12:08:17:217PM | Plasma | Ok | |
| 13 | 12:21:56:493PM | Plasma | Ok | |
| 14 | 12:37:03:850PM | Plasma | Ok | |
| 15 | 12:53:52:990PM | Plasma | Ok | |
| 16 | 01:07:18:377PM | Plasma | Ok | |
| 17 | 01:20:09:487PM | Plasma | Ok | |
| 18 | 01:33:42:780PM | Plasma | Ok | |
| 19 | 01:47:05:710PM | Plasma | Ok | |
| 20 | 02:01:24:083PM | Plasma | Ok | |
| 21 | 02:14:20:420PM | Plasma | Ok | |
| 22 | 02:34:07:397PM | Plasma | Ok | |
| 23 | 02:46:54:467PM | Plasma | Ok | |
| 24 | 03:01:31:620PM | Plasma | Ok | |
| 25 | 03:15:25:867PM | Plasma | Ok | |
| 26 | 03:34:46:230PM | Plasma | Ok | |
| 27 | 03:55:24:833PM | Plasma | Ok | |
| 28 | 04:09:31:563PM | Plasma | Ok | |
| 29 | 04:28:13:850PM | Plasma | Ok | |
| 30 | 04:41:11:077PM | Plasma | Ok | |
| 31 | 04:54:23:010PM | Plasma | Ok | |