| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Martin Greenwald |
| Physics operator(s): | Ron Parker |
| Engineering operator(s): | Gary Dekow,Ed Fitzgerald,Bill Parkin |
| Engineering Operator Run Comment |
| MP#300 TF Ramps; SL:Greenwald; PO:Parker; EO:Dekow/Fitz/Parkin |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:03:490PM |
| Author: Martin Greenwald |
| Run Summary for 1040311 MP 300 - BT scans and ITB hysteresis Session Leader - Greenwald Phys Op - Parker Background and approach: We've observed a sharp threshold in BT for formation of ITBs produced by off-axis RF heating. The threshold is interpreted as an effect of deposition radius, with barriers formed when the ICRF resonance location is greater than about |r/a| = 0.45. The threshold is seen for deposition on both the low and high field side and is quite sharp - amounting to about 0.1 T or less than 5-10% in r/a. The point of today's experiment is to probe this threshold boundary dynamically to look for hysteresis which could help categorize the transition and shed light on the underlying physics. Plan: 1. Start at with a shot like 1040309029 - 4.5 T - demonstrate ITB 2. Begin a Bt ramp - upward starting somewhat after the ITB transition and ramping at a rate that would get us to about 4.8 T before the end of flat-top If the ITB is not lost, increase Bt ramp rate 3. Start with Bt above the threshold ~ 4.8T - demonstrate lack of ITB 4. Ramp Bt down at the rate established in 2. Results: Ragged. Some data was obtained, but the data server problems got so severe that the run had to be cancelled. As in the previous 2 days, ITBs were produced routinely. Ramping Bt did not extend range of ITBs. Clearest example is 012 which started developing as an ITB then quietly returned to an ordinary H-mode when the ramped field exceeded 4.7 T. There was no build-up of radiation, no back transition and no RF faults. So the tentative conclusion based on this sparse data set is that there is not significant hysteresis. Shot Bt ramp result 03 4.55-4.55 itb steady 04 4.55-4.55 itb steady 05 4.55-4.8 itb til back transition at 4.62 (radiation?) 06 4.55-4.8 itb til back transition at 4.66 (radiation?) 07 4.55-4.8 itb til back transition at 4.65 (radiation?) 09 4.55-4.8 itb til back transition at 4.65 (radiation?) 12 4.6 -5.0 brief itb, degrades after 4.7 13 4.6 -4.9 no itb 14 4.6 -4.8 itb til back transition at 4.77 T (radiation?) 15 4.6 -4.9 no itb 16 4.6 -4.9 v. weak itb with no back transition no improvement w/ Bt > 4.7 |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:49:490PM |
| Author: Ron Parker |
| ;; This buffer is for notes you don't want to save, and for Lisp evaluation. ;; If you want to create a file, visit that file with C-x C-f, ;; then enter the text in that file's own buffer. Physop Summary 1040311 The purpose of the run was to explore the possibility of hysteresis in ITB formation by slow ramping of the TF, once an ITB is formed. The run started promptly and the first several shots went off without a hitch.But after the 3rd shot, a data system problem developed. The fix only delayed the shot sequence by ~ 5 minutes, but the event was a harbinger of things to come. A PLC hangup also developed after shot 3 and this took 45 minutes to find a workaround. The PLC malfunction was not a problem thereafter.Shots 4-7 ran well and the program of ramped fields was underway. However, a data system problem developed after shot 7, resulting in a 20 minute delay. Shot 8 was a peculiar fizzle, with the plasma current twice reaching 100 kA before dying. Shot 9 ran well, and this was followed by a hold for Jim Decker's visit in the cell. But the hold was extended for Tom to "fix" the data system problem. The hold was over an hour. Shot 10 had data system problems, but Tom managed to recover the data although it was a no power shot. Shot 11 was a no power shot. Shot 12 was completely normal,no data system problems. Shots 13 - 16 ran well, and data were collected.Then the data system problems, which had been intermittent, became permanent. Three no power shots were run,and all had data system problems. Tom's view was that it was unlikely to that the problem would be fixed before the end of the run , so the run was scrubbed at this point (~16:00). Scorecard: 13 good shots (machine ran well) 1 peculiar fizzle (over 100 kA a fizzle?), 5 no power shots due to data system problems. Engineering Setup and Run Plan 1040311 ECDC overnight in D2, stopping at 07:00 Run begins at 09:00 and ends at 17:00 Purpose: MP#300 TF Ramps Session leader: Greenwald Physop: Parker Engineering Setup: Power Supplies as on 1040309029 Gas System Setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper with 15 psi He3 Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) fill NINJA (lower cap) with 8 psi D2 Diagnostic gate valve permissives for ECE, VUV, DNB assuming no vacuum problems RF: Transmitters #1 and 2 in RUN-ON by 08:00 Run Plan The purpose of this run is to investigate ITB formation threshhold, hysteresis behavior and operational parameter space. In particular, ITB's will be formed and the field ramped (up and down) to determine if the ITB will be maintained once formed. We'll start with shot 1040309029 at 4.5 T as a fudicial ITB shot. Then we'll begin a TF ramp, ramping up after the ITB forms and reaching about 4.8 T at the end of the flat-top. If the ITB persists, we'll increase the ramp rate. Then we'll begin with the field above the threshhold, e.g., 4.8 T and demonstrate no ITB formation. We'll then ramp the field down from 4.8 T at the rate established above. If time, we'll repeat with the resonance on the low field side, starting with shot 1040310012, BT ~ 6.4 T and again investigate the effect of a field ramp. |
| Session Leader Comments | |||
| Mar 11 2004 08:48:09:393AM | Martin Greenwald | MP 300 - BT scans and ITB hysteresis Session Leader - Greenwald Phys Op - Parker Background and approach: We've observed a sharp threshold in BT for formation of ITBs produced by off-axis RF heating. The threshold is interpreted as an effect of deposition radius, with barriers formed when the ICRF resonance location is greater than about |r/a| = 0.45. The threshold is seen for deposition on both the low and high field side and is quite sharp - amounting to about 0.1 T or less than 5-10% in r/a. The point of today's experiment is to probe this threshold boundary dynamically to look for hysteresis which could help categorize the transition and shed light on the underlying physics. Plan: 1. Start at with a shot like 1040309029 - 4.5 T - demonstrate ITB 2. Begin a Bt ramp - upward starting somewhat after the ITB transition and ramping at a rate that would get us to about 4.8 T before the end of flat-top If the ITB is not lost, increase Bt ramp rate 3. Start with Bt above the threshold ~ 4.8T - demonstrate lack of ITB 4. Ramp Bt down at the rate established in 2. If time allows, repeat with the resonance on the low-field side - starting with say shot 1040310012 Bt ~ 6.4 T (ramps performed in opposite direction) | |
| Mar 11 2004 04:33:22:327PM | Martin Greenwald | Results: Ragged. Some data was obtained, but the data server problems got so severe that the run had to be cancelled. As in the previous 2 days, ITBs were produced routinely. Ramping Bt did not extend range of ITBs. Clearest example is 012 which started developing as an ITB then quietly returned to an ordinary H-mode when the ramped field exceeded 4.7 T. There was no build-up of radiation, no back transition and no RF faults. So the tentative conclusion based on this sparse data set is that there is not significant hysteresis. Shot Bt ramp result 03 4.55-4.55 itb steady 04 4.55-4.55 itb steady 05 4.55-4.8 itb til back transition at 4.62 (radiation?) 06 4.55-4.8 itb til back transition at 4.66 (radiation?) 07 4.55-4.8 itb til back transition at 4.65 (radiation?) 09 4.55-4.8 itb til back transition at 4.65 (radiation?) 12 4.6 -5.0 brief itb, degrades after 4.7 13 4.6 -4.9 no itb 14 4.6 -4.8 itb til back transition at 4.77 T (radiation?) 15 4.6 -4.9 no itb 16 4.6 -4.9 v. weak itb with no back transition no improvement w/ Bt > 4.7 | |
| Mar 11 2004 09:10:58:440AM | 1040311001 | Martin Greenwald | Multiple H-modes, perhaps weak ITB on last one. No power from D |
| Mar 11 2004 09:22:40:747AM | 1040311002 | Martin Greenwald | Multiple H-modes RF power higher but still some trips ITB late |
| Mar 11 2004 09:53:24:820AM | 1040311003 | Martin Greenwald | better - ITB seems to collapse at about 1.2 seconds on its own (data system hang - lost a few signals?) |
| Mar 11 2004 10:46:31:143AM | 1040311004 | Martin Greenwald | Similar to previous shot Barrier formed at about 0.9 seconds will begin Bt ramp on next shot starting at that time |
| Mar 11 2004 10:58:03:730AM | 1040311005 | Martin Greenwald | Bt ramp starting at 0.9 sec 4.5T to 4.8 at 1.5 sec ITB was somewhat briefer |
| Mar 11 2004 11:35:49:080AM | 1040311006 | Martin Greenwald | similar to last shot (+ another data system glitch) |
| Mar 11 2004 11:35:17:890AM | 1040311007 | Martin Greenwald | another problem with data system |
| Mar 11 2004 12:04:11:947PM | 1040311008 | Martin Greenwald | fizzle |
| Mar 11 2004 12:04:49:260PM | 1040311008 | Martin Greenwald | fizzle - to 120 kA |
| Mar 11 2004 02:06:09:130PM | 1040311012 | Martin Greenwald | Good shot ITB starts to develop, but is lost at .9 sec when Bt reaches 4.7 T |
| Mar 11 2004 02:20:51:933PM | 1040311013 | Martin Greenwald | reduced Bt ramp by 2% but No ITB |
| Mar 11 2004 02:49:06:013PM | 1040311015 | Martin Greenwald | No ITB |
| Mar 11 2004 03:13:46:170PM | 1040311016 | Martin Greenwald | very weak itb - no back transition |
| Physics Operator Comments | |||
| Mar 11 2004 09:18:13:010AM | 1040311001 | Ron Parker | The first shot was programmed the same as shot 1040309029, and it ran as such. However, the plasma tripped out of H-mode twice, so we'll repeat until a sustained H-Mode is obtained. |
| Mar 11 2004 09:22:40:760AM | 1040311002 | Ron Parker | Shot again had multiple H-modes. Continue the shot on shot 3. |
| Mar 11 2004 10:37:56:367AM | 1040311003 | Ron Parker | Shot 3 again had the H-mode drop out. Data system problem being attended to. Data system fixed, 5 min delay, but PLC problem developed. The problem was fixed with a workaround. 45 minute delay. |
| Mar 11 2004 10:47:15:850AM | 1040311004 | Ron Parker | After the delay of 45 minutes, shot was run, similar to shots 1-3. For next shot, TF will be ramped from 4.5 to 4.8 T over the time interval 0.9 s to 1.5 s |
| Mar 11 2004 04:25:55:520PM | 1040311005 | Ron Parker | Shot 5 ran well with appearance of an ITB. |
| Mar 11 2004 11:19:39:947AM | 1040311006 | Ron Parker | Shot 6 ran OK, similar to other shots. Computer problems. |
| Mar 11 2004 12:01:43:483PM | 1040311007 | Ron Parker | Shot 7 ran after short delay to fix data system problem. Looks like the data system is hung up again. After 20 minute delay, ready for shot 8. |
| Mar 11 2004 12:08:32:990PM | 1040311008 | Ron Parker | Shot 8 sort of fizzled, but after reaching over 100 kA. |
| Mar 11 2004 12:25:03:813PM | 1040311009 | Ron Parker | Shot 9 ran OK. Pause for VIP tour in cell. |
| Mar 11 2004 12:33:56:377PM | 1040311009 | Ron Parker | There will be a hold for Tom to deal with computer issues. The hold might be 30-40 minutes or hours. |
| Mar 11 2004 01:50:19:950PM | 1040311010 | Steve Wolfe | Shot#10: No power cycle after Tom did a disk transplant on AlcDaq. Shot ran through, but data doesn't come up. Tom did some more magic and data came up after a while. |
| Mar 11 2004 01:58:25:433PM | 1040311011 | Steve Wolfe | Shot#11: Another no power cycle after Tom did a disk transplant on AlcDaq. Data coming through. |
| Mar 11 2004 02:01:44:397PM | 1040311012 | Steve Wolfe | Shot#12: increase tf ramp by .1T at start and .2T at end of ramp. first point from -122000 to -124800; second point from -131000 to -136600 plasma full length. Parker is back and will take over as Physop again. |
| Mar 11 2004 02:13:21:220PM | 1040311012 | Ron Parker | Parker back as PO. Shot 12 will be repeated, except field at end of ramp will be decreased by 0.1 T. |
| Mar 11 2004 02:22:24:297PM | 1040311013 | Ron Parker | Shot ran well, no ITB. Ramp will be again reduced on next shot by 0.1 T at end of ramp. |
| Mar 11 2004 02:38:49:790PM | 1040311014 | Ron Parker | Shot 14 ran well, no ITB. Next: reload shot 13, i.e., restore 0.1 T to ramp. |
| Mar 11 2004 02:53:21:883PM | 1040311015 | Ron Parker | Shot 15 OK, for next shot the ramp will be delayed by 150 ms. |
| Mar 11 2004 03:26:56:593PM | 1040311016 | Ron Parker | Shot ran well, next shot repeats. Oops, a no power shot because data system hung during countdown. Next shot: another no power shot |
| Mar 11 2004 03:50:20:777PM | 1040311017 | Ron Parker | Shot 17 was a no power shot |
| Mar 11 2004 03:51:05:870PM | 1040311018 | Ron Parker | Shot 18 was a no power shot. |
| Mar 11 2004 03:51:26:590PM | 1040311019 | Ron Parker | Shot 19 was a no power shot. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:04:14:527AM | Plasma | Ok | |
| 2 | 09:17:40:383AM | Plasma | Ok | |
| 3 | 09:32:40:327AM | Test | Bad | |
| 4 | 10:36:20:673AM | Plasma | Ok | |
| 5 | 10:50:56:910AM | Plasma | Ok | |
| 6 | 11:06:47:963AM | Test | Bad | |
| 7 | 11:28:51:370AM | Plasma | Ok | |
| 8 | 12:01:21:403PM | Plasma | Ok | |
| 9 | 12:14:03:137PM | Plasma | Ok | |
| 10 | 01:26:34:183PM | Test | Ok | |
| 11 | 01:49:33:513PM | Test | Ok | |
| 12 | 01:59:19:357PM | Plasma | Ok | |
| 13 | 02:14:57:660PM | Plasma | Ok | |
| 14 | 02:30:41:857PM | Plasma | Ok | |
| 15 | 02:45:06:250PM | Plasma | Ok | |
| 16 | 03:00:46:093PM | Plasma | Ok | |
| 19 | 03:47:53:163PM | Test | Bad | |