| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Bruce Lipschultz |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| Divertor geometry/higher pre-charge |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:52:863PM |
| Author: To Be Determined |
| Higher Precharge Development. PO Hutch, SL Blip, EO Bertolino. Summary The objectives of this run were not met, and the main achievement was to demonstrate that it is impossible to get much more precharge with the present performance of the power supplies. After shot 1 showed that the OH2 supplies were not giving the 30kA requested, shots 2 to 8 tried tweaking the power-supplies to help, finally blowing a lot of fuses. Thereafter it was accepted that this is presently mission impossible, so we lowered the sights to 26kA on OH2. Shots 10-21 attempted to tweak up the configuration. Four flashes were obtained. Shot 21 still needs field null tuning but is getting close. However, EF1 PSs, especially lower, were a major headache. Engineering We have demonstrated in this run that the OH2s are dead (i.e. down to 20V or less) at about 27kA at 5.3T. This is unacceptable. We need a serious proposal to fix the control board so that this does not happen. The EF1 problem is basically that these power supplies whose nominal performance is 200V, 15kA, give less than 150V under modest load and trip out at 6kA. Again this is unacceptable. We need a plan to get more voltage, if we are to move forward in machine performance. Scorecard: 8 duds, 4 fizzles, 7 PLC-controlled tests. 1 loud bang. Shot sequence: Scaled the initiation from 950112031. All prebreakdown currents stretched to Coil OH1 OH2 EF1U EF1L EF2U EF2L EF4 Demand -22950 -30531 -6411 -6433 -2171 -2163 -1400 Increased the EF1 V to -160V throughout precharge. Added some early EF1 points to encourage the current up early. Commutation resistors lowered by a factor of 1.36 Load segment 2 from 941220018: a slot divertor. Shot 1 dud Lots of power supplies did not reach demand. OH1 -21764 OH2U -25k OH2L -22k Ef1 -5480 -4908 Ef2 -1937 -2324 EF4 -1340. OH2s appear to be self-limiting. EF1 hasn't got the volts. 2 Power Supply test under PLC. OH2 only. Reached 30kA 3 PS test. OH1,2 TF, PLC. Clear evidence of not reaching current and sagging. This appears to be the margin angle regulation on the PS. Go into PS tweak mode. Tweak on angle. 4 PS test OH2u=28k, OH2L=25kA, both still sagging. 5 PS test OH2U=30k, OH2L=27kA sagging. 6 Ditto 7 Ditto OH2U=30.7k, OH2L=28.5 sagging. 8 PS test Blew fuses in OH2. Lots of PS work. Rescaled the current demands to 1.2 times the old values. Coil OH1 OH2 EF1 EF2 EF4 Demand -20100 -26600 -5690 -1970 -1240 Resistors scaled appropriately. 9 PS test. Margin angle at 30 similar to shot half way between 4 and 5. Ok at 10kA. 10 PS test. Got 26.7kA, 28.6kA on OH2s. Return to a full try with all PS. 11 dud EF1l 5181. Oh2 24.5. Oh1 19.1 Asked for 28 margin angle. Ef1 earlier start and close. 12 dud Ef1L=5148 EF1U=5667, OH1 19.06, OH2U 24.8, Oh2U=25.4 Increased EF1L drawn early. Increased OH1,2 Vs to -100, -35V. 13 dud Ef1L=5132 EF1U=5639 OH1=20020 OH2U=25580 OH2L=25600. Symmetrized EF1s like EF1L. 14 dud EF1 faulted. Moved OH drawn to -1.2 (.1s earlier.) and end of ramp .2 ms earlier. Tweaked up their voltages. OH Start times to -1.2s. 15 dud Looked better. EF1L 5377, EF1U 5620. OH1 20210 OH2U 26205 OH2 26136. Bz is 30mT too high and quite curved. Kept EF1 programmed V on till t-0. Oh1 demand to 19.5kA. EF2s to 2400A demand. 16 Fiz Flash at 17ms. EF1L=-5405, EF1U=-5717A Put OH2 close switch to 1s. Increased EF1L voltage to 300V at 0s. 17 Fiz Flash at 15ms. EF1L=-5404. Moved EF1 .1s earlier. 18 dud Worse if anything Moved OH stack start to -1.35s 19 dud EF1U tripped at close to 6kA for no obvious reason. Backed off the EF1U demand to try to avoid trips. 20 fiz Breakdown at 17ms. EF1L -5542A. Bz rather low. EF4 to -1140, from 1240. 21 fiz Breakdown at 10ms. Current 25kA. |
| Session Leader Comments | |||
| Jan 13 1995 08:51:06:060AM | Bruce Lipschultz | run 9501013
Physics Op.: Ian Hutchinson Session Leader: B. Lipschultz Eng. Operator: V. Bartolino Mini-proposal # 69: Equilibrium development for Divertor Studies The primary purpose of todays run is to improve the 'slot' divertor equilibrium developed on 12/20. In that run the x-point was basically located on the nose of the inner divertor in order to get the outer divertor strike point down the slot. To remedy this, the primary change is to allow larger OH precharge. In theory this will allow the outer separatrix leg to curve around EF1 more. In addition the EF4 power supplies have been upgraded to allow higher current. This is also supposed to help. There are some additional goals of this run: (1) Determine the maximum gain on RXL and ZXL compatible with controlling the strike point with STRKPSI. (2) Determine the STRKPSI values which corr. to locating the strike point at different points on the divertor plate and floor. (3) Bring the slot equilibrium closer to the scanning probe. (4) Spend a few shots trying to obtain a flat-plate equilibrium such that the scanning probe can reach it. | |
| Jan 13 1995 08:53:45:570AM | Bruce Lipschultz | run 9501013
Physics Op.: Ian Hutchinson Session Leader: B. Lipschultz Eng. Operator: V. Bartolino Mini-proposal # 69: Equilibrium development for Divertor Studies The primary purpose of todays run is to improve the 'slot' divertor equilibrium developed on 12/20. In that run the x-point was basically located on the nose of the inner divertor in order to get the outer divertor strike point down the slot. To remedy this, the primary change is to allow larger OH precharge. In theory this will allow the outer separatrix leg to curve around EF1 more. In addition the EF4 power supplies have been upgraded to allow higher current. This is also supposed to help. There are some additional goals of this run: (1) Determine the maximum gain on RXL and ZXL compatible with controlling the strike point with STRKPSI. (2) Determine the STRKPSI values which corr. to locating the strike point at different points on the divertor plate and floor. (3) Bring the slot equilibrium closer to the scanning probe. (4) Spend a few shots trying to obtain a flat-plate equilibrium such that the scanning probe can reach it. | |
| Jan 13 1995 08:59:39:620AM | Bruce Lipschultz | Eng. Operator: V. Bertolino
Mini-proposal # 69: Equilibrium development for Divertor Studies The primary purpose of todays run is to improve the 'slot' divertor equilibrium developed on 12/20. In that run the x-point was basically located on the nose of the inner divertor in order to get the outer divertor strike point down the slot. To remedy this, the primary change is to allow larger OH precharge. In theory this will allow the outer separatrix leg to curve around EF1 more. In addition the EF4 power supplies have been upgraded to allow higher current. This is also supposed to help. There are some additional goals of this run: (1) Determine the maximum gain on RXL and ZXL compatible with controlling the strike point with STRKPSI. (2) Determine the STRKPSI values which corr. to locating the strike point at different points on the divertor plate and floor. (3) Bring the slot equilibrium closer to the scanning probe. (4) Spend a few shots trying to obtain a flat-plate equilibrium such that the scanning probe can reach it. | |
| Jan 13 1995 09:02:53:850AM | Bruce Lipschultz | Eng. Operator: V. Bertolino
Mini-proposal # 69: Equilibrium development for Divertor Studies The primary purpose of todays run is to improve the 'slot' divertor equilibrium developed on 12/20. In that run the x-point was basically located on the nose of the inner divertor in order to get the outer divertor strike point down the slot. To remedy this, the primary change is to allow larger OH precharge. In theory this will allow the outer separatrix leg to curve around EF1 more. In addition the EF4 power supplies have been upgraded to allow higher current. This is also supposed to help. | |
| Jan 13 1995 09:04:12:700AM | Bruce Lipschultz | There are some additional goals of this run:
(1) Determine the maximum gain on RXL and ZXL compatible with controlling the strike point with STRKPSI. (2) Determine the STRKPSI values which corr. to locating the strike point at different points on the divertor plate and floor. (3) Bring the slot equilibrium closer to the scanning probe. (4) Spend a few shots trying to obtain a flat-plate equilibrium such that the scanning probe can reach it. | |
| Jan 22 1995 03:26:37:280PM | Jim Terry | The H_alpha signal from the camera viewing from the right side
of H port was abnormally low for this run, presumably because the view was being obscured by ice (frost) on the camera and/or window. This is signal \SPECTROSCOPY::TOP.Z_METER:INCAA16:INPUT_05 (uncalibrated) or \SPECTROSCOPY::top.uvis:HA_2_BRIGHT (calibrated). The other camera on H port \SPECTROSCOPY::TOP.Z_METER:INCAA16:INPUT_02 (uncalibrated) or \SPECTROSCOPY::top.uvis:HA_1_BRIGHT (calibrated) may have been affected as well. | |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:35:48:410AM | Plasma | Bad | oh2's don't reach current desired |
| 2 | 09:58:50:230AM | Test | Ok | oh2's only |
| 3 | 10:19:50:370AM | Test | Ok | oh2's,oh1 and tf |
| 4 | 10:36:23:080AM | Test | Ok | oh's and tf |
| 5 | 10:50:53:060AM | Test | Ok | oh2's,oh1 and tf |
| 6 | 11:11:27:830AM | Test | Ok | oh's, tf only |
| 7 | 11:24:20:590AM | Test | Ok | test |
| 8 | 11:41:22:370AM | Test | Bad | comm faults |
| 9 | 01:11:53:260PM | Test | Ok | oh2's only |
| 10 | 01:44:13:280PM | Test | Ok | tf,oh's only |
| 11 | 01:58:34:820PM | Plasma | Ok | no faults |
| 12 | 02:19:59:070PM | Plasma | Ok | no faults |
| 13 | 02:35:13:290PM | Plasma | Ok | no faults |
| 14 | 02:50:30:830PM | Plasma | Ok | comm and cond faults |
| 15 | 03:32:37:730PM | Plasma | Ok | no faults |
| 16 | 03:49:04:590PM | Plasma | Ok | no faults |
| 17 | 04:03:08:350PM | Plasma | Ok | no faults |
| 18 | 04:17:38:620PM | Plasma | Ok | no faults |
| 19 | 04:29:52:540PM | Plasma | Bad | ef1u cond fault |
| 20 | 04:45:46:410PM | Plasma | Ok | no faults |
| 21 | 04:57:58:790PM | Plasma | Ok | no faults |