| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | John Heard |
| Physics operator(s): | Joseph Snipes |
| Engineering operator(s): | Frank Silva |
| Engineering Operator Run Comment |
| Te Fluctuations/Snipes/Silva |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:20:943PM |
| Author: To Be Determined |
| Session Leader's summary of run 990519 MP#213A - Temperature Fluctuation profile measurements during ohmic discharges Physics Operator: Snipes Session Leader: Heard Purpose: Take initial measurements of T~/T via ECE correlation radiometry using F-port high resolution ECE system. Plan: Run 5.4 T, Low Ip (700 kA) Ohmic discharges for multiple shot averaging of correlated ECE signals gathered during current flattop. Result: An EF4 test was performed before discharges to check for pickup between the correlation channels and EF4 voltage. EF4 voltage swings are evident on all channels, but lees noticible that on disruptions (990526016) and previous EF4 tests (990521004). 350 Hz voltage ripple evident on some channels, but lower in amplitude than previous tests Reproducible plasmas were established for this fiducial-like discharge. Initial correlation measurements showed very small low frequency ( f < 50 kHz) fluctuations in only one correlation pair. Moderate signal contamination (pi phasing in the correlation) was seen in two of the channel pairs. One section of the correlation system had very low signals, and a rebuild of the section during a cell access did not improve the signals remarkably. The miniproposal was stopped early and the extra time was used for ohmic h-mode exploration. Improvement of the grounding and testing of the correlation system is continuing. Shielding of power supplies appears necessary to minimize EF4 effects. one positive result is that the omegatron was able to do a large number of scans for scrapeoff impurities. See Rob Nachtrieb for details. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:01:410PM |
| Author: To Be Determined |
| Run 990527 MP213A Te Fluctuation Profile Measurements in Ohmic L-mode followed by Ohmic H-modes at 1.2 MA Session Leader: John Heard Physics Operator: Joseph Snipes Engineer in Charge: Frank Silva 1 hour ECDC in D2 prior to run, stopping in time to begin run at 08:00. Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid DISABLED leave B-side upper as is Hybrid DISABLED fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV The purpose of the run is to check-out the new ECE Heterodyne system for measuring Te fluctuations. The run will be constant fiducial-like shots at 5.4 T, though lower current, 0.6 - 0.8 MA, to minimize sawtooth amplitude with nebar = 1.5 - 2 x 10^20 m^-3 and standard lower single null diverted plasmas. We will probably start with an EF4 test for diagnostic pick-up tests. Impurities are frowned upon during this run at least during the flattop. Except for some difficulties with fizzles, the machine ran very well. Reducing the early OH1 and OH2 voltages (at Wolfe's suggestion) reduced the rate of rise of the current and led to more reliable current rises. There was a one hour delay for the session leader to fix things on his diagnostic in the cell. Then, in the early afternoon, he punted and the run turned to ohmic H-modes. We got a number of nice ohmic H-modes from shot 21 - 26 that can be used for rotation studies in support of MP#249 Impurity Transport in Ohmic H-mode. Shot 1: OH1 commutation test shot. O.K. Shot 2: Loading EF4 only test for John Heard from 990521005. O.K. Shot 3: Loading 990225002 as a standard 5.4 T, nl04 = 1 x 10^20 m^-3. Ip set initially to 0.8 MA flattop. Changed timing to invert TF and ramp down Ip at 1.1 sec to save I^2t cooling time since Heard's digitizers can only sample for 0.5 sec. Good shot with some hard x rays. Shot 4: Changed Ip to 0.7 MA flattop. Increased EF4 current by 30 A to -1310 A at breakdown. Fizzle! Shot 5: Returned EF4 current to -1280 A and reduced Br by 1 mT to 0.001 T. Good shot. Shot 6: Fizzle! Shot 7: Increased Br offset by to +0.002 T and increased EF4 current to -1290A Good shot! Shot 8: Repeat. Fizzle! Shot 9: Try reducing OH1 and OH2 voltages by 20 V and 4 V respectively between 0.005 and 0.02 sec to reduce the rate of rise of the current. Fizzle! Shot 10: Try reducing OH1 and OH2 by another 70 V and 14 V respectively since the rate of rise of the current did not come down. Increased the prepuff by 5 msec to 23 msec duration. Good shot thanks to Steve Wolfe's suggestion to decrease the OH1 and OH2 voltages a lot. Shot 11: Dropped nl04 programming to zero after 1.1 sec instead of 1.2 sec as it had been programmed. Good shot. Ramped down nicely. Shot 12: Changed the rampdown slightly after 1.4 sec to try to improve the rampdown even more. Fizzle! Shot 13: Reduced prepuff from 23 to 20 msec duration. Good shot. Shot 14: Repeat. Good shot. Shot 15: Repeat. Fizzle! Shot 16: Short delay for John Heard to go into the cell and change his detectors. Reduced Br offset by 1 mT to 0.001 T. After an hour's delay, we got a good shot. Shot 17: Repeat. Good shot. Shot 18: Modified rampdown after 1.4 sec to try to get down to 100 kA and let the fizzle detector take out the plasma. Good shot. Shot 19: Repeat with step in TF from 0.9 to 1.0 sec from -150000 A to -157000 A to sweep the GPC channels. Shot 20: Repeat. Good shot. John Heard says he is done. Shot 21: Copied shot 990520021, which was an ohmic H-mode shot at 1.2 MA and 5.4 T. Copied segment 1 from shot 990527020. Good shot. Ohmic H-mode in the rampdown. Shot 22: Increase Ip to 1.25 MA and decrease Bt to 5.0 T so that the ECE grating can be easily adjusted to give decent ECE data and still allow us to get decent ohmic H-modes. ELM-free ohmic H-mode then a ratty EDA-like H-mode in the rampdown. Shot 23: Copied shot 990521022 and increased the low field portion to 5.0 T. No H-mode. Shot 24: Decreased the field back to 4.6 T from 0.3 to 0.8 sec, then ramped back up to 5.4 T at the end of the shot. Reduced nl04 from 1.2 to 1.1 x 10^20 m^-2 at the beginning of the shot. Good shot with H-modes. Shot 25: Repeat. Good shot. One H-mode late just after the field starts to ramp back up. Shot 26: Reduced Bt to 4.4 T from 0.3 to 0.8 sec. Reduced preprogrammed gas feed after 0.3 sec. Good shot with 3 H-modes. ELM-free early, then nearly EDA, then clear EDA H-mode just at the beginning of the ramp down. Summary: Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.021 2 0.000 0.005 3 1.553 0.771 4 0.000 0.037 5 1.552 0.719 6 0.000 0.037 7 1.551 0.719 8 0.000 0.047 9 0.000 0.047 10 1.247 0.724 11 1.552 0.719 12 0.000 0.037 13 1.566 0.719 14 1.554 0.724 15 0.000 0.047 16 1.569 0.719 17 1.559 0.724 18 1.566 0.724 19 1.568 0.724 20 1.562 0.727 21 1.519 1.197 22 1.520 1.256 23 1.656 1.238 24 1.657 1.255 25 1.654 1.235 26 1.656 1.249 26 shots. 18 plasmas. 6 fizzles. 2 tests. |
| Session Leader Comments | |||
| May 27 1999 09:31:59:750AM | 990527003 | John Heard | Looks okay. Ip= ~760 kA. Something at t=.68 dropped into the flattop. Sawteeth look small enough for my processing. |
| May 27 1999 09:47:55:153AM | 990527005 | John Heard | Ip= ~710 kA. resonance positions moved ~2mm in rmid in. |
| May 27 1999 10:04:53:747AM | 990527007 | John Heard | Ip= ~720 kA. wiggle around t=.54 that is EF4 pickup. |
| May 27 1999 11:30:32:950AM | 990527010 | John Heard | wiggle around t=.54. part of fsp injection? Something at .95 as well my resonance positions are @ .872,.87,.866 etc. the burps make it in to the sample volume bottom. |
| May 27 1999 11:51:44:547AM | 990527013 | John Heard | wiggle around t=.54. fsp injection moved to .6,.8,1. OH1 crossover. Wolfe says unavoidable (unmovable) |
| May 27 1999 12:14:17:560PM | 990527014 | John Heard | shot looks okay. Signals still low on 10-14 GHz section. Need cell access to try to fix sma connector problem |
| May 27 1999 02:06:05:483PM | 990527016 | John Heard | shot looks okay. Signals still low on rebuilt 10-14 GHz section. Correlations unimproved on 8.25 & 8.875 GHz |
| May 27 1999 02:11:56:360PM | 990527018 | John Heard | Bt pedestal sweep set @ t= .9-1.1 for next shot. |
| May 27 1999 02:57:45:733PM | 990527021 | John Heard | Switched to ohmic hmode study |
| Physics Operator Comments | |||
| May 27 1999 07:44:06:090AM | Joseph Snipes | Setup for 990527 Te Fluctuations in Ohmic Plasmas Engineering Setup for Thursday, 990527 Load from 990520004 (0.8 MA, 1.4 s long flattop, nl_04=1.0e20 m-2) 1 hour ECDC in D2 prior to run, stopping in time to begin run at 08:00. Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid DISABLED leave B-side upper as is Hybrid DISABLED fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV The purpose of the run is to check-out the new ECE Heterodyne system for measuring Te fluctuations. The run will be constant fiducial-like shots at 5.4 T, though lower current, 0.6 - 0.8 MA, to minimize sawtooth amplitude with nebar = 1.5 - 2 x 10^20 m^-3 and standard lower single null diverted plasmas. We will probably start with an EF4 test for diagnostic pick-up tests. Impurities are frowned upon during this run at least during the flattop. | |
| May 27 1999 08:14:22:357AM | 990527001 | Joseph Snipes | Shot 1: OH1 commutation test shot. O.K. |
| May 27 1999 08:19:29:357AM | 990527002 | Joseph Snipes | Shot 2: Loading EF4 only test for John Heard from 990521005. O.K. |
| May 27 1999 08:33:47:077AM | 990527003 | Joseph Snipes | Shot 3: Loading 990225002 as a standard 5.4 T, nl04 = 1 x 10^20 m^-3. Ip set initially to 0.8 MA flattop. Changed timing to invert TF and ramp down Ip at 1.1 sec to save I^2t cooling time since Heard's digitizers can only sample for 0.5 sec. Good shot with some hard x rays. |
| May 27 1999 08:58:05:700AM | 990527004 | Joseph Snipes | Shot 4: Changed Ip to 0.7 MA flattop. Increased EF4 current by 30 A to -1310 A at breakdown. Fizzle! |
| May 27 1999 09:48:42:497AM | 990527005 | Joseph Snipes | Shot 5: Good shot. |
| May 27 1999 09:48:06:090AM | 990527006 | Joseph Snipes | Shot 6: Returned EF4 current to -1280 A and reduced Br by 1 mT to 0.001 T. Fizzle! |
| May 27 1999 09:49:13:233AM | 990527007 | Joseph Snipes | Shot 7: Increased Br offset by to +0.002 T and increased EF4 current to -1290A. Good shot. |
| May 27 1999 10:15:14:997AM | 990527008 | Joseph Snipes | Shot 8: Repeat. Fizzle! |
| May 27 1999 10:26:35:640AM | 990527009 | Joseph Snipes | Shot 9: Try reducing OH1 and OH2 voltages by 20 V and 4 V respectively between 0.005 and 0.02 sec to reduce the rate of rise of the current. Fizzle! |
| May 27 1999 10:49:54:763AM | 990527010 | Joseph Snipes | Shot 10: Try reducing OH1 and OH2 by another 70 V and 14 V respectively since the rate of rise of the current did not come down. Increased the prepuff by 5 msec to 23 msec duration. Good shot thanks to Steve Wolfe's suggestion to decrease the OH1 and OH2 voltages a lot. |
| May 27 1999 10:53:30:013AM | 990527011 | Joseph Snipes | Shot 11: Dropped nl04 programming to zero after 1.1 sec instead of 1.2 sec as it had been programmed. Good shot. Ramped down nicely. |
| May 27 1999 11:31:52:687AM | 990527012 | Joseph Snipes | Shot 12: Changed the rampdown slightly after 1.4 sec to try to improve the rampdown even more. Fizzle! |
| May 27 1999 11:32:27:687AM | 990527013 | Joseph Snipes | Shot 13: Reduced prepuff from 23 to 20 msec duration. Good shot. |
| May 27 1999 11:51:49:577AM | 990527014 | Joseph Snipes | Shot 14: Repeat. Good shot. |
| May 27 1999 12:04:20:000PM | 990527015 | Joseph Snipes | Shot 15: Repeat. Fizzle! |
| May 27 1999 01:10:18:170PM | 990527016 | Joseph Snipes | Shot 16: Short delay for John Heard to go into the cell and change his detectors. Reduced Br offset by 1 mT to 0.001 T. After an hour's delay, we got a good shot. |
| May 27 1999 01:32:56:717PM | 990527017 | Joseph Snipes | Shot 17: Repeat. Good shot. |
| May 27 1999 02:08:40:030PM | 990527018 | Joseph Snipes | Shot 18: Modified rampdown after 1.4 sec to try to get down to 100 kA and let the fizzle detector take out the plasma. Good shot. |
| May 27 1999 02:15:52:497PM | 990527019 | Joseph Snipes | Shot 19: Repeat with step in TF from 0.9 to 1.0 sec from -150000 A to -157000 A to sweep the GPC channels. Good shot. |
| May 27 1999 02:49:06:950PM | 990527021 | Joseph Snipes | Shot 20: Repeat. Good shot. John Heard says he is done. |
| May 27 1999 02:50:22:530PM | 990527021 | Joseph Snipes | Shot 21: Copied shot 990520021, which was an ohmic H-mode shot at 1.2 MA and 5.4 T. Copied segment 1 from shot 990527020. Good shot. |
| May 27 1999 03:02:57:107PM | 990527021 | Joseph Snipes | Shot 21: Copied shot 990520021, which was an ohmic H-mode shot at 1.2 MA and 5.4 T. Copied segment 1 from shot 990527020. Good shot. Ohmic H-mode in the rampdown. |
| May 27 1999 03:23:12:047PM | 990527022 | Joseph Snipes | Shot 22: Increase Ip to 1.25 MA and decrease Bt to 5.0 T so that the ECE grating can be easily adjusted to give decent ECE data and still allow us to get decent ohmic H-modes. ELM-free ohmic H-mode then a ratty EDA-like H-mode in the rampdown. |
| May 27 1999 03:49:53:983PM | 990527023 | Joseph Snipes | Shot 23: Copied shot 990521022 and increased the low field portion to 5.0 T. No H-mode in the flattop, but there is an H-mode in the rampdown. |
| May 27 1999 03:50:35:513PM | 990527024 | Joseph Snipes | Shot 24: Decreased the field back to 4.6 T from 0.3 to 0.8 sec, then ramped back up to 5.4 T at the end of the shot. Reduced nl04 from 1.2 to 1.1 x 10^20 m^-2 at the beginning of the shot. Good shot with H-modes. |
| May 27 1999 04:51:45:373PM | 990527025 | Joseph Snipes | Shot 25: Repeat. Good shot. One H-mode late just after the field starts to ramp back up. |
| May 27 1999 05:08:27:907PM | 990527026 | Joseph Snipes | Shot 26: Reduced Bt to 4.4 T from 0.3 to 0.8 sec. Reduced preprogrammed gas feed after 0.3 sec. Good shot with 3 H-modes. ELM-free early, then nearly EDA, then clear EDA H-mode just at the beginning of the ramp down. |
| May 27 1999 05:19:07:640PM | 990527026 | Joseph Snipes | Except for some difficulties with fizzles, the machine ran very well. Reducing the early OH1 and OH2 voltages (at Wolfe's suggestion) reduced the rate of rise of the current and led to more reliable current rises. There was a one hour delay for the session leader to fix things on his diagnostic in the cell. Then, in the early afternoon, he punted and the run turned to ohmic H-modes. We got a number of nice ohmic H-modes from shot 21 - 26 that can be used for rotation studies in support of MP#249 Impurity Transport in Ohmic H-mode. |
| May 27 1999 05:21:07:950PM | 990527026 | Joseph Snipes | Summary: Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.021 2 0.000 0.005 3 1.553 0.771 4 0.000 0.037 5 1.552 0.719 6 0.000 0.037 7 1.551 0.719 8 0.000 0.047 9 0.000 0.047 10 1.247 0.724 11 1.552 0.719 12 0.000 0.037 13 1.566 0.719 14 1.554 0.724 15 0.000 0.047 16 1.569 0.719 17 1.559 0.724 18 1.566 0.724 19 1.568 0.724 20 1.562 0.727 21 1.519 1.197 22 1.520 1.256 23 1.656 1.238 24 1.657 1.255 25 1.654 1.235 26 1.656 1.249 26 shots. 18 plasmas. 6 fizzles. 2 tests. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:07:18:030AM | Test | Ok | OH1,OH2U,OH2L commutation switch test |
| 2 | 08:18:01:437AM | Test | Ok | EF4 hybrid test |
| 3 | 08:31:33:687AM | Plasma | Ok | no faults/plasma |
| 4 | 08:51:15:577AM | Plasma | Ok | no faults/fizzel |
| 5 | 09:06:00:513AM | Plasma | Ok | no faults/plasma |
| 6 | 09:25:13:810AM | Plasma | Ok | no faults/fizzel |
| 7 | 09:43:26:640AM | Plasma | Ok | no faults/plasma |
| 8 | 09:59:35:373AM | Plasma | Ok | no faults/fizzel |
| 9 | 10:15:41:153AM | Plasma | Ok | no faults |
| 10 | 10:33:25:077AM | Plasma | Ok | No Faults |
| 11 | 10:51:10:043AM | Plasma | Ok | No Faults except EFC Chopper static volts jumped up. |
| 12 | 11:14:55:547AM | Plasma | Ok | No Faults |
| 13 | 11:29:27:233AM | Plasma | Ok | no faults |
| 14 | 11:45:17:607AM | Plasma | Ok | No Faults |
| 15 | 12:02:20:810PM | Plasma | Ok | No Faults |
| 16 | 01:07:15:233PM | Plasma | Ok | No Faults |
| 17 | 01:23:31:043PM | Plasma | Ok | No Faults |
| 18 | 01:41:30:873PM | Plasma | Ok | No Faults |
| 19 | 02:09:47:093PM | Plasma | Ok | No Faults |
| 20 | 02:28:03:687PM | Plasma | Ok | No Faults |
| 21 | 02:48:45:483PM | Plasma | Ok | No Faults |
| 22 | 03:10:13:640PM | Plasma | Ok | No Faults |
| 23 | 03:30:03:437PM | Plasma | Ok | No Faults |
| 24 | 03:49:00:077PM | Plasma | Ok | No Faults |
| 25 | 04:40:13:043PM | Plasma | Ok | No Faults |
| 26 | 04:57:17:077PM | Plasma | Ok | No Faults |