| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | M. Sampsell |
| Physics operator(s): | Joseph Snipes |
| Engineering operator(s): | Ed Fitzgerald,Bill Parkin |
| Engineering Operator Run Comment |
| MP #368 Ohmic EDA/A-coils PO:Snipes SL:Sampsell EO:Fitzgerald,Parkin |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:34:897PM |
| Author: M. Sampsell |
| 1st Half, MP #368 - The A-Coil Effect on Ohmic EDA H-Mode Operation 2nd Half, MP #334 - QC Mode in Ohmic EDA's - Radial Extent, k-poloidal, and high frequency companions PO: Snipes SL: Sampsell Purpose of MP #368: The purpose of MP #368 is to investigate the A-Coil's effect on Ohmic EDA H-mode operation. Run plan for MP #368: We'll start by loading shot 1030703004. This was a failed attempt at an EDA that disrupted. The disruption was possibly due to poloidal error fields. Then we will take a series of identical shots at various A-Coil currents, increasing from 0 to max. Along the way we hope to find a range of A-Coil currents that give us disruption-free, EDA shots. We will stop increasing the current when we conclude the A-Coil is imposing such a large field that it is causing disruptions (i.e. is clearly above the optimal operating point for ohmic EDA's). After this scan, if the disruption mitigation and EDA production are still suspect, we may try varying the A-Coil configuration and/or the minimum value of the magnetic field ramp. Once we have a satisfactory EDA shot that is reproducible, we'll move on to MP #334. Purpose and Run Plan of MP #334: The main purpose of 334 is to make various measurements of the QC mode including: 1) Searching for high frequency "companion" oscillations, using the Langmuir probe at 3MHz digitization. 2) Simultaneous width measurements with GPI, BES, and the probe. May include outer midplane gap scans. 3) Simultaneous k-theta measurements with BES, probe, (GPI?), and PCI. May include triangularity scan. 4) Simultaneous k-R measurements with GPI, BES, and reflectometry. All QC diagnostics desired. Based on model shots, EDA expected to occur in the 1.1-1.3 s range, so diagnostics should digitize accordingly. Run Summary: -------- Overall a very successful run for both MP's. Stats -------- Fizzles: 1 (001) No Power Shots: 4 (006,009,013,026) Plasmas: 27 Total: 32 MP #368: We took the first 14 shots to do the A-Coil current scan. In all of the following the values given for I_ACoil are the RESULTANT current. This was typically ~ 400-500 A lower than the requested current. The successful shots of the A-Coil current scan are Shot I_ACoil # of Time of 1st Time of (A) H-modes Post-B-min disruption H-mode (s) (s) 003 0 2 1.17 1.82 004 0 1 1.14 1.18 005 150 1 1.14 1.25 014 500 2 1.10 1.38 012 900 3+ 1.13 1.79 011 1200 3+ 1.10 1.83 007 1800 3+ 1.10 1.84 010 2200 2 1.13 1.20 008 2650 1 1.14 1.17 As expected, there was an intermediate region of ACoil currents with very good disruption suppression. The only puzzling point was the first one (shot 3), where there was no early disruption, yet the A_Coil was off. There WAS a slight sag in Ip in shot 3 that was corrected for on all subsequent shots, and this may have played a role in the stability. This shot should be examined more closely. Based on the scan, we adopted an I_ACoil of ~900 A as our new operating point for EDA's. The results of the scan were very consistent with Steve Wolfe's model of the B21 error fields. A scope showing the calculated intrinsic, applied, and total B21 fields can be found in /home/wolfe/scopes/scope_B21.dat. This scope also shows the phases, contributions from various effects, etc. Based on the output of the model, we decided to add a ramp to I_Acoil during the shot, ultimately settling on a ramp from 900 A to 1300 A. According to the calculations, this held the total B21 field below 2 Gauss over most of the pulse. With shot 15, we moved onto production of EDA's. We obtained the first EDA on shot 16 and had them for the rest of the day. Thus, MP #368 was a success and we now have new model shots for ohmic EDA's. MP #334: We obtained the first EDA on shot 16 and then had them for the rest of the day. There were several EDA's that lasted longer than 200-300 ms. Shot # of EDA's Time of 1st Length of EDA (s) longest EDA (ms) General Measurement 016 1 1.20 360 017 2 1.10 200 018 1 1.20 340 019 2 1.08 280 020 3 1.20 180 021 2 1.08 270 022 1 1.17 370 023 3+ 1.08 230 Outer Midplane Gap Scans 024 2 1.18 300 025 3+ 1.15 120 027 3+ 1.18 120 028 1 1.17 330 Additional variation of density and triangularity 029 2 1.12 150 (choppy) 030 3+ 1.13 100 (choppy) 031 3+ 1.24 60 (choppy) 032 2 1.08 270 PCI was the best monitor of the QC mode shot to shot, but the mode was seen by all of the QC diagnostics several times, and we should have some useful data in all of the following categories: 1) Search for high frequency "companion" oscillations: We had 3+ MHz digitization on BES, PCI, and the Langmuir probe. Thus, we have now looked for high frequency modes in density, magnetic, and electric potential signals and have seen no evidence of them. The lack of a high-f potential fluctuation detectable by the Langmuir probe could be particularly "damning" with regards to the Alvénic mode predicted by BOUT. 2) Simultaneous width measurements with GPI, BES, and the probe: There were some shots where the probe likely plunged through the mode (18-20,23,30) and we had simultaneous GPI on all of those. BES was only simultaneous on 23 and 30. For BES and GPI, we also had a few outer midplane gap scans (24-28). This data may be useful in getting improved effective radial resolution of the QCM by those diagnostics. 3) Simultaneous k-theta measurements with BES, probe, (GPI?), and PCI: There were some shots that should be good for this, conditional on future analysis. The probe definitely got some useful k-theta data, including some sweeps measuring broadband fluctuations along with the QC mode. This may lead to some insight into plasma rotation. There were also Argon rotation measurements on some shots. 4) Simultaneous k-R measurements with GPI, BES, and reflectometry: We obtained some shots that should be good for this, conditional on future analysis. Unfortunately, poor DNB performance means that data from BES was not as comprehensive nor as high S/N as was hoped, which may impact the completion of items 2-4. Left to do on MP #334: Use of a new Langmuir probe head with two radially offset probes to study the probe's quenching effect on the mode. We also may want to extend the various measurements to more triangularities, densities, and q's, as well as retake some of the BES data once the DNB is operating well. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:19:787PM |
| Author: Joseph Snipes |
| Engineering setup for Friday, 21 Nov 2003 MP#368 Ohmic EDA/A-coils Session leader : Matt Sampsell Physics operator: Joseph Snipes ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Bake at 60 C overnight as well. Run begins at 09:00 and ends at 17:00. Power systems the same as on 1030703004 A-coils should be hooked up as on 1031114027 (+Dtop -Dbot -Jtop +Jbot), and the power supply should be disabled for the first shot Gas 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 as is Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) Enable gatevalves (there will be no vacuum problems): ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: No RF ------------------------------------------------------------------------------- Run Plan: The run will begin by copying shot 1030703004, which was an attempt to obtain Ohmic EDA H-mode by ramping down and back up the toroidal field. The first shot will be without the A-coils and a disruption is expected late in the shot due to the error fields. Then, we will increase the A-coil current in 8 steps up to the maximum current looking for effects on the error fields, disruption, and EDA nature of the plasma. If we successfully find a nice reproducible EDA regime, we will then proceed with MP 334 which involves detailed diagnosis of EDA H-mode plasmas. Summary: There were a number of ACK and IGOR failures that cost us four shots, but otherwise it was quite a good run. After scanning the A-coil current, we settled on a ramping current from a request of 1400 ramping to 1800 A, which gives 900 to 1400 A actual current and then ran many EDA H-mode shots where good QCM data was obtained on probes, PCI, magnetics, and gas puff imaging. Only the first shot fizzled, then all other plasma attempts were full length plasmas, though there were a number of error field induced disruptions. Scorecard: 1 fizzle, 4 no power shots due to computer system failures, 27 plasmas out of 32 shots. Quite a successful run. Shot 1: Copied shot 1030703004 and then loaded segment 1 from 1031120015 to get yesterday's startup. Set the A coil current to zero. Expect a disruption just below q95 = 3 around 1.14 s. Fizzle! Shot 2: Reduced prepuff by 1 ms to 21 ms duration. Try again. Good shot. No disruption. Shot 3: Turned off NINJA puff. Then repeat. Good shot. Got two brief H-modes. Shot 4: Put in a ramp of Ip from just before 0.5 s to 1.5 s increasing from 800 to 870 kA to compensate for the drooping current. Added 375 A of A-coil current ramping from 0 at 0.5 s up to 375 A at 0.7 s then ramping down at 1.5 s to 0 at 1.7 s. Good shot. Disrupted at 1.17 s. Shot 5: Increased A-coil current up to 750 A. A-coil voltage was set to 300 V and it should be set to 600 V. It will be changed for shot 6. Disrupted again at 1.22 s. Shot 6: Increased A-coil current to 2200 A. IGOR fault. No power shot. Shot 7: Try again. Good shot. No disruption. Several H-modes. Shot 8: Increased A-coil current to 3000 A. Good shot. Disrupted at 1.16 s. Shot 9: Decreased A-coil current to 2600 A. ACK failure. No power shot. Shot 10: Try again. Good shot. Disrupted at 1.19 s. Brief H-mode at 0.7 s. Shot 11: Decreased A-coil current to 1700 A. Note that the actual A-coil current is coming out some 400 A lower than the request. Good shot. Several H-modes. Shot 12: Decreased A-coil current to 1400 A. Good shot. Several H-modes. Shot 13: Decreased A-coil current to 1050 A. ACK failure. No power shot. Cryo is hung causing an unknown length of delay. Shot 14: Try again. Good shot. Two H-modes. Disrupted at 1.37 s. Shot 15: Increased A-coil current to 1400 A at 0.7 s, then ramping to 1500 A by 1.5 s. Raise the minimum toroidal field during the current flattop from 2.6 to 2.75 T and then clamped the field at 2.9 T until rampdown. Good shot. Several H-modes. Disrupted at 1.69 s. Shot 16: Increased nl04 to 7.5 x 10^19 m^-2. Finally got the EDA H-mode. Strong QCM on PCI during the second H-mode from 1.2 - 1.55 s. Shot 17: Increased nl04 to 8 x 10^19 m^-2. Raised toroidal field to flattop at 2.83 T (-74730 A). Good shot. Two EDA H-modes. Disrupted at 1.5 s. Shot 18: Raised A-coil ramp up to 1800 A at 1.85 s. Good shot. ELM-free then EDA H-mode. Shot 19: Raised TF to 2.9 T. Good shot. EDA H-mode. Disrupted at 1.76 s. Shot 20: Raised Bt to 3 T. Increased Ar puff to 40 ms duration. ELM-free then EDA H-mode. EDA is not as good. Shot 21: Reduced Ar puff back to 30 ms duration to improve the quality of the H-mode. Good shot. Two EDA H-modes. Disrupted at 1.62 s. Shot 22: Dropped Bt back to 2.9 T and brought the early nl04 point up from 7.5 x 10^19 m^-2 to 8 x 10^19 m^-2. Good shot. ELM-free then EDA H-mode. Disrupted at 1.74 s. Shot 23: Added 10 ms back to the Ar puff to make it 40 ms duration. Good shot. ELM-free then EDA H-mode. Disrupted at 1.695 s. Shot 24: Put in a scan of the outer gap from +1.5 cm to 0.5 cm from 1.33 s to 1.43 s then back to 1 cm gap. Good shot. ELM-free then EDA H-mode. Got the opposite gap scan from what I wanted. Shot 25: Swapped the gap scan around to give me what I wanted originally on shot 24. Still did not get the gap to go out to 1.5 cm. H-modes are intermittent ELM-free then EDA. Shot 26: Try decreasing RCUR by 2 mm to increase the outer gap to 1.5 cm as requested. No power shot ACK fault. Shot 27: Try again. Good shot. In and out of H-mode ELM-free and EDA. Shot 28: Modified the outer gap scan to not go as close to the limiter. Then, removed 10 ms from the Ar puff to put it back to 30 ms duration. ELM-free then nice long EDA H-mode. The Ar really does seem to make the EDA's worse. Shot 29: Raised nl04 to 1 x 10^20 m^-2 and took out the gap scan. Good shot. Only brief H-mode then L-mode. Disrupted at 1.69 s. Shot 30: Lowered nl04 to 0.9 x 10^20 m^-2. Reduced RXL and RXU by 1 cm to increase the triangularity. Good shot. Several ELM-free H-modes. Shot 31: Lowered nl04 to 0.8 x 10^20 m^-2. Good shot. Got a number of ELM-free H-modes again. Shot 32: Reloaded shot 1031121022. Good shot. Two EDA H-modes much like the shot we copied. |
| Session Leader Comments | |||
| Nov 21 2003 07:14:35:550AM | M. Sampsell | MP's 368 and 334: No RF today. All QC mode diagnostics desired, especially for MP 334. Also need magnetics and edge profiles. May make some Argon rotation measurements. Most shots today will be typical of ohmic EDA shots, starting with a downward B ramp from ~5 T to ~2.5 T, followed by an upward ramp to some value in the 3-5 T range. Run plan for MP 368: The purpose of MP #368 is to investigate the A-Coil's effect on Ohmic EDA H-mode operation. We'll start by loading shot 1030703004. This was a failed attempt at an EDA that disrupted. The disruption was possibly due to poloidal error fields. Then we will take a series of identical shots at various A-Coil currents, increasing from 0 to max. Along the way we hope to find a range of A-Coil currents that give us disruption-free, EDA shots. We will stop increasing the current when we conclude the A-Coil is imposing such a large field that it is causing disruptions (i.e. is clearly above the optimal operating point for ohmic EDA's). After this scan, if the disruption mitigation and EDA production are still suspect, we may try varying the A-Coil configuration and/or the minimum value of the magnetic field ramp. Once we have a satisfactory EDA shot that is reproducible, we'll move on to MP 334. Run Plan for MP 334: The main purpose of 334 is to make various measurements of the QC mode including: 1) Searching for high frequency "companion" oscillations, using the Langmuir probe at 3MHz digitization. 2) Simultaneous width measurements with GPI, BES, and the probe. May include outer midplane gap scans. 3) Simultaneous k-theta measurements with BES, probe, (GPI?), and PCI. May include triangularity scan. 4) Simultaneous k-R measurements with GPI, BES, and reflectometry. All QC diagnostics desired. Based on model shots, EDA expected to occur in the 1.1-1.3 s range, so diagnostics should digitize accordingly. | |
| Nov 21 2003 09:26:31:917AM | 1031121002 | M. Sampsell | Result: Plasma. Doesn't disrupt at B-min like model shot. Density rise prior to min due to He Ninja puff? Next: Retry without Ninja puff. |
| Nov 21 2003 09:40:29:963AM | 1031121003 | M. Sampsell | Result: 1st H-mode at 1.16. No disruption. No EDA. Next: Add slight current ramp. A-Coil current to 375 A. Short time QC diagnostics can shift 60 ms later. |
| Nov 21 2003 09:50:57:900AM | 1031121004 | M. Sampsell | Result: H-mode at 1.14. No EDA. Disruption. A-Coil doesn't do much due to offset? Next: A-Coil current to 750 A. |
| Nov 21 2003 10:05:55:807AM | 1031121005 | M. Sampsell | Result: H-mode @ 1.14. No EDA. Disruption @ 1.24. Resultant I_ACoil ~ 160 A. Next: Requesting I_ACoil to 2200 A. Will then probably start stepping DOWN on subsequent shots. |
| Nov 21 2003 10:46:42:133AM | 1031121007 | M. Sampsell | Result: 1st H-mode @ 1.14. No disruption. Resultant I_Acoil ~ 1780. Next: Request I_Acoil = 3000 A. |
| Nov 21 2003 10:54:21:807AM | 1031121008 | M. Sampsell | Result: Brief H-mode @ 1.14. Disruption @ 1.19. Resultant I_Acoil ~ 2600 A. Next: Request I_Acoil = 2600 A. Expect about ~2100 A. |
| Nov 21 2003 11:39:38:613AM | 1031121010 | M. Sampsell | Result: Early H-mode @ .7 s. H-mode @ 1.13. Disruption @ 1.19. Resultant I_Acoil ~ 2200 A. Next: Request I_Acoil = 1700 A. Expect about ~1200 A. |
| Nov 21 2003 11:51:54:367AM | 1031121011 | M. Sampsell | Result: 1st H-mode @ 1.11. No Disruption. Resultant I_Acoil ~ 1200 A. Next: Request I_Acoil = 1400 A. Expect about ~900 A. |
| Nov 21 2003 12:10:32:823PM | 1031121012 | M. Sampsell | Result: Early H-mode @ .9 s. 1st of late H-modes @ 1.11. No Disruption. Resultant I_Acoil ~ 900 A. Next: Request I_Acoil = 1050 A. Expect about ~550 A. This will be the last of the A-coil current scan. Then we will go back to the most promising A-coil current (request ~ 1450 A, maybe with a ramp) and vary B, ne, Ip, etc to encourage the EDA. |
| Nov 21 2003 12:57:57:687PM | 1031121013 | M. Sampsell | Shot 13 had a data acq hangup. No shot. Now we have a delay due to a hang-up in the cryo system. Shot 14 at 12:59 pm. |
| Nov 21 2003 01:09:39:497PM | 1031121014 | M. Sampsell | Result: Early H-mode @ .72 s. Late H-mode @ 1.08. Disruption @ 1.37. Resultant I_Acoil ~ 500 A. Next: Request I_Acoil = 1400 A, then ramping up to 1500 instead of flat top. Also, raising Bmin of down ramp to 2.75 T. Also clamping B-field at 2.9 T instead of ramping back to 4 T. |
| Nov 21 2003 01:48:26:503PM | 1031121016 | M. Sampsell | Result: Nice EDA starts at 1.2s. QC very clear on PCI. No DNB. Next: Slightly higher density and flattened the B. GPI and probe in at 1.35s. |
| Nov 21 2003 01:58:05:517PM | 1031121017 | M. Sampsell | Result: Nice EDA's starts at 1.09s and 1.23s. QC very clear on PCI, GPI, and magnetics. Next: A-coil ramping a little more aggressive on next shot. Probe will plunge deeper. |
| Nov 21 2003 02:07:30:567PM | 1031121018 | M. Sampsell | Result: Nice EDA starts at 1.2s. QC + some lower frequency MHD seen. Probe went through the mode this time. Next: B to 2.9 on next shot. |
| Nov 21 2003 03:55:19:077PM | 1031121025 | M. Sampsell | We are scanning the gap from 1.5 to .5 cm during 1.35 to 1.45 s. |
| Nov 21 2003 05:00:41:447PM | 1031121028 | M. Sampsell | Result: Got another good gap scan. This was the last gap scan. Next: Lower the density and increase the triangularity. |
| Nov 21 2003 04:32:33:847PM | 1031121029 | M. Sampsell | Result: Density was raised and we did not get as long an EDA. Next: Lower the density and increase the triangularity. |
| Nov 21 2003 05:09:56:600PM | 1031121032 | M. Sampsell | Result: Last shot. Successful. Another 250+ ms EDA. |
| Nov 24 2003 05:33:54:107AM | 1031121032 | M. Sampsell | 1st Half, MP #368 - The A-Coil Effect on Ohmic EDA H-Mode Operation 2nd Half, MP #334 - QC Mode in Ohmic EDA's - Radial Extent, k-poloidal, and high frequency companions PO: Snipes SL: Sampsell Purpose of MP #368: The purpose of MP #368 is to investigate the A-Coil's effect on Ohmic EDA H-mode operation. Run plan for MP #368: We'll start by loading shot 1030703004. This was a failed attempt at an EDA that disrupted. The disruption was possibly due to poloidal error fields. Then we will take a series of identical shots at various A-Coil currents, increasing from 0 to max. Along the way we hope to find a range of A-Coil currents that give us disruption-free, EDA shots. We will stop increasing the current when we conclude the A-Coil is imposing such a large field that it is causing disruptions (i.e. is clearly above the optimal operating point for ohmic EDA's). After this scan, if the disruption mitigation and EDA production are still suspect, we may try varying the A-Coil configuration and/or the minimum value of the magnetic field ramp. Once we have a satisfactory EDA shot that is reproducible, we'll move on to MP #334. Purpose and Run Plan of MP #334: The main purpose of 334 is to make various measurements of the QC mode including: 1) Searching for high frequency "companion" oscillations, using the Langmuir probe at 3MHz digitization. 2) Simultaneous width measurements with GPI, BES, and the probe. May include outer midplane gap scans. 3) Simultaneous k-theta measurements with BES, probe, (GPI?), and PCI. May include triangularity scan. 4) Simultaneous k-R measurements with GPI, BES, and reflectometry. All QC diagnostics desired. Based on model shots, EDA expected to occur in the 1.1-1.3 s range, so diagnostics should digitize accordingly. Run Summary: -------- Overall a very successful run for both MP's. Stats -------- Fizzles: 1 (001) No Power Shots: 4 (006,009,013,026) Plasmas: 27 Total: 32 MP #368: We took the first 14 shots to do the A-Coil current scan. In all of the following the values given for I_ACoil are the RESULTANT current. This was typically ~ 400-500 A lower than the requested current. The successful shots of the A-Coil current scan are Shot I_ACoil # of Time of 1st Time of (A) H-modes Post-B-min disruption H-mode (s) (s) 003 0 2 1.17 1.82 004 0 1 1.14 1.18 005 150 1 1.14 1.25 014 500 2 1.10 1.38 012 900 3+ 1.13 1.79 011 1200 3+ 1.10 1.83 007 1800 3+ 1.10 1.84 010 2200 2 1.13 1.20 008 2650 1 1.14 1.17 As expected, there was an intermediate region of ACoil currents with very good disruption suppression. The only puzzling point was the first one (shot 3), where there was no early disruption, yet the A_Coil was off. There WAS a slight sag in Ip in shot 3 that was corrected for on all subsequent shots, and this may have played a role in the stability. This shot should be examined more closely. Based on the scan, we adopted an I_ACoil of ~900 A as our new operating point for EDA's. The results of the scan were very consistent with Steve Wolfe's model of the B21 error fields. A scope showing the calculated intrinsic, applied, and total B21 fields can be found in /home/wolfe/scopes/scope_B21.dat. This scope also shows the phases, contributions from various effects, etc. Based on the output of the model, we decided to add a ramp to I_Acoil during the shot, ultimately settling on a ramp from 900 A to 1300 A. According to the calculations this held the total B21 field below 2 Gauss over most of the pulse. With shot 15, we moved onto production of EDA's. We obtained the first EDA on shot 16 and had them for the rest of the day. Thus, MP #368 was a success and we now have new model shots for ohmic EDA's. MP #334: We obtained the first EDA on shot 16 and then had them for the rest of the day. There were several EDA's that lasted longer than 200-300 ms. Shot # of EDA's Time of 1st Length of EDA (s) longest EDA (ms) General Measurement 016 1 1.20 360 017 2 1.10 200 018 1 1.20 340 019 2 1.08 280 020 3 1.20 180 021 2 1.08 270 022 1 1.17 370 023 3+ 1.08 230 Outer Midplane Gap Scans 024 2 1.18 300 025 3+ 1.15 120 027 3+ 1.18 120 028 1 1.17 330 Additional variation of density and triangularity 029 2 1.12 150 (choppy) 030 3+ 1.13 100 (choppy) 031 3+ 1.24 60 (choppy) 032 2 1.08 270 PCI was the best monitor of the QC mode shot to shot, but the mode was een by all of the QC diagnostics several times, and we should have some useful data in all of the following categories: 1) Search for high frequency "companion" oscillations: We had 3+ MHz digitization on BES, PCI, and the Langmuir probe. Thus, we have now looked for high frequency modes in density, magnetic, and electric potential signals and have seen no evidence of them. The lack of a high-f potential fluctuation detectable by the Langmuir probe could be particularly "damning" with regards to the Alvénic mode predicted by BOUT. 2) Simultaneous width measurements with GPI, BES, and the probe: There were some shots where the probe likely plunged through the mode (18-20,23,30) and we had simultaneous GPI on all of those. BES was only simultaneous on 23 and 30. For BES and GPI, we also had a few outer midplane gap scans (24-28). This data may be useful in getting improved effective radial resolution of the QCM by those diagnostics. 3) Simultaneous k-theta measurements with BES, probe, (GPI?), and PCI: There were some shots that should be good for this, conditional on future analysis. The probe definitely got some useful k-theta data, including some sweeps measuring broadband fluctuations along with the QC mode. This may lead to some insight into plasma rotation. There were also Argon rotation measurements on some shots. 4) Simultaneous k-R measurements with GPI, BES, and reflectometry: We obtained some shots that should be good for this, conditional on future analysis. Unfortunately, poor DNB performance means that data from BES was not as comprehensive nor as high S/N as we were hoping for, which may impact the completion of items 2-4. Left to do on MP #334: Use of a new Langmuir probe head with two radially offset probes to study the probe's quenching effect on the mode. We also may want to extend the various measurements to more triangularities, densities, and q's, as well as retake some of the BES data once the DNB is operating well. |
| Physics Operator Comments | |||
| Nov 21 2003 08:34:00:683AM | Joseph Snipes | Engineering setup for Friday, 21 Nov 2003 MP#368 Ohmic EDA/A-coils Session leader : Matt Sampsell Physics operator: Joseph Snipes ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Bake at 60 C overnight as well. Run begins at 09:00 and ends at 17:00. Power systems the same as on 1030703004 A-coils should be hooked up as on 1031114027 (+Dtop -Dbot -Jtop +Jbot), and the power supply should be disabled for the first shot Gas 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 as is Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) Enable gatevalves (there will be no vacuum problems): ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: No RF ------------------------------------------------------------------------------- Run Plan: The run will begin by copying shot 1030703004, which was an attempt to obtain Ohmic EDA H-mode by ramping down and back up the toroidal field. The first shot will be without the A-coils and a disruption is expected late in the shot due to the error fields. Then, we will increase the A-coil current in 8 steps up to the maximum current looking for effects on the error fields, disruption, and EDA nature of the plasma. If we successfully find a nice reproducible EDA regime, we will then proceed with MP 334 which involves detailed diagnosis of EDA H-mode plasmas. | |
| Nov 21 2003 09:07:51:727AM | 1031121001 | Joseph Snipes | Shot 1: Copied shot 1030703004 and then loaded segment 1 from 1031120015 to get yesterday's startup. Set the A coil current to zero. Expect a disruption just below q95 = 3 around 1.14 s. Fizzle! |
| Nov 21 2003 09:23:07:697AM | 1031121002 | Joseph Snipes | Shot 2: Reduced prepuff by 1 ms to 21 ms duration. Try again. Good shot. No disruption. Density increases gradually after 1 sec perhaps due to NINJA He puff. |
| Nov 21 2003 09:32:51:933AM | 1031121003 | Joseph Snipes | Shot 3: Turned off NINJA puff. Then repeat. Good shot. Got two brief H-modes. |
| Nov 21 2003 09:47:41:993AM | 1031121004 | Joseph Snipes | Shot 4: Put in a ramp of Ip from just before 0.5 s to 1.5 s increasing from 800 to 870 kA to compensate for the drooping current. Added 375 A of A-coil current ramping from 0 at 0.5 s up to 375 A at 0.7 s then ramping down at 1.5 s to 0 at 1.7 s. Good shot. Disrupted at 1.17 s. |
| Nov 21 2003 09:59:31:620AM | 1031121005 | Joseph Snipes | Shot 5: Increased A-coil current up to 750 A. A-coil voltage was set to 300 V and it should be set to 600 V. It will be changed for shot 6. Disrupted again at 1.22 s. |
| Nov 21 2003 10:14:51:417AM | 1031121006 | Joseph Snipes | Shot 6: Increased A-coil current to 2200 A. IGOR fault. No power shot. |
| Nov 21 2003 10:36:30:430AM | 1031121007 | Joseph Snipes | Shot 7: Try again. Good shot. No disruption. Several H-modes. |
| Nov 21 2003 10:49:05:743AM | 1031121008 | Joseph Snipes | Shot 8: Increased A-coil current to 3000 A. Good shot. Disrupted at 1.16 s. |
| Nov 21 2003 11:01:41:667AM | 1031121009 | Joseph Snipes | Shot 9: Decreased A-coil current to 2600 A. ACK failure. No power shot. |
| Nov 21 2003 11:29:36:573AM | 1031121010 | Joseph Snipes | Shot 10: Try again. Good shot. Disrupted at 1.19 s. Brief H-mode at 0.7 s. |
| Nov 21 2003 11:44:26:317AM | 1031121011 | Joseph Snipes | Shot 11: Decreased A-coil current to 1700 A. Note that the actual A-coil current is coming out some 400 A lower than the request. Good shot. Several H-modes. |
| Nov 21 2003 11:56:22:050AM | 1031121012 | Joseph Snipes | Shot 12: Decreased A-coil current to 1400 A. Good shot. Several H-modes. |
| Nov 21 2003 12:39:57:120PM | 1031121013 | Joseph Snipes | Shot 13: Decreased A-coil current to 1050 A. ACK failure. No power shot. |
| Nov 21 2003 12:50:49:213PM | 1031121013 | Joseph Snipes | Cryo is hung causing an unknown length of delay. |
| Nov 21 2003 01:01:23:490PM | 1031121014 | Joseph Snipes | Shot 14: Try again. Good shot. Two H-modes. Disrupted at 1.37 s. |
| Nov 21 2003 01:20:32:370PM | 1031121015 | Joseph Snipes | Shot 15: Increased A-coil current to 1400 A at 0.7 s, then ramping to 1500 A by 1.5 s. Raise the minimum toroidal field during the current flattop from 2.6 to 2.75 T and then clamped the field at 2.9 T until rampdown. Good shot. Several H-modes. Disrupted at 1.69 s. |
| Nov 21 2003 01:34:40:690PM | 1031121016 | Joseph Snipes | Shot 16: Increased nl04 to 7.5 x 10^19 m^-2. Finally got the EDA H-mode. Strong QCM on PCI during the second H-mode from 1.2 - 1.55 s. |
| Nov 21 2003 01:51:27:700PM | 1031121017 | Joseph Snipes | Shot 17: Increased nl04 to 8 x 10^19 m^-2. Raised toroidal field to flattop at 2.83 T (-74730 A). Good shot. Two EDA H-modes. Disrupted at 1.5 s. |
| Nov 21 2003 02:07:35:957PM | 1031121018 | Joseph Snipes | Shot 18: Raised A-coil ramp up to 1800 A at 1.85 s. Good shot. ELM-free then EDA H-mode. |
| Nov 21 2003 02:18:01:457PM | 1031121019 | Joseph Snipes | Shot 19: Raised TF to 2.9 T. Good shot. EDA H-mode. Disrupted at 1.76 s. |
| Nov 21 2003 02:31:15:780PM | 1031121020 | Joseph Snipes | Shot 20: Raised Bt to 3 T. Increased Ar puff to 40 ms duration. ELM-free then EDA H-mode. EDA is not as good. |
| Nov 21 2003 02:42:30:043PM | 1031121021 | Joseph Snipes | Shot 21: Reduced Ar puff back to 30 ms duration to improve the quality of the H-mode. Good shot. Two EDA H-modes. Disrupted at 1.62 s. |
| Nov 21 2003 02:52:48:950PM | 1031121022 | Joseph Snipes | Shot 22: Dropped Bt back to 2.9 T and brought the early nl04 point up from 7.5 x 10^19 m^-2 to 8 x 10^19 m^-2. Good shot. ELM-free then EDA H-mode. Disrupted at 1.74 s. |
| Nov 21 2003 03:05:45:103PM | 1031121023 | Joseph Snipes | Shot 23: Added 10 ms back to the Ar puff to make it 40 ms duration. Good shot. ELM-free then EDA H-mode. Disrupted at 1.695 s. |
| Nov 21 2003 03:22:22:750PM | 1031121024 | Joseph Snipes | Shot 24: Put in a scan of the outer gap from +1.5 cm to 0.5 cm from 1.33 s to 1.43 s then back to 1 cm gap. Good shot. ELM-free then EDA H-mode. Got the opposite gap scan from what I wanted. |
| Nov 21 2003 03:35:48:133PM | 1031121025 | Joseph Snipes | Shot 25: Swapped the gap scan around to give me what I wanted originally on shot 24. Still did not get the gap to go out to 1.5 cm. H-modes are intermittent ELM-free then EDA. |
| Nov 21 2003 03:44:34:963PM | 1031121026 | Joseph Snipes | Shot 26: Try decreasing RCUR by 2 mm to increase the outer gap to 1.5 cm as requested. No power shot ACK fault. |
| Nov 21 2003 03:57:16:433PM | 1031121027 | Joseph Snipes | Shot 27: Try again. Good shot. In and out of H-mode ELM-free and EDA. |
| Nov 21 2003 04:12:03:770PM | 1031121028 | Joseph Snipes | Shot 28: Modified the outer gap scan to not go as close to the limiter. Then, removed 10 ms from the Ar puff to put it back to 30 ms duration. ELM-free then nice long EDA H-mode. The Ar really does seem to make the EDA's worse. |
| Nov 21 2003 04:24:27:313PM | 1031121029 | Joseph Snipes | Shot 29: Raised nl04 to 1 x 10^20 m^-2 and took out the gap scan. Good shot. Only brief H-mode then L-mode. Disrupted at 1.69 s. |
| Nov 21 2003 04:39:10:870PM | 1031121030 | Joseph Snipes | Shot 30: Lowered nl04 to 0.9 x 10^20 m^-2. Reduced RXL and RXU by 1 cm to increase the triangularity. Good shot. Several ELM-free H-modes. |
| Nov 21 2003 04:47:41:670PM | 1031121031 | Joseph Snipes | Shot 31: Lowered nl04 to 0.8 x 10^20 m^-2. Good shot. Got a number of ELM-free H-modes again. |
| Nov 21 2003 05:03:29:410PM | 1031121032 | Joseph Snipes | Shot 32: Reloaded shot 1031121022. Good shot. Two EDA H-modes much like the shot we copied. |
| Nov 21 2003 05:04:28:500PM | 1031121032 | Joseph Snipes | Summary: There were a number of ACK and IGOR failures that cost us four shots, but otherwise it was quite a good run. After scanning the A-coil current, we settled on a ramping current from a request of 1400 ramping to 1800 A, which gives 900 to 1400 A actual current and then ran many EDA H-mode shots where good QCM data was obtained on probes, PCI, magnetics, and gas puff imaging. Only the first shot fizzled, then all other plasma attempts were full length plasmas, though there were a number of error field induced disruptions. Scorecard: 1 fizzle, 4 no power shots due to computer system failures, 27 plasmas out of 32 shots. Quite a successful run. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:02:49:343AM | Plasma | Ok | |
| 2 | 09:15:08:573AM | Plasma | Ok | |
| 3 | 09:29:17:557AM | Plasma | Ok | |
| 4 | 09:41:55:150AM | Plasma | Ok | |
| 5 | 09:54:34:837AM | Plasma | Ok | |
| 6 | 10:12:29:683AM | Plasma | Bad | Ack TFailure |
| 7 | 10:33:30:010AM | Plasma | Ok | |
| 8 | 10:46:13:790AM | Plasma | Ok | |
| 9 | 10:58:49:900AM | Plasma | Bad | Ack Failure |
| 10 | 11:27:09:643AM | Plasma | Ok | |
| 11 | 11:39:10:240AM | Plasma | Ok | |
| 12 | 11:51:43:820AM | Plasma | Ok | |
| 13 | 12:13:03:030PM | Plasma | Bad | ACK Failure |
| 14 | 12:57:30:450PM | Plasma | Ok | |
| 15 | 01:14:03:963PM | Plasma | Ok | |
| 16 | 01:30:04:803PM | Plasma | Ok | |
| 17 | 01:43:01:230PM | Plasma | Ok | |
| 18 | 01:57:38:893PM | Plasma | Ok | |
| 19 | 02:11:24:403PM | Plasma | Ok | |
| 20 | 02:23:55:307PM | Plasma | Ok | |
| 21 | 02:36:44:850PM | Plasma | Ok | |
| 22 | 02:49:23:360PM | Plasma | Ok | |
| 23 | 03:02:26:230PM | Plasma | Ok | |
| 24 | 03:16:53:693PM | Plasma | Ok | |
| 25 | 03:29:44:613PM | Plasma | Ok | |
| 26 | 03:42:45:420PM | Test | Ok | No power shot Ack fail in IGOR |
| 27 | 03:54:34:000PM | Plasma | Ok | |
| 28 | 04:07:10:200PM | Plasma | Ok | |
| 29 | 04:19:35:743PM | Plasma | Ok | |
| 30 | 04:32:43:817PM | Plasma | Ok | |
| 31 | 04:45:19:530PM | Plasma | Ok | |
| 32 | 04:57:54:560PM | Plasma | Ok | |