| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Martin Greenwald |
| Physics operator(s): | Joseph Snipes |
| Engineering operator(s): | Andy Pfeiffer,Ed Fitzgerald,Bill Byford |
| Engineering Operator Run Comment |
| MPs 456 and 403 Low Density ITBs SL: M. Greenwald/D. Mikkelsen PO: J. Sn |
| Session Leader Plans |
| Entered: Jul 19 2006 09:18:33:550AM |
| Author: Martin Greenwald |
| MP 456 low collisionality ITBs
After overnight boronization... We start with shot 1060510010, but with field at 5.3 T target nebar ~ 0.5e20 PRF ~ 2.5 MW 80 MHz (D+E) [we will want to do Bt sweeps on a few shots at the beginning to help with ECE cross calibration. A ramp of approx. 0.08T in the OH phase after RF will suffice] When conditions similar to that shot are achieved, low-density H-mode (w/ELMs).... Drop field to 4.5 T and look for/optimize ITBs. Faster development of the ITBs is possible due to a (predicted) increase in the particle pinch at low collisionality. [We probably can begin conditioning the J port antenna by tacking on a pulse after the main D+E pulse, during this phase of the experiment] Begin adding 70 MHz power to test control of barrier under conditions of low collisionality During these experiments, we want as good coverage of fluctuations and profiles as we can achieve - special attention to reflectometry to achieve localized fluctuation data at and inside barrier foot. ........ If successful, we can begin work on MP 428, by applying significant on axis power early... |
| Physics Operators Plans |
| Entered: Jul 19 2006 09:49:54:953AM |
| Author: Joseph Snipes |
| Physop plan and engineering setup for Wednesday, 19-July-2006 MPs 456 and 403 Low Density ITBs SL: M. Greenwald/D. Mikkelsen PO: J. Snipes Overnight boronization. Boronization Recipe: 10% B2D6 / 90% He 6L bottle. vessel temperature at 60/60/60. 120 psi to be deposited. PEI setting to 44/70/80 (Rmin/Rres/Rmax) with no pulser. 20 s/60 s sweep time Gas Pressures: TC3/TC6/TC9/TC6Request = [4 to 7]/150/95/150 Helium ECDC at 5e-5 Torr to be started after the boronization. Run until 7am. Multipactor conditioning is needed before the run for the ICRF. Engineering setup: ------------------- Power system setup as on 1060510010 Gas Setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1) leave B-side upper as is DO NOT TOUCH fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3) NINJA not needed (Disable) Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters. RF setup: FMIT#1,2, 3 and 4 in Run-on by 8:30AM Diagnostic needs: Fluctuation diagnostics throughout the ICRF with special attention to the reflectometry. Need density and temperature profiles for transport analysis. Run plan: Start with shot 1060510010 but at 5.3 T with target nebar ~ 0.5 x 10^20 and with PRF ~ 2.5 MW at 80 MHz central heating. Looking to produce low density H-modes (w/ small ELMs). Then, reduce the toroidal field to 4.5 T and try to obtain and optimize the internal transport barriers (ITBs). Once optimized, then add 70 MHz RF with J-port to control the barrier (density peaking) at low collisionality. |
| Session Leader Summaries |
| Entered: Jul 20 2006 04:48:36:527PM |
| Author: Martin Greenwald |
| We were able to achieve most of the objectives of the MP, however it took most of the run day to get just two shots with ITBs. We began by trying to duplicate low density ELMy H-modes from 1060510, but at 5.3T. Because of the previous night's boronization, the ICRF required substantial conditioning time. Weak H-modes were produced at first - all with discrete ELMs. Shots 06 - 09 had sustained H-modes with strong ELMs. Getting the low densities required to see peaking was also difficult - we were close to runaway conditions and probably very close to the low density limit for the L-H threshold. Mild peaking was observed on some of these early shots.
On shot 14 we dropped the field to 4.5T and began the attempt to form ITBs. As expected, it was difficult at first to get good H-modes, we were probably near the low density limit and far off-axis heating is never as effective. (a curious observation since one might think that simply heating inside the LCFS would be sufficient for the threshold and that the core profiles would be stiff. The answer might lie in the lack of good fast-wave focussing at the resonance location.) Shots 25 and 26 had strong density peaking and seemed to be the ITB discharges we were looking for. 26 was the best with ne0/neped ~ 4. There was not a clear foot, perhaps because an anomalous pinch, at low-collisionality, was acting over the entire cross section. The next steps will be TRANSP analysis to look at local transport, then gs2 simulations to try to understand the physics. |
| Physics Operator Summaries |
| Entered: Jul 19 2006 05:10:17:750PM |
| Author: Joseph Snipes |
| The machine ran quite well. All plasma attempts had plasmas except for shot 5 where the breakers were accidentally left open so there was no breakdown. There was difficulty getting decent H-modes at very low density, particularly at 5.4 T. We did manage to get some peaked density H-modes such as shots 25 and 26 at relatively low collisionality ~ 0.1. The start up changed throughout the day as I tweaked Br0 and Bz0 several times to avoid fizzles. Shot,Duration(s),Ipmax(MA),Result Shot,Duration(s),Ipmax,Result | 01 1.500 0.900 Plasma | 02 0.252 0.812 Plasma | | 03 1.951 0.926 Plasma | 04 1.951 0.944 Plasma | | 05 0.000 0.024 Dud | 06 1.950 0.953 Plasma | | 07 1.952 0.954 Plasma | 08 1.954 0.948 Plasma | | 09 1.952 0.944 Plasma | 10 1.957 0.936 Plasma | | 11 0.930 0.982 Plasma | 12 0.197 0.719 Plasma | | 13 0.644 0.939 Plasma | 14 1.955 0.822 Plasma | | 15 1.954 0.829 Plasma | 16 1.957 0.834 Plasma | | 17 1.955 0.832 Plasma | 18 0.751 0.889 Plasma | | 19 1.955 0.832 Plasma | 20 1.955 0.835 Plasma | | 21 1.957 0.831 Plasma | 22 1.955 0.766 Plasma | | 23 1.957 0.768 Plasma | 24 1.956 0.766 Plasma | | 25 1.955 0.762 Plasma | 26 1.314 0.766 Plasma | | 27 1.957 0.764 Plasma | 28 1.958 0.745 Plasma | | 29 1.957 0.749 Plasma | 30 1.953 0.765 Plasma | Date 1060719: 30 shots. 29 plasmas. 0 fizzles. 1 Operator Error. (Plasma = Ip gt 50.0 kA Dud = H_alpha lt 0.40 V) Total plasma duration: 48.59 s (exceeding -90 kA) |
| Session Leader Comments | |||
| Jul 19 2006 09:21:41:850AM | 1060719001 | Martin Greenwald | plasma, rough start on Ip ramp
Prf ~ 1.5 MW no H-mode |
| Jul 19 2006 09:46:38:610AM | 1060719002 | Martin Greenwald | Early disruption
|
| Jul 19 2006 10:18:27:090AM | 1060719003 | Martin Greenwald | Better shot
weak H-mode, discrete ELMs RF > 2MW, but ragged |
| Jul 19 2006 10:22:07:620AM | 1060719004 | Martin Greenwald | Another longish H-mode with ELMs
RF ragged nebar to about 2e20, some signs of peaking H98y approaching 1 |
| Jul 19 2006 10:48:03:210AM | 1060719005 | Martin Greenwald | No plasma (breakers out) |
| Jul 19 2006 11:06:07:250AM | 1060719006 | Martin Greenwald | Good plasma
long H-mode (extends about 0.5 sec into OH phase) strong ELMs nebar still a bit higher than we want |
| Jul 19 2006 11:18:41:020AM | 1060719007 | Martin Greenwald | Good Shot
Long H-mode, ELMs Density down about 25% signs of v. weak peaking |
| Jul 19 2006 11:33:38:337AM | 1060719008 | Martin Greenwald | Similar to shot 007 |
| Jul 19 2006 12:08:49:040PM | 1060719009 | Martin Greenwald | Similar to previous shots
long Ohmic H-mode after RF is off strong ELMs throughout, including OH phase RF cleaning up |
| Jul 19 2006 12:25:18:827PM | 1060719010 | Martin Greenwald | Similar again, but more dropouts on RF |
| Jul 19 2006 12:34:43:377PM | 1060719011 | Martin Greenwald | Disrupts before 1 second |
| Jul 19 2006 12:38:11:800PM | 1060719012 | Martin Greenwald | Disrupts early |
| Jul 19 2006 12:54:58:370PM | 1060719013 | Martin Greenwald | Early disruption again |
| Jul 19 2006 01:31:26:570PM | 1060719014 | Martin Greenwald | Lowered field to 4.5 T, Ip to 0.8 MA
RF at 2 MW steady no H-mode nebar ~ 0.5e20 |
| Jul 19 2006 01:47:44:110PM | 1060719015 | Martin Greenwald | Raised density slightly
RF power to 2.75 MW signs of H-mode but nothing definitive |
| Jul 19 2006 02:03:13:007PM | 1060719016 | Martin Greenwald | Similar to shot 15
a few very brief weak H-modes |
| Jul 19 2006 02:22:19:420PM | 1060719017 | Martin Greenwald | Better shot
H-mode lasts about 0.2 sec pedestal Te to 1keV |
| Jul 19 2006 02:31:48:813PM | 1060719018 | Martin Greenwald | Early disruption ~ 0.75 sec |
| Jul 19 2006 02:50:35:730PM | 1060719019 | Martin Greenwald | Late H-mode, ELMs |
| Jul 19 2006 03:09:15:673PM | 1060719021 | Martin Greenwald | V. weak ELMy H-modes
|
| Jul 19 2006 03:36:13:590PM | 1060719022 | Martin Greenwald | Lowered Ip to 0.7 to match q of 1060510
RF power low only ragged h-modes |
| Jul 19 2006 03:42:01:763PM | 1060719023 | Martin Greenwald | Similar to shot 22 |
| Jul 19 2006 04:02:42:710PM | 1060719024 | Martin Greenwald | H-mode going between ELMy and ELMfree
RF ragged |
| Jul 19 2006 04:04:28:650PM | 1060719025 | Martin Greenwald | Good shot
RF better (but not great) clear density peaking from 1 to 1.17 sec |
| Jul 19 2006 04:42:35:053PM | 1060719026 | Martin Greenwald | Good shot but disrupts at 1.3 sec
TV shows signs of strong peaking (bright core) TS too, ne0/nebar ~ 1.5 no sign of foot, but very peaked ne0/neped ~ 4 |
| Jul 19 2006 04:27:35:220PM | 1060719027 | Martin Greenwald | OK H-mode but no ITB peaking
RF trips and loses power in latter half of pulse |
| Jul 19 2006 04:39:17:613PM | 1060719028 | Martin Greenwald | Similar to previous shot
no sign of peaking maybe slipping into type III ELM regime |
| Jul 19 2006 04:52:39:103PM | 1060719029 | Martin Greenwald | Similar to previous shot |
| Jul 19 2006 05:07:00:047PM | 1060719030 | Martin Greenwald | Same again
H-mode but with no distinct peaking |
| Physics Operator Comments | |||
| Jul 19 2006 09:47:17:327AM | 1060719001 | Joseph Snipes | Shot 001: This run is dedicated to Bob Snipes. Copied shot 1060510010 but changed the TF current to 150 kA to provide 5.4 T. I also recalculated all of the magnetics predictors to take into account the flux loop change since that shot happened. The overnight boronization finished the diborane bottle unexpectedly after a change in pressure of ~100 psi whereas a full boronization usually uses 120 psi. Also set the TF rampdown to start at 1.3 s while the Ip rampdown starts at 1.4 s. Good shot though something took a bite out of the current rise and it disrupted in rampdown at 1.5 s. |
| Jul 19 2006 09:51:02:220AM | 1060719002 | Joseph Snipes | Shot 002: Cell access for DNB, Thomson, TCI, and active MHD. Otherwise, repeat shot 1. Disrupted at 0.25 s. |
| Jul 19 2006 09:57:46:347AM | 1060719003 | Joseph Snipes | Shot 3: Raised ZXL a bit around 0.25 s in the hope that a small shape change will avoid the early disruption. Good shot all the way down. |
| Jul 19 2006 10:36:30:847AM | 1060719004 | Joseph Snipes | Shot 4: Repeat. Good shot. |
| Jul 19 2006 10:47:53:023AM | 1060719005 | Joseph Snipes | Shot 5: Cell access to change out a diborane sensor box due to a diborane alarm that is believed to be false. Removed puff from PG3 in segment 2 and programmed nl04 to 3 x 10^19 m^-2 to bring the density down still further. Breakers were accidentally left open. No breakdown. |
| Jul 19 2006 11:01:28:840AM | 1060719006 | Joseph Snipes | Shot 6: Try again. Good shot. Nice H-modes with ELMs. |
| Jul 19 2006 11:14:24:207AM | 1060719007 | Joseph Snipes | Shot 7: Removed more pre-programmed gas from segment 1 dropping from 40 V between 0.08 and 0.1 s down to 20 V. Good shot. |
| Jul 19 2006 11:30:49:383AM | 1060719008 | Joseph Snipes | Shot 8: Set PG3 to zero from 0.08 to 0.1 s in segment 1 to reduce the target density a bit more. Changed TF ramp from 1.2 to 1.4 s from 150 kA to 147 kA then constant at 147 kA until 1.5 s. Good shot. |
| Jul 19 2006 11:50:13:937AM | 1060719009 | Joseph Snipes | Shot 9: Repeat. Good shot. |
| Jul 19 2006 12:18:48:543PM | 1060719010 | Joseph Snipes | Shot 10: Repeat. Good shot. |
| Jul 19 2006 12:25:53:733PM | 1060719011 | Joseph Snipes | Shot 11: Removed TF sweep between 1.2 and 1.4 s. Kept TF current at 150 kA up to 1.4 s then ramped down. Disrupted at 0.925 s. |
| Jul 19 2006 12:38:34:893PM | 1060719012 | Joseph Snipes | Shot 12: Repeat. Disrupted at 0.18 s. |
| Jul 19 2006 01:01:45:387PM | 1060719013 | Joseph Snipes | Shot 13: Programmed lower TF down to 124.5 kA after 0.5 s. Lowered Ip to 0.8 MA. Lots of runaways followed by a disruption at 0.64 s. Density goes well below the request of 3 x 10^19 m^-2 down as far as 5 x 10^18 m^-2. |
| Jul 19 2006 01:34:49:517PM | 1060719014 | Joseph Snipes | Shot 14: Raised nl04 to 5 x 10^19 m^-2. Better shot but still some runaways and no H-mode with 2 MW ICRF. Perhaps, we are now below the low density limit for H-mode. |
| Jul 19 2006 01:43:59:047PM | 1060719015 | Joseph Snipes | Shot 15: Increased PG3 puff in segment 1 from 0.08 to 0.1 s back to 40 V. Reduced TF current to 123.1 kA. Good shot but still some runaways and at most only a very weak ELMy H-mode from 0.82 to 0.87 s visible on the fast magnetics and D alpha. |
| Jul 19 2006 02:00:36:537PM | 1060719016 | Joseph Snipes | Shot 16: Reduced TF current again to 122 kA. Good shot but no clear H-modes. |
| Jul 19 2006 02:15:49:420PM | 1060719017 | Joseph Snipes | Shot 17: Raised nl04 to 5.5 x 10^19 m^-2. Good shot now with ELMy H-mode from 0.8 to 1.0 s. |
| Jul 19 2006 02:27:30:813PM | 1060719018 | Joseph Snipes | Shot 18: Repeat with longer RF pulse. Disrupted at 0.75 s. |
| Jul 19 2006 02:48:27:180PM | 1060719019 | Joseph Snipes | Shot 19: Reduced Br0 by 0.3 mT to -0.8 mT. Startup is a bit better. Small ELMs between 1 and 1.2 s. |
| Jul 19 2006 03:06:17:547PM | 1060719021 | Joseph Snipes | Shot 21: Repeat. Good shot. |
| Jul 19 2006 03:21:37:537PM | 1060719022 | Joseph Snipes | Shot 22: Reduced Ip to 0.7 MA. Try again. Good shot, but the RF tripped. |
| Jul 19 2006 03:33:24:823PM | 1060719023 | Joseph Snipes | Shot 23: Reduced EF4 current by 10 A to -1345 A. Good shot. |
| Jul 19 2006 03:46:57:750PM | 1060719024 | Joseph Snipes | Shot 24: Repeat hopefully with more ICRF power. Good shot. H-mode lasted throughout most of the ICRF pulse, but the RF was tripping regularly. |
| Jul 19 2006 04:03:20:380PM | 1060719025 | Joseph Snipes | Shot 25: Reduced Br0 by 0.2 mT to -1 mT. Good shot. |
| Jul 19 2006 04:12:11:150PM | 1060719026 | Joseph Snipes | Shot 26: Reduced EF4 current by another 10 A to -1355 A. Disrupted at 1.3 s. |
| Jul 19 2006 04:27:12:250PM | 1060719027 | Joseph Snipes | Shot 27: Repeat. Good shot but the ICRF tripped after 1.2 s. |
| Jul 19 2006 04:38:39:660PM | 1060719028 | Joseph Snipes | Shot 28: Reduced Ip to 0.65 MA and nl04 to 4.5 x 10^19 m^-2. Good shot but the ICRF is tripping repeatedly. |
| Jul 19 2006 04:52:26:760PM | 1060719029 | Joseph Snipes | Shot 29: Repeat. Runaways early but otherwise a good shot though the ICRF was tripping frequently. |
| Jul 19 2006 05:10:02:893PM | 1060719030 | Joseph Snipes | Shot 30: Set Ip to 0.7 MA and make one last attempt. Set fizzle detector end time to 2.1 sec, OH1, OH2, and TF invert times to 2.3 s because there was an OH resistance > 2.5 uOhm for shot 29. Good shot. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:14:37:533AM | Plasma | Ok | |
| 2 | 09:41:11:340AM | Plasma | Ok | |
| 3 | 09:55:02:063AM | Plasma | Ok | |
| 4 | 10:12:40:523AM | Plasma | Ok | |
| 5 | 10:45:45:303AM | Plasma | Bad | TMX breakers not closed |
| 6 | 10:59:20:040AM | Plasma | Ok | |
| 7 | 11:12:07:547AM | Plasma | Ok | |
| 8 | 11:27:43:273AM | Plasma | Ok | |
| 9 | 11:48:41:000AM | Plasma | Ok | |
| 10 | 12:10:55:727PM | Plasma | Ok | |
| 11 | 12:23:31:730PM | Plasma | Ok | |
| 12 | 12:36:04:563PM | Plasma | Ok | |
| 13 | 12:53:14:150PM | Plasma | Ok | |
| 14 | 01:22:05:670PM | Plasma | Ok | |
| 15 | 01:36:03:313PM | Plasma | Ok | |
| 16 | 01:54:47:943PM | Plasma | Ok | |
| 17 | 02:11:46:793PM | Plasma | Ok | |
| 18 | 02:25:26:890PM | Plasma | Ok | |
| 19 | 02:37:58:083PM | Plasma | Ok | |
| 20 | 02:50:55:527PM | Plasma | Ok | |
| 21 | 03:04:48:220PM | Plasma | Ok | |
| 22 | 03:17:53:600PM | Plasma | Ok | |
| 23 | 03:30:54:340PM | Plasma | Ok | |
| 24 | 03:43:22:483PM | Plasma | Ok | |
| 25 | 03:55:46:037PM | Plasma | Ok | |
| 26 | 04:10:00:260PM | Plasma | Ok | |
| 27 | 04:22:48:640PM | Plasma | Ok | |
| 28 | 04:35:04:347PM | Plasma | Ok | |
| 29 | 04:47:35:227PM | Plasma | Ok | |
| 30 | 05:02:09:280PM | Plasma | Ok | |