| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Joseph Snipes |
| Physics operator(s): | Jim Irby |
| Engineering operator(s): | Ed Fitzgerald,Bill Parkin,Bill Byford,Gary Dekow |
| Engineering Operator Run Comment |
| Purpose: Active TAE Gap Scan/Snipes/Irby/Dekow |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:32:227PM |
| Author: To Be Determined |
| Run Plan for Wednesday 1030521 Active TAE Gap Scan Session Leader: J Snipes Physics Operator: J Irby Start with segment 2 from shot 1021003012 which ramps Bt up to 6.9 T and then back down 4.2 T by the end of the shot at 0.8 MA and nl04 = 1.6 x 10^20 m^-2 with a limited plasma. This shot had an outer gap of about 1.5 cm. We will then excite the Active MHD antenna at ~400 kHz and look for a TAE resonance as the Alfven frequency decreases with the toroidal field. Then, we will decrease the outer gap shot-to-shot in 0.5 cm increments and look at the changes in the observed resonant mode amplitude. Then, we will switch to a standard lower single null plasma using 1030516005 but copying the Bt waveform from 1021003012, which had a 1 cm outer gap. Then, vary the outer gap between 0 cm and 2 cm shot-to-shot to look for changes in the TAE resonant mode amplitude. Then, if time permits, we will change to constant Bt and make frequency sweeps around the expected TAE resonant frequency and vary the flattop Bt value shot to shot to vary the TAE resonance a small amount about the frequency sweep. Again if time permits, we will then go back to constant frequency and attempt to modulate the TF current about the expected TAE resonance either with diverted plasma or limited plasma depending on the quality of the resonances obtained. Summary: Despite a number of natural disruptions, Li pellet induced disruptions, fizzles and misloads by the PO, we did manage to get some very good data from the Active MHD Spectroscopy system. We did a complete outer gap scan in inner wall limited plasmas from zero outer gap to 2.5 cm outer gap and we found resonances in all cases with a damping rate that increased with increasing outer gap. Then, we turned to the diverted plasma comparison and we had a number of problems. Still, we did manage to scan the outer gap from 0.7 cm to 0.2 cm and found a very broad resonance with the larger gap and several narrow resonances with the smaller gap. So, in both limited and diverted plasmas, it appears that the damping rate increases with increasing gap. We had hoped to get at least a 1.5 cm outer gap in diverted plasmas, but a misloaded shot followed by a couple of fizzles, followed by a data system hang ended the run. Preliminary analysis of the damping rates indicates that they vary from 0.7% < gamma/omega < 3.5% with the gap changing from 0.2 cm to 2.7 cm in limited plasmas and the damping rates in diverted plasmas were not that different, though perhaps a bit larger. Overall, it was a successful run. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:17:940PM |
| Author: To Be Determined |
| Physop Summary for 1030520 Active TAE Modes EO Dekow, Byford, Fitzgerald, Parkin SS Snipes PO Irby This day was a pretty bad for the physop, though I think some interesting MHD data was obtained. We started off with a couple of cycle tests to make sure the TF scanner was working. The TF scanner was particularly important since we planned to run the TF above 6T today. We then ran limited plasmas with a TF ramp until shot 12 when we had our first fizzle following a full current disruption on shot 11. Most of the rest of the day was spent toggling between plasmas, often with disruptions, and fizzles. Two or three disruptions were Li pellet induced. tests 1, 2 plasmas 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 16, 18, 19, 21, 23, 25, 26 fizzle 12, 14, 15, 17, 20, 22, 24, 27, 28 |
| Session Leader Comments | |||
| May 20 2003 08:34:35:257AM | Joseph Snipes | Run Plan for Wednesday 1030521 Active TAE Gap Scan Session Leader: J Snipes Start with segment 2 from shot 1021003012 which ramps Bt up to 6.9 T and then back down 4.2 T by the end of the shot at 0.8 MA and nl04 = 1.6 x 10^20 m^-2 with a limited plasma. This shot had an outer gap of about 1.5 cm. We will then excite the Active MHD antenna at ~400 kHz and look for a TAE resonance as the Alfven frequency decreases with the toroidal field. Then, we will decrease the outer gap shot-to-shot in 0.5 cm increments and look at the changes in the observed resonant mode amplitude. Then, we will switch to a standard lower single null plasma using 1030516005 but copying the Bt waveform from 1021003012, which had a 1 cm outer gap. Then, vary the outer gap between 0 cm and 2 cm shot-to-shot to look for changes in the TAE resonant mode amplitude. Then, if time permits, we will change to constant Bt and make frequency sweeps around the expected TAE resonant frequency and vary the flattop Bt value shot to shot to vary the TAE resonance a small amount about the frequency sweep. Again if time permits, we will then go back to constant frequency and attempt to modulate the TF current about the expected TAE resonance either with diverted plasma or limited plasma depending on the quality of the resonances obtained. | |
| May 20 2003 09:34:18:480AM | 1030520003 | Joseph Snipes | To avoid going to particularly high field and to avoid late disruptions, we will reduce the TF ramp to 6.4 T down to 5 T. Very clear resonance centered at 1.065 s at 5.92 T even with a gap of 1.8 cm. |
| May 20 2003 10:09:20:293AM | 1030520004 | Joseph Snipes | Very clear resonance centered at 1.1 s even with a gap of 2.2 cm. However, despite slightly increasing the ramp rate of the TF, the resonance is even broader. |
| May 20 2003 10:19:58:623AM | 1030520005 | Joseph Snipes | Irby forgot to increase the outer gap, so we got a repeat. gamma/omega = 2.3% from FFT analysis. |
| May 20 2003 10:30:21:093AM | 1030520006 | Joseph Snipes | Increase the outer gap to 2.5 cm. Density feedback failed. So, we cannot calculate the TAE frequency without the TCI. There is also no Thomson data because there are no Thomson people present. There was a small resonance at 1.15 s, but it is not nearly as broad as the others. So, let's repeat this shot to get the TCI data. |
| May 20 2003 11:11:05:373AM | 1030520007 | Joseph Snipes | Increase the outer gap to 2.5 cm. Repeat went well. Very broad resonance with gamma/omega = 3.5%. |
| May 20 2003 11:12:59:173AM | 1030520008 | Joseph Snipes | Reduce outer gap to 1 cm. TCI failed again. The density was not as requested. Still, there were a couple of resonances early at 0.34 s and about 0.5 s. |
| May 20 2003 11:44:18:440AM | 1030520009 | Joseph Snipes | Gap was a bit small on Shot 8, so increase the outer gap to 1.2 cm. No, we got 1.48 cm gap. The resonance moved to 0.87 s and is narrower again. gamma/omega = 1.5 %. |
| May 20 2003 11:55:43:410AM | 1030520010 | Joseph Snipes | Reduce gap to 1 cm, got 1.2 cm. Resonance moved to 0.84 s. The resonance is a bit noisy, but the fitted gamma/omega ~0.7%. So, the damping increases with increaseing gap! Curious result! |
| May 20 2003 12:26:33:313PM | 1030520011 | Joseph Snipes | Reduce gap to 1 cm. Good shot. Very weak resonance, if any, at the corner of the TF ramp at 0.775 s, appears to be limited by the ramp. |
| May 20 2003 12:27:06:110PM | 1030520012 | Joseph Snipes | Reduce gap to 0.5 cm. Fizzle! |
| May 20 2003 12:55:14:780PM | 1030520013 | Joseph Snipes | Reduce gap to 0.5 cm. Got 0.4 cm gap. Appears to have a resonance at 0.85 s, but the mode is very weak (5 mG). |
| May 20 2003 12:57:31:300PM | 1030520014 | Joseph Snipes | Fizzle! |
| May 20 2003 01:23:22:683PM | 1030520015 | Joseph Snipes | Fizzle! |
| May 20 2003 01:43:21:840PM | 1030520016 | Joseph Snipes | Got plasma and nearly zero gap, but the D-Tacq PCI data acquisition failed so I got no Active MHD data. |
| May 20 2003 01:43:39:183PM | 1030520017 | Joseph Snipes | Fizzle! |
| May 20 2003 03:29:41:987PM | 1030520018 | Joseph Snipes | Good shot. Small resonance at 0.745 s with gamma/omega = 0.9%!? |
| May 20 2003 03:32:41:317PM | 1030520021 | Joseph Snipes | Copied shot 1030516005 and changed the TF and density waveforms to be like the previous shots today. Now lower single null diverted plasmas. Good shot. BP20_ABK shows a broad resonance at 0.96 s, but it is not visible on BP03_ABK. Here the gap was 0.8 cm. |
| May 20 2003 03:32:59:320PM | 1030520022 | Joseph Snipes | Fizzle! |
| May 20 2003 03:49:00:610PM | 1030520023 | Joseph Snipes | Reduce outer gap to 0.5 cm or so. Good shot. Resonances are not clear on BP03_ABK but there are two fairly sharp resonances on BP20_ABK. They occur at 0.7 and 0.83 s and the gamma/omega ~ 1.3%. |
| May 20 2003 04:35:09:353PM | 1030520025 | Joseph Snipes | Reduce outer gap to 0.2 cm or so. Good shot. Resonances are clear on BP20_ABK as the TAE frequency passes the Active MHD frequency between 0.6 and 0.85 s. |
| May 20 2003 04:36:39:933PM | 1030520026 | Joseph Snipes | Reduce outer gap to 0.2 cm or so. Good shot. Resonances are clear on BP20_ABK as the TAE frequency passes the Active MHD frequency between 0.6 and 0.85 s. This was a repeat of shot 25 because Irby did not load the change to a larger gap into model. |
| May 20 2003 04:37:03:387PM | 1030520027 | Joseph Snipes | Fizzle! |
| May 20 2003 04:57:45:637PM | 1030520028 | Joseph Snipes | Fizzle! |
| May 20 2003 05:31:33:110PM | 1030520028 | Joseph Snipes | Summary: Despite a number of natural disruptions, Li pellet induced disruptions, fizzles and misloads by the PO, we did manage to get some very good data from the Active MHD Spectroscopy system. We did a complete outer gap scan in inner wall limited plasmas from zero outer gap to 2.5 cm outer gap and we found resonances in all cases with a damping rate that increased with increasing outer gap. Then, we turned to the diverted plasma comparison and we had a number of problems. Still, we did manage to scan the outer gap from 0.7 cm to 0.2 cm and found a very broad resonance with the larger gap and several narrow resonances with the smaller gap. So, in both limited and diverted plasmas, it appears that the damping rate increases with increasing gap. We had hoped to get at least a 1.5 cm outer gap in diverted plasmas, but a misloaded shot followed by a couple of fizzles, followed by a data system hang ended the run. Preliminary analysis of the damping rates indicates that they vary from 0.7% < gamma/omega < 3.5% with the gap changing from 0.2 cm to 2.7 cm in limited plasmas and the damping rates in diverted plasmas were not that different, though perhaps a bit larger. Overall, it was a successful run. |
| Physics Operator Comments | |||
| May 20 2003 08:54:07:357AM | Jim Irby | Loaded shot 1021003012 --- limited, TF ramp from 6.9 to 4.2 T., 1.6e20 m^2 nl04 TF peak current set to: 181.0 kA --- 6.4 T TF min current set to: 141.5 kA --- 5.0 T ----- try to keep from disrupting First shot will be a cycle test to make sure the TF scanner is running properly | |
| May 20 2003 09:14:22:753AM | 1030520001 | Jim Irby | Cycle test: no TF scanner |
| May 20 2003 09:15:36:977AM | 1030520002 | Jim Irby | Cycle test: TF scanner back on-line |
| May 20 2003 09:44:33:100AM | 1030520003 | Jim Irby | Try for plasma Good shot ---- Joe sees resonace |
| May 20 2003 10:01:53:943AM | 1030520004 | Jim Irby | Dropped peak TF to 6.1 T, raised min field to 5.4 T Changed timing of ramp to speed it up a little RCUR reduced by 2.5 mm to give 5 mm increase in outer gap Nice plasma |
| May 20 2003 10:15:45:413AM | 1030520005 | Jim Irby | Decreased RCUR another 2.5 mm Operator error: didn't load it! |
| May 20 2003 10:27:51:277AM | 1030520006 | Jim Irby | Loaded the 5 mm increase in outer gap plasma, but I didn't check the CO2 laser ---- lost feedback. Got larger gap |
| May 20 2003 10:44:50:550AM | 1030520007 | Jim Irby | Will repeat to get density at this outer gap for Joe's resonance calculations Plasma --- TCI okay |
| May 20 2003 11:17:39:180AM | 1030520008 | Jim Irby | Outer gap to .01 m Plasma, but lost TCI again! Measured outer gap was .0078 m, will increase for next shot. |
| May 20 2003 11:34:24:020AM | 1030520009 | Jim Irby | Increased outer gap by .004 m Got outer gap of 1.45 cm at 1.0 s TCI okay |
| May 20 2003 11:50:31:090AM | 1030520010 | Jim Irby | Increased RCUR by .001 m Outer gap .012 m --- getting close to what Joe wants Plasma --- h/(h+d) is 3 to 5% |
| May 20 2003 12:04:43:987PM | 1030520011 | Jim Irby | Increase RCUR by another mm Outer gap about .01 m at 1 s plasma okay |
| May 20 2003 12:33:08:107PM | 1030520012 | Jim Irby | Increased RCUR by .002 m Increased TF peak to 6.4 T Fizzle --- previous shot disruption |
| May 20 2003 12:50:18:867PM | 1030520013 | Jim Irby | Br0 from .0005 to .00025 T Plasma, but lost it at 1.41 s. ---- Li pellet Got the 0.005 m outer gap |
| May 20 2003 12:54:33:997PM | 1030520014 | Jim Irby | Increased RCUR another .002 m Increased gas puff by 1 ms fizzle ---- didn't take care of disruption... |
| May 20 2003 01:22:58:947PM | 1030520014 | Jim Irby | Gas reduced by 1 ms (back to shot 12) Fizzle |
| May 20 2003 01:43:53:790PM | 1030520016 | Jim Irby | EF4 from -1350 to -1370. Plasma --- disrupts at 1.58 s ---- startup not very good |
| May 20 2003 01:53:35:213PM | 1030520017 | Jim Irby | reduced Br0 by .00025 T reduced outer gap another .002 m fizzle |
| May 20 2003 02:15:31:857PM | 1030520018 | Jim Irby | Bz0 from -1370 to -1350 gas puff increased by 1 ms plasma to 1.56 s Note we have had large increases in CII light beyond 0.25 s. |
| May 20 2003 02:40:58:333PM | 1030520019 | Jim Irby | Loaded shot 1030516005 Increased density request to 1.6e20 disrupted --- lots of gas |
| May 20 2003 02:46:50:390PM | 1030520020 | Jim Irby | reduced gas puff by 2 ms reduced early density programming fizzle --- gas change didn't help on this one... |
| May 20 2003 03:15:56:260PM | 1030520021 | Jim Irby | Gas puff reduced by 2 ms EF4 from -1320 to -1340 A Plasma to 1.72 s h/(h+d) at 5% |
| May 20 2003 03:26:56:683PM | 1030520022 | Jim Irby | Increased RCUR by .0015 m fizzle --- Bz0? |
| May 20 2003 03:48:04:543PM | 1030520023 | Jim Irby | Bz0 to -1360 from -1340 A Increased gas puff by 1 ms plasma for 1.718 s |
| May 20 2003 04:01:18:880PM | 1030520024 | Jim Irby | Increased RCUR by .001 m early ramping up by .002 m at 1.7 s Fizzle --- Joe suggests Br0 is too positive. |
| May 20 2003 04:17:44:623PM | 1030520025 | Jim Irby | Br0 1 mT more negative plasma for 1.38 s |
| May 20 2003 04:26:57:543PM | 1030520026 | Jim Irby | Reduced RCUR by .00625 m --- trying for 1.5 cm outer gap plasma for 1.86 s Another PO error ---- didn't load larger gap!!! |
| May 20 2003 04:44:40:477PM | 1030520027 | Jim Irby | repeat with larger gap loaded in PCS fizzle ----- |
| May 20 2003 05:03:53:710PM | 1030520028 | Jim Irby | reduced gas puff by 1 ms fizzle --- Bz0 too positive again? |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:52:02:507AM | Test | Ok | Data System And TF Scanner Test |
| 2 | 09:09:44:553AM | Test | Ok | TF Scanner Test |
| 3 | 09:22:33:447AM | Plasma | Ok | |
| 4 | 09:51:37:603AM | Plasma | Ok | |
| 5 | 10:04:35:060AM | Plasma | Ok | |
| 6 | 10:18:48:247AM | Plasma | Ok | |
| 7 | 10:37:13:807AM | Plasma | Ok | |
| 8 | 10:56:20:087AM | Plasma | Ok | |
| 9 | 11:18:50:290AM | Plasma | Ok | |
| 10 | 11:41:38:343AM | Plasma | Ok | |
| 11 | 11:55:43:800AM | Plasma | Ok | |
| 12 | 12:19:45:897PM | Plasma | Ok | |
| 13 | 12:37:21:270PM | Plasma | Ok | |
| 14 | 12:52:08:667PM | Plasma | Ok | |
| 15 | 01:05:30:827PM | Plasma | Ok | |
| 16 | 01:24:30:107PM | Plasma | Ok | |
| 17 | 01:41:56:540PM | Plasma | Ok | |
| 18 | 01:56:58:233PM | Plasma | Ok | |
| 19 | 02:24:42:340PM | Plasma | Ok | |
| 20 | 02:42:31:837PM | Plasma | Ok | |
| 21 | 03:00:25:237PM | Plasma | Ok | |
| 22 | 03:17:28:060PM | Plasma | Ok | |
| 23 | 03:31:29:910PM | Plasma | Ok | |
| 24 | 03:50:54:470PM | Plasma | Ok | |
| 25 | 04:05:05:743PM | Plasma | Ok | |
| 26 | 04:20:19:843PM | Plasma | Ok | |
| 27 | 04:33:48:710PM | Plasma | Ok | |
| 28 | 04:47:10:730PM | Plasma | Ok | |