| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | E. Nelson Melby |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Gary Dekow |
| Engineering Operator Run Comment |
| MP#272A Investigation of ICRF Mode Conversion SL:Melby PO: Granetz EO:D |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:26:100PM |
| Author: To Be Determined |
| Session Leader summary for run 1001222 MP #272A Investigation of ICRF Mode Conversion Session leader: Eric Nelson-Melby Using the PCI in high-resolution mode, we will run plasmas consisting of hydrogen, deuterium, and helium-3 to look for mode conversion near the center of the plasma. The mode conversion layer becomes more of a vertical line as the poloidal field is reduced, so we will scan down in current, starting at 0.4 MA and going lower, if possible, and then up to 0.6. Other parameters and settings: Btor=5.8 T, nl_04=0.5e20 m-2, lower single null, L-mode, Prf=1 MW. If we get into H-mode, then we'll switch to limited. --------------------------------- Ion Bernstein Wave (and possibly fast magnetosonic wave) signal was seen on the PCI today, and there are indications of off-axis direct electron heating from the RF modulation later in the shot. Shots 1-5 were to get the plasma with the strange mix of Helium-3, Hydrogen and Deuterium started. Shot 6 -- weak signal (low RF power) was seen at around 68 cm, which then moved as expected when final mirror in the PCI laser system was swept back and forth to get more coverage. Lots of Helium, and H/D is large. Next shot, try to reduce Helium a bit, and raise RF power. Also raise B field a bit to try to bring mode conversion layer further within PCI window. Shot 7 -- Stronger signal seen around 67 to 68 cm, during high RF power portion at .9 to 1 second. k spectrum indicates possibly fast wave (low k number <1 cm^-1) and IBW (high k number about 7 cm^-1) are both present in PCI window. Shot 8 -- RF power now about 1.2 MW on D and E initially, D on longer. PCI signal seems to be more uniform across a few channels, rather than spread out in separate chunks as at higher current in 1000623 run. k spectrum shows clear IBW signal at about .55 seconds, and again between .75 and .8 seconds. Density stayed more constant (and at a fairly low level). Shot 9 -- We tried to move the PCI laser to see if the mode conversion region extended further to the high field side, but unfortunately the pre-amplifiers were off. This shot can still be used for electron break-in-slope analysis to see off-axis electron heating from localized damping of the IBW. Shot 10 -- raised RF power even further. Strong signal (8 times background level) and localized near 67 cm. k spectrum indicates IBW -- only positive k of about 7 cm^-1 is present (no negative k, i.e. phase velocity only going towards the antenna, showing the backwards propagating nature of the IBW). Later, during the mirror sweeping period, the signal seems to disappear and briefly reappear at .94 seconds, which would seem to indicate that the signal is well localized in one major radius clump, as we had hoped by going to lower current. Though there were few shots, they helped confirm some of the TORIC code modelling that has been done since the June 23rd run when these IBW signals were first seen on the PCI. Only one current (about 400 kA) and one field (about 5.9 T) was tried, not three or four currents and a B field sweep as in the run plan, but still very interesting and useful data was obtained. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:12:940PM |
| Author: To Be Determined |
| Physics operator summary for run 1001222 (Friday): MP #272A Investigation of ICRF Mode Conversion Session leader: Eric Nelson-Melby Physics operator: R. Granetz Summary: Loss of the 13.8 kV experimental power last night caused the run to be delayed until after 14:00. In addition, the first 5 shots were fizzles and duds. So we only got five good plasma discharges for Eric's MP. The successful breakdowns had unusually high fill pressure, unusually high Br0, and unusually late breakdown times. Fortunately, the shots we got had the desired parameters, and the PCI was working well, and the IBW was clearly seen. See Eric's run summary to find out more about the physics results. Scorecard: 5 plasmas 2 fizzles 3 duds 0 test 0 aborted and/or screwed up by computer problems ---------- 10 total ------------------------------------------------------------------------------- Engineering setup: ECDC in H2 overnight on Wednesday (two nights before run), followed by ECDC in He4 on Thursday (the day before the run), ending by evening. No ECDC overnight before the run. Just let the machine pump. Power systems as on 1001220017, except increase TF limit to 175 kA. Gas setup: fill B-top with 6 psi of D2 Hybrid enabled (PG4) fill B-side lower with 1 psi of Ar Hybrid DISABLED (PG1) fill B-side upper with 16 psi of He3 Hybrid enabled (PG2) fill C-side with 30 psi of H2 Hybrid enabled (PG3) fill J-bottom with 30 psi of D2 Hybrid DISABLED (PG5) Enable the following gate valves: ECE, VUV, Beast, DNB Run starts at 09:00 and ends at 17:00. ------------------------------------------------------------------------------- RF Setup: XMTRs 1 and 2 should be made ready by 8:00 (run-on). J-port will not be used ------------------------------------------------------------------------------- Run Plan: MP #272A Investigation of ICRF Mode Conversion Session leader: Eric Nelson-Melby Using the PCI in high-resolution mode, we will run plasmas consisting of hydrogen, deuterium, and helium-3 to look for mode conversion near the center of the plasma. The mode conversion layer becomes more of a vertical line as the poloidal field is reduced, so we will scan down in current, starting at 0.4 MA and going lower, if possible, and then up to 0.6. Other parameters and settings: Btor=5.8 T, nl_04=0.5e20 m-2, lower single null, L-mode, Prf=1 MW. If we get into H-mode, then we'll switch to limited. Re-load segment 1 from 1001220021 (a good recent startup). Re-load segment 2 from 1001215024 (0.8 MA, 5.3 T, NL_ZMETER, CLEARIN offset = 12700), but change Ip to 0.4 MA, NL_ZMETER wire back to TCI nl_04 (copy from segment 3 of the same shot), increase Btor to 5.8 T (165 kA), set nl_04 to 5e19 m-2. Density feedback will initially use only the hydrogen valve, with a preprogrammed waveform for the He3 valve, taken from shot 1000623009. Also, prepare a similar limited plasma in segment 3, just in case we can't stay in L-mode. ------------------------------------------------------------------------------- Overnight ECDC in H2 was done the night before last. Daytime ECDC in He4 was done yesterday. No ECDC was done last night. Machine just pumped overnight. Hybrid coldstart done; no errors found See previous comment for details of PCS programming setup. ------------------------------------------------------------------------------- #42 of 43 OPS Date: 22-DEC-2000 07:13 Expires: 23-DEC-2000 07:10 From: BAROLO::WOLFE Subj: Run Delayed Experimental power (CELCO/NSTAR) went down last night, and is still out; the utility is looking for the fault in their lines, and hopes to restore 13.8kV service by 10:00 AM today. This meana that the alternator will not be available for operations until at least 13:00. BULLETIN> ------------------------------------------------------------------------------- The run started just after 14:00 Shot 01 -- Dud. Next shot: add +10 A to IC_EF4 and 4 ms to pre-fill puff (D2) Shot 02 -- Fizzle. Strong one (60 kA). Lost it vertically. Late breakdown. Next shot: no changes Shot 03 -- Dud. Next shot: add 2 more ms to pre-fill, add +0.3 mT to Br0 Shot 04 -- Fizzle. Just like shot 2. Next shot: add +5 mT to Br0 (on Steve's urging) Shot 05 -- Dud. Next shot: subtract 10 A from IC_EF4, add 2 ms to pre-fill. Shot 06 -- Plasma. Good shot. Ip=0.4 MA, Btor=5.85 T, nl_04=0.5-0.9e20 m-2. Prf=0.5-1.0 MW. Plasma came close to being limited between t=0.5-1.0 s, which is not what was programmed. Next shot: move RCUR in by 5 mm between t=0.5 and 1.0 s. Reduce He3 puff. Increase Btor to 5.95 T (167 kA). Shot 07 -- Plasma. Good shot. nl_04=0.5-0.8e20 m-2. Btor=5.94 T. Prf=1 MW. We had better control of outer gap on this shot. Next shot: more tweaking of RCUR from t=0.8 to 1.0 s. Reduce He3 maintenance level from 35 to 30 volts. Shot 08 -- Plasma. Good shot. nl_04 stays constant at 0.55e20 m-2. Prf=1.3 MW, fairly constant. Plasma touched outer limiter around t=1 s. Next shot: repeat with a slight RCUR tweak starting at t=1 s. Move PCI beam. Shot 09 -- Plasma. Good shot. Right gap stayed at 1 cm or larger for the entire shot. Breakdown Br0 and Bz are both drifting higher. Next shot: reduce IC_EF4 by 5 A and reduce Br0 by 0.2 mT. Shot 10 -- Plasma. Good shot. There was a big injection at t=1.24 s, but this is after the PCI data window. Steve Wolfe reports that this occurs when OH1 comes out of crossover. (It's late in the shot because we're running low plasma currents today.) End of run |
| Session Leader Comments | |||
| Dec 22 2000 02:18:15:733PM | 1001222001 | E. Nelson Melby | 1st attempt: low current, only D port at about 750 kW. Try to see IBW signal by sweeping mirror at end of PCI time window. Fizzle. |
| Dec 22 2000 02:34:24:340PM | 1001222002 | E. Nelson Melby | 1st attempt: low current, only D port at about 750 kW. Try to see IBW signal by sweeping mirror at end of PCI time window. fizzle, but higher current (60 kA) |
| Dec 22 2000 02:43:41:187PM | 1001222003 | E. Nelson Melby | Dud. |
| Dec 22 2000 03:53:09:780PM | 1001222006 | E. Nelson Melby | Low current, only D port at about 750 kW. (And a short E port pulse to get the tune). Try to see IBW signal by sweeping mirror at end of PCI time window. Faint signal there -- raise power, improve tune, shorten He3 gas puff. |
| Dec 22 2000 04:22:48:763PM | 1001222007 | E. Nelson Melby | RF power increased a bit, some hint of PCI signal at D port frequency -- could be just fast wave, but some IBW possible with k = +7 cm^-1 also. |
| Dec 22 2000 05:39:39:467PM | 1001222008 | E. Nelson Melby | IBW signal present at 350 kHz (corresponding to D port 80.5 MHz). Density stayed more constant. Raise RF power. |
| Dec 22 2000 05:40:02:437PM | 1001222009 | E. Nelson Melby | Power on D and E raised, extended E port shot. Good power modulation. |
| Dec 22 2000 05:42:29:873PM | 1001222010 | E. Nelson Melby | Good signal around 67 cm, when PCI mirror was swept, signal goes away (indicating good localization of IBW). k number about 7 or 8 cm^-1, strong signal present from about .5 sec to .8 sec. |
| Physics Operator Comments | |||
| Dec 21 2000 10:56:52:000AM | Robert Granetz | Engineering setup: ECDC in H2 overnight on Wednesday (two nights before run), followed by ECDC in He4 on Thursday (the day before the run), ending by evening. No ECDC overnight before the run. Just let the machine pump. Power systems as on 1001220017, except increase TF limit to 175 kA. Gas setup: fill B-top with 6 psi of D2 Hybrid enabled (PG4) fill B-side lower with 1 psi of Ar Hybrid DISABLED (PG1) fill B-side upper with 16 psi of He3 Hybrid enabled (PG2) fill C-side with 30 psi of H2 Hybrid enabled (PG3) fill J-bottom with 30 psi of D2 Hybrid DISABLED (PG5) Enable the following gate valves: ECE, VUV, Beast, DNB Run starts at 09:00 and ends at 17:00. ------------------------------------------------------------------------------- RF Setup: XMTRs 1 and 2 should be made ready by 8:00 (run-on). J-port will not be used ------------------------------------------------------------------------------- | |
| Dec 21 2000 11:00:44:857AM | Robert Granetz | Run Plan: MP #272A Investigation of ICRF Mode Conversion Session leader: Eric Nelson-Melby Using the PCI in high-resolution mode, we will run plasmas consisting of hydrogen, deuterium, and helium-3 to look for mode conversion near the center of the plasma. The mode conversion layer becomes more of a vertical line as the poloidal field is reduced, so we will scan down in current, starting at 0.4 MA and going lower, if possible, and then up to 0.6. Other parameters and settings: Btor=5.8 T, nl_04=0.5e20 m-2, lower single null, L-mode, Prf=1 MW. If we get into H-mode, then we'll switch to limited. Re-load segment 1 from 1001220021 (a good recent startup). Re-load segment 2 from 1001215024 (0.8 MA, 5.3 T, NL_ZMETER, CLEARIN offset = 12700), but change Ip to 0.4 MA, NL_ZMETER wire back to TCI nl_04 (copy from segment 3 of the same shot), increase Btor to 5.8 T (165 kA), set nl_04 to 5e19 m-2. Density feedback will initially use only the hydrogen valve, with a preprogrammed waveform for the He3 valve, taken from shot 1000623009. Also, prepare a similar limited plasma in segment 3, just in case we can't stay in L-mode. ------------------------------------------------------------------------------- | |
| Dec 22 2000 08:12:24:390AM | Robert Granetz | Overnight ECDC in H2 was done the night before last. Daytime ECDC in He4 was done yesterday. No ECDC was done last night. Machine just pumped overnight. Hybrid coldstart done; no errors found See previous comment for details of PCS programming setup. | |
| Dec 22 2000 08:13:36:233AM | Robert Granetz | #43 of 44 OPS Date: 22-DEC-2000 07:13 Expires: 23-DEC-2000 07:10 From: BAROLO::WOLFE Subj: Run Delayed Experimental power (CELCO/NSTAR) went down last night, and is still out; the utility is looking for the fault in their lines, and hopes to restore 13.8kV service by 10:00 AM today. This meana that the alternator will not be available for operations until at least 13:00. BULLETIN> | |
| Dec 22 2000 02:21:05:590PM | 1001222001 | Robert Granetz | Shot 01 -- Dud. Next shot: add +10 A to IC_EF4 and 4 ms to pre-fill puff (D2) |
| Dec 22 2000 02:52:24:090PM | 1001222002 | Robert Granetz | Shot 02 -- Fizzle. Strong one (60 kA). Lost it vertically. Late breakdown. Next shot: no changes |
| Dec 22 2000 02:52:11:513PM | 1001222003 | Robert Granetz | Shot 03 -- Dud. Next shot: add 2 more ms to pre-fill, add +0.3 mT to Br0 |
| Dec 22 2000 03:09:14:717PM | 1001222004 | Robert Granetz | Shot 04 -- Fizzle. Just like shot 2. Next shot: add +5 mT to Br0 (on Steve's urging) |
| Dec 22 2000 03:25:57:030PM | 1001222005 | Robert Granetz | Shot 05 -- Dud. Next shot: subtract 10 A from IC_EF4, add 2 ms to pre-fill. |
| Dec 22 2000 03:59:20:810PM | 1001222006 | Robert Granetz | Shot 06 -- Plasma. Good shot. Ip=0.4 MA, Btor=5.85 T, nl_04=0.5-0.9e20 m-2. Prf=0.5-1.0 MW. Plasma came close to being limited between t=0.5-1.0 s, which is not what was programmed. Next shot: move RCUR in by 5 mm between t=0.5 and 1.0 s. Reduce He3 puff. Increase Btor to 5.95 T (167 kA). |
| Dec 22 2000 04:17:50:170PM | 1001222007 | Robert Granetz | Shot 07 -- Plasma. Good shot. nl_04=0.5-0.8e20 m-2. Btor=5.94 T. Prf=1 MW. We had better control of outer gap on this shot. Next shot: more tweaking of RCUR from t=0.8 to 1.0 s. Reduce He3 maintenance level from 35 to 30 volts. |
| Dec 22 2000 04:45:00:623PM | 1001222008 | Robert Granetz | Shot 08 -- Plasma. Good shot. nl_04 stays constant at 0.55e20 m-2. Prf=1.3 MW, fairly constant. Plasma touched outer limiter around t=1 s. Next shot: repeat with a slight RCUR tweak starting at t=1 s. Move PCI beam. |
| Dec 22 2000 05:02:07:543PM | 1001222009 | Robert Granetz | Shot 09 -- Plasma. Good shot. Right gap stayed at 1 cm or larger for the entire shot. Breakdown Br0 and Bz are both drifting higher. Next shot: reduce IC_EF4 by 5 A and reduce Br0 by 0.2 mT. |
| Dec 22 2000 05:31:27:187PM | 1001222010 | Robert Granetz | Shot 10 -- Plasma. Good shot. There was a big injection at t=1.24 s, but this is after the PCI data window. Steve Wolfe reports that this occurs when OH1 comes out of crossover. (It's late in the shot because we're running low plasma currents today.) End of run |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 02:11:57:217PM | Plasma | Ok | |
| 2 | 02:25:41:903PM | Plasma | Ok | |
| 3 | 02:41:24:450PM | Plasma | Ok | |
| 4 | 02:59:10:857PM | Plasma | Ok | |
| 5 | 03:18:05:250PM | Plasma | Ok | |
| 6 | 03:36:34:280PM | Plasma | Ok | |
| 7 | 04:00:40:577PM | Plasma | Ok | |
| 8 | 04:25:06:233PM | Plasma | Ok | |
| 9 | 04:50:44:513PM | Plasma | Ok | |
| 10 | 05:14:37:530PM | Plasma | Ok | |