| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Rejean Boivin |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Bill Parkin,Bill Cochran |
| Engineering Operator Run Comment |
| MP #268 ICRF. Boivin/Wolfe/Cochran. |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:25:587PM |
| Author: To Be Determined |
MP#268 ICRF (J-port four-strap) SL: Boivin PO: Wolfe EO: Cochran,Parkin MP 268 J port antenna work-out Overall goals, exercise J port antenna, document any existing problem with operations, especially on the point of view of impurity generation (from the antenna itself or somewhere else in the machine). Run plan: 1) vacuum tune, verify instrumentation 2) shoot into plasma, similar to 1001020005 except for current at 0.8 MA 3) Increase power, short pulse until limit is reached. - go to upper null if H-mode is making things difficult. 4) Reduce power and lengthen pulse to see if bad effects are observed on antenna 5) Go to higher current to see if we got rid of problems from oct. 20th 2000 Results Even with the usual (now normal) small number of shots (15 plasmas today), we were able to make progress on many fronts today. Since this is the first time we run J as a 4 strap for more than 1 month we need to double check operation of the transmitters since 3 and 4 are tied through their fault circuitry and the phase feedback. Last week we ran 3 and 4 without HV fine. Shots 1 and 2 exhibit the now standard symptoms of phase feedback being reversed, leading to wild oscillations and characteristic phase measurement. We swapped cables and obtained good pulses with both. Shot 6 had the first trips and we verify that a trip on either transmitter would trip the other, avoiding monopole operation. AFter shots 7 and 8, it became apparent that XMTR 3 was losing gain in the transmitter end. The IPA/DRIVER stage appears to be the culprit. Sergey went in to retune the transmitter and found an apparent bad contact between the IPA and the DRIVER. We obtained 1.9 MW in the dummy load (without asking for more) and moved on. Starting at shot 11 we obtained 2.5 MW into the plasma (without trips). By the way we used upper null for shots 8 to 18 to keep it in L mode as much as possible. Central temperature rose to 2.5 keV (see GPC2). Starting on shot 11 we brought D and E along later in the shot, first to make sure they are operational and then to compare them with J. We else took a few shots to make sure that J3 and J4 are virtually identical in power levels so that the launched spectrum is good. Phase measurements indicated that the phase was really close to [0,pi,0,pi] throughout the day. It may be worth to look at the details of the efficiency/Pabs (and central Te) versus power from J as the temperature increased from 2.5 keV to 3.1 keV with little change in overall power but a better balanced J power level. On shot 18, J and (D+E) are virtually at the same power level and we observed that J is, at least, as good as D + E, maybe even a bit better. We went back to lower null to get H-mode info, and the last 2 shots proved to can get H-modes from either one, but obviously need work on the tune. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:12:753PM |
| Author: To Be Determined |
| Physics Operator Summary for Monday, Dec 4, 2000 MP#268 ICRF (J-port four-strap) SL: Boivin PO: Wolfe EO: Cochran,Parkin Engineering Setup ------------------ Conditioning: over-weekend ECDC in D2, ending 2 hours before start of run RF Setup: --------- XMTR 1 and 2 should be made ready, but NOT in run-on. XMTR 4 should be warmed up and in run-on by approx 7:30. See note by RF system or check with Rejean for instructions on XMTR 3 Power systems as on 1001201016 Gas system: fill B-top with 6 psi of D2 Hybrid ENABLED fill B-side lower with 1 psi of Ar Hybrid DISABLED fill B-side upper with 35 psi of D2 Hybrid DISABLED, for ECDC fill C-side with 30 psi of D2 Hybrid ENABLED leave J-bot as is Gate valves: ECE, VUV, Beast, DNB (if requested) Plan -------------------- PCS loaded as on Friday, 1001201016, except with NL04 feedback instead of NL_ZMETER, assuming TCI is working. The RF shots will be tests of J-port performance as a four-strap. When we ran in October, we were having problems with the upper corners of the antenna lighting up and generating injections. After verifying that the transmitters are working and the control/fault circuits are functional, the first thing to see is if this phenomenon reappears as the power is increased. Fire J-port into plasma, nominal density, preferably lower current (0.8 MA) to start with. Shot 1001201016 is taken as the starting point, except for density. Short pulse, check phase. Increase power gradually. When approx max power achieved, reduce power and increase pulse length. At higher power we may want to go to upper null to stay in L-mode. Also: Exercise D and E to make sure all is normal. Have those available for further testing as needed. Results: -------- The machine ran pretty well today. After a first-shot fizzle (Bz tweak) several small startup tweaks (gas, Br0) were made, with no major impact: Shots 2-12 all started up fine. Shots 13, 15, 16 and 17 fizzled; it looked like the breakdown had gotten a little bit late, but the problem may have been slightly slow current rise, and/or high fill pressure. Finally got plasmas back after lowering Br .5mT, dropping the pre-puff, and reducing Bz slightly. We ran with NL_ZMETER control on the density from shot#2 on, since TCI failed on shot 1. Actually, Rick got TCI going again and we had no more nl04 failures, but power was low, and several channels were OTL. The DNB was firing most of the day, and was also doing "duct conditioning", firing the beam into the machine between shots. Aside from the need to adjust the pre-puff, there seemed no obvious deleterious effects from beam operation. We began between-shot ECDC after shot#10, as the H/D on shot#9 had crept up to 7% (Marmar-meter). H/D continued to increase somewhat, up to ~.12, and we stopped ECDC after shot 17, in case that had something to do with the fizzles. RF worked its way up to 1.4MW from J-port by shot#7, but ran out of gain on J3. H-modes were obtained above 1MW, and we went to upper null on shot#8-18 (segment 3) to try staying in L-mode. After shot#8, Sergei re-tuned FMIT#3, after which J-port power was increased to 2.6MW. The antenna seemed pretty well behaved, with only a few injections. D&E were also run up to the 2.4MW level later in the pulse. For shot 18, we dropped the zcur position from +0.01 to 0.0, which seemed to be a better match to the antenna shape; on this shot the SSEP was less than 1cm (close to double null) and we actually had a brief H-mode. It may be better to drop zxl a little more if we want to go back to Upper null. Shot #19-20 were back to lower null, in an attempt to get J to stay on in H-mode. We got H-modes, but J and E were both faulting out; more tuning required. Shot#10 disrupted early, with ~2.3MW, after EF1U started thrashing rail-to-rail, not following command. This seemed to happen coincident with the RF pulse, and may have been caused by pickup. However, the problem did not recur, even when the power was increased. Aside from that, power systems ran well, and there were no computer/DAQ problems, except that Dave Bellofatto had to set several crates back online before the run. Scorecard: ---------- Tests 0 Duds 0 Fizzles 5 Plasmas 15 ------- -- Shots 20 |
| Session Leader Comments | |||
| Dec 7 2000 03:49:59:530PM | Rejean Boivin | MP#268 ICRF (J-port four-strap) SL: Boivin PO: Wolfe EO: Cochran,Parkin MP 268 J port antenna work-out Overall goals, exercise J port antenna, document any existing problem with operations, especially on the point of view of impurity generation (from the antenna itself or somewhere else in the machine). Run plan: 1) vacuum tune, verify instrumentation 2) shoot into plasma, similar to 1001020005 except for current at 0.8 MA 3) Increase power, short pulse until limit is reached. - go to upper null if H-mode is making things difficult. 4) Reduce power and lengthen pulse to see if bad effects are observed on antenna 5) Go to higher current to see if we got rid of problems from oct. 20th 2000 Results Even with the usual (now normal) small number of shots (15 plasmas today), we were able to make progress on many fronts today. Since this is the first time we run J as a 4 strap for more than 1 month we need to double check operation of the transmitters since 3 and 4 are tied through their fault circuitry and the phase feedback. Last week we ran 3 and 4 without HV fine. Shots 1 and 2 exhibit the now standard symptoms of phase feedback being reversed, leading to wild oscillations and characteristic phase measurement. We swapped cables and obtained good pulses with both. Shot 6 had the first trips and we verify that a trip on either transmitter would trip the other, avoiding monopole operation. AFter shots 7 and 8, it became apparent that XMTR 3 was losing gain in the transmitter end. The IPA/DRIVER stage appears to be the culprit. Sergey went in to retune the transmitter and found an apparent bad contact between the IPA and the DRIVER. We obtained 1.9 MW in the dummy load (without asking for more) and moved on. Starting at shot 11 we obtained 2.5 MW into the plasma (without trips). By the way we used upper null for shots 8 to 18 to keep it in L mode as much as possible. Central temperature rose to 2.5 keV (see GPC2). Starting on shot 11 we brought D and E along later in the shot, first to make sure they are operational and then to compare them with J. We else took a few shots to make sure that J3 and J4 are virtually identical in power levels so that the launched spectrum is good. Phase measurements indicated that the phase was really close to [0,pi,0,pi] throughout the day. It may be worth to look at the details of the efficiency/Pabs (and central Te) versus power from J as the temperature increased from 2.5 keV to 3.1 keV with little change in overall power but a better balanced J power level. On shot 18, J and (D+E) are virtually at the same power level and we observed that J is, at least, as good as D + E, maybe even a bit better. We went back to lower null to get H-mode info, and the last 2 shots proved to can get H-modes from either one, but obviously need work on the tune. | |
| Physics Operator Comments | |||
| Dec 4 2000 07:40:31:513AM | Steve Wolfe | coldstart at 07:38 crate offline error. Getting a matrix not responding error. Looks like a highway problem. | |
| Dec 4 2000 08:02:15:467AM | Steve Wolfe | put wire 14 back to nl04 (load wire from 1001201002 load/clean do another coldstart. This time it worked, but Bellafatto's test still shows some crates off-line. | |
| Dec 4 2000 09:07:52:467AM | 1001204001 | Steve Wolfe | shot#1: DNB will not open on first shot. Leave PG4 at 20msec, see how it does. fizzle. TCI didn't work, so maybe it's a good thing. next shot: 10A more positive on ef4, put wire 14 back on nl_zmeter |
| Dec 4 2000 09:33:08:030AM | 1001204002 | Steve Wolfe | shot#2:ef4 -1300 to -1290; seg2 wire 14 to nl_zmeter, change program from .25->.35 plasma, full length. state crashed after the shot tci worked, nl4~7e19. J4 has an oscillation. |
| Dec 4 2000 10:07:12:793AM | 1001204003 | Steve Wolfe | shot#3: try for a repeat. RF changes their phase feedback settings. plasma, full length. bd a bit later, 6.0msec; current rise quite fast. RF looks clean, ramp to .45MW. next shot: increase pre-puff to 22msec. |
| Dec 4 2000 10:24:09:437AM | 1001204004 | Steve Wolfe | shot#4: increase pg4 to 22msec. Also enable DNB at 1.4sec( hopefully, won't increase pressure too much). Enable Ar from b-side lower (25msec) plasma, full length. bd getting a little late(6.8), br drifting up? p0 up to 77uTorr, but current rise still pretty fast. RF to .76MW next shot: drop br0 .5mT |
| Dec 4 2000 10:45:24:763AM | 1001204005 | Steve Wolfe | shot#5: drop br0 from .002 to .0015 plasma, full length. H-mode as RF goes off. 1.1MW current rise looks slower. Br0 did drop to -.0005; not sure it likes it better. next shot: back to 20msec pre-puff. |
| Dec 4 2000 11:03:13:560AM | 1001204006 | Steve Wolfe | shot#6: back to 20msec pre-puff. plasma, full length. H-mode, during the rf pulse, but RF faults out. Looks like a slight imbalance in J3/J4 power. bd at 6.8msec, p0=.07mTorr. next shot: back to .002 on Br0 |
| Dec 4 2000 11:26:49:420AM | 1001204007 | Steve Wolfe | shot#7: back to .002 on Br0 plasma, full length. another h-mode. Two injections during rf. 1.4MW. See one spark at the side of the antenna (not on the corner). bd maybe a little earlier. next shot: Go to upper null |
| Dec 4 2000 11:47:10:810AM | 1001204008 | Steve Wolfe | shot#8: Go to upper null -- turn on seg#3, load wire 14 from seg 2 (still on zmeter, although TCI has been ~ok since shot#2). Chris has removed ND filter from J-port camera. plasma, full length. J3 is max-ing out; need to retune FMIT#3. Nice upper null. Note that Zcur3 d-gain turns off at 1.86sec - extend to 2sec. Next shot: in about an hour -- RF retuning |
| Dec 4 2000 12:43:23:937PM | 1001204009 | Steve Wolfe | shot#9: #3 now getting 1.9 MW into dummy load. Try another upper null shot. No pcs changes. plasma, full length but a big injection at .9sec (after the rf). RF to 1.8MW next shot: repeat, higher power. |
| Dec 4 2000 01:03:05:513PM | 1001204010 | Steve Wolfe | shot#10: repeat, higher power. D&E on at 1sec, .5MW each. disruption at .8 sec, during J-port pulse. EF1U seems to be going cray, not following demand, from 0.63sec. RF faulting at 2.4MW. Begin between-shot ECDC. |
| Dec 4 2000 01:28:18:170PM | 1001204011 | Steve Wolfe | shot#11: repeat, go back to power ramp on J, see if EF1U problem is possible RF pickup. plasma, full length. EF1's look ok this time. RF ran ok, 2.5MW from J, 1MW from D+E. p0~.075mTorr, startup still ok, a little slower current rise. next shot: raise power and extend pulse a little. |
| Dec 4 2000 02:01:35:263PM | 1001204012 | Steve Wolfe | shot#12: raise power and extend pulse a little. disrupted at 1.25 during D,E RF pulse, following an injection at 1.15sec J pulse looks good at 2.5MW, D+E at 1.6MW. J3 still a little less than J4. H/D up to ~.08, even with ECDC between shots. next shot: raise J3 power. |
| Dec 4 2000 02:14:17:810PM | 1001204013 | Steve Wolfe | shot#13: Shrink D,E, extend J, increase J3 some more. fizzle. current rise a little on the slow side, back off 2msec on pg4. |
| Dec 4 2000 02:42:56:420PM | 1001204014 | Steve Wolfe | shot#14: pg4 to 18msec. Shrink D,E, extend J, increase J3 some more. plasma, full length. injection at .83, J3 and J4 pretty balanced. next shot: drop zcur by 1cm |
| Dec 4 2000 03:05:25:780PM | 1001204015 | Steve Wolfe | shot#15: drop zcur by 1cm, zxl by .5cm to try to center plasma on antenna better. fizzle. slow current rise, bd 6.5msec. next shot: Ef4 10Amps more negative, try to get bd a little earlier. |
| Dec 4 2000 03:31:38:263PM | 1001204016 | Steve Wolfe | shot#16: Ef4 back to -1300, try to get bd a little earlier. Another fizzle. Must have gone the wrong way; bd a little later. DNB gate valve will close for next shot, and some after; next shot: put gas back to 20msec. EF4 to -1285. |
| Dec 4 2000 03:59:51:623PM | 1001204017 | Steve Wolfe | shot#17: put gas back to 20msec. EF4 to -1285. Another fizzle. Stop the ECDC for awhile. Very late breakdown, 8.6msec. Bz too positive; so why didn't it get better on 16? P0 down to .068, will be lower next time. Next shot: ef4 back to -1300. Br0 to .0015 |
| Dec 4 2000 04:25:10:497PM | 1001204018 | Steve Wolfe | shot#18: ef4 back to -1300. Br0 to .015 Finally, plasma full length. Lots of injections. H-mode at .8sec? 2.4 - 2.5 MW from each rf pulse. bd still a little late, 6.2msec, next shot: Back to lower null. |
| Dec 4 2000 04:35:51:780PM | 1001204019 | Steve Wolfe | shot#19: Back to lower null (seg2 on, seg 3 off). plasma,full length, h-modes; EDA during second pulse. j faulted out in the first H-mode, retries failed. E faulted during second H-mode, D stayed on. next shot: DNB will open again (mtg over). |
| Dec 4 2000 05:03:56:467PM | 1001204020 | Steve Wolfe | shot#20: DNB will open again (mtg over), drop pg4 to 16msec. plasma, full length, h-modes. J stayed on a little better, heating was pretty poor though. E faulted worse than 19, J similar, maybe a little better. almost lost the startup outside, pressure may have dropped too far (p0~.06)? That's all for today. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:56:55:840AM | Plasma | Ok | Shot #1 All Systems Fired. |
| 2 | 09:26:21:670AM | Plasma | Ok | |
| 3 | 10:01:06:560AM | Plasma | Ok | |
| 4 | 10:15:35:997AM | Plasma | Ok | |
| 5 | 10:38:06:263AM | Plasma | Ok | |
| 6 | 10:57:14:217AM | Plasma | Ok | |
| 7 | 11:17:16:437AM | Plasma | Ok | |
| 8 | 11:37:26:187AM | Plasma | Ok | |
| 9 | 12:35:44:233PM | Plasma | Ok | |
| 10 | 12:56:42:123PM | Plasma | Ok | |
| 11 | 01:19:57:420PM | Plasma | Ok | |
| 12 | 01:43:55:860PM | Plasma | Ok | |
| 13 | 02:09:08:123PM | Plasma | Ok | |
| 14 | 02:32:37:467PM | Plasma | Ok | |
| 15 | 02:59:23:013PM | Plasma | Ok | |
| 16 | 03:23:32:390PM | Plasma | Ok | |
| 17 | 03:47:57:560PM | Plasma | Ok | |
| 18 | 04:02:54:560PM | Plasma | Ok | |
| 19 | 04:29:34:543PM | Plasma | Ok | |
| 20 | 04:55:41:390PM | Plasma | Ok | |