| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Robert Granetz |
| Physics operator(s): | John Goetz |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| closed loop |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:51:037PM |
| Author: To Be Determined |
| Physics operator summary for 940506 EO: Bertilino PO: Goetz SL: Granetz Run 940506 was in support of Mini-Proposal #041 - Startup C-Mod in 1994. To this end, shot 940505020 was loaded into the hybrid. This was the last 'good' shot from 940505. Today's goals were to try and complete MP #041 and bring some of the predictors up to speed with the present set of flux loops and Bp coils. To that end, MP #041 is still not complete as the best discharge was ~400kA and 0.5 sec in duration. Discharges all day were dirty as determined by spectroscopy corner (mostly moly, some stainless steel). The discharges that did go were very disruptive. Reproducibility was a problem today. The nulls today were acceptable and the only tweak, a 1mT change in Bz, caused a dud. Fill pressure was moved up and down, ~20%, in a random fashion and it did not appear to be much of a factor in plasma vs. fizzle. From an operator standpoint, the RCUR, ZXL, RXL, and CLEARIN predictors were recalculated with the latest set of 'good' flux loops and Bp coils. RCUR and CLEARIN appeared to function correctly, but ZXL and RXL had no data to determine their performance. Recommendation: Remember to COLDSTART the hybrid before the run begins. Another Recommendation: Clean up the machine so that the moly fraction decreases. Engineering today: Reliable day today for the power systems. Some unexplained crowbars of the TF but that is all. The fizzle detector was tested on the TF, OH, EF3, and EF1 supplies and appeared to be working. An attempt to put the TMX supplies on the fizzle detector will occur next run day. This inversion of supplies at detection of the 'no plasma' condition saved on coil cooling time significantly. Scorecard: 26 shots = 10 plasmas + 14 fizzles + 2 duds Shot summary for Run 940506 Reload of 940505020 Changes: Fizzle detector hooked up, turned on at 0.1sec Invert times on PF supplies moved to 0.5sec Shot change result ____ _____ ______ 1 P_0=1.2e-5 dud 2 COLDSTART hybrid plasma 3 PULSE_GAS_3 to 60V early fizzle 4 PULSE_GAS_3 moved to -.01 kludged the RCUR and ZCUR to get IP reference fizzle 5 P_0=1.4e-5; turn on chopper @ .06sec; V_CHOPPER=1000V @ .05sec fizzle 6 IC_EF4U to -990A; P_0=1.2e-5 dud 7 reload 940506002 fizzle 8 P_0=1.1e-5 plasma 9 recalculate RCUR predictor (offset = 10000.) plasma 10 no changes fizzle 11 no changes fizzle 12 P_0=1.0e-5 plasma 13 S_IP = -500000 @ .152sec plasma 14 lower PULSE_GAS_3 to 30V @ .1sec; turn on ZCUR integrator @ .1 plasma 15 lower PULSE_GAS_3 early; ZCUR integral gain to 4. fizzle 16 S_IP=-300000 fizzle 17 no changes fizzle 18 no changes fizzle 19 P_0=1.1e-5 fizzle 20 P_0=1.2e-5 plasma 21 S_IP=-400000; calculate CLEARIN predictor; CLEARIN=0.0 fizzle 22 no changes plasma 23 lower PULSE_GAS_3 between .1 & .3 sec fizzle 24 no changes plasma 25 S_IP=-600000; P_0=1.1e-5 fizzle 26 S_IP=-750000; recalculate ZXL and RXL predictors; P_0=1.2e-5 plasma |
| Session Leader Comments | |||
| May 6 1994 08:14:11:340AM | Robert Granetz | Continuation of miniproposal #41. Start with yesterday's shot #20, which had
0.31 MA, and raise it to eventually get an 0.8 MA diverted plasma with sufficient clearance from the inner and outer limiters. | |
| May 6 1994 09:12:07:410AM | 940506001 | Robert Granetz | Complete garbage coming out of the hybrid. There was also a late fault on
OH2L and EF1L (at 0.3 s). The hybrid has subsequently been coldstarted, and PCS reloaded with shot 20 from yesterday. |
| May 6 1994 09:32:42:710AM | 940506002 | Robert Granetz | Plasma. Ip=0.30 MA, duration=0.19 s. Plasma became disruptive at 0.10 s,
and vertical position was lost at 0.15 s. Fizzle detector also seems to work, but it is not yet connected. Next shot, same except tweak up the pulse gas. |
| May 6 1994 09:51:36:440AM | 940506003 | Robert Granetz | Fizzle. Probably the alternating shot syndrome. After this shot, the
hybrid problem with the wavegen Ip reference was fixed for the first three wires (RCUR, ZCUR(slow), and ZCUR(fast)). Pulse gas is not showing up until t=0.040 s, so we have moved it 0.010 s earlier for the next shot. |
| May 6 1994 10:04:03:800AM | 940506004 | Robert Granetz | Another fizzle. Null looks similar to the good shot (002). For the next
attempt, I've turned on the EFC for fast ZCUR control, starting at 0.060 s. Also, the fill pressure will be increased slightly. |
| May 6 1994 10:39:17:470AM | 940506005 | Robert Granetz | Fizzle. Increase Bz by +1 mT (=+15 A change in EF4). Also reduce pre-fill
from 1.4 to 1.2e-5. |
| May 6 1994 10:46:21:660AM | 940506006 | Robert Granetz | No breakdown. The extra 1 mT seems to have been the wrong thing to do.
Other differences between this shot and the previous plasma (002) is: Pulse gas turns on earlier (gas shows up at 0.020 s) EFC feedback turns on at 0.060 s Ip referenced wires now work For the next shot, reload shot 002. |
| May 6 1994 10:58:19:510AM | 940506007 | Robert Granetz | Flash, but no current. Null reconstructions look alot better. Breakdown
started at 0.006 s. Next shot, lower pre-fill from 1.2 to 1.2e-5 |
| May 6 1994 11:34:00:830AM | 940506008 | Robert Granetz | Plasma. Ip=-0.27 MA, duration=0.205 s. Plasma becomes very disruptive
starting at 0.10 s. This corresponds to a sudden increase in H-alpha, so we're hitting the limiter then. It also appears that we were diverted starting at 0.14 s. For the next shot, re-calculate the RCUR predictor to bring in the corrections for the broken magnetics. |
| May 6 1994 11:52:14:340AM | 940506009 | Robert Granetz | Got plasma. Two in a row! Ip=0.25 MA, duration=0.235 s.
X-rays say the radial position is reasonably well controlled. Disruptive behavior starts at 0.105 s. The plasma TV shows that the plasma starts up detached, and then grows in minor radius until it hits on the inner wall, probably corresponding to the start of disruptive behavior. This means that there's nothing we can do to improve plasma performance prior to making it diverted. Next shot, no changes. |
| May 6 1994 12:02:00:000PM | 940506010 | Robert Granetz | Breakdown, but no current. No changes for next shot.
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| May 6 1994 12:13:28:560PM | 940506011 | Robert Granetz | Fizzle. Next shot: lower pre-fill from 1.1 to 1.0e-5 torr.
|
| May 6 1994 12:36:18:900PM | 940506012 | Robert Granetz | Plasma. Ip=0.28 MA, duration=0.22 s. Disruptive behavior starts at 0.115 s.
For the next shot, raise Ip demand from 0.35 to 0.50 MA. This was done in a way that also raises dI/dt. |
| May 6 1994 12:56:55:420PM | 940506013 | Robert Granetz | Plasma...two in a row again. Ipmax=0.33 MA, duration=0.22 s. Position
gradually drifts upward, even though the programmed demand on ZCUR is to move down to -2 cm. Xrays are sawtoothing prior to the disruptive phase. Next shot: decrease pulse gas a bit, and turn on integral gain feedback for the slow ZCUR control. |
| May 6 1994 01:18:14:910PM | 940506014 | Robert Granetz | Three in a row. Ip=0.30 MA, duration=0.28 s. Z-xray is still gradually
rising. I don't think ZCUR control works well enough yet. Next shot, increase the integral gain on ZCUR and also drop the pulse gas a little more. |
| May 6 1994 02:17:37:090PM | 940506015 | Robert Granetz | Fizzle. We have figured out that the reason the ZCUR was not being controlled
very well on previous shots is because the OH's are overloaded by the Ip feedback. Since we've increased the Ip demand several shots ago, the OH's voltage has been railing, due to the high resistivity. This leaves no control of the ZCUR. For the next shot, lower the Ip demand down to 0.300 MA. |
| May 6 1994 02:18:09:800PM | 940506016 | Robert Granetz | Fizzle. There was a 20 minute delay to investigate an alternator problem.
No changes for next shot. |
| May 6 1994 02:18:20:800PM | 940506017 | Robert Granetz | Fizzle. No changes for next shot.
|
| May 6 1994 02:41:07:860PM | 940506018 | Robert Granetz | Fizzle. H-alpha arrays indicate that on this shot, the breakdown plasma
went outwards. There was actually the beginnings of a current rise (to 40 kA), so perhaps dI/dt was too fast. Therefore, for the next shot we will raise the pre-fill from 1.0 to 1.1e-5. Null looks good, as it has all day. |
| May 6 1994 02:57:20:670PM | 940506019 | Robert Granetz | Fizzle. No change in dI/dt. Next shot: raise pre-fill from 1.1 to 1.2e-5.
|
| May 6 1994 03:21:01:920PM | 940506020 | Robert Granetz | Hey, we got a reasonable plasma. Ip=0.4 MA, duration=0.39 s. Plasma may
have touched the outer limiters. We just missed pulling a divertor. On the next shot, we will turn on CLEARIN feedback, in an effort to get a divertor. For the next shot, CLEARIN is set to zero. Also, Ip is set to 0.4 MA. |
| May 6 1994 03:37:27:850PM | 940506021 | Robert Granetz | Fizzle. No changes for next shot.
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| May 6 1994 03:55:04:450PM | 940506022 | Robert Granetz | Another reasonably good plasma. Ip=0.4 MA, duration=0.34 s. Control of
CLEARIN is not convincing yet. For the next shot, reduce the pulse gas a bit. |
| May 6 1994 04:20:23:070PM | 940506023 | Robert Granetz | Fizzle. No changes for the next shot.
|
| May 6 1994 04:35:14:510PM | 940506024 | Robert Granetz | Best shot of the day so far. Ip=0.40 MA (which is what the demand is),
duration=0.48 s. Diverted plasma after t=0.175 s. There is also a sudden 50% drop in the H-alpha at 0.4 s, but none of the other typical H-mode signatures were observed. Wasn't a shark fin either. Next shot, increase Ip to 0.6 MA and decrease pre-fill from 1.2 to 1.1e-5. |
| May 6 1994 05:00:24:800PM | 940506025 | Robert Granetz | Fizzle. For the next shot:
1) Raise pre-fill to 1.2e-5 2) Increase Ip to 0.75 MA 3) Re-calculate R_XL and Z_XL predictors to take account of the bad flux loops and Bp coils. |
| May 6 1994 05:10:26:550PM | 940506026 | Robert Granetz | Plasma, but it disrupted early. Ip is about 0.37 MA, duration=0.20 s. All
the photon radiation signals were really high, indicating a possible impurity problem. End of run. End of week. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:59:09:280AM | Plasma | Ok | poor programming |
| 2 | 09:18:10:680AM | Plasma | Ok | no faults |
| 3 | 09:31:14:110AM | Plasma | Bad | oh1 comm fault |
| 4 | 09:48:24:960AM | Plasma | Ok | no faults |
| 5 | 10:09:19:540AM | Plasma | Ok | no faults |
| 6 | 10:30:45:710AM | Plasma | Ok | oh1 comm fault after inversion |
| 7 | 10:46:51:380AM | Plasma | Ok | no faults |
| 8 | 11:07:24:140AM | Plasma | Ok | no faults |
| 9 | 11:27:59:350AM | Plasma | Ok | no faults |
| 10 | 11:49:17:900AM | Plasma | Ok | oh1 comm fault |
| 11 | 12:06:31:340PM | Plasma | Ok | oh1 comm fault |
| 12 | 12:21:57:710PM | Plasma | Ok | no faults |
| 13 | 12:41:07:920PM | Plasma | Ok | no faults |
| 14 | 01:01:07:290PM | Plasma | Ok | no faults |
| 15 | 01:20:29:840PM | Plasma | Ok | no faults |
| 16 | 01:38:28:030PM | Plasma | Ok | |
| 17 | 02:07:58:550PM | Plasma | Ok | |
| 18 | 02:23:35:670PM | Test | Ok | |
| 19 | 02:41:50:710PM | Plasma | Ok | |
| 20 | 02:59:49:750PM | Plasma | Bad | OH1 comm fault Good plasma shot |
| 21 | 03:22:01:850PM | Plasma | Ok | |
| 22 | 03:36:36:330PM | Plasma | Bad | TF c-bar |
| 23 | 03:57:55:050PM | Plasma | Ok | |
| 24 | 04:23:18:470PM | Plasma | Bad | TF c-bar |
| 25 | 04:46:14:810PM | Plasma | Ok | |
| 26 | 05:01:50:420PM | Plasma | Bad | 400 kA plasma. OH1 commutation fault induced by plasma disruption. |