| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Bruce Lipschultz |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| divertor geometry |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:11:727PM |
| Author: To Be Determined |
| Run of 941214 Physics Operator - I. Hutchinson Session Leader - B. Lipschultz Engineering - V. Bartolino MP# 69: Development of New Equilibria for Divertor Geometry Studies The primary goal of this run was achieved; to produce the so-called 'slot-divertor' equilibrium. This required implementation of the STRKPSI controller which has been accomplished. For details of the gain changes required in this implementation refer to the physics op summary. Slot-divertor equilibria were obtained for most of the shot (see shots 11-16 & 18). Because the STRKPSI location was 5 cm above the floor (near probe 3) the flux surface location was held well there but the actual strike point swept across the floor by about 4 cm during the shot. On balance, we did achieve the basic slot configuration but ran into problems maintaining this configuration in general and particularly at high densities. Again refer to Ian's summary for details of why this is so. His recommendation is that we develop a startup scenario with more initial precharge to alleviate these problems. There was also the previous recommendation that the EF4 power supply be upgraded. When we did increase the density it appeared that a localized detachment did occur, affecting the lower probes on the outer divertor. Shots 19, 20 and 22 should be looked at more closely with this in mind. shot 01: Shot went fine, strike point on outer divertor high - around probes 6-7. shot 02: The strike points on the outer divertor are lower. This shot had a little gain on STRKPSI. The gain will be raised for the next shot. The plasma will be lowered as well to reduce Kappa. The outer gap will be increased. shot 04: The strike point appears to have been moved down. The peak in ISAT on the outer divertor seems to be on probe 4. This shot had a very low zxl - -41.5. shot 05: The stike points seem even lower somewhere in the region of probes 2 and 3. shot 06: During the period 420 - 520 ms the strike point is almost at the bottom of the divertor plate. shot 07: Again during the early part of the shot, 400-500 ms, EFIT claims we have a slot divertor. The probes are certainly showing higher current there with a maximum on probe 2. Ian has implemented a 'jog' in the STRKPSI at 500 ms. This has a major effect on the plasma strike points and is only a test of the strength of control. shot 08: The jog in STRKPSI has been moved out to 600 ms. The density has been lowered to ~ 1.5 e20. The plasma has been moved outward slightly. According to EFIT the plasma is in a slot configuration until 620 ms. shot 09: Slot for longer period. Ian is still incresaing the gain on STRKPSI. shot 10: slot lasted longer to almost 750 ms. Ian will lower the gain on RXL and ZXl some more. He is also adding a 'jog' to the ZXL gain at 800 ms where he lowers the gain for 50 ms. Shot 11-13: still twiddling gains on STRKPSI and ZXL. shot 17: We moved the STRKPSI reference point to the bottom of the divertor from the region of probe 3. This did a better job of holding the strike point constant but the x-point was moved quite a bit - a case of the 'tail wagging the dog'. For the next shot we will go back to STRKPSI in the usual place. shot 18: Back to STRKPSI in the usual place, prpare for a density scan shot 19: Higher density but not quite reaching the levels set. The x-point seems to be moving towards the inner divertor nose as the density rises. We will raise the fill pressure to see if we can achieve the programmed density. shot 20: We obtained the required density flattops. The probe is scanned in at .6 and .8 seconds. The x-point is still a problem. shot 21: disruption, we pushed the gas too hard. shot 22: Recovered but the equilibrium needs some shifting down to be in range of the scanning probe. Also, it appears that there may be a localized detachment appearing on probes 1 & 2 at the outer divertor. When the density steps up at .6 seconds, the Isats on those probes decay. When the density drops at .8 seconds, the Isats increase. shot 23: This one barely makes it through current rise and disrupts at inversion. We will try to lower the gas and push the plasma further down closer to the scanning probe. shot 24: This shot makes it all the way. The max. density is 2.8e20. The Isat on probe 1 is low untile 800 ms when the density decreases. The Isats on probes 2 & 3 seem to be affected as well (but not as much as probe 1). The next shot will be the same. shot 25: disruption at 350 ms. Blame it on the gas. shot 26: disruption at 750ms. Again blame it on the gas. Lower the gas. shot 27: fizzle |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:52:520PM |
| Author: To Be Determined |
| Phys Op Summary 941220 PO Hutch, SL Blip, EO Bertolino "In search of Slots" Starting from the current shot. Imported Segment 2 from Wolfe's STRKPSI controller shot 941210003. This has rank-deficient controllers for the STRKPSI, and STRKIN and is based on shot 941209028, a good divertor shot. Increased the Integral gain on clearin to match the current shot. Plan: Get the STRKPSI controller line going and lower the gains on RXL,ZXL while trying to get this across to STRKPSI. If this seems to help us get a slot then exploit it. If this doesn't seem to get us what we want or if it sends us into a part of current space where no man has gone before (or wants to!), try to get a plasma diverted earlier and use the tendency of the early part of the flux swing to give slots. Summary: Both parts of the plan were completed with reasonable success. The STRKPSI controller was implemented and its gain turned up to the point where it was dominant over RXL/ZXL. Integral gain on this line was working by shot 15, at which point good slots were obtained for most of the shot. Shot 16 had the reciprocating probe inserted. Shot 17 used a STRKPSI estimator moved down to the bottom of the plate. It controlled correctly but at the expense of large x-point excursion. This was not pursued. Thereafter the density was raised to look for detachment. The effect of the higher density was to cause the x-point to move in till it was nearly on the inner nose. A further problem with these shots was that EF2L was zeroing out by about 0.9s and the current rampdown scenario then caused a big vertical asymmetry and a disruption. A couple of shots were gassed out in the current rise. Shot 26 disrupted at high density for no obvious reason. nL of 1.8e20 was obtained on several. Computing: The run was seriously handicapped by computer hangs of IGOR, apparently caused by overloading of certain workstations. This is a problem that needs to be addressed. Engineering: The EF3 power supply was disobeying its command during current ramp-down and causing otherwise attractive ramps to terminate abrubptly by crashing on the outer limiter. This appeared to be due to a trip that arose soon after the TF inversion. This problem needs to be addressed. Scorecard: Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 1.382 0.828 2 1.453 0.833 3 1.426 0.830 4 1.392 0.830 5 1.418 0.830 6 1.355 0.828 7 1.439 0.828 8 1.478 0.835 9 1.477 0.833 10 1.460 0.835 11 1.461 0.835 12 1.437 0.835 13 1.310 0.830 14 1.323 0.830 15 1.334 0.830 16 1.349 0.830 17 1.372 0.830 18 1.368 0.833 19 1.260 0.825 20 1.298 0.825 21 0.345 0.579 22 1.012 0.840 23 1.011 0.840 24 1.074 0.838 25 0.362 0.616 26 0.745 0.910 27 0.000 0.026 Finished summary for 941220 Total of 27 shots. 27 shots. 26 plasmas. 1 fizzles. 0 duds. Notice that the first 20 shots had were good and did not disrupt. 26 plasmas in a row. Shots: P0=1.5e-5. 1 Pla A fine shot. Mo injection at .35s Lowered ZXL to -1. Put gain on STRKPSI at P=.5, drawn 0. 2 Pla Strike lowered STRkpsi=.002 @ .6s STRKPSI gain to 1. Drew ZXU +.03 (instead of +.02). Drew ZCUR to -.02 from -.15. Drew RCUR to .65 from .657 3 Pla Strike rather similar. Plasma moved as asked. STRKPSI=.0016 Argon on. STRKPSI gain to 2 with a notch. Drew RXL to -.005 Drew ZXL to -.02 4 Pla Got STRKPSI=.0009. But EF2 railed. Drew RXL to -.01 Drew STRKPSI to -.003 Drew ZXL to -.015 Delayed the PS inversion to 1.7s Adjust the ramp down. 5 Pla STRKPSI=-.001 Negative! Drew ZXL to -.01 Drew ZXU to +.025 Moved the STRKPSI notch to .5s 6 Pla Close to a slot at .4-.5s. Got STRKPSI=-.0015 at .5s. Notch shows up. Slowed the current ramp down slightly. Raised CLEARIN to -.005 at .29s Drew ZXL to -.005 Dropped RXL gain to 2 (from 3). Raised gas puff to 40 at 21ms to get at the moly influx early. 7 Pla Got STRKPSI=-.0012 and ZXL moved up. Moved notch to .6s ZXU/L gains to 4 in ramp down and stretched it out. Lowered NL to .8 from 1.1 STRKPSI gain to 3. RCUR out to .657. 8 Pla Got STRKPSI=-.0018. Solid slot according to EFIT .4 to .6s STRKPSI gain to 4. Removed gain notch. Put in a Drawn notch at .7s CLEARIN gain raised early. CLEARIN lowered during ramp and gain continued. 9 Pla Got STRKPSI=-.0021 RXL gain to 1 from 2. ZXL gain to 5 from 9. Draw jog negative. Increased CLEARIN gain early. Adjusted programming. Drew -.065 clearin during ramp. 10 Pla STRKPSI=-.0023. Diverted slot from .3s throughout. Lengthened the drawn RCUR and its gain at the end. ZXL gain to 3. Put a zero gain notch .8 to .85s Removed strkpsi programmed jog (Bruce told me to!) Had a problem with IGOR. 11 Pla STRKPSI=-.0025. Still have the RCUR problem at 1.34s. The EF3 supply is not following demand. ZXL gain notch not seen. Moved STRKPSI to wire 9 where there is integrator. Zeroed wire 10. Raised early gas V some more. RXL gain to 0.7. Vinnie delayed the invert timer on EF3. 12 Pla STRkpsi=-.0026. EF3 not fixed. NL raised to 1.e20. TF invert time to 1.1s. Low voltage suspected for EF3 problems. 13 Pla STRKPSI=-.0025. EF3 Faulted earlier. TFinvert to 1.4s Put integral gain on STRKPSI. Gate .5-.8s. Gain .5. Made current ramp faster because the engineers haven't fixed EF3. 14 Pla Termination different due to density rise. Integral gain barely visible STRKPSI=-.0027 slightly less drift. STRKPSI I to 1.0 ZCUR to -0.015 15 Pla Error improved later. Integral basically works. unchanged for flat top so scanning probe can be used. slow the current ramp back now. Call for scan of probe 16 Pla Probe went in. Changed the strkpsi reference point to rsout=.6295,zxout=-.5739. Drew strkpsi at -.001. 17 Pla Succeeded in controlling the new strkpoint but banged the x-point into the inner nose. Restored default strkpsi Drew strkpsi=-.003 Edit zcur controller OH2 weights increased at 1s to 2.5 from 2. (at limit.) Kept C integrator gate on till 1 sec. 18 Pla Similar to 16. STRKPSI=-.0027 NL two levels: 1.2 and 1.4e20 raised early gas V to 50. 19 Pla Density takes a while to equilibrate. Gas valve appears full open. X=point is moving more inward. Raise plenum pressure to 20psi from 14. Raise NL earlier on ramp. 20 Pla Got the density. But the x-point is still further inside. Raise ZXL to 0. Raise NL to 1.6,1.9e20. 21 Pla Disrupts at .34s owing to choking on too much gas. Lowered drawn density, especially early. 1.4/1.75e20 Installed the superstition. (Ip ramp from .8 to .85MA) 22 Pla Disruption at 1.s. Appears to be caused by asymmetrical EF2 termination. Got the density we asked for. X-point still inside. Moved ZCUR controller switch to .9s Drew zcur at -.02 (c.f.-.015) Drew strkpsi at -.0025 (c.f. -.003) 23 Pla Disrupts at 1s again. Nearly choked at .3s eased off on early gas some more. made the start of the clearin ramp much slower to try to fix the EF2 turn off problem. 24 Pla Disrupts at 1.05s. EF2U goes the other way. We need somewhere between the two settings. 25 Pla Disrupts at 0.35s. Lowered early gas 26 Pla Disrupts at .75s. Lowered NL drawn to 0.5e20. 27 Fiz |
| Session Leader Comments | |||
| Dec 20 1994 08:41:52:730AM | 941220001 | Bruce Lipschultz | shot 01: Shot went fine, strike point on outer divertor high - around
probes 6-7. |
| Dec 20 1994 09:02:51:320AM | 941220002 | Bruce Lipschultz | shot 02: The strike points on the outer divertor are lower. This shot had
a little gain on STRKPSI. The gain will be raised for the next shot. The plasma will be lowered as well to reduce Kappa. The outer gap will be increased. |
| Dec 20 1994 09:24:34:760AM | 941220004 | Bruce Lipschultz | shot 04: The strike point appears to have been moved down. The peak in
ISAT on the outer divertor seems to be on probe 4. |
| Dec 20 1994 09:56:42:440AM | 941220005 | Bruce Lipschultz | shot 05: The stike points seem even lower somewhere in the region of
probes 2 and 3. |
| Dec 20 1994 10:08:14:470AM | 941220006 | Bruce Lipschultz | shot 06: During the period 420 - 520 ms the strike point is almost at the
bottom of the divertor plate. |
| Dec 20 1994 10:42:28:670AM | 941220007 | Bruce Lipschultz | shot 07: Again during the early part of the shot, 400-500 ms, EFIT claims
we have a slot divertor. The probes are certainly showing higher current there with a maximum on probe 2. Ian has implemented a 'jog' in the STRKPSI at 500 ms. This has a major effect on the plasma strike points and is only a test of the strength of control. but |
| Dec 20 1994 10:54:30:620AM | 941220008 | Bruce Lipschultz | shot 08: The jog in STRKPSI has been moved out to 600 ms. The density has
been lowered to ~ 1.5 e20. The plasma has been moved outward slightly. According to EFIT the plasma is in a slot configuration until 620 ms. |
| Dec 20 1994 11:18:04:070AM | 941220009 | Bruce Lipschultz | shot 09: Slot for longer period. Ian is still incresaing the gain on
STRKPSI. He will reduce the gain RXL and ZXL slightly. |
| Dec 20 1994 11:37:28:000AM | 941220010 | Bruce Lipschultz | shot 10: slot lasted longer to almost 750 ms. Ian will lower the gain
on RXL and ZXl some more. He is also adding a 'jog' to the ZXL gain at 800 ms where he lowers the gain for 50 ms. |
| Dec 20 1994 12:42:19:870PM | 941220013 | Bruce Lipschultz | shot 10-13: various and sundry modifications of the gains to understand
the relationship of the different controllers. |
| Dec 20 1994 02:04:32:390PM | 941220017 | Bruce Lipschultz | shot 17: We moved the STRKPSI reference point to the bottom of the divertor from
the region of probe 3. This did a better job of holding the strike point constant but the x-point was moved quite a bit - a case of the 'tail wagging the dog'. For the next shot we will go back to STRKPSI in the usual place. |
| Dec 20 1994 02:20:48:600PM | 941220018 | Bruce Lipschultz | shot 18: Back to STRKPSI in the usual place, prpare for a density scan
|
| Dec 20 1994 02:45:18:110PM | 941220019 | Bruce Lipschultz | shot 19: Higher density but not quite reaching the levels set. The
x-point seems to be moving towards the inner divertor nose as the density rises. We will raise the fill pressure to see if we can achieve the programmed density. |
| Dec 20 1994 02:57:54:650PM | 941220020 | Bruce Lipschultz | shot 20: We obtained the required density flattops. The probe is scanned
in at .6 and .8 seconds. The x-point is still a problem. |
| Dec 20 1994 03:33:14:290PM | 941220022 | Bruce Lipschultz | shot 22: Recovered but the equilibrium needs some shifting down to be in
range of the scanning probe. Also, it appears that there may be a localized detachment appearing on probes 1 & 2 at the outer divertor. When the density steps up at .6 seconds, the Isats on those probes decay. When the density drops at .8 seconds, the Isats increase. |
| Dec 20 1994 03:54:33:110PM | 941220023 | Bruce Lipschultz | shot 23: This one barely makes it through current rise and disrupts at
inversion. We will try to lower the gas and push the plasma further down closer to the scanning probe. |
| Dec 20 1994 04:12:19:870PM | 941220024 | Bruce Lipschultz | shot 24: This shot makes it all the way. The max. density is 2.8e20.
The Isat on probe 1 is low untile 800 ms when the density decreases. The Isats on probes 2 & 3 seem to be affected as well (but not as much as probe 1). The next shot will be the same with probe insertion. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:29:16:590AM | Plasma | Ok | no faults |
| 2 | 08:46:13:110AM | Plasma | Ok | no faults |
| 3 | 09:02:32:170AM | Plasma | Ok | no faults |
| 4 | 09:18:33:500AM | Plasma | Ok | no faults |
| 5 | 09:36:01:100AM | Plasma | Ok | no faults |
| 6 | 09:53:14:220AM | Plasma | Ok | no faults |
| 7 | 10:14:47:590AM | Plasma | Ok | plasma ok oh1 com fail |
| 8 | 10:37:43:500AM | Plasma | Ok | ok |
| 9 | 11:00:22:090AM | Plasma | Ok | no faults |
| 10 | 11:20:41:690AM | Plasma | Ok | no faults |
| 11 | 11:40:48:660AM | Plasma | Ok | no faults |
| 12 | 12:19:45:900PM | Plasma | Bad | ef3 inverting early - loss of synch voltage fault |
| 13 | 12:34:03:870PM | Plasma | Bad | ef3 inverts early |
| 14 | 12:53:54:610PM | Plasma | Ok | no faults |
| 15 | 01:08:50:280PM | Plasma | Ok | no faults |
| 16 | 01:25:17:480PM | Plasma | Ok | No faults. |
| 17 | 01:44:50:980PM | Plasma | Ok | No faults. |
| 18 | 02:05:19:870PM | Plasma | Ok | Comm Fault EF1 U&L OH1 |
| 19 | 02:20:21:240PM | Plasma | Ok | Comm fault EF1 L OH1 |
| 20 | 02:40:31:420PM | Plasma | Ok | Comm Faults OH1 & EF1 U & L |
| 21 | 02:58:24:610PM | Plasma | Ok | No faults, Fizzle |
| 22 | 03:15:36:070PM | Plasma | Ok | Comm fault OH2U & OH1 |
| 23 | 03:35:19:100PM | Plasma | Ok | Comm Fault OH2U & OH1 |
| 24 | 03:54:08:400PM | Plasma | Ok | Comm.Fault OH2L & OH1 |
| 25 | 04:19:57:330PM | Plasma | Ok | No Faults, Disruption |
| 26 | 04:45:36:980PM | Plasma | Ok | No faults |
| 27 | 05:07:34:470PM | Plasma | Ok | No faults |