| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Robert Granetz,T.C. Hender |
| Physics operator(s): | Jim Irby |
| Engineering operator(s): | Ed Fitzgerald,Gary Dekow,Bill Parkin |
| Engineering Operator Run Comment |
| MP#398 PO:Irby SL:Granetz EO:Fitzgerald,Dekow and Parkin |
| Session Leader Plans |
| Entered: Jul 3 2006 04:58:42:240PM |
| Author: Robert Granetz |
| I've connected the argon bottle to the gas jet system and filled the plenum to 70 bar. It's all set to go for Thursday's run. |
| Entered: Jul 5 2006 11:50:36:760AM |
| Author: T.C. Hender |
| Run begins at 9:00 and ends at 17:00 Note: A-coil configuration [Btop -Dbot -Gtop +Jbot] initially RF Setup: NONE - no RF for this run. --------------------------------------------------------------- Run Plan for MP#398: q95=3.2 (I=1.55MA, B=7.85T, "JET shape") 1060426018 is a good reference at the right Ip/Bt but needs the JET shape from e.g. 1050805016 Trying to get LM data at high field (7.85T)and quench VDE with MGI 1. Establish configuration and tune to get q95=3.25 at some convenient density NL04~1.2e20 and [Btop -Dbot -Gtop +Jbot] at ~2500A (or better under B21_PROJ feedback control). 2a) Run under B21_PROJ feedback until close to flattop time, then drop A-coil current to zero as quickly as possible after start of flattop. If no locked mode appears then decrease the density and try again, learning the intrinsic threshold density. Once we get a mode, refine the threshold in the lower A-coil current by finding a reduced but non-zero current that does not result in a locked mode. 2b) Same as 2a, but instead of decreasing the A-coil to zero ramp it up to maximum in, around 3.7kA, in flattop. If we are at a density that results in a locked mode at this current then back off current to find a threshold. Otherwise, decrease density until the locked mode appears for max current. 2c) If we didn't get it as part of 2a, find the intrinsic density threshold in flattop by repeating the case where we drop the A-coil to zero and raising the density until the locked mode does not appear. This gives us three points on a scaled circle plot for one A-coil orientation, thought they probably aren't very far apart in angle and the magnitude is dominated by the intrinsic error. 3) With A-coil off try to increase density above intrinsic threshold. If successful go to (4)and (5); else skip to (6). 4) Reverse polarity to -[Btop -Dbot -Gtop +Jbot] and get threshold value 5) Change to -[+Bbot +Dtop -Gbot -Jtop] and get threshold value with high density point. 6) Reverse polarity to [+Bbot +Dtop -Gbot -Jtop] and repeat 2b , preferably at the same density as (2) but may need to adjust. |
| Physics Operators Plans |
| Entered: Jul 5 2006 04:41:49:577PM |
| Author: Jim Irby |
| SL: Hender, Wolfe, Granetz
PO: Irby ECDC overnight in D2 at 2e-4 Torr Vessel bake at 60 C Power systems as on 1060509020 (8T) OPS should prepare for 8T, high current operation (TF start at -1.5 s, 20 minutes between shot, TF scanners checked out and operational) A-Coil configuration: +Btop -Dbot -Gtop +Jbot -Bbot -Dtop +Gbot +Jtop (use new jumpers; supply leads not connected) Gas jet disruption mitigation will be enabled Gas Setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3) leave NINJA as is DISABLED Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters No ICRF is required for this run |
| Session Leader Summaries |
| Entered: Jul 8 2006 05:30:24:293AM |
| Author: T.C. Hender |
| A reasonably good session overall. We managed to successfully complete parts 1-4 of the session plan, but time lost due to the high number of fizzles meant that we were not able to achieve parts 5-6.
We got good data from 7 shots. Locked modes were observed on four of these and three shots ran through with no locked mode, providing a lower bound on the locked mode threshold. Other plasma shots were marred by early disruptions and/or injections. Preliminary analysis indicates that the locked mode threshold (Bpen) is the same as that found at 6.3T, though significantly less that that at 4.1T. Useful shots: Shots with locked modes: 6, 7, 17 and 18. Full length shots with no locked mode: 10, 13 and 15. |
| Physics Operator Summaries |
| Entered: Jul 6 2006 06:37:54:677PM |
| Author: Jim Irby |
| Enginnering systems performed well today at the high fields and plasma
currents. However, post distruption fizzles were a problem for which we did not find a solution. We dropped the prefill gas throughout the day, but possibly not aggresively enough. Both Bz0 and Br0 were okay throughout the day, and no tweaks were made. We had several early disruptions at the beginning of the run. These seemed to be caused by running the strike-point right on the outer divertor nose. Moving RXL in 5 mm fixed this problem. We still had full current disruptions following this change, but at 1.5 s instead of 0.8 or 0.9 s. We tried to improve the rampdown by lowering the density, and taking the plasma current down faster, but we had only slight success in this effort (0.95 MA vs 1.2 MA). On shot 08 a rather large chunk of something could be seen bouncing off the inner wall (see wide 2 camera). In a preops checkout this morning a blown TF fuse was found and replaced. Two more blown fuses were found and replaced during the run. no power shot 11 fizzles 02,04,09,12,14,16 plasmas 01,03,05,06,07,08,10,13,15,17,18 |
| Session Leader Comments | |||
| Jul 6 2006 09:54:57:297AM | 1060706001 | Robert Granetz | Shot 01 -- Gas jet fired by DPCS at t=0.982 s. Current quench spike is at t=0.982 s. Current quench duration is about 1-1.5 ms. I_halo=231 kA Prf=0.0 MW Wth=80 kJ. Plenum gas: argon Pulse length (ms): 2.0 Plenum pre -pulse pressure (bar): 70.5 Plenum post-pulse pressure (bar): 65 Plenum change in pressure (bar): 5-6 |
| Jul 6 2006 09:56:47:610AM | 1060706001 | Robert Granetz | I don't think the gas jet actually triggered this disruption.
It fired at just about the same time as the current spike occurs. |
| Jul 6 2006 10:25:12:213AM | 1060706002 | Robert Granetz | Shot 02 -- Fizzle. Gas jet did not fire. |
| Dec 11 2012 10:20:13:020AM | 1060706003 | Robert Granetz | Shot 03 -- It wasn't me. The gas jet was disabled and definitely did not
fire...the voltage signal on the fast valve power supply remains zero, and the plenum pressure remained unchanged at 70 bar. |
| Physics Operator Comments | |||
| Jul 6 2006 09:43:08:480AM | 1060706001 | Jim Irby | loaded in Steve's setup shot from his pcs_scratch directory.
TF current 220 kA Ip 1.6 MA nl_04 request 1.2e20/m^2 zeroed A-field current in seg02. load/clean One bad fuse found in TF supply and replaced. TF scanner data looked very good during 1060705 run. approx 20 minutes late because of slow cooling of C-Right (cooling turned off search for some reason). ********************************************** plasma to 0.98 s --- gas jet fired 0.982 s Bt 7.822 T at 216 kA, Ip 1.56 MA Q 3.24 at 1 s dT TF about +16C EF4 railed halo current warning: IBt> 1500 kAT EF2U/EF2L coil stress warning Very high pressure in ECE beamline shuts it down (vented). TF joint resistance scanner looks very good |
| Jul 6 2006 10:05:22:190AM | 1060706002 | Jim Irby | gas jet treshold from 11000 to 15000 but jet disabled for this shot
load/clean ECE should be back online Integral gain on a-coil feedback from 4 to 0. Proportional gain on a-coil feedback from 1 to 0. load/clean fizzle --- CIII very high --- pressure up |
| Jul 6 2006 10:53:24:697AM | 1060706003 | Jim Irby | prepuff from 22 to 20 ms
load/clean basepressure 1,0e-6 Torr plasma with disruption at 0.852 s A-Coil feedback should have been on from 0.2 to 0.8 s, but I turned them off for the entire shot. EF2 coils stress and halos current warnings again. TF scanner looks very good. Bz0 drifted up about 1 mT between shot 1 and 3. |
| Jul 6 2006 10:59:22:057AM | 1060706004 | Jim Irby | a-coil feedback from 0.2 to 0.8 s
integral gain 4.0 prop gain 1.0 load/clean fizzle --- should have dropped the gas? Lots of carbon III again fields look very good |
| Jul 6 2006 11:27:55:433AM | 1060706005 | Jim Irby | prefill to 18 ms from 20.
nl_04 request to 1.1 from 1.2e20 /m^2 load/clean plasma for 0.908 s a-coil feedback continues past 0.8 s --- looks like program samples-and-holds last current value?? |
| Jul 6 2006 11:57:14:430AM | 1060706006 | Jim Irby | added new point at 0.8 s to integrator C and zeroed gate from 0.8 to 2.0 s.
added new points to a-coil integral and prop gains. Both gains now zero from 0.8 to 2. s. prepuff gas from 18 to 17 ms load/clean RXL from 0.025 to 0.020 in attempt to reduce impurity influx plasma for 1.6 s a-coils did turn off. |
| Jul 6 2006 12:15:17:920PM | 1060706007 | Jim Irby | a-coils programmed for 1100A from 0.8 to 1.3 s with a rampdown to zero at 1.4.
alternator to 1718 RPM to make sure bearing #2 vibration stays low plasma for 1.45 s TF scanner data looks good. |
| Jul 6 2006 12:57:08:967PM | 1060706008 | Jim Irby | a-coils to 4000 A from 0.8 to 1.3 s then rampdown to 0 at 1.4s
plasma for 0.73 s --- large injection ends plasma large chunk of something seen on wide2 camera moves in from well outside and bounces off of inner wall. not clear if it's from the outer divertor or somewhere closer to the midplane. |
| Jul 6 2006 01:05:00:970PM | 1060706009 | Jim Irby | no DPCS changes
fizzle --- fields okay --- early carbon increase sparker current very low === about 45 uA |
| Jul 6 2006 01:25:52:807PM | 1060706010 | Jim Irby | sparker start from -3.9 to -3.99 s. Duration 4.05 s.
plasma to 1.517 s |
| Jul 6 2006 02:19:41:750PM | 1060706011 | Jim Irby | going into cell to reverse a-coil leads
nl_04 request to 2e20/m^2 a-coil feedback control integral and prop gain to 0.0 a-coil programmed current to 0.0 A. Pulled RXL toward zero after 1.3 s to help with rampdown. load clean found blown fuses in TF.... everyone back in control room at t=54:00 minutes igt at 6.3e-7 Torr at check no power shot --- didn't ramp up alternator --- also had scanner reset issue. |
| Jul 6 2006 02:46:11:807PM | 1060706012 | Jim Irby | try again
after a long wait, a fizzle fields good, pressue okay. |
| Jul 6 2006 03:04:07:343PM | 1060706013 | Jim Irby | one more try --- no DPCS changes
IGT at 5.4e-7 Torr plasma for 1.5 s --- density well above 2e20? |
| Jul 6 2006 03:23:52:400PM | 1060706014 | Jim Irby | a-coils ramp up from 0.7 to 0.8 s to 2000 A then rampdown starting at 1.3 s.
prefill from 17 to 16 ms fizzle --- carbon peak again, h-alpha stays high |
| Jul 6 2006 03:51:56:143PM | 1060706015 | Jim Irby | rampdown Ip to 0.0 bu 1.7 s --- try to have a little smaller disruption current
nl_04 request to -8e19/m^2 beyond 1.3 s pulsed gas 3 request negative past 1.3 s load/clean plasma for 1.48 s. --- Ip down to .947MA at disruption (was about 1.2 MA) |
| Jul 6 2006 04:25:25:470PM | 1060706016 | Jim Irby | prepuff to 14 ms from 16 ms.
still got a fizzle --- carbon up as usual |
| Jul 6 2006 04:34:40:240PM | 1060706017 | Jim Irby | repeat
plasma for 1.40 s |
| Jul 6 2006 06:11:37:120PM | 1060706018 | Jim Irby | nl_04 density request goes negative at 0.8 s
pg03 gas request goes negative at 0.8 s loaded shot 1060706010 into seg 2 load/clean a-coil connections put back in original configuration. plasma for 1.503 s |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:21:07:393AM | Plasma | Ok | |
| 2 | 09:59:12:910AM | Plasma | Ok | |
| 3 | 10:22:41:900AM | Plasma | Ok | |
| 4 | 10:53:20:637AM | Plasma | Ok | |
| 5 | 11:16:53:897AM | Plasma | Ok | |
| 6 | 11:40:41:987AM | Plasma | Ok | |
| 7 | 12:03:41:590PM | Plasma | Ok | |
| 8 | 12:31:07:053PM | Plasma | Ok | |
| 9 | 12:55:25:920PM | Plasma | Ok | |
| 10 | 01:18:02:460PM | Plasma | Ok | |
| 11 | 02:16:58:060PM | Plasma | Bad | No Power, Alternator Excitation Field Not Ramp in Time |
| 12 | 02:29:05:410PM | Plasma | Ok | |
| 13 | 02:52:39:873PM | Plasma | Ok | |
| 14 | 03:17:20:943PM | Plasma | Ok | |
| 15 | 03:39:53:703PM | Plasma | Ok | |
| 16 | 04:02:32:007PM | Plasma | Ok | |
| 17 | 04:25:12:907PM | Plasma | Ok | |
| 18 | 04:54:21:060PM | Plasma | Ok | |