| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | T.C. Hender |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| MP#361 JET/C-Mood locked mode identity |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:04:443PM |
| Author: T.C. Hender |
| Session Leader Summary for Thursday, April 8, 2004 MP#361: JET/C-Mod Locked mode identity SL: Hender/Wolfe PO: Marmar Moderately good run with the locked mode threshold established at 2 densities and intrinsic error found at lower density. The main problem was failed breakdowns particularly from shot 27 onwards. Shots 14 and 16 established the threshold at about -1950A at nl4=2.1e20 and with Btop-Dbot-Gtop+Jbot. Likewise shots 19 and 21 showed a limit of about -1550A. Shot 22 got an intrinsic locked mode at nl4~1.0. The problems with the attempts at high density are unclear. Shot 4 had a density prumpout at 0.8s - probably due to a locked mode (but this needs further checking). Pulse 1 was fairly successful at reaching high'ish density. The later attempts at high density pulses 26, 31 and 32 were plagued by MARFES. Some consideration needs to be given on how to get around this next time. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:49:817PM |
| Author: Earl Marmar |
| physop run summary for 1040408 __________________________________________________ Engineering setup for Thursday, 08 Apr 2004 MP#361 JET/C-Mod locked mode identity Session leader: Hender/Wolfe Physics operator: Marmar Overnight ECDC in D2 at 2e-4 Torr Run begins at 09:00 and ends at 17:00. Power systems the same as 1031219031, but be sure TF PLC limit is at least 180kA (6.32 Tesla). A-coils should be configured (+Btop -Dbot -Gtop +Jbot) Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper with 15 psi He3 Hybrid disabled (PG2) fill C-side with 40 psi D2 Hybrid enabled (PG3) Fill NINJA to 40 psi D2, and enable Enable the following gatevalves: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: no RF required for this run ------------------------------------------------------------------------------- Results: The run started off pretty well, with some locked mode results (see session leader summary). However, after shot 8, we started having fizzle problems. Most shots had high current disruptions at 6.3 tesla, but it's not clear if that was the main problem. It appeared that startup improved with lowered prefill puff (as typical with disruptions, particularly when the plasmas are high density, as these were) and with a fairly negative Br_0. Getting high density (nl_04~3e20) proved tricky. Shot 26 was the most successful in this regard, but a number of attempts ended in big marfes and early disruptions. Loop voltage is high for these ohmic shots, and some power supplies run close to, or at their limits. Increasing the OH limits on the positive swing (-ve on PLC) improved things. We tried NINJA on a few shots to supplement the normal fueling puff, but it only seemed to make things worse. The interferometer was having some problems, so we switched to nl_zmeter feedback for shot 5 and subsequent. This worked without incident. Computers and power supplies worked well: shot 24 was lost to the EF3 breaker pulling just before the pulse. Summary: plasmas 20 fizzles 11 PS dud 1 Total cycles 32 |
| Session Leader Comments | |||
| Apr 8 2004 08:57:50:280AM | T.C. Hender | MP 361 Error Field Identity Experiments with JET Aims are to make rho*, nu* matches with JET Ohmic error field thresholds. JET shots are available equivalent to 1.27MA, 6.3T (q95=3.3) and 1MA, 6.3T (q95=4.1). The Acoil will be used in Btop-Dbot-Gtop+Jbot mainly as this gives best match to JET or as Dtop+Dbot-Jtop-Jbot. The main issue for the run will be to get into the density window between where low density intrinsic locked modes occur and where there is enough current in the Acoil to make locked modes. A possible additional set of shots is match the equivalent of 8T and 1.6MA pulses from JET. | |
| Apr 8 2004 09:18:19:547AM | 1040408001 | T.C. Hender | Shot 1040408001 Sligthly too much density leading to a loss of vertical control at 1.2s (the fringe jump in nl4 may not have helped). Next shot less density aiming for nl4=2.3e20 |
| Apr 8 2004 09:30:40:893AM | 1040408002 | T.C. Hender | Shot 1040408002 Disruption at 0.37s. Cause not clear, try less density in next shot |
| Apr 8 2004 09:46:23:180AM | 1040408003 | T.C. Hender | Shot 1040408003. Better. Disruption at 0.84s. Try less density in next shot, turn off NINJA |
| Apr 8 2004 10:08:16:997AM | 1040408004 | T.C. Hender | Shot #4. Density pump out at 0.8s, is it a locked mode? (not clear but it seems the most likely cause) Only option is to try slightly more denisty. |
| Apr 8 2004 10:23:01:723AM | 1040408005 | T.C. Hender | Shot #5. Good. Z-feedback works. nl4 tops out at ~2e20. Next shot put on A-coil at 0.8s and ramp to 3.5kA at 1.1s. |
| Apr 8 2004 10:40:09:000AM | 1040408006 | T.C. Hender | Shot #6. OK but no locked mode from A-coil which ramps to +2.4kA. It appears +ve current in the A-coil may be subtracting from the intrinsic error so try -ve current in next shot |
| Apr 8 2004 11:04:36:833AM | 1040408007 | T.C. Hender | Shot #7. Disruption at 0.45s. UFO event? Try again. |
| Apr 8 2004 11:14:42:380AM | 1040408008 | T.C. Hender | Shot #8. Still disrupts early at 0.53s. Is it the Ar puff? Try again with lower Ar puff. |
| Apr 8 2004 11:29:36:137AM | 1040408009 | T.C. Hender | Shot #9. Fizzle. |
| Apr 8 2004 11:43:32:800AM | 1040408010 | T.C. Hender | Shot #9. Fizzle. |
| Apr 8 2004 11:46:25:023AM | 1040408010 | T.C. Hender | Shot #10. First driven locked mode at 1.08s and Acoil=-2960A, nl4=2.1e20. Repeat with Acoil flat-topped to 2.5kA to see if that makes a locked mode. |
| Apr 8 2004 11:49:06:027AM | 1040408011 | T.C. Hender | Shot #11. Fizzle. Try again |
| Apr 8 2004 12:10:04:900PM | 1040408012 | T.C. Hender | Shot #12. Good but locked mode at 1.07s again with Acoil=-2570A and nl4=2.1. So try again with Acoil=-1500A. |
| Apr 8 2004 12:18:07:913PM | 1040408013 | T.C. Hender | Shot #13. Fizzle again |
| Apr 8 2004 12:49:14:133PM | 1040408014 | T.C. Hender | Shot #14.Good shot. Locked mode at 1.21s with Acoil=-1890A. Interferometer failed |
| Apr 8 2004 12:52:48:767PM | 1040408015 | T.C. Hender | Another failed breakdown. Try again |
| Apr 8 2004 01:13:16:437PM | 1040408016 | T.C. Hender | Shot #16 Locked mode at 1.12s with -2070A in A-coil. This one clearly pins down the locked mode value. |
| Apr 8 2004 01:21:57:247PM | 1040408017 | T.C. Hender | Shot #17 and another odd-shot number fizzle. |
| Apr 8 2004 01:44:21:110PM | 1040408018 | T.C. Hender | Shot #18. Good pulse at lower density nl4~1.6e20 and no locked mode (A-coil off). Next pulse put the A-coil on |
| Apr 8 2004 01:57:09:300PM | 1040408019 | T.C. Hender | Shot #19. Good pulse locked mode at 1.07s anbd 1675A nl4=1.57e20. Pulse lands OK. |
| Apr 8 2004 02:01:56:543PM | 1040408020 | T.C. Hender | Shot #20 Fizzle |
| Apr 8 2004 02:25:34:530PM | 1040408021 | T.C. Hender | Shot #21. Makes loked mode in flat-top phase of A-coil with -1440A and at 1.0s with nl14=1.5e20. So that's OK and now move on to lower density in next pulse (nl20=1.2e20) |
| Apr 8 2004 02:35:37:157PM | 1040408022 | T.C. Hender | Shot #22. Makes an intrinsic locked mode (no A-coil) at 0.61s |
| Apr 8 2004 02:49:57:193PM | 1040408023 | T.C. Hender | Shot #23. Early disruption at 0.24s. Turn off NINJA in next pulse |
| Apr 8 2004 02:57:54:237PM | 1040408024 | T.C. Hender | Shot #24. No plasma. |
| Apr 8 2004 03:17:28:237PM | 1040408025 | T.C. Hender | Shot #25. Fizzle. |
| Apr 8 2004 03:41:16:493PM | 1040408026 | T.C. Hender | Shot #26. No A-coil on and no locked mode. Density reaches (nl4) 3.6e20 and large MARFE. Next shot back density down by 15% and add A-coil |
| Apr 8 2004 03:44:44:263PM | 1040408027 | T.C. Hender | Shot #27. Fizzle |
| Apr 8 2004 04:00:16:663PM | 1040408028 | T.C. Hender | Shot #28. And another fizzle unfortunately. |
| Apr 8 2004 04:10:59:270PM | 1040408029 | T.C. Hender | Shot #29. And another fizzle unfortunately. |
| Apr 8 2004 04:23:54:993PM | 1040408030 | T.C. Hender | Shot #30. And another fizzle unfortunately. |
| Apr 8 2004 04:54:35:950PM | 1040408031 | T.C. Hender | Shot #31. Got beyond the fizzle this time, but disruption at 0.38s. Locked mode at 0.25s, but not clear if this is the real problem. |
| Apr 8 2004 05:06:38:623PM | 1040408032 | T.C. Hender | Shot #32. Very similar to previous shot. Got beyond the fizzle this time, but disruption at 0.38s. Locked mode at 0.26s again |
| Physics Operator Comments | |||
| Apr 8 2004 08:49:50:127AM | Earl Marmar | Engineering setup for Thursday, 08 Apr 2004 MP#361 JET/C-Mod locked mode identity Session leader: Hender/Wolfe Physics operator: Marmar Overnight ECDC in D2 at 2e-4 Torr Run begins at 09:00 and ends at 17:00. Power systems the same as 1031219031, but be sure TF PLC limit is at least 180kA (6.32 Tesla). A-coils should be configured (+Btop -Dbot -Gtop +Jbot) Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper with 15 psi He3 Hybrid disabled (PG2) fill C-side with 40 psi D2 Hybrid enabled (PG3) Fill NINJA to 40 psi D2, and enable Enable the following gatevalves: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: no RF required for this run ------------------------------------------------------------------------------- | |
| Apr 8 2004 09:17:32:420AM | 1040408001 | Earl Marmar | Load from 1031219031 import segment 1 from 1040407002 adjust segment 2 TF current to -174,500 from -170,000 (want 6.32T at R=0.66) turn on nl_04 feedback; adjust voltage preprog on PG3 NINJA on at 0.2 s, .2 s pulse A-coils programmed to 0 current plasma startup looks ok density higher than desired EF1 reached limit |
| Apr 8 2004 09:28:58:013AM | 1040408002 | Earl Marmar | reduce nl_04 target to 1.8e20 reduce PG3 preprog voltage to 40 reduce NINJA to 0.16 pulse width, still starting at .2 seconds plasma; early disruption (.37 s) strong density rise around .29 early hards pf breaker pulled after the disruption |
| Apr 8 2004 09:45:06:773AM | 1040408003 | Earl Marmar | reduce nl_04 program plasma density feedback not behaving (vibrations on interferometer) density higher than desired |
| Apr 8 2004 09:58:02:090AM | 1040408004 | Earl Marmar | disable NINJA nl_04 prog to 2.2e20 plasma looks ok until about .8 s, then density dives disrupt at 1.01 s halo current warning (Ihalo*B > 1.5 MA-T) |
| Apr 8 2004 10:18:30:480AM | 1040408005 | Earl Marmar | go to nl_zmeter density feedback prog to 2.0 volt add 10 msec to argon puff plasma nl_04 to 2e20 |
| Apr 8 2004 10:32:48:567AM | 1040408006 | Earl Marmar | enable A-coils: on at 0.8 rising to 4000 at 1.1, then ramp down again after 1.5 increase argon another 10 msec (now 60 ms) plasma got the a-coil currents no sign of a locked mode Wolfe is thinking about effect of a-coil currents on error fields |
| Apr 8 2004 11:02:42:720AM | 1040408007 | Earl Marmar | reverse polarity on a-coils now: -Btop +Dbot +Gtop -Jbot add 10 more msec to argon puff plasma disrupt at .45; injection around .41 |
| Apr 8 2004 11:09:42:607AM | 1040408008 | Earl Marmar | no pcs changes lasted a bit longer, disrupting at .52 |
| Apr 8 2004 11:21:49:093AM | 1040408009 | Earl Marmar | reduce argon puff by 20 msec; now 50 msec increase early nl_zmeter target a bit fizzle |
| Apr 8 2004 11:45:21:240AM | 1040408010 | Earl Marmar | reduce BR_0 by 0.5 mT to -.0005 T plasma got the locked mode on this one |
| Apr 8 2004 11:51:49:483AM | 1040408011 | Earl Marmar | program a-coils to 3000 at 1s, flat to 1.15, then up to 4000 at 1.35 s fizzle |
| Apr 8 2004 12:09:04:430PM | 1040408012 | Earl Marmar | reduce prepuff by 1 msec plasma locked mode around 1.08 s (as on shot 10) |
| Apr 8 2004 12:19:22:463PM | 1040408013 | Earl Marmar | reduce a-coil demand fizzle |
| Apr 8 2004 12:41:49:950PM | 1040408014 | Earl Marmar | reduce prepuff another 1 msec change plc limits on all 3 oh coils to 30 kA (positive swing, -ve on PLC) plasma locked mode around 1.23 |
| Apr 8 2004 12:54:43:737PM | 1040408015 | Earl Marmar | increase oh1 -ve PLC limit to 33kA Move end of flattop earlier, to 1.3 seconds fizzle |
| Apr 8 2004 01:32:01:027PM | 1040408016 | Earl Marmar | Modified a-coil time history plasma |
| Apr 8 2004 01:31:51:730PM | 1040408017 | Earl Marmar | a-coils off reduce density: nl_zmeter prog to .45 volt fizzle |
| Apr 8 2004 01:40:48:777PM | 1040408018 | Earl Marmar | no pcs changes plasma nl_04 = 1.5e20 |
| Apr 8 2004 01:51:04:683PM | 1040408019 | Earl Marmar | reduce prefill puff by 1 msec (now 12 msec) A-coils back on plasma |
| Apr 8 2004 02:02:13:620PM | 1040408020 | Earl Marmar | modified a-coil programming (increased early, max unchanged) fizzle |
| Apr 8 2004 02:27:07:880PM | 1040408021 | Earl Marmar | reduce BR_0 offset 0.5 mT, to -.001 T plasma |
| Apr 8 2004 02:49:20:270PM | 1040408022 | Earl Marmar | add 1 msec to prepuff a-coils off (PLC) nl_zmeter demand to .26 volt reduce pg3 preprog to 35 V (from 40) plasma |
| Apr 8 2004 02:50:38:523PM | 1040408023 | Earl Marmar | nl_zmeter demand to 1.6 volt increase pg3 segment 2 preprog voltage NINJA on .2s for .16s plasma early disruption; too much gas |
| Apr 8 2004 02:59:08:193PM | 1040408024 | Earl Marmar | disable NINJA PS dud: EF3 breaker opened just before the shot |
| Apr 8 2004 03:20:35:617PM | 1040408025 | Earl Marmar | no pcs changes fizzle; B_R took a negative lurch around 10 msec |
| Apr 8 2004 03:43:40:667PM | 1040408026 | Earl Marmar | add .5mT to BR_0 offset; now -.0005 T plasma got to nl_04=3.5e20; disrupt at 1.11 plasma current drooping a bit before the disruption |
| Apr 8 2004 03:51:21:663PM | 1040408027 | Earl Marmar | reduce nl_zmeter target to 1.25V fizzle |
| Apr 8 2004 03:59:12:677PM | 1040408028 | Earl Marmar | no pcs changes fizzle |
| Apr 8 2004 04:13:49:293PM | 1040408029 | Earl Marmar | reduce prepuff 1 msec increase BR_0 offset .5mT (now 0.0000T) fizzle |
| Apr 8 2004 04:26:26:267PM | 1040408030 | Earl Marmar | BR_0 offset to -.0007 T add 1 msec to prepuff fizzle |
| Apr 8 2004 04:40:51:930PM | 1040408031 | Earl Marmar | BR_0 offset to -.001 T plasma disrupt at .38 |
| Apr 8 2004 05:05:30:467PM | 1040408032 | Earl Marmar | no pcs changes plasma early disruption, very similar to 31 |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:01:59:083AM | Plasma | Ok | |
| 2 | 09:18:28:123AM | Plasma | Bad | OH1 self powered circuit fired |
| 3 | 09:34:10:287AM | Plasma | Ok | |
| 4 | 09:47:26:747AM | Plasma | Ok | |
| 5 | 10:11:44:517AM | Plasma | Ok | |
| 6 | 10:24:59:147AM | Plasma | Ok | |
| 7 | 10:52:19:050AM | Plasma | Ok | |
| 8 | 11:05:15:380AM | Plasma | Ok | |
| 9 | 11:19:50:183AM | Plasma | Ok | |
| 10 | 11:32:31:890AM | Plasma | Ok | |
| 11 | 11:46:56:460AM | Plasma | Ok | |
| 12 | 12:01:42:047PM | Plasma | Ok | |
| 13 | 12:16:06:600PM | Plasma | Ok | |
| 14 | 12:32:20:360PM | Plasma | Ok | |
| 15 | 12:50:22:260PM | Plasma | Ok | |
| 16 | 01:04:48:707PM | Plasma | Ok | |
| 17 | 01:19:10:413PM | Plasma | Ok | |
| 18 | 01:33:48:030PM | Plasma | Ok | |
| 19 | 01:46:33:927PM | Plasma | Ok | |
| 20 | 01:59:27:883PM | Plasma | Ok | |
| 21 | 02:11:53:810PM | Plasma | Ok | |
| 22 | 02:25:58:890PM | Plasma | Ok | |
| 23 | 02:42:50:200PM | Plasma | Ok | |
| 24 | 02:55:23:673PM | Plasma | Ok | |
| 25 | 03:14:36:297PM | Plasma | Ok | |
| 26 | 03:27:12:533PM | Plasma | Ok | |
| 27 | 03:42:49:307PM | Plasma | Ok | chopper current looked ugly |
| 28 | 03:55:42:220PM | Plasma | Ok | |
| 29 | 04:08:53:020PM | Plasma | Ok | |
| 30 | 04:21:58:133PM | Plasma | Ok | |
| 31 | 04:36:01:873PM | Plasma | Ok | PF breaker open due to a disruption |
| 32 | 05:02:05:650PM | Plasma | Ok | PF breaker opened after disruption |