Miniproposals

Miniproposal: 455 Date Filed: 5/26/2006 Title: Determination of LHCD efficiency First Author: J. Randall Wilson Session Leader: J. Randall Wilson (shots 1-24)

Engineering Operator Run Comment

MP#455 Determination of LHCD efficiency Session leader: Wilson Physics O

Session Leader Plans

Entered: Jun 14 2006 04:16:14:180PM

Author: J. Randall Wilson

Session leader plan for 100615 MP#455 Determination of LHCD efficiency Session leader: Wilson Physics Operator: Parker The primary goal of this run is to determine LHCD current drive efficency by performing a power scan at fixed plasma parameters and fitting the loop voltage change to a theoritical form Run plan: 0) Establish LHCD target discharge at 500 kA 1) Scan LH power in small steps (~50 kW) from zero to max at 90 degree CD phasing 2) plot loop voltage drop versus normalized power and check fit to formula - if fit good enough repeat scan at 60 and 120 degree phaing

Physics Operators Plans

Session Leader Summaries

Entered: Jun 15 2006 03:15:49:217PM

Author: J. Randall Wilson

Session leader summary Achieved good power scan at 90 degree CD phasing Power from ~100-500 kW injected Preliminary look at loop voltage data indicates much cleaner set than in past Some central heating observed on TS which will have to be taken into account nearly linear voltage drop with power coupler protection circuitry functioned well

Physics Operator Summaries

Entered: Jun 15 2006 03:30:50:753PM

Author: Ron Parker

The run was abbreviated by 1 hour due to PFSC BBQ, beginning at 8:00 and ending at 3:00. The object was to do a power scan to determine the fraction of current driven by LHCD. The plan was to do this at 500 kA, so that the LH current at high power would be a significant fraction of the total current. It turned out that this presented a machine problem because the OH current did not reverse for the programmed waveform at that relatively low plasma current. A fix was to bring the current up to 700 -800 kA at the end of the pulse, but this caused a few disruptions to occur, which was then followed by a fizzle. Better would have been to bring the current up to 800 kA at the beginning of the pulse and then ramp it down to 500 kA. But the problem did not appear until mid-run and it was decided not to change the discharge evolution in the middle of the power scan. Overall, the LH system ran very well, in particular the new fault protection system based on the reflection levels at the Jungle Gym couplers. Hats off to Dave Terry and his crew for this development. Scorecard: 24 plasma attempts, 2 duds (1st two shots had gas pressure ~ .04 mT, vs nomnal 0.06 mT), 2 fizzles (caused by end of shot disruptions as explained above), 1 early disruption (also likely due to end-of-shot disruption on previous shot) and 19 useful shots. A pretty good day, especially for the LH.

Session Leader Comments
Jun 15 2006 09:40:49:180AM	1060615005	J. Randall Wilson	change rf pulse to 0.895 s
Jun 15 2006 09:42:15:090AM	1060615006	J. Randall Wilson	increase rf power to 30kW/klystron still seeing "excursion" after 50 ms of pulse excursion involves plasma motion, loss of ECE emmision and rise in voltage
Jun 15 2006 10:03:02:567AM	1060615007	J. Randall Wilson	excursion seems to be due to OH current going flat during pulse
Jun 15 2006 10:03:48:927AM	1060615008	J. Randall Wilson	increase rf power to 35 kW/klystron increase pulse width by 100 ms
Jun 15 2006 10:18:38:837AM	1060615009	J. Randall Wilson	increase rf power to 40 kW/klystron
Jun 15 2006 10:49:53:223AM	1060615010	J. Randall Wilson	increase rf power to 40 kW/klystron good shot nice clean change in loop voltage at end of rf pulse
Jun 15 2006 11:29:18:333AM	1060615011	J. Randall Wilson	increase rf power to 45 kW/klystron one dropout on 9bottom restrike good
Jun 15 2006 11:39:54:710AM	1060615012	J. Randall Wilson	repeat good
Jun 15 2006 12:04:30:847PM	1060615013	J. Randall Wilson	increasew power one dropout 9 bottom again
Jun 15 2006 12:08:53:347PM	1060615014	J. Randall Wilson	increase power on all but klystron 5 one dropout on 8bottom jungle gym coupler protection working well
Jun 15 2006 12:23:58:713PM	1060615015	J. Randall Wilson	repeat no dropouts
Jun 15 2006 12:41:35:267PM	1060615016	J. Randall Wilson	one dropout 22 bottom rasied power by 5 kW each klystron
Jun 15 2006 01:18:49:327PM	1060615018	J. Randall Wilson	try again good pulse 400 kW
Jun 15 2006 02:17:58:070PM	1060615020	J. Randall Wilson	re set protection raise power 415 kW
Jun 15 2006 02:32:09:607PM	1060615021	J. Randall Wilson	one trip 3 bottom 450 kW
Jun 15 2006 03:01:55:210PM	1060615023	J. Randall Wilson	good 480 kW
Jun 15 2006 03:07:40:057PM	1060615024	J. Randall Wilson	no lh power supply trip

Physics Operator Comments
Jun 14 2006 04:56:49:447PM		Ron Parker	Physop Plan and Engineering Setup Thursday, June 15, 2006 ***********NOTE***********Run starts at 8:00 and ends at 3:00 for BBQ MP#455 Determination of LH Efficiency SL: Wilson PO: Parker ECDC overnight in D2 at 2.e-4 Torr Power systems as on 1060511001 A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled. C-coil Start=0.3sec, Invert=2.0sec ICRF: Need 2 MW reliable from D&E midway through run Gas Setup: ---------- fill B-top 6psi D2 Hybrid enabled (PG4) fill B-side lower 1 psi Argon Hybrid Disabled (PG1) fill B-side Upper as is, Hybrid Disabled (PG2) fill B-main 40psi D2 Hybrid Enabled (PG3) Enable ECE, VUV, Z-bolo shutter assuming no vacuum problems Run Plan: See SL plan. We'll do a power scan on LH power with initial 90 degree phasing. If successful, try 60 and 120 phasing. Hard X-ray diagnostic should be available and operating. We also need to verify operation of CPS with RF frm D&E ports.
Jun 15 2006 08:02:05:707AM	1060615001	Ron Parker	Run is beginning at 8:00 due to early end for BBQ. Closing up, should have first shot momentarily.
Jun 15 2006 08:12:13:663AM	1060615001	Ron Parker	There was a short delay (~12 minutes) required to tune up interferometer. First shot coming up.
Jun 15 2006 08:24:01:760AM	1060615001	Ron Parker	Oops, a dud! Gas pressure seems too low (0.04 mT), so we'll increase it for next shot, from 19 to 25 ms. Also Bz lower than yeaterday, increase IC_EF4U from -1335 to -1325.
Jun 15 2006 08:35:23:517AM	1060615002	Ron Parker	Another dud!. Gas still too low -- was shot loaded? Try again.
Jun 15 2006 08:49:23:693AM	1060615003	Ron Parker	Shot 3 finally ran with LH. Needs some tuning.
Jun 15 2006 09:09:20:217AM	1060615004	Ron Parker	Shot 4 ran well.
Jun 15 2006 09:09:29:530AM	1060615005	Ron Parker	Shot 5 was OK
Jun 15 2006 09:40:32:463AM	1060615006	Ron Parker	Shot 6 was OK. For next shot, we'll extend the pulse by 0.2 s.
Jun 15 2006 10:02:37:970AM	1060615007	Ron Parker	Shot 7 was OK.
Jun 15 2006 10:02:52:660AM	1060615008	Ron Parker	Shot 8 went off OK.
Jun 15 2006 10:25:18:277AM	1060615009	Ron Parker	Shot 9 ran, but the current ramp up was poor. RF tripped, no retry. Still cocncern about double swing, try ramping to 700 kA at end of pulse.
Jun 15 2006 10:45:49:893AM	1060615010	Ron Parker	Shot 10 ran OK, also RF.
Jun 15 2006 12:08:45:037PM	1060615011	Ron Parker	Shot 11 was fine.
Jun 15 2006 12:08:55:550PM	1060615012	Ron Parker	Shot 12 ran well.
Jun 15 2006 12:09:12:893PM	1060615013	Ron Parker	Shot 13 went off as programmed.
Jun 15 2006 12:09:58:300PM	1060615014	Ron Parker	Shot 14 was good. Having problems with LH trips. But seems to recover on restrike.
Jun 15 2006 12:32:09:810PM	1060615015	Ron Parker	Shot 15 was good. No RF trip.
Jun 15 2006 01:00:14:930PM	1060615016	Ron Parker	Shot 16 was OK, but rampup at current at end (in attempt to reverse OH current to help joint heating) caused disruption.
Jun 15 2006 12:59:02:837PM	1060615017	Ron Parker	Shot 17 fizzled, no surprise considering the disruption at the end of last shot.
Jun 15 2006 01:26:45:063PM	1060615018	Ron Parker	Shot 18 ran full term, as did LH power. Short break for cell access to set trip level for one or two of the JJ couplers.
Jun 15 2006 02:01:33:797PM	1060615019	Ron Parker	Shot 19 disrupted early, again likely due to disruption on previous shot.
Jun 15 2006 02:26:17:760PM	1060615020	Ron Parker	Good shot. Sawteeth almost stabilized, very small.
Jun 15 2006 02:44:45:220PM	1060615021	Ron Parker	Shot 21 ran OK, but disrupted.
Jun 15 2006 02:45:17:953PM	1060615022	Ron Parker	Shot 22 fizzled, as expected.
Jun 15 2006 03:08:34:793PM	1060615023	Ron Parker	Shot 23 was OK.
Jun 15 2006 03:08:21:137PM	1060615024	Ron Parker	Shot was OK, but LH breaker tripped.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:15:09:977AM	Plasma	Ok
2	08:28:12:123AM	Plasma	Ok
3	08:40:53:377AM	Plasma	Ok
4	08:54:37:303AM	Plasma	Ok
5	09:07:12:420AM	Plasma	Ok
6	09:20:09:160AM	Plasma	Ok
7	09:46:52:467AM	Plasma	Ok
8	10:00:46:643AM	Plasma	Ok
9	10:16:03:490AM	Plasma	Ok
10	10:41:02:580AM	Plasma	Ok
11	11:22:46:517AM	Plasma	Ok
12	11:35:33:303AM	Plasma	Ok
13	11:48:39:497AM	Plasma	Ok
14	12:02:35:987PM	Plasma	Ok
15	12:20:16:290PM	Plasma	Ok
16	12:34:18:607PM	Plasma	Ok
17	12:47:50:957PM	Plasma	Ok
18	01:01:53:290PM	Plasma	Ok
19	01:58:26:220PM	Plasma	Ok
20	02:11:27:287PM	Plasma	Ok
21	02:25:40:777PM	Plasma	Ok
22	02:38:30:873PM	Plasma	Ok
23	02:51:10:723PM	Plasma	Ok
24	03:03:58:667PM	Plasma	Ok