Miniproposals

Miniproposal: Date Filed: Title: First Author: Session Leader: Gerry Tinios (shots 1-25)

Miniproposal: 052 Date Filed: 4/12/1994 Title: ICRF Antenna Tuning (P First Author: Yuichi Takase Session Leader: Gerry Tinios (shots 1-25)

Miniproposal: 053 Date Filed: 4/8/1994 Title: Study of Closed Loop Response of Elongated Plasmas. First Author: Gerry Tinios Session Leader: Gerry Tinios (shots 1-25)

Engineering Operator Run Comment

MP 053 Closed loop...& MP052 ICRF tuning.

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:10:197PM

Author: To Be Determined

Run Summary for 940524 SL: Tinios PO: Horne EO: Bertolino/Fairfax This run was to be dedicated to MP53 Closed Loop Response), but it ended up being a part of the allegedly completed MP41. We managed to get 9 plasmas. 5 of these ended up at the top of the machine and 4 at the bottom. Only one of these shots (shot 25) was related to MP53, and, from it, it became apparent, that we need a much better controlled baseline plasma, in order to see the ZCUR perturbations suggested in MP53. We started with the last shot from Friday and fixed the PCS bug pertaining to the linking of drawn P's for wires with the same name. We also lowered the programmed ZCUR to -1cm, hoping to reduce the number of disruptions this way. First there was an OH2 power supply problem which fixed itself without ever being identified. Then, after 4 fizzles, we got our first plasma (shot 7). This seems to have harmed the F13 partial flux loop. We then had to stop for an hour and recalculate predictors, so they do not use F13. Shots 11 and 15 were our following two plasmas. They seemed to have a problem with radial control and were resting on the outer limiter most of the time. We noticed that in shot 11 and tried to fix it by moving RCUR programming in the wrong direction for shot 15. Then, we felt confident enough to load a ZCUR step perturbation. In the process, we unintentionally turned of the integral gain in wire 2, without actually turning off the integrator. The drift of the integrator may well have caused erroneous demand signals to the power supplies (Steve Horne had warned us about this before we started running this year). Shots 16-23 were run under these conditions, and we actually managed to get 3 plasmas (shots 20,21,23), all of which had poor vertical control. None of them lived long enough to experience the ZCUR step. Finally, after fixing an offset error in wires 2 and 3, we arrived at shot 25, the only shot that lived though the ZCUR perturbation. The pertubation, which can be clearly seen in the wavegen output, is only visible to the trained and imaginative eye on any other signal. Obviously, vertical control of the plasma is poor and the injected perturbation too small to be seen in the middle of all the background vertical motion.

Physics Operator Summaries

Session Leader Comments
May 24 1994 09:02:12:910AM		Gerry Tinios	Session leader : G. Tinios Physics Op. : S. Horne Engineering Ops: D. Gwinn / S. Fairfax MP53, study of closed loop resonse of elongated plasmas, although MP41 will play a big role. MP52, ICRF tuning, is the piggy back.
May 24 1994 10:00:46:290AM	940524001	Gerry Tinios	Reload shot 940520027. Lower ZCUR programming to -1 cm. Fix KAPPA wire PCS bug. Zero KAPPA controller for the moment. ZXL programming was drawn at -1 cm. EF2U programming was changed to -3500 until 0.7 sec, ramping to 0 afterwards. Dud, OH2's did not work.
May 24 1994 10:24:15:270AM	940524002	Gerry Tinios	PLC controlled check of the OH2's. This shot worked. ==> check relay that switches from hybrid to PLC control. Nothing looks wrong.
May 24 1994 10:37:29:280AM	940524003	Gerry Tinios	Try shot 1 again. Fizzle. OH2's worked this time. Try again.
May 24 1994 10:49:33:410AM	940524004	Gerry Tinios	Fizzle again. Drop the gas to 1.0e-5 and try again.(It was 1.2 before).
May 24 1994 11:05:15:510AM	940524005	Gerry Tinios	Fizzle. Try a Bz tweak for next shot: change EF4 current before commutation by -15 A to prevent the plasma from hittin the inner wall.
May 24 1994 11:16:49:750AM	940524006	Gerry Tinios	Less of a fizzle than the previous shot. Br tweak : change BR_0 programming by 0.5 mT for next shot.
May 24 1994 11:28:29:020AM	940524007	Gerry Tinios	Plasma up to 250 msec. Plasma current is not rising fast enough and we are loosing vertical control. Try the same shot again to get the expected fizzle over and done with.
May 24 1994 11:36:47:140AM	940524008	Gerry Tinios	Fizzle. For the next shot, decrease the IP feedback gain early so that OH2's do no saturate.
May 24 1994 01:04:22:530PM	940524009	Gerry Tinios	Fizzle. F13 (a partial loop) has been reported as not working since shot 7.
May 24 1994 01:19:16:680PM	940524010	Gerry Tinios	Fizzle. Replaced F13 in the predictors previously to this shot. The midplane flux is calculated now as a linear combination of f16,f29, and f14 instead of f12, f28 and f13. For next shot: change BR_0 back to -2 mT.
May 24 1994 02:06:30:690PM	940524011	Gerry Tinios	760 MA/400 msec plasma! It rests against the outboard limiter all the time and eventually flies upwards. Something seems to be wrong with the RCUR predictor. Draw RCUR 1cm further in, take the next shot and try to figure out what's wrong with RCUR.
May 24 1994 02:17:11:220PM	940524012	Gerry Tinios	A dud. Increase prefill to 1.2e-5 for next shot.
May 24 1994 02:26:16:910PM	940524013	Gerry Tinios	Feeble fizzle. Try again, no changes.
May 24 1994 02:52:04:000PM	940524014	Gerry Tinios	Fizzle. Drop the gas to 1.e-5. Increase EF4 current programming by 15 A.
May 24 1994 02:57:00:680PM	940524015	Gerry Tinios	500 msec plasma. Still rests against outer limiter. When RCUR was changed previously, it was changed in the wrong direction. RCUR was changed by 2cm inwards for the next shot.
May 24 1994 03:07:12:130PM	940524016	Gerry Tinios	Fizzle. Try it again. Also introduce a sqaure wave perturbation in ZCUR between 450 and 500 msec.
May 24 1994 03:23:37:570PM	940524017	Gerry Tinios	440 msec plasma. We never get to the ZCUR step. The plasma dies downwards. It still rests against the outer limiter for tmost of the shot. For the next shot, move RCUR another cm in.
May 24 1994 03:36:22:270PM	940524018	Gerry Tinios	Dud. Bz tweak: change EF4 programming by -15A
May 24 1994 03:49:05:800PM	940524019	Gerry Tinios	Fizzle. Set gas at 9.e-6 for next shot.
May 24 1994 04:04:53:380PM	940524020	Gerry Tinios	Sparkly plasma. Disrupts downwards before the programmed vertical step. For next shot: Raise the gas to 1.1e-5 Move step in ZCUR to 0.4 sec Move gain step in Ip wire from 250 to 350 msec.
May 24 1994 04:24:53:320PM	940524021	Gerry Tinios	400 msec plasma. Dies before ZCUR step. There is loss of vertical control at 340 msec. It has a huge Z-excursion down and then dies upwards. For next shot, reduce RXL gain.
May 24 1994 04:36:05:470PM	940524022	Gerry Tinios	Fizzle. For the next shot, change offsets of wires 2,3 to 0. It was observed that the plasma is riding at -2cm when ZCUR was drawn at -1cm.
May 24 1994 04:37:29:830PM	940524022	Gerry Tinios	Fizzle. For the next shot, change offsets of wires 2,3 to 0. It was observed that the plasma is riding at -2cm when ZCUR was drawn at -1cm.
May 24 1994 04:48:51:190PM	940524023	Gerry Tinios	Plasma, 400 msec. Dies down. Integral gain in wire 2 was turned off (inadvertently) after shot 16 without disabling the integarator (integrator drift effect). For next shot set integrator gain to 5.
May 24 1994 05:01:30:420PM	940524024	Gerry Tinios	Short plasma. Put 10000 offsets back into wires 2,3 for the next shot.
May 24 1994 05:40:05:370PM	940524025	Gerry Tinios	470 msec plasma. Made it to the step in ZCUR, although one cannot really see it.

Physics Operator Comments

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:43:41:280AM	Plasma	Bad	no oh2's
2	10:05:51:730AM	Test	Ok	oh2 plc shot -- ok
3	10:27:34:500AM	Plasma	Ok	no faults
4	10:38:39:670AM	Plasma	Ok	no faults
5	10:51:08:250AM	Plasma	Ok	no faults
6	11:03:32:710AM	Plasma	Ok	no faults
7	11:15:28:780AM	Plasma	Ok	no faults
8	11:27:22:020AM	Plasma	Ok	no faults
9	11:39:47:000AM	Plasma	Ok	no faults
10	12:56:40:240PM	Plasma	Ok	no faults
11	01:14:49:290PM	Plasma	Ok	800 kA disruption at .42 sec
12	02:07:36:690PM	Plasma	Ok	dud no faults
13	02:17:53:950PM	Plasma	Ok	Fizzle again
14	02:28:28:910PM	Plasma	Ok	Fizzle..........................
15	02:40:00:530PM	Plasma	Ok	Another 800 kA disruption
16	02:55:49:340PM	Plasma	Ok	fizzle again
17	03:08:17:950PM	Plasma	Ok	yet another 800 kA disruption
18	03:25:02:540PM	Plasma	Ok	Fizzle
19	03:36:42:990PM	Plasma	Ok	Fizzle
20	03:50:06:640PM	Plasma	Ok	800 kA disruption at 0.4 sec
21	04:05:19:900PM	Plasma	Ok	Another 800 kA disruption at 0.4 sec
22	04:22:55:140PM	Plasma	Ok	fizzle
23	04:36:58:120PM	Plasma	Ok	800 kA disruption at 0.4 seconds
24	04:47:07:610PM	Plasma	Ok	400 kA disruption at 0.2 sec. At least it's different!
25	04:59:09:120PM	Plasma	Ok	800 kA disruption at 0.45 second