Miniproposals

Miniproposal: Date Filed: Title: First Author: Session Leader: Martin Greenwald (shots 1-15)

Engineering Operator Run Comment

g granetz silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:09:087PM

Author: To Be Determined

Physics operator's summary for run 931012 Session leader: M. Greenwald Physics operator: R. Granetz Engineering leader: F. Silva The primary goal of today's run was to achieve plasma currents of 1.0 MA (actually -1.0 MA), and that was realized on shots #7,8,11, and 13. However, all of these shots ended in a major disruption. We also had a very nice 0.76 MA discharge (#5). A secondary goal of today's operation was to acquire more data for ohmic confinement, and this was achieved by virtue of the new current levels. However, this being a Tuesday run, we had our share of hardware problems, particularly with fuses and SCR's in OH1, and with a computer problem, resulting in some lengthy delays and only 15 shots. (But what counts is quality, not quantity!). One problem that we did NOT seem to have was getting a plasma. There were only two fizzles, and all shots broke down (other than a dud due to no EF3 on one shot). The run was preceeded with 1 hour of ECDC, and the first shot was copied from 931007024 last week. Working gas was deuterium. Shot Comments Changes for next shot 1 Ip=-0.62 MA, disrupted at 0.61 s. lowered pulse gas voltage (PGV) 2 Ip=-0.66 MA, duration=1.13 s, detaches Raise Ip to -0.75 MA at 0.7 s. Nice shot. 3 Runaway, high density. OH1 fuses and SCR's Tweak PGV initial blown. 2 hr 40 min downtime to repair supply. spike 4 Fizzle Tweak PGV initial spike 5 Ip=-0.76 MA (new record), duration=1.15 s, Raise Ip to -1.00 MA Very nice shot. OH1 blew more fuses. 6 No EF3, no breakdown 7 Ip=-1.0 MA (new record), major disruption at Raise PLC current t=0.94 s. Hit PLC limits on OH1, OH2's. limits on OH1, OH2's 8 Ip=-1.00 MA, major disruption at 0.90 s. Lots Engineers adjusted of molybdenum injections. Spectroscopic evidence OH2 circuitry of stainless steel contamination seen. 9 Short, disruptive 10 Short, disruptive Tweak PGV by 2 to 4v 11 Ip=-1.0 MA, major disruption at 0.59 s. Large Tweak PGV initial impurity injection at 0.35 s spike 12 Computer problems cause 1 hr delay. Short, disruptive 13 Ip=-1.0 MA, major disruption at 0.75 s. Tweak PGV 14 Short, disruptive Tweak PGV 15 Fizzle.

Physics Operator Summaries

Session Leader Comments
Oct 12 1993 09:01:16:250AM		Martin Greenwald	Run Plan - Start with shot 931007024 Ramp current to 1 MA, keep kappa safely below limit Look for scaling of confinement time.
Oct 12 1993 09:07:48:940AM	931012001	Martin Greenwald	Start with shot 931007024 breaks down, but disrupts at .62 sec
Oct 12 1993 09:31:37:310AM	931012002	Martin Greenwald	Lower gas slightly Good shot, Ip = .67 MA, shark fin at .7 sec nl goes almost to 1e20
Oct 12 1993 09:59:24:450AM	931012003	Martin Greenwald	Runaways early, disrupts at .28 sec
Oct 12 1993 12:30:47:220PM	931012004	Martin Greenwald	Repeat more or less after long delay to fix power supply problem fizzle
Oct 12 1993 01:28:28:870PM	931012005	Martin Greenwald	Very good shot Ip = .77 MA - new record!
Oct 12 1993 01:28:55:980PM	931012006	Martin Greenwald	Dud - no EF3
Oct 12 1993 02:00:31:580PM	931012007	Martin Greenwald	Reached .995 MA !!! disrupted at .93 sec, .83 MA in 2 msec probably due to a plc current limit
Oct 12 1993 02:56:32:930PM	931012008	Martin Greenwald	raise program Ip by 10-20 kA fix plc limit Reached 1.00 MA !!
Oct 12 1993 02:57:23:160PM	931012009	Martin Greenwald	Disrupts at .2 sec
Oct 12 1993 03:25:42:390PM	931012010	Martin Greenwald	Another early disruption
Oct 12 1993 03:26:09:130PM	931012011	Martin Greenwald	Reaches 1 MA but disrupts shortly thereafter.
Oct 12 1993 04:10:57:560PM	931012012	Martin Greenwald	Another early disruption.
Oct 12 1993 04:25:22:750PM	931012013	Martin Greenwald	Reaches 1 MA But disrupts at .75.
Oct 12 1993 04:45:20:100PM	931012014	Martin Greenwald	Disrupts early.
Oct 12 1993 04:55:04:350PM	931012015	Martin Greenwald	fizzle.

Physics Operator Comments
Oct 12 1993 09:18:41:650AM	931012001	Robert Granetz	Got a plasma, but it was ugly and disruptive due to too much gas. Ip=-0.62 MA, duration=0.61 s. No interferometer data on this shot. For the next shot, I lowered the pulse gas by about 6% (from 55 to 52 v for the initial spike, and from 49 to 46 from t=0.1 to 0.8 s.
Oct 12 1993 09:32:16:720AM	931012002	Robert Granetz	Reasonably good shot. Ip=-0.66 MA, duration=1.13 s. Disrupted halfway down the current rampdown. There may have been a change to a detached plasma at t=0.7 s, because the density begins rising suddenly there. The latter half of the shot has nl=1.0-0.8 e20.
Oct 12 1993 09:37:26:110AM	931012002	Robert Granetz	For the next shot, the only change is to increase the plasma current demand to -0.75 MA.
Oct 12 1993 09:53:48:110AM	931012003	Robert Granetz	Short, disruptive, runaway shot, but density rises quite fast. Ip reaches -0.54 MA before the major disruption at 0.27 s. No changes were made to anything before 0.3 s. There was a PF fault, after the disruption I think. OH1 lost two fuses.
Oct 12 1993 10:05:48:270AM	931012003	Robert Granetz	Tom Hsu opened the ECE gate valve during the CHECK state, which may not have given the gas pre-fill system enough time to settle down. However, the ratiomatic doesn't corroborate this. For the next shot, the only change is to increase the initial spike on the pulse gas programming from 52 to 55 v.
Oct 12 1993 12:25:15:980PM	931012004	Robert Granetz	Between this shot and the previous one there was an extended downtime in order to fix several blown fuses and SCR's in OH1.
Oct 12 1993 12:43:40:060PM	931012004	Robert Granetz	Fizzle. Protoplasma shoots outwards at t=0.019 s. For the next shot, just decrease the initial pulse gas spike from 55 to 53 v.
Oct 12 1993 01:39:23:390PM	931012005	Robert Granetz	Good shot. Ip=-0.76 MA, duration=1.15 s. Really nice. Blew a few more OH1 fuses though. This is a new record plasma current.
Oct 12 1993 01:40:25:750PM	931012005	Robert Granetz	No changes for the next shot.
Oct 12 1993 01:39:51:340PM	931012006	Robert Granetz	No EF3. No breakdown. No changes for next shot.
Oct 12 1993 02:02:26:340PM	931012007	Robert Granetz	Ip=1.0 MA ! (actually 0.995 MA). Shot ended with a vertical instability downward. dIp/dt=-(0.4 to 0.5) MA/ms. The current started drooping prior to the requested start of rampdown, because we hit the PLC limits for the OH1 and OH2's. That may also explain the problem with ZCUR control. For the next shot, the only change is to increase Ip from 1.00 to 1.01 MA.
Oct 12 1993 02:20:50:270PM	931012007	Robert Granetz	For the next shot, raise the PLC limits on the OH1 and OH2's to +20 kA.
Oct 12 1993 02:20:05:340PM	931012008	Robert Granetz	Ip=1.00 MA, but again ended in a major disruption, this time with dIp/dt=-0.4 MA/ms. There were lots of molybdenum injections on this shot. The ZCUR feedback doesn't seem to be working well.
Oct 12 1993 02:44:11:060PM	931012008	Robert Granetz	OH2L is not following the voltage demand from the hybrid. The engineers have adjusted something in the supply. No changes for the next shot.
Oct 12 1993 02:59:57:570PM	931012009	Robert Granetz	Ugly, short, disruptive. Shot ends at 0.21 s with a major disruption, when the current is still ramping up. Density ramp looks very similar to the previous two shots. No changes for the next shot.
Oct 12 1993 03:18:55:060PM	931012010	Robert Granetz	Ugly, short, disruptive. Slightly longer than the last shot though. Shot terminated during the current rampup. There were a lot of runaways on this one. For the next shot, raise the initial pulse gas spike from 52 to 54 v, and also from 46 to 50 v at 0.8 s.
Oct 12 1993 03:42:14:860PM	931012011	Robert Granetz	Another 1 MA, but it disrupted at t=0.59 s. The major disruption took nearly 3 msec. There was a large impurity injection at 0.35 s. I don't think this diruption was caused by a vertical control problem. For the next shot, increase the initial pulse gas spike from 55 to 57 v, and also add a second argon gas puff after the shot (at 1.2 s), for calibration purposes in preparation for the divertor argon gas puff run on Thursday.
Oct 12 1993 04:04:22:710PM	931012012	Robert Granetz	Prior to this shot there was a long pause due to computer problems.
Oct 12 1993 04:13:22:060PM	931012012	Robert Granetz	Ugly, short, disruptive. For the next shot, reduce the initial pulse gas spike from 57 to 55 volts.
Oct 12 1993 04:28:50:940PM	931012013	Robert Granetz	Better. Ip=-1.00 MA, duration=0.75 s. Terminated by a major disruption. The initial plasma was disruptive, and there were many impurity injections throughout the discharge. For the next shot, decrease the initial pulse gas spike from 55 to 54 volts, and increase the demand Ip from 1.01 to 1.02 MA (negative).
Oct 12 1993 04:50:13:390PM	931012014	Robert Granetz	Ugly, short, disruptive. For the next shot, reduce the pulse gas during the valley at about t=0.030 s to 35 volts.
Oct 12 1993 04:55:44:190PM	931012015	Robert Granetz	Fizzle.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:01:19:640AM	Plasma	Ok	run on time, plasma on first shot
2	09:21:33:860AM	Plasma	Ok	plasma comm fail
3	09:41:52:830AM	Plasma	Ok	comm fail
4	12:26:24:150PM	Plasma	Ok	ps,s ok
5	12:42:34:570PM	Plasma	Ok	fuses blown in oh1
6	01:25:08:760PM	Plasma	Bad	no ef3
7	01:41:57:550PM	Plasma	Ok	ps,s ok record plasma 995 ka
8	02:02:52:310PM	Plasma	Ok	ps,s ok no faults 1.04 ma
9	02:46:03:220PM	Plasma	Ok	margin angle change on oh2l ps,s ok no faults
10	03:01:14:530PM	Plasma	Ok	no countdown or pulse announce
11	03:21:19:820PM	Plasma	Ok	1.03 ma ps,s ok
12	04:00:13:640PM	Plasma	Ok	igor problem fixed ps,s ok
13	04:19:49:980PM	Plasma	Ok	ps,sok
14	04:35:43:710PM	Plasma	Ok	ps,s ok
15	04:52:46:380PM	Plasma	Ok	last shot fizzel?