Miniproposals

Miniproposal: 048 Date Filed: 4/8/1994 Title: HIREX Troubleshooting First Author: John Rice Session Leader: Steve Golovato (shots 1-22)

Miniproposal: 052 Date Filed: 4/12/1994 Title: ICRF Antenna Tuning (P First Author: Yuichi Takase Session Leader: Steve Golovato (shots 1-22)

Engineering Operator Run Comment

icrf tunning, HIREX trobleshoot

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:10:400PM

Author: To Be Determined

Session Leader Summary - 940526 --------------------------------- SL - Golovato PO - Snipes EO - Silva and Daigle Starting with shot 940525031, last good shot of last run. See the logbook under session_leader for shot-by-shot comments. After a frustrating start, this turned out to be an excellent run, probably the best so far this year. We may have found an important problem that led to a lot of the shot-to-shot irreproducibility in breakdown and current ramp. The power supply for the isolation amps for the magnetics signals going to the hybrid may have been flaky, leading to large and varying offsets in the magnetics signals. The fix today was jiggling the wires, we probably should find a clearer identification of the problem and a more robust solution, We eventually made full pulse length plasmas at 600 ka and applied over 1 MW of rf power. There is clear evidence of heating on ece Te ( several hundred eV) and the EFIT stored energy (up to 10 kJ). The power appears limited to about 1 MW at 10 Ohms loading. We get this loading with the plasma on or close to the outer limiter. Moving it in (on the last shot) reduces loading. We need additional conditioning (vacuum and plasma) to get the power up, but this is a great start for only two erratic runs. We got long (in time) plasmas by reducing elongation later in the shot and releasing it from the lower divertor (leaving off feedback on clearin, zxl, and rxl, as was done yesterday), making the coil currents symmetric up-down, and centering zcur. For deltails see the physics operator summary. The run was interrupted for an hour by a computer network crash and a half hour to check (fix) the isolation amp power supply. There appeared to be a problem with injecting argon. Four shots were affected, with the symptom being a slow (not disruptive) decrease in current, killing off the shot (#s 12, 13, 19, 21). On shots 18 and 20, lower argon didn't kill shot but Rice couldn't see it. On the last shot, there was a scandium injection at 750ms. Shot Accounting: Fizzles - 8 Plasmas - 13 (3 very short, 4 argon spoiled, 6 good) Test - 1 (of data system to get offsets)

Physics Operator Summaries

Entered: Jul 7 2004 04:36:51:600PM

Author: To Be Determined

From: BRIGHT::SNIPES Date: 26-MAY-1994 18:27:24 Description: Physics Operator Summary for 940526 This was an RF tuning run with backup HIREX troubleshooting. In the end, it was a successful run, though plagued with problems early. We started by copying shot 940525031 and got 4 fizzles in a row. Then, the computers crashed and held us up for about an hour to reboot. Shots 5-7 had short plasmas with disruptions during the current rise. Shot 8 fizzled. Shot 9 had again a short plasma. Then, it was noticed that the hybrid offsets were changing shot to shot indicating an intermittent problem in the hybrid. So, we opened the cell to investigate and after wiggling some wires, the hybrid power supply voltages steadied. Shot 10 was a test shot for checking the hybrid offsets. Shot 11 fizzled again. Shots 12-13 had short plasmas and 14 fizzled again. Finally, shot 15 looked pretty good with 600 kA lasting up to almost 600 ms, then disrupting. Shot 16 then fizzled after the big disruption. Shots 17 - 18 looked good, then increasing the Ar puff, led to an early disruption on shot 19. Shot 20 was then good with less Ar. Shot 21 disrupted early with increased Ar. Finally, shot 22 was the best shot of the day with little Ar lasting until the fizzle detector knocked it down at 100 kA. The last few good shots had relatively high RF power up to about 1 MW modulated to look for changes. Electron heating was observed together with increases in the stored energy. The power supplies worked very well! Scorecard 8 fizzles 8 short plasmas 5 good plasmas 1 test shot

Session Leader Comments
May 26 1994 09:06:14:490AM		Steve Golovato	staring with shot 31 from yesterday. goal for today is good reproducible plasmas matched well to antenna so we can continue raising power. limited, not so elongated plasmas are ok, we'd like to avoid the strong disruptions that contribute to irreproducibility. we had hints of heating yesterday and we'd really like to get enough power to make it clear.
May 26 1994 06:04:13:020PM		Steve Golovato	Session Leader Summary - 940526 --------------------------------- SL - Golovato PO - Snipes EO - Silva and Daigle Starting with shot 940525031, last good shot of last run. See the logbook under session_leader for shot-by-shot comments. After a frustrating start, this turned out to be an excellent run, probably the best so far this year. We may have found an important problem that led to a lot of the shot-to-shot irreproducibility in breakdown and current ramp. The power supply for the isolation amps for the magnetics signals going to the hybrid may have been flaky, leading to large and varying offsets in the magnetics signals. The fix today was jiggling the wires, we probably should find a clearer identification of the problem and a more robust solution, We eventually made full pulse length plasmas at 600 ka and applied over 1 MW of rf power. There is clear evidence of heating on ece Te ( several hundred eV) and the EFIT stored energy (up to 10 kJ). The power appears limited to about 1 MW at 10 Ohms loading. We get this loading with the plasma on or close to the outer limiter. Moving it in (on the last shot) reduces loading. We need additional conditioning (vacuum and plasma) to get the power up, but this is a great start for only two erratic runs. We got long (in time) plasmas by reducing elongation later in the shot and releasing it from the lower divertor (leaving off feedback on clearin, zxl, and rxl, as was done yesterday), makin
May 26 1994 09:09:35:480AM	940526001	Steve Golovato	940526001 shot 31 from yesterday fizzle.
May 26 1994 09:40:32:880AM	940526002	Steve Golovato	940526002 fizzled, but better according to wolfe.
May 26 1994 09:53:16:590AM	940526003	Steve Golovato	940526003 fizzled.
May 26 1994 10:01:05:410AM	940526004	Steve Golovato	940526004 fizzles again.
May 26 1994 11:58:05:110AM	940526005	Steve Golovato	940526005 after about an hour delay as computers crashed. got a plasma, 200ka, 130ms, pretty ragged.
May 26 1994 12:09:40:860PM	940526006	Steve Golovato	940526006 plasma again, 200ka,200ms. getting earlier breakdowns, 6ms, but moved bz ramp earlier to get current to ramp. current ramps faster at first until contacts outer limiter, knocking off crud. we're trying to keep plasma off outer limiter.
May 26 1994 12:30:10:760PM	940526007	Steve Golovato	940526007 plasma, 600ka, 400ms. plasma jumping between diverted and limited, inner and outer limiters, elongated, not so elongated.
May 26 1994 12:45:43:350PM	940526008	Steve Golovato	940526008 fizzle. br looks low.
May 26 1994 01:53:01:270PM	940526009	Steve Golovato	940526009 150ka, 140ms, pretty ragged.
May 26 1994 01:57:27:230PM	940526010	Steve Golovato	940526010 test shot to check offsets. it is thought that the power supply to the isoamps for the magnetics is going. no plasma, no power supplies. there was also a delay to enter the cell and check the supply which was not obviously broken. test shows offsets to now be zero.
May 26 1994 02:23:13:780PM	940526011	Steve Golovato	940526011 the offsets in pcs may not be right now that the isoamp supply has been "fixed", that is, they wiggled the leads and the outputs changed to something more reasonable. this power supply may have been flaky for a while and a source of the chronic irreproducibility we've been experiencing. fizzle. br now a little high, offset needs changing.
May 26 1994 02:33:11:700PM	940526012	Steve Golovato	940526012 plasma, 300ka, 180ms. moved in and died.
May 26 1994 02:47:59:050PM	940526013	Steve Golovato	940526013 much like last shot.
May 26 1994 03:02:55:430PM	940526014	Steve Golovato	940526014 fizzle, though everything looks the same.
May 26 1994 03:17:31:430PM	940526015	Steve Golovato	940526015 first good shot in a long time. 600ka, 600ms. adjust ef1 and ef2 to avoid elongation after 450ms.
May 26 1994 03:28:14:190PM	940526016	Steve Golovato	940526016 (ignor fizzle comment in entry for previous shot, it belonged here) fizzle after disruption.
May 26 1994 03:44:26:990PM	940526017	Steve Golovato	940526017 good shot, made it into rampdown. 600ka, 800ms. Prf=1.1MW, plasma diveted after 600ms, 10 Ohms loading. definite electron heating, 10kJ stored energy increase.
May 26 1994 03:59:40:820PM	940526018	Steve Golovato	940526018 another good one, 600ka, 900ms.
May 26 1994 04:16:29:620PM	940526019	Steve Golovato	940526019 reduce gas after 400 ms to maintain constant density. lost early, looks like the argon may be the problem, which was back on at full force.
May 26 1994 04:31:31:500PM	940526020	Steve Golovato	940526020 another 900ms shot, 1MW rf. argon puff moved later, doesn't affect plasma.
May 26 1994 04:53:07:050PM	940526021	Steve Golovato	940526021 move plasma in a little after 500ms, see if it reduces rf arcing late in shot with plasma on outer limiter. problem may be argon again, it was increased for this shot. starts down about 430ms, out at 490ms.
May 26 1994 05:10:50:880PM	940526022	Steve Golovato	940526022 lowered argon to level where it didn't affect shot. unfortunately, this level also may not be enough to open valve. full length shot, fizzle detector turned it off at 1 sec when it went below 100ka. clear heating on ece and W_efit. plasma moved off outer limiter after 500 ms as programmed, limiter on inside.

Physics Operator Comments
May 26 1994 09:39:31:610AM	940526001	Joseph Snipes	Copied shot 940525031 with Ar programming from 940525032. Fizzle!
May 26 1994 09:44:37:390AM	940526001	Joseph Snipes	Shot 1 Fill pressure set to 1.2 x 10**-5 torr.
May 26 1994 09:40:22:350AM	940526002	Joseph Snipes	One more time! Fizzle!
May 26 1994 09:43:39:410AM	940526003	Joseph Snipes	Shot 3 Added 0.5 mT to Br to try to get better breakdown. Also made EF1 upper and lower waveforms equal to the EF1U waveform after 0.18 sec to -500 A. Fizzle!
May 26 1994 09:56:05:850AM	940526004	Joseph Snipes	Shot 4 Fill pressure set to 1.1 x 10**-5 torr. Fizzle!
May 26 1994 11:28:47:260AM	940526004	Joseph Snipes	Long delay due to computer crash on the LEADER segment.
May 26 1994 11:53:19:870AM	940526005	Joseph Snipes	Shot 5 Increased EF4U by 33 A to -995 A before breakdown to increase Bz by about 2 mT. Got plasma!
May 26 1994 12:01:06:670PM	940526006	Joseph Snipes	Shot 6 Ramping in the radial position somewhat faster early. Also increased EF1U and EF1L to -688 A during flattop. Now got 200 ms of plasma. Slowly improving.
May 26 1994 12:28:09:270PM	940526007	Joseph Snipes	Shot 7 Zeroed the Z position. Better 400 ms.
May 26 1994 12:34:30:240PM	940526008	Joseph Snipes	Shot 8 Reduced EF2U and L after about 0.1 sec during the flattop to try to reduce the elongation. Fizzle!
May 26 1994 01:47:35:390PM	940526009	Joseph Snipes	Shot 9 Increased Br offset to -1.5 mT. Trying again. Short plasma.
May 26 1994 01:48:57:370PM	940526009	Joseph Snipes	Long delay due to intermittent power supply in the Hybrid control system. After checking it in the cell, it seems sometimes o.k. So, we will try to run with it while Parkin looks for a new power supply.
May 26 1994 02:15:56:170PM	940526010	Joseph Snipes	Test shot of data acquisition for checking hybrid offsets.
May 26 1994 02:16:30:590PM	940526011	Joseph Snipes	Try again. Fizzle!
May 26 1994 02:37:54:910PM	940526012	Joseph Snipes	Shot 12 Lowered Br by another mT to -2.5 mT, since the hybrid now reads a different offset. Good current rise, then went bad after 100 ms.
May 26 1994 02:43:21:820PM	940526013	Joseph Snipes	Shot 13 Changed RCUR programming from 0.65 m to 0.67 m and changed the ramp inward to go more gradually inward during the current rise. Short plasma.
May 26 1994 02:50:58:800PM	940526014	Joseph Snipes	Shot 14 Turned off Ar puff that had been on since shot 12. Try again.
May 26 1994 03:02:29:400PM	940526014	Joseph Snipes	Shot 14 fizzle!
May 26 1994 03:05:38:850PM	940526014	Joseph Snipes	Shot 15 Try lowering Br by yet another 0.5 mT to -3.0 mT. Plasma!
May 26 1994 03:11:51:490PM	940526014	Joseph Snipes	Shot 15 Try lowering Br by yet another 0.5 mT to -3.0 mT. Plasma! Last almost 600 ms and reached 600 kA.
May 26 1994 03:26:55:800PM	940526016	Joseph Snipes	Shot 16 Lowered EF1U and L and EF2U and L after about 200 ms to reduce the elongation during the current flattop. Fizzle!
May 26 1994 03:36:59:850PM	940526017	Joseph Snipes	Shot 17 One more time . . . Good plasma!
May 26 1994 04:00:02:550PM	940526018	Joseph Snipes	Shot 18 Set EF1U and L controllers to zero after 0.6 sec in the Ip controller. Ramped EF4U down to zero between 0.5 sec and 1 sec. Good plasma!
May 26 1994 04:09:45:760PM	940526019	Joseph Snipes	Shot 19 Decreased H gas after 0.4 sec. Increased Ar puff back to previous levels. Disrupted at 140 ms. Perhaps due to the Ar.
May 26 1994 04:24:45:010PM	940526020	Joseph Snipes	Shot 20 Decreased Ar puff from 100 V to 80 V and moved it from 100 ms to after 300 ms. Good plasma!
May 26 1994 04:49:28:410PM	940526021	Joseph Snipes	Shot 21 Increased Ar puff from 80 V to 90 V. Reduced gain on OH2U and L in the Ip controller by a factor of 2. Moved RCUR from 0.5 to 0.8 sec in to 0.665 m. Disrupted early!
May 26 1994 05:11:18:230PM	940526021	Joseph Snipes	Shot 22 Decreased Ar puff from 90 V to 84 V. Sc injection at 0.75 s. Very good plasma ramped down until 100 kA when it was knocked down by the fizzle detector. Sc injection was observed. RF results were good.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:54:33:910AM	Plasma	Ok	good start 08:59
2	09:25:49:420AM	Plasma	Ok	delay ef1l diagnose temp
3	09:41:37:480AM	Plasma	Ok
4	09:53:10:920AM	Plasma	Ok	no problem
5	11:28:03:970AM	Plasma	Ok	190 ka
6	11:56:09:500AM	Plasma	Ok	plasma
7	12:13:25:630PM	Plasma	Ok	comm fail oh2l
8	12:30:29:520PM	Plasma	Ok	fizzel
9	12:43:37:230PM	Plasma	Ok	Plasma
10	01:52:55:360PM	Test	Ok	Power Supplies Dissabled
11	02:12:36:690PM	Plasma	Ok	Dud Power supplies O.K.
12	02:24:22:120PM	Plasma	Ok	good shot
13	02:39:28:320PM	Plasma	Ok	Short pulse no faults
14	02:50:35:630PM	Plasma	Ok	dud no faults
15	03:03:31:980PM	Plasma	Ok	Good shot No faults
16	03:20:24:840PM	Plasma	Bad	dud no faults
17	03:31:19:410PM	Plasma	Ok	good shot o.k.
18	03:49:49:560PM	Plasma	Ok	Good shot no faults
19	04:04:18:460PM	Plasma	Ok	fizzle no faults
20	04:17:12:100PM	Plasma	Ok	Good shot No faults
21	04:41:15:400PM	Plasma	Ok	Good No Faults
22	04:54:56:200PM	Plasma	Ok	good