Miniproposals

Miniproposal: 170a Date Filed: 5/13/1997 Title: Restart Operation: May 1997 First Author: Robert Granetz Session Leader: Unknown (shots 1-51)

Engineering Operator Run Comment

Start Up/Hutch/Bertolino,Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Entered: Jul 7 2004 04:36:57:270PM

Author: To Be Determined

Physop summary 970521 _____________________ MP 170A Restart. Summary. ________ Today we used a magnetics program that gives a nice looking null and has a field index under reasonable control. It is intended to have a slower field ramp at the breakdown time. Experimentally, it was found not to give reliable breakdown at lower pressures but tolerable at high pressure. 11 plasmas were obtained, 10 of which were decent. 2 plasmas were with the x-point laser firing. 6 fizzles were with the x-point laser firing. 0 duds were with the x-point laser firing. Things learnt today. ____________________ 1. We confirmed that the X-point laser is an excellent preionizer. It essentially guaranteed an early breakdown, around 3-4ms. This is an indisputable demonstration that we can substantially avoid the dudding problems with additional preionization. It is a high priority to install a reliable preionization. It may be that the filling of the ports with various diagnostics has reduced the effectiveness of filaments to the point where they are inadequate. 2. Preionization is not everything. If you have a startup tuned for a later breakdown, then the earlier breakdown with laser preionization can lead to a fizzle. 3. One can get plasmas at up to at least 33ms of fill puff. Breakdown is somewhat more reliable/earlier at higher fill, at least with today's magnetic programming, but by no means perfect. 4. Rcur offset is perhaps the best knob for adjusting the Bz ramp rate. Changes of 1000 are BIG. 200 is noticeable. The end point was 6700, which is more tolerant of a slow current rise than 7000. It might be worth trying this with a magnetics configuration that gives easier breakdown. 5. Machine is still dirty. CII of order .01. There is no obvious difference after last night's low current glow. But once we have plasmas they mostly OK. Probably the limiting factor now is getting a reliable breakdown. 6. The B_z is not reliable at the 2 mT level, shot to shot. In level and time evolution are observed and appear to alter the breakdown time significantly. Scorecard _________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.016 2 1.371 0.802 3 0.000 0.019 4 1.401 0.802 5 0.000 0.024 6 0.000 0.016 7 1.403 0.802 8 0.000 0.027 9 0.000 0.016 10 1.398 0.802 11 0.000 0.019 12 0.000 0.027 13 1.497 0.802 14 0.000 0.024 15 1.512 0.802 16 0.000 0.027 17 0.000 0.032 18 0.000 0.005 19 0.000 0.005 20 0.000 0.027 21 0.000 0.024 22 0.793 0.776 23 0.000 0.024 24 0.000 0.027 25 0.000 0.024 26 0.000 0.016 27 0.000 0.016 28 0.000 0.027 29 0.000 0.027 30 0.000 0.037 31 0.000 0.019 32 0.000 0.027 33 0.000 0.037 34 0.000 0.047 35 0.000 0.016 36 1.545 0.802 37 0.000 0.024 38 0.000 0.024 39 1.469 0.802 40 0.000 0.021 41 0.000 0.016 42 0.000 0.024 43 0.000 0.016 44 1.637 0.802 45 0.000 0.027 46 0.000 0.024 47 0.000 0.024 48 0.000 0.016 49 0.000 0.027 50 1.625 0.802 Finished summary for 970521 Total of 50 shots. 50 shots. 11 plasmas. 25 fizzles. 14 duds. Fizzle = gt 20 lt 50kA.

Session Leader Comments

Physics Operator Comments
May 21 1997 08:35:10:040AM		Ian Hutchinson	Overnight low current glow in D_2. Load from shot 970520031. Set fill pulse to 20ms. Plan. Try to improve the reliability in respect of breakdown. By investigating different nulls with somewhat higher fill pressure. See what the overnight low currect glow has done. Worry about teflon puffs.
May 21 1997 08:43:06:140AM	970521001	Ian Hutchinson	Dud. Null is ghastly but apparently not much worse than yesterday. Fill reads .053. X-point laser was not firing. Load segment 1 from 970516041. Fill puff to 20ms.
May 21 1997 08:53:19:370AM	970521002	Ian Hutchinson	Plasma. Laser was firing.CII .014, Breakdown at 3ms! Current hesitates. Goes to 1.37 seconds. No changes.
May 21 1997 09:09:55:360AM	970521003	Ian Hutchinson	Fizzle. No laser. Fill =0.057. Breakdown at 6ms. CII=.015. Bz is a bit more negative. EF4s are -1323,-1390. On 2 they were -1315,-1384. Perhaps 5A difference. No changes.
May 21 1997 09:21:19:610AM	970521004	Ian Hutchinson	Plasma. X-point laser on. Breakdown at 3ms. Bz more like shot 2.CII .011. Fill .055. No changes
May 21 1997 09:30:12:900AM	970521005	Ian Hutchinson	Fiz. Laser on. Breakdown at .35s. CII .011. No obvious null changes. No changes. Asked for laser off.
May 21 1997 09:38:04:430AM	970521006	Ian Hutchinson	Dud without laser. Nothing else looks bad. No Changes, Ask for laser.
May 21 1997 09:47:42:190AM	970521007	Ian Hutchinson	Plasma. Breakdown at 3.5 ms. CII=.011.
May 21 1997 09:58:28:620AM	970521008	Ian Hutchinson	Fiz. With laser. Early breakdown. Called the Rcur algorithm in segment 2. Trying to understand the plasma moving in too fast at the ramp-down. Did not load.
May 21 1997 10:05:22:760AM	970521009	Ian Hutchinson	Dud. No laser. Changed RCUR offset in seg 2 during ramp-down.
May 21 1997 10:16:44:930AM	970521010	Ian Hutchinson	Plasma. No laser. Breakdown at 9ms. Minimal hesitation. CII=.009 The offset switch is rather obvious. Adjusted the rcur offset switch.
May 21 1997 10:22:21:580AM	970521011	Ian Hutchinson	Dud no laser. Fill puff to 25ms.
May 21 1997 10:46:20:130AM	970521012	Ian Hutchinson	Fiz. Breakdown at 10ms. EF4 to -1355 from -1360.
May 21 1997 10:53:59:060AM	970521013	Ian Hutchinson	Plasma. No laser. Breakdown at 0.072. Ramp down to 1.5s. EF4 to -1350. Enable Argon gas puff.
May 21 1997 10:59:56:060AM	970521014	Ian Hutchinson	Fiz. Laser on. Breakdown at .37s but CII rose very slowly. Laser off. No changes.
May 21 1997 11:12:21:290AM	970521014	Ian Hutchinson	Plasma. Nolaser. Breakdown at 6.5ms. CII=.007. Rcur vanishes. EF4 to -1345.
May 21 1997 11:21:35:540AM	970521016	Ian Hutchinson	Fiz. Laser fires. Breakdown at 4.2ms. CII=.01 Add Ar puff from 1.2 to 1.3 s.
May 21 1997 11:27:13:280AM	970521017	Ian Hutchinson	Fiz. Laser fires. Bkdwn at 4ms. CII .01 Laser off.
May 21 1997 11:29:19:290AM	970521018	Ian Hutchinson	Magnet resistance fault. RXL at 1.2 sec to .003 from .005, a small ramp to help with the x-point control.
May 21 1997 12:07:37:250PM	970521019	Ian Hutchinson	Dud. Magnetics errors. Coil currents screwed up. Giant OH2 imbalance. Granetz had changed the magnetics tree. It seems the integrators were not triggered. But wee need to be sure.Clearly the hybrid thinks the Br is wrong and is working to fix it. Got the magnetics switched back.
May 21 1997 12:18:54:770PM	970521020	Ian Hutchinson	Fiz. Laser fires after the breakdown.. Seems to show that it was the magnetics. Add a point on the EF3 trace at 12ms at 200V, to decrease the rapid upswing at about 15ms.
May 21 1997 12:25:19:960PM	970521021	Ian Hutchinson	Fiz. Breakdown at 10ms. Bz may have got a bit too positive. Fill to 30 ms.
May 21 1997 12:36:04:880PM	970521022	Ian Hutchinson	Plasma. Very resitive. Density rises to 2e20 and disrupts at .79s. Not clear why. CII.007. Camac errors on traq3.Breakdown at 7ms. Repeat.
May 21 1997 12:45:15:070PM	970521023	Ian Hutchinson	Fiz. Breakdown at 6ms. CII=.012. Bz seemd to drop a tad. Repeat.
May 21 1997 12:53:47:480PM	970521024	Ian Hutchinson	Fiz. 6ms. Bz stayed down. Fill puff to 27ms.
May 21 1997 01:02:26:870PM	970521025	Ian Hutchinson	Fiz. Late breakdown. At 11ms. Bz slightly higher. EF4 to -1350.
May 21 1997 01:08:21:140PM	970521026	Ian Hutchinson	Dud, Magnetics looks ok. Fill puff to 32ms.
May 21 1997 01:16:52:970PM	970521027	Ian Hutchinson	Dud, OOps Made a mistake. Put in 21ms. Got about .06mtorr. Fill to 31ms.
May 21 1997 01:24:03:120PM	970521027	Ian Hutchinson	Fiz. Bdown at 9.2 ms. CII=.01. EF4 to -1345.
May 21 1997 01:31:09:910PM	970521029	Ian Hutchinson	Fiz. Very late breakdown. 12 ms. Rcur offset to 8000 from 7000 in segment 1.
May 21 1997 01:44:58:410PM	970521029	Ian Hutchinson	Fiz. 6ms bdown. Crunched on the inner wall by rapid Bz rise. I forgot the negative current sign. Bz offset to 6000.
May 21 1997 01:51:42:280PM	970521031	Ian Hutchinson	Dud. Got a significnatly lower Bz during 0-6ms, by ~2mT. Seemed to be the problem. Repeat
May 21 1997 02:02:10:380PM	970521032	Ian Hutchinson	Fiz. Breakdown at 11ms. CII .08. Ask for laser early.
May 21 1997 02:24:26:440PM	970521033	Ian Hutchinson	Fiz. Laser did NOT fire. Bdwn at 8.4ms. Got 44KA and then crashed. CII-.08.Looks as if 6000 is a bit too far on Rcur. Rcur offset to 6500.
May 21 1997 02:44:24:160PM	970521034	Ian Hutchinson	Fiz. Breakdown at 4.5ms. Got to 50kA. Then lost. Looks as if it may have gone vertically. OH2s are tending to go back negative at about 15 ms. Changed OH2V to -10 from -20V at 10ms.
May 21 1997 02:49:15:990PM	970521035	Ian Hutchinson	Dud. No laser. Repeat.
May 21 1997 02:58:38:640PM	970521036	Ian Hutchinson	Plasma. Runs to 1.5s.. Breakdown at 6ms. Substantial hesitation, but rcur tracks well. CII .011. No laser. Pump out Ar plenum. Add pulse 1.2 to 2.2s ****Warning. Don't do this at home.********
May 21 1997 03:06:33:950PM	970521036	Ian Hutchinson	Fiz. Laser fires. Breakdown at 4.5ms. Teflon puff 1e-6 on ratiomatic. Fizzle detector was at 1.7s sec so we only got 1/2 s on the Ar valve. OH2V to 0V at 10ms.
May 21 1997 03:18:08:280PM	970521038	Ian Hutchinson	Fiz. No laser. Bkdwn at 6ms. CII =.012 Looks as if we have slightly too little Bz. Rcur offset to 6700.
May 21 1997 03:26:44:280PM	970521039	Ian Hutchinson	Plasma. Took till 25ms for the current to take off. However, this may be a good Rcur setting. CII=.01.Breakdown at 5.5ms. No laser. Ar pulse was disabled by engineering. Got to 1.46s. Repeat.
May 21 1997 03:34:27:480PM	970521040	Ian Hutchinson	Fiz.Breakdown at 13ms. Fill puff to 29ms.
May 21 1997 03:43:12:230PM	970521041	Ian Hutchinson	Dud. Bz drifting down.. Fill back to 31ms. EF4 to -1340. from -1345.
May 21 1997 03:52:19:920PM	970521042	Ian Hutchinson	Fiz. Breakdown at 20ms.! Fill puff to 21ms.
May 21 1997 03:59:51:590PM	970521043	Ian Hutchinson	Dud. Fill puff to 33ms.
May 21 1997 04:10:12:760PM	970521044	Ian Hutchinson	Plasma. Breakdown at 7ms. CII=.01. Pause till take-off. Br slightly negative. Ramp down to 1.64s. Repeat.
May 21 1997 04:31:37:880PM	970521045	Ian Hutchinson	Fiz. CII-.012. Breakdown at 5.5ms. Bz lower initially. The Bz bounces around from shot to shot by 2 mT or so. This may be a partial cause of irreproducible breakdown. Br offset to .0055 from .005.
May 21 1997 04:40:40:770PM	970521046	Ian Hutchinson	Fiz. After a long wait for IGOR. Late Breakdwon at 12ms. Repeat.
May 21 1997 04:48:23:440PM	970521047	Ian Hutchinson	Fiz late breakdown. Br offset back to .005T
May 21 1997 04:54:29:240PM	970521048	Ian Hutchinson	Dud. Repeat
May 21 1997 04:59:30:270PM	970521049	Ian Hutchinson	Fiz. Breakdown at 5.7ms.CII=0.011. Repeat.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:33:27:450AM	Plasma	Ok	First shot 08:32
2	08:44:19:220AM	Plasma	Ok
3	08:54:06:050AM	Plasma	Ok
4	09:06:44:260AM	Plasma	Ok
5	09:21:01:040AM	Plasma	Ok
6	09:28:41:460AM	Plasma	Ok
7	09:35:00:130AM	Plasma	Ok
8	09:46:15:700AM	Plasma	Ok
9	09:56:10:650AM	Plasma	Ok
10	10:03:28:900AM	Plasma	Ok
11	10:15:01:430AM	Plasma	Ok
12	10:21:42:240AM	Plasma	Ok
13	10:39:56:470AM	Plasma	Ok
14	10:52:52:210AM	Plasma	Ok
15	11:00:33:450AM	Plasma	Ok
16	11:10:51:640AM	Plasma	Ok
17	11:20:07:080AM	Plasma	Ok
18	11:27:36:310AM	Plasma	Bad	mag resist fault
19	11:33:38:960AM	Plasma	Ok
20	12:06:59:140PM	Plasma	Ok
21	12:17:23:210PM	Plasma	Ok
22	12:23:52:560PM	Plasma	Ok
23	12:34:48:420PM	Plasma	Ok
24	12:43:30:190PM	Plasma	Ok
25	12:51:18:840PM	Plasma	Ok
26	01:00:41:040PM	Plasma	Ok
27	01:06:44:450PM	Plasma	Ok
28	01:15:22:290PM	Plasma	Ok
29	01:22:31:370PM	Plasma	Ok
30	01:34:58:500PM	Plasma	Ok
31	01:43:20:120PM	Plasma	Ok
32	01:50:20:590PM	Plasma	Ok
33	02:00:40:370PM	Plasma	Ok
34	02:22:40:500PM	Plasma	Ok
35	02:41:07:750PM	Plasma	Ok
36	02:47:32:180PM	Plasma	Ok
37	02:59:23:600PM	Plasma	Ok
38	03:07:33:260PM	Plasma	Ok
39	03:16:42:910PM	Plasma	Ok
40	03:25:25:760PM	Plasma	Ok
41	03:32:41:690PM	Plasma	Ok
42	03:41:28:990PM	Plasma	Ok
43	03:50:01:280PM	Plasma	Ok
44	03:58:13:120PM	Plasma	Ok
45	04:08:39:750PM	Plasma	Ok
46	04:30:16:950PM	Plasma	Ok
47	04:39:18:090PM	Plasma	Ok
48	04:46:41:370PM	Plasma	Ok
49	04:52:58:720PM	Plasma	Ok
50	04:59:07:360PM	Plasma	Ok
51	05:11:29:900PM	Test	Bad