| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | Yuichi Takase |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| Continuing to try to raise plasma current. Ian is driving the bus today. |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:07:257PM |
| Author: To Be Determined |
From: LEADER::HUTCH Date: 19-MAY-1993 17:38:29 Description: Summary of 19 May 93 Run Summary of 19 May 93 Run 29 Shots total. Approximately 13 had plasma current above 100kA. Strategy of reducing the voltages on OH1/2 EF1, which control the flux swing on the inboard side, combined with minimizing the EF3 current at breakdown was successful in giving plasma current rise. Shot 3, immediately after lowering the commutation resistors, had 150kA. Shot 5 had 300kA; however, it also gave a small bright afterglow spot on the outboard limiter. This was interpreted as a runaway electron effect. Thereafter, pulse gas was moved earlier, to 20ms or less, and no further bright heating spots were seen. During the morning, rather repeatable current rises were obtained, up to shot 11. (Shot 9 had very early gas pulse -- Oms -- and fizzled.) During the afternoon, with pulse gas at 10 ms, rather irreproducible current rises were obtained. Some of the familiar instability/phasing problems were observed on OH2. But it is not clear that they were the cause. Shots 24 on had a further reduction in OH2 commutation resistance and good looking current ramps on those shots that went (25,27,28). Suggested priorities for the rest of the week. 1. Get reproducible current rise. 2. Get radial position feedback going. 3. Bring up and debug diagnostics. 4. Flat-top the current at about 300kA for 0.1-0.2 s. 5. Move to the proportional internal regulator on OH2. 6. Clean up the plasma and try to avoid disruptions. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| May 19 1993 09:04:03:300AM | Yuichi Takase | Try to get the vertical field to rise faster so we don't lose equilibrium.
Ian has a few things to try: reduce the EF3 front porch to 0 delay EF3 turn on crowbar OH's at around 8msec lower commutation resistors invert EF2 harder start with the same settings as yesterday's shot 9. | |
| May 19 1993 09:06:28:410AM | 930519001 | Yuichi Takase | Shot 1
Same settings as yesterday's shot 9. 36kA @ 14ms. Bd at 9ms |
| May 19 1993 09:24:57:660AM | 930519002 | Yuichi Takase | Shot 2
Lowered EF3 front porch V to 0 (was -50 to -100) Delayed EF3 ramp start to 0 (was -2ms), ramp end at 2ms (unchanged) Lowered EF4 to 600A (was 663.55) Ip 20kA @ 11ms, ragged current rise. |
| May 19 1993 09:57:25:020AM | 930519003 | Yuichi Takase | Shot 3
Changed commutation resistors: from to OH1 156 100 mOhm OH2 47 32 EF1 253 180 150 kA !!!!! Bd at 4ms, 7V, -3mT Linear current rise (slower Ip rise, faster Bz rise). Bz wasn't on long enough. |
| May 19 1993 10:19:19:080AM | 930519004 | Yuichi Takase | shot 4
Extended EF3 to 50ms. Enabled hybrid gas control. 49kA @ 15ms, Bz=-10mT, Bd @ 4ms. |
| May 19 1993 10:28:38:320AM | 930519005 | Yuichi Takase | shot 5
Repeat. 300kA @ 60ms. Hot spot on the outboard limiter (looks like runaway e's), lasts for 20 frames (3sec) after the shot. |
| May 19 1993 10:46:07:840AM | 930519006 | Yuichi Takase | shot 6
Moved pulsed gas early to 20ms. 260kA No hot spot on the limiter. |
| May 19 1993 10:57:47:510AM | 930519007 | Yuichi Takase | shot 7
Moved pulsed gas earlier to 10ms, kept on till 100ms. Extended EF3 to 80ms, then slow ramp down. Similar to shot 6. |
| May 19 1993 11:19:24:300AM | 930519008 | Yuichi Takase | shot 8
Doubled pulsed gas height to 60V. Extended EF3 to 80ms, then slow ramp down. (not for last shot) Current rises till 100msec. 2 on 3 scale pressure excursion after shot. Sawteeth on soft X-rays. Event at 60msec (soft X-ray down, H_alpha up), maybe transition from diverted to limited plasma. Gas is showing up on H_alpha at about 20-30ms. |
| May 19 1993 11:26:29:710AM | 930519009 | Yuichi Takase | Shot 9
Moved pulsed gas. 60V (0-50ms), 30V (50-100ms). gas excursion to 1.5 on 3 after shot. dud (15kA). |
| May 19 1993 11:45:48:240AM | 930519009 | Yuichi Takase | Shot 10
Moved pulsed gas later by 5ms. 60V (5-55ms), 30V (55-105ms). 200kA, losing current after 90ms. |
| May 19 1993 11:49:13:650AM | 930519011 | Yuichi Takase | Shot 11
Moved pulsed gas later by 5ms. 60V (5-55ms), 0 after 55ms. OH2 crowbars fire at 50ms. Fizzled (20kA). |
| May 19 1993 12:59:13:130PM | 930519012 | Yuichi Takase | Shot 12
First shot after lunch break. Pulsed gas start moved back, 60V (10-55ms), 0 after 55ms. Fizzled (36kA). |
| May 19 1993 01:11:33:910PM | 930519013 | Yuichi Takase | Shot 13
Lowered fill pressure to 5.e-5 Torr (was 6). 80kA. |
| May 19 1993 01:40:03:730PM | 930519014 | Yuichi Takase | Shot 14
Lowered EF4 to 580A (was 600A). Good shot 290kA. Have TCI data, Luke and Irby don't agree on calibration. |
| May 19 1993 02:00:18:500PM | 930519015 | Yuichi Takase | Shot 15
Lowered EF4 to 560A. Bd @ 5.6ms (late). Disrupted during current rise @ 180kA. OH2 problem and vertical position. |
| May 19 1993 02:12:55:520PM | 930519016 | Yuichi Takase | Shot 16
Raised EF4 to 580A. Lowered gas to 50V. 40kA, horizontal field problem? |
| May 19 1993 02:26:40:930PM | 930519017 | Yuichi Takase | Shot 17
Started OH2 voltage down-ramp at 46ms (vs 48ms), reaches -100V at 50ms. 35kA, late break down (10ms). |
| May 19 1993 02:40:49:130PM | 930519018 | Yuichi Takase | Shot 18
Fill pressure increased to 8.e-5. 30kA still horiz. field problem. |
| May 19 1993 03:05:14:570PM | 930519019 | Yuichi Takase | Shot 19
Fill pressure decreased to 4.e-5. SX shows sawteeth. Light shows drift down followed by disruption (300kA/ms). OH2 breaker pulled. |
| May 19 1993 03:23:58:580PM | 930519020 | Yuichi Takase | Shot 20
Repeat after OH2 check. No breakdown. |
| May 19 1993 03:27:59:300PM | 930519021 | Yuichi Takase | Shot 21
Fill pressure 6.e-5. Bd @ 5ms, 25kA @ 12ms, no H_alpha burnout. |
| May 19 1993 03:45:17:800PM | 930519022 | Yuichi Takase | Shot 22
EF4 back to 600A. Fizzle (30kA). |
| May 19 1993 03:53:42:970PM | 930519023 | Yuichi Takase | Shot 23
Moved OH1 commutation to -0.5ms (was at 0). Fizzled. |
| May 19 1993 04:10:57:250PM | 930519024 | Yuichi Takase | Shot 24
OH2 comm. resistor to 25 mOhm (from 32). OH2 demand voltage after commutation to 0 (from +100V). Bd @ 5ms, Bz=0, 20kA. |
| May 19 1993 04:27:38:000PM | 930519025 | Yuichi Takase | Shot 25
OH2 demand to 30V (was 0), OH1 demand to -300V (was -400V), want faster Bz ramp. Bd @ 5ms, Bz=-2mT, more circular, disrupted at 230kA. |
| May 19 1993 04:38:15:980PM | 930519026 | Yuichi Takase | Shot 26
OH2 demand ramped from -84V @ 50ms to -40V @ 100ms. No change prior to 50ms. Weak bd @ 5ms, Bz a little higher. |
| May 19 1993 04:51:00:190PM | 930519027 | Yuichi Takase | Shot 27
OH1 comm. back to 0ms (was @ -0.5ms). Good shot, disrupted at 230kA. |
| May 19 1993 05:03:43:770PM | 930519028 | Yuichi Takase | Shot 28
OH1 comm. to +0.5ms. EF3 voltage ramps to 0 at 0.1s (was 0.13s). Ip max at 0.1s (220kA) then ramps down. Predictor for B_r has been overflowing since Shot 14. Reduced it by a factor of 2 for Shot 29. |
| May 19 1993 05:18:58:660PM | 930519029 | Yuichi Takase | Shot 29
Reduced the predictor for B_r by a factor of 2 for Shot 29. OH1 voltage at 45ms -150V. Lost it again, 20kA. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:52:16:880AM | Plasma | Ok | plasma I 36 ka |
| 2 | 09:08:49:030AM | Plasma | Ok | 1 comm 100, 2 comm 32m, ef1 comm 180m |
| 3 | 09:37:24:830AM | Plasma | Ok | 150ka plasma |
| 4 | 09:54:09:110AM | Plasma | Ok | 50 ka shorter plasma |
| 5 | 10:06:40:100AM | Plasma | Ok | 303 ka!! |
| 6 | 10:23:59:040AM | Plasma | Ok | ok .26ma |
| 7 | 10:42:40:270AM | Plasma | Ok | .25 MA |
| 8 | 10:59:33:200AM | Plasma | Ok | getting better 240 ka |
| 9 | 11:17:22:790AM | Plasma | Ok | low current < 20kA |
| 10 | 11:31:00:180AM | Plasma | Ok | 200 ka |
| 11 | 11:43:08:490AM | Plasma | Ok | got cocky 20 KA |
| 12 | 12:46:32:790PM | Plasma | Ok | 30 KA |
| 13 | 12:59:42:520PM | Plasma | Ok | 80 KA |
| 14 | 01:13:54:850PM | Plasma | Ok | 300 KA |
| 15 | 01:36:24:920PM | Plasma | Ok | ok |
| 16 | 01:58:07:360PM | Plasma | Ok | 40KA |
| 17 | 02:13:22:220PM | Plasma | Ok | 30ka |
| 18 | 02:29:36:420PM | Plasma | Ok | 30ka |
| 19 | 02:45:51:180PM | Plasma | Ok | 300ka OH2 comm fail |
| 20 | 03:02:45:340PM | Plasma | Ok | |
| 21 | 03:17:00:580PM | Plasma | Ok | 20KA |
| 22 | 03:29:47:140PM | Plasma | Ok | 20 KA |
| 23 | 03:44:57:960PM | Plasma | Ok | 20 KA |
| 24 | 04:01:08:770PM | Plasma | Ok | 20KA |
| 25 | 04:13:34:410PM | Plasma | Ok | 240 KA |
| 26 | 04:29:12:870PM | Plasma | Ok | 20 KA |
| 27 | 04:39:51:360PM | Plasma | Ok | 230 ka |
| 28 | 04:51:55:440PM | Plasma | Ok | 220 KA |
| 29 | 05:03:47:410PM | Plasma | Ok | good run |