| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Earl Marmar |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| Plasma run. |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:07:883PM |
| Author: To Be Determined |
| Statistics: 32 Shots. 27 plasmas with >50kA. 5 fizzles, 0 no flash.. ____________________________________________________________________ This run demonstrates the ability to run shot after shot with strong current rise. There are two requirements. (1) Correct field programming. (2) Gas not exceeding a certain level. Shots 1-6 were used to adjust the field configuration, in two ways. The OH2 voltage demand during early current rise was made more negative to improve the FIELD INDEX and prevent the vertical instabilities that we observed to be causing many of the fizzles that had formed a channel on the UVtomo. In addition, the HORIZONTAL FIELD demand was tuned, with a final setting of 7 mT. This gives zero, due to unknown offsets. There is a persistent observation that the OH2 current must be imbalanced to give zero field. When OH2U-OH2L ~ 350 A, one gets zero BR. The current ramp is sensitive to the BR demand at about the 1mT level. It was found that the first good shot raises the base pressure (mostly hydrogen) very substantially. The following shots, if run at a fill pressure above about 4E-5 torr will fizzle. Shots 7-26 ( a record run of 20 in a row) were at 4E-5 and early current ramp was always achieved, although there were other inexplicable irreproducibilities. Shot 27 had its pressure raised to 6E-5 to demonstrate the effect of fill pressure. It fizzled as advertized. Shots 28-32 were a pressure scan down to 2.7E-5 without excessive hard x-rays. This establishes that there is a decent pressure window within which to operate, although the window may move as a function of recycling and wall conditions etc. A NEW HORIZONTAL POSITION PREDICTOR was installed on shot 24. It is based on the difference in flux, as reconstructed by Ian's filament code, at R=90m and R=44m. When the two fluxes are the same, making the predictor signal zero, the outer flux surface just grazes the inner and outer limiter. This predictor looks qualitatively (and to some degree quantitatively) very similar to the the old predictor of Wolfe's. However, it has essentially zero offset. In particular, it can also function directly as an average Bz measure that needs to be zero to give a good field null before the plasma. It also has the merit of being a quantitative predictor of the OUTER flux surface, which is probably the most important to control. Position control with the new predictor was good. It even managed to maintain tolerable R-control during disruptions. ____________________________________________________________________ Engineering Problems There is still a problem with the OH2 response to negative voltage demand. It is observed that after crowbar, when we require a substantial negative voltage out of OH2 to make up for the Resistive voltage just shorted out, there is a growing imbalance in the OH2 current due to imbalanced voltages. This imbalance seems worse the more negative is the demand. At the end of the run the voltage programs had been adjusted to OH2U:-70V and OH2L:-55V immediately after crowbar to compensate for the different power supply response. It would be very much nicer not to have to do this. IHH. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| Jun 9 1993 08:40:54:080AM | Earl Marmar | Today's run will concentrate on trying to improve breakdown/ramp-up reproducibility.
Focus will be on field gradients, etc. Steve Horne will also be fiddling with the later parts of the shots. Physics op: Hutchinson Assistant: Marmar | |
| Jun 9 1993 08:53:43:920AM | 930609001 | Earl Marmar | Start from 930608021, gas puff 60V at -10 ms.
Pfill = 6e-5 IGT before init = 3e-7 Result: Got about 50 kA, lasted 33 mS Lost it vertically (down) at 30 mS; slight horizontal field problem. |
| Jun 9 1993 09:09:53:270AM | 930609002 | Earl Marmar | Change for shot 2: Change demand on B_r from 8 to 10 mTesla
Gas puff B_top piezo, 60 V at -10 ms Pfill = 6e-5 IGT before init = 5.9e-7 Result: Fizzle. Worse horizontal field.e |
| Jun 9 1993 09:26:48:470AM | 930609003 | Earl Marmar | Change for shot 3: Change demand on B_r from 10 to 6 mTesla
Gas puff B_top piezo, 60 V at -10 ms Pfill = 6e-5 IGT before init = 7.6e-7 Result: 32 kA. Died at about 25 mS. Moved up. |
| Jun 9 1993 09:40:53:990AM | 930609004 | Earl Marmar | Change for shot 4: Changed OH2 demand V's just after commutation from
-10 V to -20 V Gas puff B_top piezo, 60 V at -10 ms Pfill = 6e-5 IGT before init = 6.8e-7 Result: 45 kA, lost it up starting at about 20 mS |
| Jun 9 1993 09:58:11:920AM | 930609005 | Earl Marmar | Change for shot 5: More tweaks on OH2 demand V's just after commutation
Gas puff B_top piezo, 60 V at -10 ms Pfill = 6e-5 IGT before init = 7.2e-7 Result: 180 kA; no hesitation during current rise "event" (minor disruption?) at 50 mS - drop in softs, hard burst, density drop multiple disruptions after 140 mS |
| Jun 9 1993 10:10:05:740AM | 930609006 | Earl Marmar | Change for shot 6: More tweaks (same direction) on OH2 demand V's just after commutation
Bcur to 7 mT from 6 Raised PID on Zcur from .1 to .2 Turned off PID on Zcur for t>.35 Gas puff B_top piezo, 60 V at -10 ms Pfill = 6e-5 IGT before init = 1.7e-6 Result: Fizzle. Fields all look good. |
| Jun 9 1993 10:11:05:720AM | 930609006 | Earl Marmar | Change for shot 6: More tweaks (same direction) on OH2 demand V's just after commutation
Bcur to 7 mT from 6 Raised PID on Zcur from .1 to .2 Turned off PID on Zcur for t>.35 Gas puff B_top piezo, 60 V at -10 ms Pfill = 6e-5 IGT before init = 1.7e-6 Result: Fizzle. Fields all look good. |
| Jun 9 1993 10:28:33:420AM | 930609007 | Earl Marmar | Change for shot 7: lower fill to 5e-5
Gas puff B_top piezo, 60 V at -10 ms Pfill = 5e-5 IGT before init = 1.5e-6 Result: Good shot. Very similar to shot 5. 170 kA. |
| Jun 9 1993 10:41:00:640AM | 930609008 | Earl Marmar | Change for shot 8: lower fill to 4e-5
Gas puff B_top piezo, 60 V at -10 ms Pfill = 4e-5 IGT before init = 1.6e-6 Result: Very good shot. Early disruption not as bad. Fields still look ok. |
| Jun 9 1993 11:08:12:730AM | 930609009 | Earl Marmar | Changes for shot 9:
OH1 to -200 V (from -100 V) OH2 to -20 (from -10) 25 to 50 ms Zcur feedback on time changed to 70 ms from 100 ms Gas puff B_top piezo, 60 V at -10 ms Added second gas puff, also B_top, 60 V, 25 ms starting at 400 ms, to test response Pfill = 4e-5 IGT before init = 1.7e-6 Result: 160 kA; multiple disruptions during current rise position good early; after biggest disruption at 63 ms, moves up and in. |
| Jun 9 1993 11:22:55:650AM | 930609010 | Earl Marmar | Changes for shot 10:
OH1 step down to -680 V at 50 ms, then ramp to -300 V at 100 ms OH2 step down to -100 V at 50 ms Gas puff B_top piezo, 60 V at -10 ms second gas puff, also B_top, 80 V, 30 ms starting at 400 ms Pfill = 4e-5 IGT before init = ?e-6 Result: 170 kA. disruptions through most of the shot. |
| Jun 9 1993 11:30:51:450AM | 930609011 | Earl Marmar | Changes for shot 11:
z_cur feedback gain from .1 to .15 r_cur ef3 from 2.5e-2 to 2.e-2 rcur P gain from .3 to .5 Gas puff B_top piezo, 80 V at -10 ms second gas puff, also B_top, 80 V, 30 ms starting at 400 ms Pfill = 4e-5 IGT before init = 1.9e-6 Result: |
| Jun 9 1993 11:37:25:760AM | 930609011 | Earl Marmar | Changes for shot 11:
z_cur feedback gain from .1 to .15 r_cur ef3 from 2.5e-2 to 2.e-2 rcur P gain from .3 to .5 Gas puff B_top piezo, 80 V at -10 ms second gas puff, also B_top, 80 V, 30 ms starting at 400 ms Pfill = 4e-5 IGT before init = 1.9e-6 Result: 100 kA; vertically unstable (moved up) at 56 ms. Cuurent rise slowed somewhat, leading to plasma being at smaller R. |
| Jun 9 1993 11:54:57:050AM | 930609012 | Earl Marmar | Changes for shot 12:
rcur P gain back to .3 from .5 Gas puff B_top piezo, back to 60 V at -10 ms, ramping to 40 at +35 ms second gas puff, also B_top, 80 V, 30 ms starting at 400 ms Pfill = 4e-5 IGT before init = 1.7e-6 Result: 180 kA, good position early, disruption at 75 ms. |
| Jun 9 1993 12:12:21:600PM | 930609013 | Earl Marmar | Changes for shot 13:
rcur P gain to .4 from .3 Gas puff B_top piezo, to 50 V (from 60) at -10 ms, ramping to 40 at +35 ms second gas puff, also B_top, 80 V, 30 ms starting at 400 ms Pfill = 4e-5 IGT before init = 2.4e-6 Result: 200 kA, not disruptive until after 100 ms (except for small event at 53 ms (showed up strongly on UV diode arrays) position good early, moves down and in later. |
| Jun 9 1993 12:29:14:350PM | 930609014 | Earl Marmar | Changes for shot 13:None
Pfill = 4e-5 IGT before init = 2.1e-6 Result: 240 kA, R_softs=70 cm until 110 ms, then moves rapidly in and current dies in about 8 ms. |
| Jun 9 1993 12:59:09:530PM | 930609015 | Earl Marmar | Changes for shot 15:
Ip*Rcur feedback changed from .4 to .6 Pfill = 4e-5 IGT before init = 1.8e-6 Result: 245 kA, disruptive after 90 ms |
| Jun 9 1993 12:54:49:560PM | 930609016 | Earl Marmar | Changes for shot 16: none
Pfill = 4e-5 IGT before init = e-6 Result: 200 kA, disruptive after 90 ms EF1's are imbalanced after crowbar |
| Jun 9 1993 12:55:25:440PM | 930609016 | Earl Marmar | Changes for shot 16: none
Pfill = 4e-5 IGT before init = 2.1e-6 Result: 200 kA, disruptive after 90 ms EF1's are imbalanced after crowbar |
| Jun 9 1993 01:28:26:710PM | 930609017 | Earl Marmar | Changes for shot 17:
Moved all crowbars to 70 ms (from 50) Attempted to change programming on OH's but PCS problem prevented the changes from being loaded. Crowbars were moved. Pfill = 4e-5 IGT before init = 1.4e-6 Result: 180 kA, disruptive after 90 ms |
| Jun 9 1993 01:38:23:820PM | 930609018 | Earl Marmar | Changes for shot 18:
Crowbars still at 70 ms OH changes still did not take. Pfill = 4e-5 IGT before init = 2.5e-6 Result: 150 kA, disruptive after 65 ms position problems |
| Jun 9 1993 01:55:34:250PM | 930609019 | Earl Marmar | Changes for shot 19:
OH's changed to correspond to crowbar time (70 ms) Lowered OH1 to -580 at 71 ms OH2 to -80 at 71 ms Turned on B side top valve with 80 V pulse at 400 ms Pfill = 4e-5 IGT before init = 2.6e-6 Result: Good shot. 260 kA, fast current rise to 200 kA (54 ms) Very low hard x-ray level Quite far outside until 112 ms. |
| Jun 9 1993 02:08:12:610PM | 930609020 | Earl Marmar | Changes for shot 20:
Moved R position feedback to turn on at 40 ms instead of 50 ms B side top valve with 80 V pulse at 400 ms B top valve post shot pulse turned off Pfill = 4e-5 IGT before init = 2.1e-6 Result: 190 kA disruptive after 60 ms |
| Jun 9 1993 02:24:46:050PM | 930609021 | Earl Marmar | Changes for shot 21:
B side top valve with 90 V pulse at 400 ms Removed step in EF3 voltage at 50 ms Pfill = 4e-5 IGT before init = 2.4e-6 Result: Good shot until minor disruption at 104 ms Current rise relatively slow. |
| Jun 9 1993 02:37:42:730PM | 930609022 | Earl Marmar | Changes for shot 22: None
Pfill = 4e-5 IGT before init = 2.7e-6 Result: Similar to 21, but MHD instead of sawteeth before minor disruption at 103 ms |
| Jun 9 1993 02:47:21:400PM | 930609023 | Earl Marmar | Changes for shot 23:
Lower OH2 to -70 V for ~80 at 70 ms B side top gas pulse widened to 50 ms and moved to start at 1.0 s. IGT before init = 3.0e-6 Result: 250 kA Sawteeth before disruption at 110 ms, MHD after Position pretty good |
| Jun 9 1993 03:12:45:540PM | 930609024 | Earl Marmar | Changes for shot 24:
Installed different predictor (algorithm ihh46dr4) on Ip_Rcur IGT before init =2.4 e-6 Result: 260 kA Disrupt at 50 ms, many disruptions after 108 ms New predictor seems to function properly |
| Jun 9 1993 03:29:09:000PM | 930609025 | Earl Marmar | Changes for shot 25:
OH2L to -65 V (OH2 U left at -70 V) IGT before init = 2.0 e-6 Result: 200 kA Quite disruptive, moves up after each of two disruptions |
| Jun 9 1993 03:43:56:190PM | 930609026 | Earl Marmar | Changes for shot 26:
OH2L to -60 V (OH2 U left at -70 V); attempting to cure tendency toward vertical instability IGT before init = 2.3 e-6 Result: 220 kA lost it vertically after 130 ms |
| Jun 9 1993 04:01:16:010PM | 930609027 | Earl Marmar | Changes for shot 27:
Change fill pressure to 6e-5, attempting to get a fizzle Added second post shot-gas pulse on B top (now 2, 80 V, 50 ms, separated by 50 ms) IGT before init = ? e-6 Result: Fizzle! |
| Jun 9 1993 04:15:28:910PM | 930609028 | Earl Marmar | Changes for shot 28:
Change fill pressure back to 4e-5 IGT before init = 1.2 e-6 Result: 240 kA MHD, disruptive |
| Jun 9 1993 04:27:09:730PM | 930609029 | Earl Marmar | Changes for shot 29:
Raised EF1 to -150 V at 100 ms (attempt to divert!) P fill = 4e-5 IGT before init = 2.9 e-6 Result: 210 kA, disruptive, MHD good position until 130, then lost it down and in. |
| Jun 9 1993 04:42:20:590PM | 930609030 | Earl Marmar | Changes for shot 30:
lower fill to 3.5e-5 Changed OH2L to -55 V at 71 ms P fill = 3.5 e-5 IGT before init = 2.8 e-6 Result: 225 kA disrupt at 70 ms good position until 150 ms then lose it up. |
| Jun 9 1993 05:00:24:390PM | 930609031 | Earl Marmar | Changes for shot 31:
lower fill to 3.0e-5 Changed OH2L to -45 V at 150 ms EF1's set to 100 V from 100 to 250 ms P fill = 3.0 e-5 IGT before init = ? e-6 Result: 220 kA good during current rise first disruption at 69 msec |
| Jun 9 1993 05:08:17:620PM | 930609032 | Earl Marmar | Changes for shot 32:
lower fill to 2.7e-5 EF1's set to -100 V from 90 to 250 ms P fill = 2.7 e-5 IGT before init = 2.3 e-6 Result: 220 kA good during current rise first disruption at 66 msec |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:40:08:840AM | Plasma | Ok | no flash -- no faults |
| 2 | 08:59:27:430AM | Plasma | Ok | no faults -- 20ka plasma |
| 3 | 09:12:05:460AM | Plasma | Ok | 20ka plasma -- no faults |
| 4 | 09:29:49:280AM | Plasma | Ok | 50ka plasma -- no faults |
| 5 | 09:45:36:370AM | Plasma | Ok | 170ka plasma -- no faults |
| 6 | 10:01:18:770AM | Plasma | Ok | 20ka plasma no faults |
| 7 | 10:12:29:720AM | Plasma | Ok | 170ka plasma -- bypass data link on ef1u-- suspect bad pioodal synch. |
| 8 | 10:30:12:930AM | Plasma | Ok | 170ka plasma -- no faults |
| 9 | 10:48:33:590AM | Plasma | Ok | 160ka plasma -- no faults |
| 10 | 11:11:07:800AM | Plasma | Ok | 170ka plasma |
| 11 | 11:27:54:690AM | Plasma | Ok | 120ka plasma |
| 12 | 11:44:28:030AM | Plasma | Ok | 180ka plasma |
| 13 | 11:58:18:730AM | Plasma | Ok | 200ka plasma |
| 14 | 12:13:24:350PM | Plasma | Ok | 240ka plasma -- no faults |
| 15 | 12:30:45:850PM | Plasma | Ok | 240ka plasma |
| 16 | 12:47:06:700PM | Plasma | Ok | 210ka plasma -- no faults |
| 17 | 01:12:03:760PM | Plasma | Ok | 190ka plasma -- some 60hz ripple on oh2 in invert, probably due to inv e |
| 18 | 01:25:26:510PM | Plasma | Ok | 160ka plasma no faults |
| 19 | 01:38:45:770PM | Plasma | Ok | 260ka plasma |
| 20 | 01:57:43:940PM | Plasma | Ok | 190ka plasma -- no faults |
| 21 | 02:13:05:270PM | Plasma | Ok | 230ka plasma -- no faults |
| 22 | 02:26:46:670PM | Plasma | Ok | 250ka plasma current -- no faults |
| 23 | 02:39:59:370PM | Plasma | Ok | 240ka plasma |
| 24 | 02:55:26:220PM | Plasma | Ok | 260ka plasma |
| 25 | 03:15:07:200PM | Plasma | Ok | 200ka plasma |
| 26 | 03:32:45:930PM | Plasma | Ok | 220ka plasma -- no faults |
| 27 | 03:45:11:940PM | Plasma | Ok | 20ka plasma due to fill pressure change -- oh1 gate loss at 800Amps cau |
| 28 | 04:05:43:020PM | Plasma | Ok | 230ka plasma -- no faults |
| 29 | 04:18:28:720PM | Plasma | Ok | 220ka plasma |
| 30 | 04:29:59:190PM | Plasma | Ok | 250ka plasma |
| 31 | 04:46:11:200PM | Plasma | Ok | 220ka plasma -- no faults |
| 32 | 05:01:47:440PM | Plasma | Ok | 250ka plasma |