| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Tom Luke |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| fast gas valve |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:08:070PM |
| Author: To Be Determined |
| The purpose of this run was to accomplish the tasks set out in MP011: the study of the effects of gas puffing. Namely, we wish to examine the sensitivity of the TCI to perturbations in density and to investigate the charac teristics of the new gas valve on A-side. To do this we hoped to establish a consistent baseline shot and puff gas out of the new valve as perturbations. We would then vary the duration, amplitude and frequency of the puffs. As stated by Earl Marmar in the run summary, we did not have many good shots during the run. In total, we had 8 shots that had a sustained plasma. Of these 7 can be associated with the experiment. We prefilled the machine with B-Side Upper and puffed through A-Side. We didn't vary the amplitude of the puffs (i.e. max voltage to the piezovalve was a constant 100 V) but we did vary the pulse duration and the number of puffs. We found that the time reponse of the plasma to the valve is about 20 ms; we see the density start to rise 20 ms after we open the valve. On shot 19, we opened the valve from 0V to 100 V directly. The pulse was nominally 40 ms long. However, because we were starting with zero offset, it was effectively a shorter pulse and its effect unnoticeable. A better way to run the valve is to put an initial DC level of 35V before opening. On latter shots we put this offset on to get a faster valve response. The first few shots had one puff of varying lengths. The duration of the pulses were as follows: Shot 19 ( 40 ms but no 35 V offset), shot 21 ( 60 ms), shot 23 (20 ms), shot 24 ( 30 ms). It is clear that the 60 ms pulse was too big and lead to small disruptions and a final one at 305 ms. The 20 and 30 ms pulses were fine and are clearly seen in the density and H-alpha signals. Shots 25, 27, 29, were attempts to puff in 2 pulses of varying lengths. In shot 25 the pulses were 30 ms each and resulted in a disruption. The second puff puts more gas in than the first. We therefore shortened the second puff to 20 ms and then 15 ms. 20 ms was still too long but 15 ms was ok. Overall, the run made good progress to achieving the goals of the MP. Even though we didn't get to vary the puff amplitude and increase puff frequency further, this is a good start to doing some transport measurement s. We can continue to piggyback on other experiments (ex. on Wednesday we got several shots with gas puffs) and hopefully we can fill in the gaps in our data. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| Jul 27 1993 07:57:43:490AM | Tom Luke | Session leader: Thomas Luke, Physics Operator: Earl Marmar, Engineer: Vince Bertolino.
Today's run follows mainly Miniproposal 011. The goal is to examine the sensitivity of the two color interferometer to density perturbations and to characterize a new gas valve on A-Side. We will initially try to establish a good baseline shot with a current flattop ot 300-400 kA of greater than 200 ms duration. The line integrated density signals should be smoothly rising during this flattop. Gas puffs will then be introduced to perturb the density . Variation of the puff amplitude, duration and frequency will be varied. | |
| Jul 27 1993 09:28:42:850AM | 930727001 | Tom Luke | First shot. We will reproduce shot 16 from July 23. Minor changes . Gas fill is at -6 ms
instead of -10 ms. Inversion time is .5 s instead of .45 s. Fill pressure is 1.6E-5 torr and there is no argon nor EFC. |
| Jul 27 1993 09:37:58:910AM | 930727001 | Tom Luke | First shot. We will reproduce shot 16 from July 23. Minor changes . Gas fill is at -6 ms
instead of -10 ms on B-Side upper. Inversion time is .5 s instead of .45 s. Fill pressure is 1.6E-5 torr and there is no argon nor EFC. Fizzle. Didn't have any of the OH's. |
| Jul 27 1993 10:02:30:860AM | 930727002 | Tom Luke | Try Again. We will reproduce shot 16 from July 23. Minor changes . Gas fill is at -6 ms
instead of -10 ms on B-Side upper. Eliminate gas fill at .8 s and .25 s ( quneching pulse). Inversion time is .5 s instead of .45 s. Fill pressure is 1.6E-5 torr and there is no argon. EFC is back. Flash and got all the power supplies but only 10 kA of plasma current. Slight radial field due to to current mismatch in upper and lower OH2's. |
| Jul 27 1993 10:13:13:720AM | 930727003 | Tom Luke | Try Again. Same as 930727002. Fizzle. Flash but no current.
|
| Jul 27 1993 10:13:22:150AM | 930727003 | Tom Luke | Try Again. Same as 930727002. Fizzle. Flash but no current.
|
| Jul 27 1993 10:28:45:660AM | 930727004 | Tom Luke | Try Again. Same as 930727003 but with lower fill pressure 1.4e-5. Fizzle.
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| Jul 27 1993 10:37:07:640AM | 930727005 | Tom Luke | Try Again. Same as 930727003 but with lower fill pressure 1.2e-5. Fizzle with flash.
|
| Jul 27 1993 10:58:23:420AM | 930727006 | Tom Luke | Try Again. Same as 930727004 but with lower fill pressure 1.0e-5. Changed EF2 lower from 1700 A
to 1650 A . No flash at all. |
| Jul 27 1993 11:10:48:290AM | 930727007 | Tom Luke | Try Again. Same as 930727006. Fill pressure back to 1.2e-5. Changed BR programming
from 8.5 mT to 8.0mT. The flash is back. |
| Jul 27 1993 11:22:52:580AM | 930727008 | Tom Luke | Try Again. Same as 930727007. Undo change in EF2 back to 1700 A in EF2 lower.
Flash but no plasma. |
| Jul 27 1993 11:33:49:640AM | 930727009 | Tom Luke | Switch to 930723036. Fill pressure at 1.2e-5. Timing of pulsed gas is back to -10 ms
and later pulses in the gas pulse have been eliminated. Flash but no plasma |
| Jul 27 1993 11:49:25:660AM | 930727010 | Tom Luke | Same as shot 9 except we are lowering BR demand by 1 mT. Same fill pressure.
About the same. Flash but no plasma. Plasma seems to have broken down 1 ms earlier. |
| Jul 27 1993 12:05:53:670PM | 930727011 | Tom Luke | Same as shot 10 except lowered OH2 voltage demand by 20 V from 0. Same fill
pressure. Didn't help. |
| Jul 27 1993 12:17:20:470PM | 930727012 | Tom Luke | Move EF3 slightly earlier by 2 ms. Fill pressure is still 1.2e-5. Flash again but no plasma
again. Broke down later ( couple of ms) |
| Jul 27 1993 12:29:14:510PM | 930727012 | Tom Luke | Add back 1 mT to BR demand. No flash.
|
| Jul 27 1993 12:49:09:830PM | 930727014 | Tom Luke | Increase EF4 by 30 A to give you an increase of 2 mT in Bz. Flash
|
| Jul 27 1993 01:09:20:890PM | 930727014 | Tom Luke | Lower OH2 by another 10 V. Same. Flash but no plasma.
|
| Jul 27 1993 01:12:57:830PM | 930727015 | Tom Luke | Same flash.
|
| Jul 27 1993 01:12:31:130PM | 930727016 | Tom Luke | Changed EF4 current by another 30 to increase Bz. NO change in fill pressure. Same
flash. |
| Jul 27 1993 01:32:19:090PM | 930727017 | Tom Luke | Drop fill to 1.0e-5. Got a plasma. 400 kA. HARD X-rays at the end of the shot.
Density is 4.0e19 m-2. |
| Jul 27 1993 01:45:56:420PM | 930727018 | Tom Luke | Same background as last shot. Puff at 200 ms from A-Side. ( 20 ms duration,
100 V height). Fizzle. |
| Jul 27 1993 02:01:10:210PM | 930727019 | Tom Luke | Change the duration of the gas puff to 40 ms at 200 ms. Height is still 100 V. Fill pressure
lowered to 9e-6. Got plasma. 4E19 density. No noticeable rise at 200 ms from puff. |
| Jul 27 1993 02:11:52:030PM | 930727019 | Tom Luke | Added 100 A on EF2 lower to pull the plasma down. Change the duration of the gas puff to
60 ms at 180 ms. Height is still 100 V. Put 35V pedestal from 30 ms to start opening valve. Fill pressure lowered to 8.5e-6. Add Argon puff at 50 ms ( width of 10 ms and 80 V high) Fizzle. |
| Jul 27 1993 02:14:44:850PM | 930727020 | Tom Luke | 100 A on EF2 were added at 100 ms so shouldn't have affected the initial breakdown.
|
| Jul 27 1993 02:33:08:070PM | 930727021 | Tom Luke | Repeat of shot 20. Argon valve was not open. Got plasma. 8e19 density on inside channels
Definitely saw the rise after 200 ms from the pulse. Disrupted at 300 ms. |
| Jul 27 1993 02:34:11:770PM | 930727022 | Tom Luke | Put puff of 20 ms duration at 180 ms. Turned argon valve on. Fizzle.
|
| Jul 27 1993 03:01:33:580PM | 930727023 | Tom Luke | Same as shot 22 but EF2 has extra 100 A after 100 ms. This is an attempt to move the
plasma by 1 cm. Lowered fill pressure to 8.0E-6. There is a 35 V DC offset at 30 ms to start the valve. There was plasma . Pulse is not noticeable on the z_meter. |
| Jul 27 1993 03:46:38:020PM | 930727024 | Tom Luke | Fill pressure down to 7.5e-6. Argon pulse increased 1ms in length. Gas puff is now 30 ms
long starting at 180 ms. EF2 has a has a 100 ms uptick of 200 A added at 300 ms. Got plasma and see pulse clearly on the H-alpha. Pulse shows up clearly on the density signals. |
| Jul 27 1993 04:04:03:770PM | 930727025 | Tom Luke | Put in 2 30 ms puffs at 180 and 233 ms. On EF2 lower current comes up at 200 ms rather
than 300 ms. Wire4(Z_cur) pid gain set to 5 at 30 ms. No change in the fill pressure. Got plasma. First puff is the same as shot 24 but the second puff is too big and disrupts the plasma at 265 ms. Can definitely see the 2 separate rises. |
| Jul 27 1993 04:12:14:730PM | 930727026 | Tom Luke | Put in 30 ms puffs at 180 and 20 ms at 233 ms. Argon is earlier . Fill was the
same at 7.5e-6. Dud. No Flash. |
| Jul 27 1993 04:31:05:230PM | 930727027 | Tom Luke | Identical to shot 26 except fill has been raised to 8.0e-6. Got plasma. Clearly see
the 2 pulses and it begins to disrupt after 250 ms. Final disruption at 360 ms. |
| Jul 27 1993 04:35:12:340PM | 930727028 | Tom Luke | Put in 2 pulses. Shorten first pulse to 25 ms starting at 180 ms and put second puff of 15 ms
at 225 ms. Shot was a dud. No flash |
| Jul 27 1993 04:50:09:200PM | 930727029 | Tom Luke | Same as shot 28. Raise fill pressure to 8.3e-6. Got plasma. See puffs on H-alpha and
on all the density traces. No disruption from the puffs. |
| Jul 27 1993 04:54:59:400PM | 930727030 | Tom Luke | Turned off the puffs and put fill pressure at 8.0e-6. Scanning probe is set to see
plasma at 350 ms. Dud no flash. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:27:46:660AM | Plasma | Ok | no pf switches closed |
| 2 | 09:42:55:310AM | Plasma | Ok | no faults -- plasma |
| 3 | 10:04:30:460AM | Plasma | Ok | no faults |
| 4 | 10:19:31:170AM | Plasma | Ok | no faults |
| 5 | 10:34:16:940AM | Plasma | Ok | no faults |
| 6 | 10:46:22:930AM | Plasma | Ok | no faults |
| 7 | 11:01:34:460AM | Plasma | Ok | no faults |
| 8 | 11:15:43:910AM | Plasma | Ok | no faults |
| 9 | 11:27:37:310AM | Plasma | Ok | no faults |
| 10 | 11:42:03:010AM | Plasma | Ok | no faults |
| 11 | 11:53:52:660AM | Plasma | Ok | no faults |
| 12 | 12:09:58:510PM | Plasma | Ok | no faults |
| 13 | 12:21:33:520PM | Plasma | Ok | no faults |
| 14 | 12:37:37:550PM | Plasma | Ok | no faults |
| 15 | 12:52:30:440PM | Plasma | Ok | no faults |
| 16 | 01:08:46:630PM | Plasma | Ok | no faults |
| 17 | 01:24:11:580PM | Plasma | Ok | no faults -- good plasma shot finally |
| 18 | 01:38:30:410PM | Plasma | Ok | no faults |
| 19 | 01:52:27:060PM | Plasma | Ok | no faults |
| 20 | 02:07:34:100PM | Plasma | Ok | no faults |
| 21 | 02:18:51:840PM | Plasma | Ok | no faults |
| 22 | 02:29:04:660PM | Plasma | Ok | no faults |
| 23 | 02:43:42:760PM | Plasma | Ok | no faults |
| 24 | 03:07:48:580PM | Plasma | Ok | no faults |
| 25 | 03:52:22:830PM | Plasma | Ok | no faults |
| 26 | 04:04:30:720PM | Plasma | Ok | no faults |
| 27 | 04:17:23:780PM | Plasma | Ok | no faults |
| 28 | 04:30:09:580PM | Plasma | Ok | no faults |
| 29 | 04:39:38:610PM | Plasma | Ok | no faults |
| 30 | 04:52:17:150PM | Plasma | Ok | no faults |