| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Gary McCracken |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Steve Fairfax,Vinny Bertolino |
| Engineering Operator Run Comment |
| impurity transport |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:11:257PM |
| Author: To Be Determined |
| Summary: Overall a very successful day with the main objectives of miniproposal 44 being achieved. These were (1) To puff He Ne and Ar into the private flux zone in the divertor and to measure how much gets into the confined plasma, thereby being able to estimate screening factors for impurities which can be compared to theory. (2) To measure the amount of molybdenum sputtered by injected impurities as a function of the target electron temperature and hence to get some information on the sheath potential We managed to puff in Ar,Ne and He in successive discharge at 2 main densities, nel05=5e19 and 1e20 m^-2. Measurements were made in most cases, with the Macpherson to get a line integral of the impurity concentration in the confined plasma, the oma to get the impurities in the divertor, the Hirex system for the central argon density and the reticon system with filters to get the poloidal distribution of the helium from the Btop array. Good background shots were obtained for both densities. This should allow us to calculate some impurity screening factors. Unfortunately the reticon filters for NeI and ArI do not seem to provide good signals. We also have some data from the oma for the amount of Mo sputtered by the injected impurity gases. There seems to be reasonable evidence for sputtering of Mo by Ar, but it is not so clear as yet for sputtering by Ne or He. In addition to the main objective we also observed some very distinct divertor detachments similar to those obtained in the 1993 campaign. These were considerably better than those obtained so far this year. The first example was in shot 14 at about 0.8 s. It is not yet clear why these detachments were better. It may be the higher Ip used or the fact that the equilibrium used today was an improvement on that used earlier due to the steady discharge development, or to the fact that we were injecting impurities and therefore getting more radiation. However here was no obvious difference between Ne injection on and off, compare shot 22 and 23. We started off demanding the equilibrium from shot 940621022. To this, density feedback was added by S Horne. Later on (about shot 7) Bob Granetz shifted the plasma back onto the inside limiter near the end of the shot. This reduced the disruptions in the rampdown. The initial few shot were fizzles for no clear reason, but once we got going we had good reliability and very reproducible magnetics with the X-point and the strike points being in good positions. The outer strike point was on probe 5 to6 and did not drift up the target as heretofore. The inner strike point was a bit high, being near the nose. shot 940623001 Fizzle 002 Fizzle 003 Fizzle 004 Plasma, but low density with runaways. 005 Nice shot with stable X-point and strike point. Diversion starts at 0.6 s and lasts till after 1.0 s Density nel05=6e16 m^-2 006 Ar injection at 0.6 s. delta P= 0.25 torr Volume 1.25 l. Shot slightly disruptive. 007 Ar injection : delta P =0.6 torr. Shot disrupted at 0.34 s. Too much Ar? 008 Ar injection: delta P =0.5 torr Again disrupted at 0.36 s 009 Ar injection, but delayed by 250 ms delta P=0.5 torr; disrupted at 0.82 s 010 Ar injection reduced, delta P= 0.2 torr ; disrupted at 0.95 s 011 No Ar injection. Good shot without disruption. 012 No Ar injection. Density raised to 9.5e19 m^-2 Good shot 013 Same density with Ar . delta P =0.2 torr 014 First with Neon injection; same density, delta P =0.15 torr detachment occurs at 0.82 s 015 Ne injection 100 ms earlier, same density, delta P=0.15 torr detachment again at 0.83 s 016 Ne injection same density delta P =0.2 torr no obvious detachment 017 Dud, no obvious reason why. 018 No Ne injection: good shot except that there was a large natural Mo injection 019 No TF; dud 020 Ne injection; deltaP =0.2 torr density reduced to 6e19 021 Ne injection increased; delta P=0.3 torr, disrupted at 1.05 s but otherwise good shot 022 Ne injection deltaP= 0.35 torr, density increased to 1.5e20, density ramped up during diverted phase detachment at 0.8 s 023 No Ne injection, same density ramp as last shot; detachment occurred at the same time 024 First shot with He injection; trigger time 0.3s, should get in about 0.6 s density 1e20, deltaP=1.2 torr, but for this shot only the plenum volume was 0.267 l some large Mo injections 025 Increased He injection, deltaP=0.44 s (V=1.25 l) same density 026 Background shot, No He injection, same density 027 He injection, deltaP=0.4 torr, lower density ne= 6e19, (rising through the shot) 028 Background shot, no He , similar density profile Future plans should include impurity puffing at different capillaries, further exploration of density dependence of screening and Mo producion, and more detailed measurements on the the low ionisation states with better reticon filters and better impurity lines on the oma |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:51:990PM |
| Author: To Be Determined |
| Physics operator's summary for run 940623 SL: G. McCracken PO: R. Granetz EC: V. Bertolino/S. Fairfax As explained in Gary's session leader summary, this run accomplished much of its physics goals, namely the study of impurity screening efficiency of diverted plasmas for argon, neon, and helium impurities at 2 or 3 different densities. All shots were at the same plasma current of 0.8 MA. We also were able to finally get repeatable diverted plasmas that survived long enough for the current to rampdown to inconsequential values, including a half-dozen that essentially made it all the way down (100 kA). In addition, divertor detachment was also observed on a few shots, both with and without impurity puffing. The run was not without problems, however. The first three shots, including the fiducial, were fizzles. After a very minor tweak of BR (by 0.5 mT) and a change of the pre-fill pressure, plasmas were obtained. However, I think that the lack of ECDC this morning had more to do with these startup problems than anything we changed. The first few shots with argon puffing had much more argon injected than we wanted, and there seemed to be an inverse correlation between amount of argon and length of shot. On shot 12 I changed the CLEARIN programming in order to cause the plasma to become limited after 1.0 s, in hopes of making the rampdown more stable (suggested by Ian). This worked, and problems with disruptions and halo currents were greatly ameliorated. It is true though, that when we started the TF inversion at 1.0 s (beginning with 940623019), rather than 1.1 s, the plasmas did not ramp down fully. On the last shot we moved the TF inversion back to 1.3 s and the shot again ramped down all the way. There were also several engineering and camac problems that caused some delays and lost shots, including no ECDC, a TMX circuit breaker problem, multiple camac init failures, and power supplies not firing (on one shot, 940623019). There was also a very strange shot, 940623017, which inexplicably was a dud. Just prior to this shot, the system put itself into STANDBY mode, due to a fault in the gas pre-fill system. After re-cycling, we had a shot, although the voice announcement ("entering pulse") was weirdly delayed by several seconds until after the shot had finished. It was our only dud. The next shot was fine. No changes were made during this time. I think that the most plausible explanation (although totally without factual support) is that the gas system malfunctioned and didn't actually put in any pre-fill gas. As far as disruption halo currents go, things improved greatly starting with shot 940623011. From that point on, no halo currents above 50-60 kA occurred, and many shots ramped all the way down, resulting in negligible halo currents. Early in the run, there were several 0.8 MA disruptions, with two resulting in 100 kA of lower halo current, and one having 70 kA of upper halo current. The lower rogowski and the total of the divertor shunts agreed extremely well all day. One final note: density feedback works reasonably well at low and moderate densities (up to about NL_07=1.0e20 m-2). Demands for higher density result in 100 volts on the piezo, but not much increase in electron density. Perhaps fueling directly into the divertor might do the trick. |
| Session Leader Comments | |||
| Jun 23 1994 07:35:15:030PM | Gary McCracken | Summary:
Overall a very successful day with the main objectives of miniproposal 44 being achieved. These were (1) To puff He Ne and Ar into the private flux zone in the divertor and to measure how much gets into the confined plasma, thereby being able to estimate screening factors for impurities which can be compared to theory. (2) To measure the amount of molybdenum sputtered by injected impurities as a function of the target electron temperature and hence to get some information on the sheath potential We managed to puff in Ar,Ne and He in successive discharge at 2 main densities, nel05=5e19 and 1e20 m^-2. Measurements were made in most cases, with the Macpherson to get a line integral of the impurity concentration in the confined plasma, the oma to get the impurities in the divertor, the Hirex system for the central argon density and the reticon system with filters to get the poloidal distribution of the helium from the Btop array. Good background shots were obtained for both densities. This should allow us to calculate some impurity screening factors. Unfortunately the reticon filters for NeI and ArI do not seem to provide good signals. We also have some data from the oma for the amount of Mo sputtered by the injected impurity gases. There seems to be reasonable evidence for sputtering of Mo by Ar, but it is not so clear as yet for sputtering by Ne or He. In addition to the main objective we also observed some very distinct divertor detachm | |
| Jun 23 1994 09:30:34:260AM | 940623001 | Gary McCracken | Attempt to do standard test shot. Fizzle.
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| Jun 23 1994 09:27:52:770AM | 940623002 | Gary McCracken | This is the first of 2 days requested for miniproposal 44. The idea is to continue the 1993 campaign
using Ar Ne and He as tracer impurities to measure impurity screening. A second objective is to study the sputtering of Mo by impurities in the divertor. We plan to inject the impurities Ar, Ne and He in turn into the private flux zone of the divertor with the NINJA capillary injection system. The impurities are to be measured in the main plasma using Hirex (Ar), the Macpherson and the Btop reticon using filters. and the oma visible spectrometer in the divertor, We plan to use a single null diverted discharge staring with shot 940621022. However Steve Horne has added density feed back. The magnetics will hopefully stay constant throughout the day, and the variables will be plasma density and the the amount of impurity injected. |
| Jun 23 1994 09:29:43:130AM | 940623002 | Gary McCracken | Fizzle
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| Jun 23 1994 09:32:22:210AM | 940623003 | Gary McCracken | Now trying to repeat the shot 940621022 Fizzle.
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| Jun 23 1994 09:33:38:540AM | 940623004 | Gary McCracken | Plasma at last, but low density with runaways..
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| Jun 23 1994 09:51:09:640AM | 940623005 | Gary McCracken | Quite nice shot with stable X-point and strike point. Diversion starts at about 0.6 s
and continues through to 1.0 s.nel05 about 6e16 staying reasonably constant throughout the diverted phase of the shot. We will start Ar injection in the next shot |
| Jun 23 1994 10:11:49:330AM | 940623006 | Gary McCracken | First shot with argon. The trigger is at 0.0 s but because of the delay in the capillaries the argon
does not start to enter the torus until 0.55 s. The valve is open for 0.1 s but again because of the capillaries the flow is constant for about 0.5 s. We can only control the flow rate by the plenum pressure. Pressure 32 torr initially, but there seems to be a problem with the stability of this. Argon influx seen on Macpherson and Hirex. It is only 2-3 times background. Shot equilibrium still good but shot is slightly disruptive. We don't know why. |
| Jun 23 1994 10:45:23:350AM | 940623007 | Gary McCracken | Intended to be a repeat shot with a little more Ar injected. Same timing. However the shot disrupted at
0.34 s. We had some power supply problems, so the delay between shots was longer then usual. Try again. |
| Jun 23 1994 10:56:27:460AM | 940623008 | Gary McCracken | Another disruptive shot. It looks as if the argon is going in earlier than we expected. The plenum
pressure is about60 torr. The Hirex signals, Zeff, and Prad are all going up before the disruption. We will delay the argon injection for the next shopt |
| Jun 23 1994 11:14:58:260AM | 940623009 | Gary McCracken | Ar puff now triggered at 250 ms. Argon now coming in at 600 ms as seen on Hirex. However it seems
to have induced a disruption at 0.82 s |
| Jun 23 1994 11:33:51:530AM | 940623010 | Gary McCracken | Ar plenum pressure reset to 30 torr again, triggered at 100 ms. Better discharge, but still disrupted at
about 0.95 s. Ar started coming up at 0.7 s on Hirex. It is not clear if it is still causing the disruption so we will turn it off completely for thew next shot |
| Jun 23 1994 12:01:48:770PM | 940623011 | Gary McCracken | No Ar injection to see if we can get a nondisruptive pulse and to get a background for the spectrosccopy.
Much better shot. Only disrupted in the ramp down. The argon level on the Hirex went down significantly in the diverted phase compared with the previous shot, ie doing what it is supposed to. There is also a big reduction in the Mo in the divertor on the oma. Zeff and Prad are also significantly lower, Zeff by about 0.2. Looks interesting |
| Jun 23 1994 12:23:14:970PM | 940623013 | Gary McCracken | Repeat shot but with higher ne, about 9.5e19. No argon injected due to finger trouble. Nice reduction
in Hirex, Zeff and Prad when diverted |
| Jun 23 1994 12:49:21:260PM | 940623013 | Gary McCracken | Same density set, but with argon injection. We see a good increase in the Hirex signals but there seems
to be no increase in the Zeff. Possibly a slight increase in Prad and in Mo. Very clear detachment at 0.82 s, density nel05, at 9.6e19. Nice little increase in density dn/dt at detachment. |
| Jun 23 1994 01:03:16:210PM | 940623014 | Gary McCracken | Same density set, but now with neon injection about 30 torr plenum pressure. Trigger time 0.1 s for 0.1 s
Delay expected of 0.6 s Detachment occurs at 0.83 s. Spectroscopic signals weak or non-existant. A clear indiaction on the Macpherson that Ne was goin in. |
| Jun 23 1994 01:23:41:140PM | 940623015 | Gary McCracken | Same density again, but now with neon injection trigger advanced to 0.0 s. Same 30 torr plenum pressure.
MKS pressure change about 0.2 torr, similar to argon. Volume of plenum is 1.25 l Reasonable signals on Macpherson, but still nothing on the oma or the reticon No significant rise on Zeff or Prad |
| Jun 23 1994 01:25:39:760PM | 940623015 | Gary McCracken | Detachment occurred at 0.83 s and high density observed at the divertor target, about 1e21
|
| Jun 23 1994 01:38:25:050PM | 940623016 | Gary McCracken | Repeat density and neon injection.
Reasonable neon signal on the Macpherson and some indication on the oma. No obvious detachment in the divertor. |
| Jun 23 1994 02:06:23:790PM | 940623017 | Gary McCracken | Repeat density but no neon injection.
Dud. No explanation why |
| Jun 23 1994 02:21:01:920PM | 940623018 | Gary McCracken | Repeat density (ne05=9.6e19), but no neon injection.
Good shot.Neon signal on Macpherson much reduced |
| Jun 23 1994 02:28:40:330PM | 940623019 | Gary McCracken | ne reduced to about 5 to 6e19, as in earlier shots. Neon injection on again. Trigger at 0.0 s
No TF. Dud |
| Jun 23 1994 02:57:19:420PM | 940623020 | Gary McCracken | ne set for about 5 to 6e19, as in earlier shots. Neon injection on again. Trigger at 0.0 s
Density about right, but there is a big spontaneous Mo injection at 0.6 s. Good Ne signal on the Macpherson. |
| Jun 23 1994 03:10:18:670PM | 940623021 | Gary McCracken | ne still about 6e19, Neon injection plenum pressure increased to 50 torr. Trigger at 0.0 s
Macpherson signal increased about a factor 2. Disrupted at 1.1 s, but no sign of a radiation problem Neon I seen on the oma |
| Jun 23 1994 03:33:23:210PM | 940623022 | Gary McCracken | ne increased to 1.5e19 Neon injection plenum pressure 50 torr. Trigger at 0.0 s
Very nice detachment at 0.8 s. Unfortunately there was insufficient D puffing to get to the demanded density, so ne was ramping up throughout the shot. No increase in Zeff, but slight increase in Prad and Mo |
| Jun 23 1994 03:48:43:850PM | 940623023 | Gary McCracken | ne increased to 1.5e19 with same demand preprogram as last shot. Ne time trace was
very similar to previous shot. Detachment occurred at the same time as the previous shot indicating that the detachment is unaffected by the neon. Ne signal on the Macpherson was at least an order of magnitude lower than shot 22. |
| Jun 23 1994 04:05:21:420PM | 940623023 | Gary McCracken | First shot with He injection. Trigger time 0.3 s.Delay should be 0.3 s so it will enter the
plasma at 0.6s. MKS pressure change =1 torr. Plenum pressure about 50 torr. oma Macpherson and reticon on He Ne demanded 8e19, obtained 1e20 on ne05. Good shot. HeII observed on the Macpherson staring at 0.7 s, but not on the oma. |
| Jun 23 1994 04:05:37:020PM | 940623024 | Gary McCracken | First shot with He injection. Trigger time 0.3 s.Delay should be 0.3 s so it will enter the
plasma at 0.6s. MKS pressure change =1 torr. Plenum pressure about 50 torr. oma Macpherson and reticon on He Ne demanded 8e19, obtained 1e20 on ne05. Good shot. HeII observed on the Macpherson staring at 0.7 s, but not on the oma. |
| Jun 23 1994 04:27:07:220PM | 940623025 | Gary McCracken | Same density demand. Increase He plenum pressure to 85 torr. Plenum volume back 1.25 l. Trigger still
0.3 s, but it will come in a little earlier because of the higher pressure. MKS delta P=0.5 torr Good signals on the Macpherson, the oma and the reticon. No sign of increas on Zeff or Prad. |
| Jun 23 1994 04:42:16:880PM | 940623026 | Gary McCracken | Background shot Same density demand, but no He injection. MKS delta P=0.5 torr
Good shot. Spectroscopy oma, Macpherson and reticon, ok |
| Jun 23 1994 04:59:27:180PM | 940623027 | Gary McCracken | Lower density with He injection. Plenum pressure = 80 torr Delta P about 0.4 torr
Good shot. nel05 increase throughout diverted part of shot from 5 to 7e19. Not clear why feedback did not work better 0ma on Moly:, Macpherson and reticon helium signals ok. Zeff may be increasing slightly towards the end of the shot, Prad fairly contant. |
| Jun 23 1994 05:18:17:880PM | 940623028 | Gary McCracken | Background shot, same nominal density as last shot
Good shot. nel05 increase throughout diverted part of shot from 5 to 6.3 e19, slightly less than last shot. Could this be due to the lack of helium?. 0ma on Moly:, Macpherson and reticon helium signals ok. |
| Jun 23 1994 07:39:24:450PM | 940623028 | Gary McCracken | Summary:
Overall a very successful day with the main objectives of miniproposal 44 being achieved. These were (1) To puff He Ne and Ar into the private flux zone in the divertor and to measure how much gets into the confined plasma, thereby being able to estimate screening factors for impurities which can be compared to theory. (2) To measure the amount of molybdenum sputtered by injected impurities as a function of the target electron temperature and hence to get some information on the sheath potential We managed to puff in Ar,Ne and He in successive discharge at 2 main densities, nel05=5e19 and 1e20 m^-2. Measurements were made in most cases, with the Macpherson to get a line integral of the impurity concentration in the confined plasma, the oma to get the impurities in the divertor, the Hirex system for the central argon density and the reticon system with filters to get the poloidal distribution of the helium from the Btop array. Good background shots were obtained for both densities. This should allow us to calculate some impurity screening factors. Unfortunately the reticon filters for NeI and ArI do not seem to provide good signals. We also have some data from the oma for the amount of Mo sputtered by the injected impurity gases. There seems to be reasonable evidence for sputtering of Mo by Ar, but it is not so clear as yet for sputtering by Ne or He. In addition to the main objective we also observed some very distinct divertor detachm |
| Physics Operator Comments | |||
| Jun 23 1994 08:34:51:220AM | Robert Granetz | Mini-proposal #44, Impurity transport and impurity sputtering in the divertor.
Plan: a) Argon injection in divertor, measure source rates and plasma concentration. Determine screening efficiency. Repeat over a range of densities. b) Neon injection in divertor, measure source rates and plasma concentration. Determine screening efficiency. Repeat over a range of densities. c) (If enough time) helium injection in divertor, measure source rates and plasma concentration. Determine screening efficiency. Repeat over a range of densities. We will start with shot 940621022, except that density feedback will be setup on wire 09 in segment 2 (after the fiducial shot, 940603015). | |
| Jun 23 1994 08:45:28:010AM | 940623001 | Robert Granetz | Fiducial shot was a fizzle. For next shot, load in 940621022, with density
feedback enabled. |
| Jun 23 1994 08:46:14:610AM | 940623001 | Robert Granetz | Argon I filter inserted in B-top array.
|
| Jun 23 1994 09:16:36:960AM | 940623002 | Robert Granetz | Fizzle. No ECDC was done this morning. Steve Horne's statistics program
indicates that the gas pressure was a little high. Next shot, reduce pre-fill to 1.0e-5 torr. |
| Jun 23 1994 09:22:08:560AM | 940623003 | Robert Granetz | Fizzle. Null looks pretty good. Next shot, increase BR by 0.5 mT.
|
| Jun 23 1994 09:27:14:760AM | 940623004 | Robert Granetz | Runaway shot. Next shot, increase pre-fill from 1.0 to 1.2e-5.
|
| Jun 23 1994 09:52:12:620AM | 940623005 | Robert Granetz | Plasma. Ip=0.8 MA, duration=1.2 s. Plasma current ramps down to 0.4 MA before
terminating in a disruption. Nicely diverted from t=0.60 to 1.00 s. There was no argon puffing on this shot. Next shot, enable the NINJA injection system with argon for the next shot. |
| Jun 23 1994 10:16:05:000AM | 940623006 | Robert Granetz | Plasma. Seems to become disruptive at 0.66 s. Some argon signal seen
on the McPherson, but not much difference on the B-top reticon array. Plasma terminates at 1.11 s in a disruption. Next shot, move CLEARIN to -3 after t=1.0 s to try and alleviate this. Also, increase argon gas puff. |
| Jun 23 1994 10:44:00:990AM | 940623007 | Robert Granetz | This shot was delayed for 15 minutes due to a TMX circuit breaker problem.
Bad plasma shot. Disruption terminated at 0.35 s. There were also some hard x-rays early on. The pre-fill is already at 1.2e-5, so I'm not going to change that. I hope these problems were caused by the extra long wait between shots. No changes for next shot. |
| Jun 23 1994 10:58:30:060AM | 940623008 | Robert Granetz | Another short shot, nearly identical to the previous one, except no hard x-rays
All the radiation signals (HIREX on argon, 2pi bolo, x-rays, Zeff) all start climbing precipitously around 0.3 s. Next shot, delay argon injection by 0.25 s. Also, change segment switching time from 0.25 to 0.30 s. |
| Jun 23 1994 11:10:43:520AM | 940623009 | Robert Granetz | Better plasma. Terminated by disruption at 0.85 s. Argon comes in later
than before, and also the HIREX argon signal increases strongly starting at about 0.6 s. I think the disruption was due to too much argon. Next shot, no PCS changes, but the argon plenum pressure will be reduced. |
| Jun 23 1994 11:27:56:500AM | 940623010 | Robert Granetz | This shot was delayed due to a camac init failure on the high voltage bus
instrumentation. A little better. Terminated by a disruption at 0.95 s, but it looks like things were beginning to decrapitate about 50 ms earlier. Next shot, no argon injection. |
| Jun 23 1994 12:01:22:370PM | 940623011 | Robert Granetz | Good shot. Plasma terminates at 1.17 s. Current ramps down to about 400 kA.
This shot had no argon puffing, and the residual argon signals drop noticeably when the plasma diverts. Next shot, increase density from nl=5.e19 to 8.e19. I just noticed that the change I made to CLEARIN after 1.0 s was made in segment 1, not segment 2. For the next shot, The CLEARIN demand in segment 1 was copied to segment 2. (The change is to reduce CLEARIN after 1.0 s.) |
| Jun 23 1994 12:07:25:500PM | 940623011 | Robert Granetz | The next shot will also have argon puffing again.
|
| Jun 23 1994 12:17:53:660PM | 940623012 | Robert Granetz | Great shot. Current ramped all the way down. Ip=0.81 MA, duration=1.3 s.
This was a good fiducial shot for diverted plasmas at 0.8 MA. Density also responded nicely to the increased demand. NL_07=8e19 m-2, as requested. Contrary to our directions, there was no argon puff on this shot. Next shot will have argon. No other changes. |
| Jun 23 1994 12:41:24:360PM | 940623013 | Robert Granetz | Good plasma. Terminates in a disruption at 1.13 s, part way down the current
ramp. Density was not as flat as previous shot (argon maybe?). Next shot, switch to neon injection. I changed the B-top filter to Neon I. |
| Jun 23 1994 01:01:14:310PM | 940623014 | Robert Granetz | Another great diverted shot. Duration=1.24 s. Spectroscopic signals
are kind of weak. As with the previous good shots, there is a huge increase in Halpha and plasma density at 1.1 s when the plasma becomes re-limited. Next shot, repeat, except start neon injection 0.100 s earlier. |
| Jun 23 1994 01:16:25:380PM | 940623015 | Robert Granetz | Another great shot. Very similar to the previous one.
Next shot, exact repeat. |
| Jun 23 1994 01:38:24:780PM | 940623016 | Robert Granetz | Another great shot. Current ramps down to 100 kA at 1.29 s.
For the next shot, bring the density demand down very quickly after 1.000 s, and move the TF invert time from 1.3 s to 1.1 s. Also, no neon on the next shot. |
| Jun 23 1994 02:09:12:450PM | 940623017 | Robert Granetz | Something strange happened on that shot. The power supplies fired before
the voice prompt had counted down. Dud. But I'll chalk it up to an engineering problem. Repeat with no changes. |
| Jun 23 1994 02:20:35:960PM | 940623018 | Robert Granetz | Another great shot. This shot had no neon injection.
Next shot, reduce density demand from nl=8e19 to 5e19 m-2. Also turn on neon puff again. |
| Jun 23 1994 02:24:59:710PM | 940623018 | Robert Granetz | Also for the next shot, move TF invert time from 1.1 to 1.0 s.
|
| Jun 23 1994 02:29:10:070PM | 940623019 | Robert Granetz | Several power supplies failed to turn on, including the TF, OH1, and the
EF1's. Dud. Next shot, try again with no changes. |
| Jun 23 1994 02:53:24:080PM | 940623020 | Robert Granetz | Reasonably good plasma, but there were some serious molybdenum injections
that took a divot out of the plasma current and caused the density feedback to work extra hard. We got the lower density, as requested. Next shot, increase the neon puff. |
| Jun 23 1994 03:07:30:620PM | 940623021 | Robert Granetz | Reasonably good shot, but it was terminated by a disruption at 1.06 s, just
after the beginning of rampdown. Density was around 5e19, as requested. Plasma current showed signs of drooping a little after 0.9 s. Maybe there really is a correlation with larger impurity gas puffs. Ihalo_L=70 kA. Next shot, increase density from nl=5e19 to 1.5e20. |
| Jun 23 1994 03:25:09:770PM | 940623022 | Robert Granetz | Reasonably good shot. Terminated in a disruption at 1.08 s, partway down the
current ramp. The density didn't come close to the demand until the plasma detached at 0.78 s. (The deuterium gas valve had 100 volts on it for the entire duration of feedback.) Ihalo_L=60 kA. Next shot, no neon injection. Same high density demand. |
| Jun 23 1994 03:39:33:890PM | 940623022 | Robert Granetz | For this shot, Jim Terry mistakenly changed the B-top reticon filter from
Neon I to Helium I. |
| Jun 23 1994 03:45:31:980PM | 940623023 | Robert Granetz | Good plasma. Terminated by a disruption at 1.12 s, halfway through the
rampdown. Density was similar to the previous shot (nl=0.8-1.2e20 m-2). Very similar to previous shot, including the time at which plasma detached. Ihalo_L=45 kA. Next shot, lower density demand from nl=1.5e20 to 8e19 m-2. Also start puffing in helium. Change filter in Btop and Bside to be Helium I. |
| Jun 23 1994 04:02:35:520PM | 940623024 | Robert Granetz | Good plasma. Plasma terminated at 1.15 s, most of the way down the current
ramp. There were two molybdenum injections. nl=0.8-0.9e19, as requested. Mike Graf reports seeing helium on the McPherson. Ihalo_L=25-30 kA. Next shot, larger helium puff. |
| Jun 23 1994 04:19:41:530PM | 940623025 | Robert Granetz | Another good shot. Density was nl=0.8-0.9e20, as requested. Terminated at
t=1.16 s. Negligible halo currents. Next shot, no helium injection. |
| Jun 23 1994 04:38:17:540PM | 940623026 | Robert Granetz | Another good shot. Plasma terminates at 1.17 s. Reasonable density control,
about nl=9e19 m-2. Next shot, lower density demand to nl=5e19 m-2, and turn back on the helium puff. |
| Jun 23 1994 04:53:35:810PM | 940623027 | Robert Granetz | Another good shot. Terminates at 1.16. Got the lower density, nl=5e19 m-2,
as requested. There was an event on the H-alpha around 0.4 s...cause is unknown. Next shot, repeat except with no helium puffing. That will be the last shot of the day. |
| Jun 23 1994 05:05:44:550PM | 940623028 | Robert Granetz | Another good plasma. Ip=0.80 MA, duration=1.30 s. Slightly better density
control. Good day. End of run. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:39:18:940AM | Plasma | Ok | no faults |
| 2 | 08:59:14:580AM | Plasma | Ok | no faults |
| 3 | 09:12:57:520AM | Plasma | Ok | no faults |
| 4 | 09:23:52:930AM | Plasma | Ok | no faults |
| 5 | 09:33:44:420AM | Plasma | Ok | no faults |
| 6 | 09:54:49:620AM | Plasma | Ok | disruption induced comm fails in oh1, oh2 and ef1 |
| 7 | 10:18:53:860AM | Plasma | Ok | no faults |
| 8 | 10:46:17:120AM | Plasma | Ok | no faults |
| 9 | 10:58:30:990AM | Plasma | Ok | disruption induced comm fail ef1l |
| 10 | 11:15:27:640AM | Plasma | Ok | disruption induced comm faults in ef1 and oh1 |
| 11 | 11:34:53:920AM | Plasma | Ok | no faults |
| 12 | 12:02:06:870PM | Plasma | Ok | no faults |
| 13 | 12:22:04:200PM | Plasma | Ok | no faults |
| 14 | 12:42:00:290PM | Plasma | Ok | no faults |
| 15 | 01:04:58:690PM | Plasma | Ok | Nice 800 kA discharge |
| 16 | 01:24:31:440PM | Plasma | Ok | another nice shot; 150 MJ delivered to magnets |
| 17 | 01:53:04:960PM | Plasma | Ok | dud! 7 camac errors; can't see much data. |
| 18 | 02:04:28:150PM | Plasma | Ok | Nice host; 8 DAQ3 Camac TMO errors; cycled power to 4 crates |
| 19 | 02:23:46:640PM | Plasma | Bad | TF and OH1 did not fire |
| 20 | 02:39:53:110PM | Plasma | Ok | 400 ka disruption during rampdown |
| 21 | 02:58:33:720PM | Plasma | Ok | 800 kA disruption |
| 22 | 03:11:37:840PM | Plasma | Ok | 600 kA disruption |
| 23 | 03:36:47:390PM | Plasma | Ok | 400 kA disruption, no faults |
| 24 | 03:49:28:650PM | Plasma | Ok | 300 kA disruption |
| 25 | 04:12:45:170PM | Plasma | Ok | 300 kA disruption |
| 26 | 04:30:01:960PM | Plasma | Ok | 300 kA disruption |
| 27 | 04:42:11:250PM | Plasma | Ok | 350 kA disruption, no data from most engineering camac |
| 28 | 04:58:21:320PM | Plasma | Ok | Plasma ramped down further with TF extended to 1.3 |