Miniproposals

Miniproposal: 161 Date Filed: 7/18/1996 Title: JET/C-Mod Dimensionless Identity Experiments First Author: Ian Hutchinson Session Leader: Ian Hutchinson (shots 1-42)

Engineering Operator Run Comment

mp 971218 hutchinson silva,cochran,bertolino

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:17:553PM

Author: To Be Determined

Run summary 971222. Additional run on Jet Similarity and Control. _________________________________________________________________ SL/PO Hutch. EO Various. Overview. _________ The plan was to try to get reliable JET shapes with the vertical control problem fixed and then heat them. We made some progress and got 2MW RF into JET shaped plasmas. However, it is clear that these JET shapes yield ELM-free H-modes, which have the usual impurity accumulation problem and are difficult to couple RF to. The same shape at 1MA is also ELM-free, whereas the normal, higher triangularity shape at 1MA and everything else the same are EDA. This seems to be strongly suggestive that it really is the triangularity that controls the EDA, although there are of course simultaneous changes in the divertor strike-point geometry that also could have an effect. Physop Stuff. _____________ We had lots of fizzles today. Power supplies did not seem to be very reproducible at initiation. We were getting roughly 1-2mT random variations in the Bz and as much as 1mT on Br. Shot 10 had a 1.2MA disruption. After that the initiation was different in that the rogowski read 34kA when there was no plasma. This is about 50% higher than the normal value, which we had been getting up till then. It would appear that we have done something to the machine that has changed the apparent conductivity of the stuff that links the rogowski coil. (The other possibility, of there being an intrumentation problem, is not ruled out but there clearly was a change to the initiation that could not be due to a change in the rogowski signal alone.) At the end of the day I reloaded shot 2 segment 1 and got a dud. This proves that a combination of the internals change and/or the power-supply irreproducibility has significantly changed the initiation. Vertical control was very ticklish for the JET shape, and in view of previous problems and clear incipient instabilities, I did not push the elongation. Instead the gains on first the fast (3) and then the slow (2) zcur were lowered. Lowering the fast gain without the slow did not seem to help. Lowering the slow gain to 1 (from 1.5) in addition, seemed to help. However this is hardly definitive. I do not think that it would be profitable to keep trying for a better JET similarity shot until we have reason to believe that machine conditions are improved, either RF conditioning or otherwise better impurity control. Alternatively, if we figure out how to get EDA modes in the low triangularity (which seems less likely) that would be good. The shot to load then (segment 2) is probably 32. Scorecard. __________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.018 2 1.650 0.823 3 1.685 0.833 4 1.445 1.205 5 0.000 0.027 6 1.719 1.221 7 0.000 0.027 8 1.716 1.221 9 0.000 0.032 10 1.062 1.246 11 0.000 0.037 12 0.000 0.042 13 0.000 0.042 14 0.000 0.037 15 0.000 0.042 16 0.373 0.879 17 0.000 0.042 18 1.687 0.843 19 0.000 0.042 20 1.705 0.843 21 1.720 1.236 22 0.837 1.293 23 1.426 1.231 24 0.984 1.231 25 0.000 0.037 26 0.000 0.037 27 0.000 0.005 28 1.475 1.231 29 1.718 1.236 30 1.718 1.236 31 0.000 0.037 32 1.718 1.236 33 0.000 0.037 34 0.000 0.042 35 0.000 0.042 36 0.321 0.807 37 1.724 1.040 38 1.716 1.029 39 0.000 0.042 40 1.717 1.029 41 0.000 0.027 42 0.370 0.885 Finished summary for 971222 Total of 42 shots. 42 shots. 22 plasmas. 18 fizzles. 2 duds. Fizzle = gt 20 lt 50kA. Details _______ -------------------------------------------------------------------------------- 971222xxx HUTCH PHYSICS_OPERATOR 22-DEC-1997 08:46:13.84 Extra Run. Shape stability and desity control at higher current. JET Similarity if possible. 30 psi D2 1 psi Ar. Did cold start. No errors. pcs Import segment 4 to segment 2. Ar pulse to 22ms. Import seg 2 to seg 4. Change to fiducial is to increase the Ar pulse to 22ms. This is not a significant change since Ar is normally off. Load. RF has a problem on FMIT 1 high voltage. This must be looked at. -------------------------------------------------------------------------------- 971222001 HUTCH PHYSICS_OPERATOR 22-DEC-1997 08:55:50.56 OH test. -------------------------------------------------------------------------------- 971222002 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:07:36.54 Fiducial shot but with only one transmitter. Long current pause but eventually went. No H-mode. Put in two steps to the zcur in segment 2. They are from -.015 to -.0146 (i.e. 0.4mm) in 1ms, and back. This should put an impulse on the vertical position. Raise fill to 18ms. -------------------------------------------------------------------------------- 971222003 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:22:07.90 Plasma. Got H-mode. Current-rise density is perhaps a bit high. But gas flow is only a total of about 15 torr-l. No zcur effects are visible. Interferometer gate-valve closes at 1s. Import segment 2 from 971217007 -------------------------------------------------------------------------------- 971222004 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:41:09.44 Plasma till1.45s. No H-mode. Reduce zcur fast gain to 6 at .22s. Rduce the puff V to about 40V. -------------------------------------------------------------------------------- 971222005 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:55:22.55 Fizzle. EF4 to -1340 from -1345 Bz a tad low. Also mflux shows some slight Br but in the past it has liked it. Put in a 1mm zcur step from .5s to .55s -------------------------------------------------------------------------------- 971222006 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:11:51.67 Plasma till 1.7s, H-mode at .95s. RF trips out. Major impurity accumulation. Increase zcur step to 2mm. -------------------------------------------------------------------------------- 971222007 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:19:58.05 Fizzle EF4 to -1335. Br offset to 5.8 from 6.0 mT. -------------------------------------------------------------------------------- 971222008 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:31:09.42 Plasma till 1.7s. ELM-free H-mode with accumulation. RF1.6MW. A couple of trips. 170 kJ. nl04 to 2.8e20. zcur gain to 5 at .22s. rcur to .667 from .668 at .9s. Enable argon. -------------------------------------------------------------------------------- 971222009 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:51:32.78 Fizzle. Slightly late breakdown. Br is somewhat higher this shot. It is not reproducible. EF4 to 1340. Br offset to 5.5mT. -------------------------------------------------------------------------------- 971222010 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:04:28.60 Plasma. Disruption at 1.05s. Cuased by grwoing vertical instability. No H-mode. We can see a 90Hz oscillation on this and shot 8 at .55s induced by the zcur step. This must be fixed first. Set Rcur back to .668. zcur P to 3.8 at .6s. -------------------------------------------------------------------------------- 971222011 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:16:29.52 Fizzle. Late breakdown. CII .004. 45kA but this is really strange because the light goes away and we still have a lot of measured current. I hope we haven't done something bad. Br offset to 5.2 mT. -------------------------------------------------------------------------------- 971222011 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:47:41.27 I just noticed that the zcur trace is much higher also for this shot after the disruption. It certainly looks as if something changed significantly. -------------------------------------------------------------------------------- 971222012 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:27:45.21 Fizzle. Current trace stays funny. Same late breakdown: 8.5ms. It looks as if the non-plasma conductivity of whatever links the rogowski has increased by about 50% following the disruption on shot 10. Also breakdown is significantly delayed. EF4 to -1345. -------------------------------------------------------------------------------- 971222013 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:38:11.28 Fizzle. Slightly earlier breakdown. Current trace still high. EF4 to -1350. Fill puff to 20ms. -------------------------------------------------------------------------------- 971222014 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:47:30.04 Fizzle. breakdown back to 6ms. Rcur offset to 6000 from 6300 in segment 1. -------------------------------------------------------------------------------- 971222015 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:56:53.82 Fizzle. rcur offset to 5800. ef4 to -1355. -------------------------------------------------------------------------------- 971222016 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:13:33.63 Plasma disrupts at .37s. 0.8MA. Vertical instability at about 100 Hz. This is well before any of the zcur changes. Not clear why. The OH2s are not in antiphase. OH2U seems to lead OH2L by about 3ms. Shut Mcpherson and Mo monitor. Because there seemed to be a gas puff. Reload shot 3 fiducial into segment 2. -------------------------------------------------------------------------------- 971222017 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:27:12.27 Fizzle. The gas puff was gone. Enable Mo monitor gate valve. rcur segment 1 offset to 5500. -------------------------------------------------------------------------------- 971222018 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:38:47.41 Fiducial plasma. FMIT 1 is back. H-modes with trips a voltage limits. OH2 V to 0V at .01s from 20V. zcur2 D to 1. from 1.5. The old ratio of D/P in physicsl units was 1ms. -------------------------------------------------------------------------------- 971222019 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:43:14.98 Fizzle. Br to 4.5mT in segment 1. -------------------------------------------------------------------------------- 971222020 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:03:33.16 Plasma. Big injection at .7s. RF got 2.6MW. 130 kJ. Import seg 2 from shot 11 to seg 2. Seg 1 rcur offset to 5800 from 5500. Slow zcur to D=1. from 1.5. -------------------------------------------------------------------------------- 971222021 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:13:01.61 Plasma. ELM-free H-modes. Still incipient instabilities. zcur 3 to 4 at .22s. and to 4.2 at .95s. -------------------------------------------------------------------------------- 971222022 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:23:19.34 Plasma disrupts at .83s. A brick. Repeat. -------------------------------------------------------------------------------- 971222023 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:42:52.73 Plasma till 1.4s. 2MW RF ELM-free. Accumulation. zcur 3 to P=3.6 at .95s. zcur 2 to D=.5 at .7s. -------------------------------------------------------------------------------- 971222024 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:58:08.59 Plasma. Disrupts at 1s. Vertical thrash as it drops out of H-mode. OH fuse blows. No, bad reading. Reduce zcur 2 gain to 1 from 1.5 at .65s. -------------------------------------------------------------------------------- 971222025 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:05:50.68 Fizzle. No-light current is now 34kA. CII to .006. Big excursion on Br. Repeat. -------------------------------------------------------------------------------- 971222026 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:17:37.37 Fizzle. Br and Bz seems to be rather erratic. Repeat. -------------------------------------------------------------------------------- 971222027 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:18:07.89 Mgnet resistance fault. No power supplies. -------------------------------------------------------------------------------- 971222028 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:40:24.80 Plasma. Nice current rise. Lower puff V to 35V. nl04 demand to 1e20 from 12.e20. -------------------------------------------------------------------------------- 971222029 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:52:37.27 Plasma. 3 H-modes, ELM free. -------------------------------------------------------------------------------- 971222030 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:05:08.10 Plasma. Slightly longer H phases. Fewer RF trips. 2MW RF. 178kJ. Disable argon. -------------------------------------------------------------------------------- 971222031 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:13:27.33 Fizzle. No-light current 35kA. Br offset to 5mT from 4.5mT -------------------------------------------------------------------------------- 971222032 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:28:15.75 Plasma. No EDA. Injection on RF trip. 180kJ. Lower Ip to 1MA. Reenable argon. -------------------------------------------------------------------------------- 971222033 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:35:06.58 Fizzle. Fill puff to 18ms. -------------------------------------------------------------------------------- 971222034 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:44:04.20 Fizzle. EF3 V to 1800 at 12 to 20 ms, from 2000V. -------------------------------------------------------------------------------- 971222035 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:50:54.24 Fizzle. EF3 V back to 2100-2000V. Rcur offset to 6000. -------------------------------------------------------------------------------- 971222036 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:03:20.66 Plasma for .325s. Hit by a brick. EF3 to 2300 at 12ms. -------------------------------------------------------------------------------- 971222037 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:18:00.59 Plasma. ELM free at 2MW RF, one trip. 150kJ. RXL, ZXL to 0, RXU to -.015 from -.025 -------------------------------------------------------------------------------- 971222038 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:30:15.32 Plasma. EDA mode, but with some big injections. Tweak up EF3 at 7 to 10 ms. zxu to .045, rxu to .005. -------------------------------------------------------------------------------- 971222039 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:36:57.07 Fizzle. Repeat -------------------------------------------------------------------------------- 971222040 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:51:11.22 Plasma. EDA, but quite a lot of radiation. Import segment one from shot 2. This is where we started. nl04 to 14.e20. -------------------------------------------------------------------------------- 971222041 HUTCH PHYSICS_OPERATOR 22-DEC-1997 17:06:36.79 Dud. Clear verification of (1) 34 kA of no-plasma current. (2) Completely different (non)-startup. Load segment 1 from shot 40, the last that went. -------------------------------------------------------------------------------- 971222042 HUTCH PHYSICS_OPERATOR 22-DEC-1997 17:08:09.09 Plasma Disrupts at .36s. Growing vertical instability. Perhaps enhanced by the stronger gas puff for higher density.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:58:333PM

Author: To Be Determined

Run summary 971222. Additional run on Jet Similarity and Control. _________________________________________________________________ SL/PO Hutch. EO Various. Overview. _________ The plan was to try to get reliable JET shapes with the vertical control problem fixed and then heat them. We made some progress and got 2MW RF into JET shaped plasmas. However, it is clear that these JET shapes yield ELM-free H-modes, which have the usual impurity accumulation problem and are difficult to couple RF to. The same shape at 1MA is also ELM-free, whereas the normal, higher triangularity shape at 1MA and everything else the same are EDA. This seems to be strongly suggestive that it really is the triangularity that controls the EDA, although there are of course simultaneous changes in the divertor strike-point geometry that also could have an effect. Physop Stuff. _____________ We had lots of fizzles today. Power supplies did not seem to be very reproducible at initiation. We were getting roughly 1-2mT random variations in the Bz and as much as 1mT on Br. Shot 10 had a 1.2MA disruption. After that the initiation was different in that the rogowski read 34kA when there was no plasma. This is about 50% higher than the normal value, which we had been getting up till then. It would appear that we have done something to the machine that has changed the apparent conductivity of the stuff that links the rogowski coil. (The other possibility, of there being an intrumentation problem, is not ruled out but there clearly was a change to the initiation that could not be due to a change in the rogowski signal alone.) At the end of the day I reloaded shot 2 segment 1 and got a dud. This proves that a combination of the internals change and/or the power-supply irreproducibility has significantly changed the initiation. Vertical control was very ticklish for the JET shape, and in view of previous problems and clear incipient instabilities, I did not push the elongation. Instead the gains on first the fast (3) and then the slow (2) zcur were lowered. Lowering the fast gain without the slow did not seem to help. Lowering the slow gain to 1 (from 1.5) in addition, seemed to help. However this is hardly definitive. I do not think that it would be profitable to keep trying for a better JET similarity shot until we have reason to believe that machine conditions are improved, either RF conditioning or otherwise better impurity control. Alternatively, if we figure out how to get EDA modes in the low triangularity (which seems less likely) that would be good. The shot to load then (segment 2) is probably 32. Scorecard. __________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.018 2 1.650 0.823 3 1.685 0.833 4 1.445 1.205 5 0.000 0.027 6 1.719 1.221 7 0.000 0.027 8 1.716 1.221 9 0.000 0.032 10 1.062 1.246 11 0.000 0.037 12 0.000 0.042 13 0.000 0.042 14 0.000 0.037 15 0.000 0.042 16 0.373 0.879 17 0.000 0.042 18 1.687 0.843 19 0.000 0.042 20 1.705 0.843 21 1.720 1.236 22 0.837 1.293 23 1.426 1.231 24 0.984 1.231 25 0.000 0.037 26 0.000 0.037 27 0.000 0.005 28 1.475 1.231 29 1.718 1.236 30 1.718 1.236 31 0.000 0.037 32 1.718 1.236 33 0.000 0.037 34 0.000 0.042 35 0.000 0.042 36 0.321 0.807 37 1.724 1.040 38 1.716 1.029 39 0.000 0.042 40 1.717 1.029 41 0.000 0.027 42 0.370 0.885 Finished summary for 971222 Total of 42 shots. 42 shots. 22 plasmas. 18 fizzles. 2 duds. Fizzle = gt 20 lt 50kA. Details _______ -------------------------------------------------------------------------------- 971222xxx HUTCH PHYSICS_OPERATOR 22-DEC-1997 08:46:13.84 Extra Run. Shape stability and desity control at higher current. JET Similarity if possible. 30 psi D2 1 psi Ar. Did cold start. No errors. pcs Import segment 4 to segment 2. Ar pulse to 22ms. Import seg 2 to seg 4. Change to fiducial is to increase the Ar pulse to 22ms. This is not a significant change since Ar is normally off. Load. RF has a problem on FMIT 1 high voltage. This must be looked at. -------------------------------------------------------------------------------- 971222001 HUTCH PHYSICS_OPERATOR 22-DEC-1997 08:55:50.56 OH test. -------------------------------------------------------------------------------- 971222002 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:07:36.54 Fiducial shot but with only one transmitter. Long current pause but eventually went. No H-mode. Put in two steps to the zcur in segment 2. They are from -.015 to -.0146 (i.e. 0.4mm) in 1ms, and back. This should put an impulse on the vertical position. Raise fill to 18ms. -------------------------------------------------------------------------------- 971222003 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:22:07.90 Plasma. Got H-mode. Current-rise density is perhaps a bit high. But gas flow is only a total of about 15 torr-l. No zcur effects are visible. Interferometer gate-valve closes at 1s. Import segment 2 from 971217007 -------------------------------------------------------------------------------- 971222004 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:41:09.44 Plasma till1.45s. No H-mode. Reduce zcur fast gain to 6 at .22s. Rduce the puff V to about 40V. -------------------------------------------------------------------------------- 971222005 HUTCH PHYSICS_OPERATOR 22-DEC-1997 09:55:22.55 Fizzle. EF4 to -1340 from -1345 Bz a tad low. Also mflux shows some slight Br but in the past it has liked it. Put in a 1mm zcur step from .5s to .55s -------------------------------------------------------------------------------- 971222006 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:11:51.67 Plasma till 1.7s, H-mode at .95s. RF trips out. Major impurity accumulation. Increase zcur step to 2mm. -------------------------------------------------------------------------------- 971222007 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:19:58.05 Fizzle EF4 to -1335. Br offset to 5.8 from 6.0 mT. -------------------------------------------------------------------------------- 971222008 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:31:09.42 Plasma till 1.7s. ELM-free H-mode with accumulation. RF1.6MW. A couple of trips. 170 kJ. nl04 to 2.8e20. zcur gain to 5 at .22s. rcur to .667 from .668 at .9s. Enable argon. -------------------------------------------------------------------------------- 971222009 HUTCH PHYSICS_OPERATOR 22-DEC-1997 10:51:32.78 Fizzle. Slightly late breakdown. Br is somewhat higher this shot. It is not reproducible. EF4 to 1340. Br offset to 5.5mT. -------------------------------------------------------------------------------- 971222010 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:04:28.60 Plasma. Disruption at 1.05s. Cuased by grwoing vertical instability. No H-mode. We can see a 90Hz oscillation on this and shot 8 at .55s induced by the zcur step. This must be fixed first. Set Rcur back to .668. zcur P to 3.8 at .6s. -------------------------------------------------------------------------------- 971222011 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:16:29.52 Fizzle. Late breakdown. CII .004. 45kA but this is really strange because the light goes away and we still have a lot of measured current. I hope we haven't done something bad. Br offset to 5.2 mT. -------------------------------------------------------------------------------- 971222011 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:47:41.27 I just noticed that the zcur trace is much higher also for this shot after the disruption. It certainly looks as if something changed significantly. -------------------------------------------------------------------------------- 971222012 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:27:45.21 Fizzle. Current trace stays funny. Same late breakdown: 8.5ms. It looks as if the non-plasma conductivity of whatever links the rogowski has increased by about 50% following the disruption on shot 10. Also breakdown is significantly delayed. EF4 to -1345. -------------------------------------------------------------------------------- 971222013 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:38:11.28 Fizzle. Slightly earlier breakdown. Current trace still high. EF4 to -1350. Fill puff to 20ms. -------------------------------------------------------------------------------- 971222014 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:47:30.04 Fizzle. breakdown back to 6ms. Rcur offset to 6000 from 6300 in segment 1. -------------------------------------------------------------------------------- 971222015 HUTCH PHYSICS_OPERATOR 22-DEC-1997 11:56:53.82 Fizzle. rcur offset to 5800. ef4 to -1355. -------------------------------------------------------------------------------- 971222016 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:13:33.63 Plasma disrupts at .37s. 0.8MA. Vertical instability at about 100 Hz. This is well before any of the zcur changes. Not clear why. The OH2s are not in antiphase. OH2U seems to lead OH2L by about 3ms. Shut Mcpherson and Mo monitor. Because there seemed to be a gas puff. Reload shot 3 fiducial into segment 2. -------------------------------------------------------------------------------- 971222017 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:27:12.27 Fizzle. The gas puff was gone. Enable Mo monitor gate valve. rcur segment 1 offset to 5500. -------------------------------------------------------------------------------- 971222018 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:38:47.41 Fiducial plasma. FMIT 1 is back. H-modes with trips a voltage limits. OH2 V to 0V at .01s from 20V. zcur2 D to 1. from 1.5. The old ratio of D/P in physicsl units was 1ms. -------------------------------------------------------------------------------- 971222019 HUTCH PHYSICS_OPERATOR 22-DEC-1997 12:43:14.98 Fizzle. Br to 4.5mT in segment 1. -------------------------------------------------------------------------------- 971222020 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:03:33.16 Plasma. Big injection at .7s. RF got 2.6MW. 130 kJ. Import seg 2 from shot 11 to seg 2. Seg 1 rcur offset to 5800 from 5500. Slow zcur to D=1. from 1.5. -------------------------------------------------------------------------------- 971222021 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:13:01.61 Plasma. ELM-free H-modes. Still incipient instabilities. zcur 3 to 4 at .22s. and to 4.2 at .95s. -------------------------------------------------------------------------------- 971222022 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:23:19.34 Plasma disrupts at .83s. A brick. Repeat. -------------------------------------------------------------------------------- 971222023 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:42:52.73 Plasma till 1.4s. 2MW RF ELM-free. Accumulation. zcur 3 to P=3.6 at .95s. zcur 2 to D=.5 at .7s. -------------------------------------------------------------------------------- 971222024 HUTCH PHYSICS_OPERATOR 22-DEC-1997 13:58:08.59 Plasma. Disrupts at 1s. Vertical thrash as it drops out of H-mode. OH fuse blows. No, bad reading. Reduce zcur 2 gain to 1 from 1.5 at .65s. -------------------------------------------------------------------------------- 971222025 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:05:50.68 Fizzle. No-light current is now 34kA. CII to .006. Big excursion on Br. Repeat. -------------------------------------------------------------------------------- 971222026 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:17:37.37 Fizzle. Br and Bz seems to be rather erratic. Repeat. -------------------------------------------------------------------------------- 971222027 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:18:07.89 Mgnet resistance fault. No power supplies. -------------------------------------------------------------------------------- 971222028 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:40:24.80 Plasma. Nice current rise. Lower puff V to 35V. nl04 demand to 1e20 from 12.e20. -------------------------------------------------------------------------------- 971222029 HUTCH PHYSICS_OPERATOR 22-DEC-1997 14:52:37.27 Plasma. 3 H-modes, ELM free. -------------------------------------------------------------------------------- 971222030 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:05:08.10 Plasma. Slightly longer H phases. Fewer RF trips. 2MW RF. 178kJ. Disable argon. -------------------------------------------------------------------------------- 971222031 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:13:27.33 Fizzle. No-light current 35kA. Br offset to 5mT from 4.5mT -------------------------------------------------------------------------------- 971222032 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:28:15.75 Plasma. No EDA. Injection on RF trip. 180kJ. Lower Ip to 1MA. Reenable argon. -------------------------------------------------------------------------------- 971222033 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:35:06.58 Fizzle. Fill puff to 18ms. -------------------------------------------------------------------------------- 971222034 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:44:04.20 Fizzle. EF3 V to 1800 at 12 to 20 ms, from 2000V. -------------------------------------------------------------------------------- 971222035 HUTCH PHYSICS_OPERATOR 22-DEC-1997 15:50:54.24 Fizzle. EF3 V back to 2100-2000V. Rcur offset to 6000. -------------------------------------------------------------------------------- 971222036 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:03:20.66 Plasma for .325s. Hit by a brick. EF3 to 2300 at 12ms. -------------------------------------------------------------------------------- 971222037 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:18:00.59 Plasma. ELM free at 2MW RF, one trip. 150kJ. RXL, ZXL to 0, RXU to -.015 from -.025 -------------------------------------------------------------------------------- 971222038 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:30:15.32 Plasma. EDA mode, but with some big injections. Tweak up EF3 at 7 to 10 ms. zxu to .045, rxu to .005. -------------------------------------------------------------------------------- 971222039 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:36:57.07 Fizzle. Repeat -------------------------------------------------------------------------------- 971222040 HUTCH PHYSICS_OPERATOR 22-DEC-1997 16:51:11.22 Plasma. EDA, but quite a lot of radiation. Import segment one from shot 2. This is where we started. nl04 to 14.e20. -------------------------------------------------------------------------------- 971222041 HUTCH PHYSICS_OPERATOR 22-DEC-1997 17:06:36.79 Dud. Clear verification of (1) 34 kA of no-plasma current. (2) Completely different (non)-startup. Load segment 1 from shot 40, the last that went. -------------------------------------------------------------------------------- 971222042 HUTCH PHYSICS_OPERATOR 22-DEC-1997 17:08:09.09 Plasma Disrupts at .36s. Growing vertical instability. Perhaps enhanced by the stronger gas puff for higher density.

Session Leader Comments

Physics Operator Comments
Dec 22 1997 08:46:13:840AM		Ian Hutchinson	Extra Run. Shape stability and desity control at higher current. JET Similarity if possible. 30 psi D2 1 psi Ar. Did cold start. No errors. pcs Import segment 4 to segment 2. Ar pulse to 22ms. Import seg 2 to seg 4. Change to fiducial is to increase the Ar pulse to 22ms. This is not a significant change since Ar is normally off. Load. RF has a problem on FMIT 1 high voltage. This must be looked at.
Dec 22 1997 08:55:50:560AM	971222001	Ian Hutchinson	OH test.
Dec 22 1997 09:07:36:540AM	971222002	Ian Hutchinson	Fiducial shot but with only one transmitter. Long current pause but eventually went. No H-mode. Put in two steps to the zcur in segment 2. They are from -.015 to -.0146 (i.e. 0.4mm) in 1ms, and back. This should put an impulse on the vertical position. Raise fill to 18ms.
Dec 22 1997 09:22:07:900AM	971222003	Ian Hutchinson	Plasma. Got H-mode. Current-rise density is perhaps a bit high. But gas flow is only a total of about 15 torr-l. No zcur effects are visible. Interferometer gate-valve closes at 1s. Import segment 2 from 971217007
Dec 22 1997 09:41:09:440AM	971222004	Ian Hutchinson	Plasma till1.45s. No H-mode. Reduce zcur fast gain to 6 at .22s. Rduce the puff V to about 40V.
Dec 22 1997 09:55:22:550AM	971222005	Ian Hutchinson	Fizzle. EF4 to -1340 from -1345 Bz a tad low. Also mflux shows some slight Br but in the past it has liked it. Put in a 1mm zcur step from .5s to .55s
Dec 22 1997 10:11:51:670AM	971222006	Ian Hutchinson	Plasma till 1.7s, H-mode at .95s. RF trips out. Major impurity accumulation. Increase zcur step to 2mm.
Dec 22 1997 10:19:58:050AM	971222007	Ian Hutchinson	Fizzle EF4 to -1335. Br offset to 5.8 from 6.0 mT.
Dec 22 1997 10:31:09:420AM	971222008	Ian Hutchinson	Plasma till 1.7s. ELM-free H-mode with accumulation. RF1.6MW. A couple of trips. 170 kJ. nl04 to 2.8e20. zcur gain to 5 at .22s. rcur to .667 from .668 at .9s. Enable argon.
Dec 22 1997 10:51:32:780AM	971222009	Ian Hutchinson	Fizzle. Slightly late breakdown. Br is somewhat higher this shot. It is not reproducible. EF4 to 1340. Br offset to 5.5mT.
Dec 22 1997 11:04:28:600AM	971222010	Ian Hutchinson	Plasma. Disruption at 1.05s. Cuased by grwoing vertical instability. No H-mode. We can see a 90Hz oscillation on this and shot 8 at .55s induced by the zcur step. This must be fixed first. Set Rcur back to .668. zcur P to 3.8 at .6s.
Dec 22 1997 11:16:29:520AM	971222011	Ian Hutchinson	Fizzle. Late breakdown. CII .004. 45kA but this is really strange because the light goes away and we still have a lot of measured current. I hope we haven't done something bad. Br offset to 5.2 mT.
Dec 22 1997 12:47:41:270PM	971222011	Ian Hutchinson	I just noticed that the zcur trace is much higher also for this shot after the disruption. It certainly looks as if something changed significantly.
Dec 22 1997 11:27:45:210AM	971222012	Ian Hutchinson	Fizzle. Current trace stays funny. Same late breakdown: 8.5ms. It looks as if the non-plasma conductivity of whatever links the rogowski has increased by about 50% following the disruption on shot 10. Also breakdown is significantly delayed. EF4 to -1345.
Dec 22 1997 11:38:11:280AM	971222013	Ian Hutchinson	Fizzle. Slightly earlier breakdown. Current trace still high. EF4 to -1350. Fill puff to 20ms.
Dec 22 1997 11:47:30:040AM	971222014	Ian Hutchinson	Fizzle. breakdown back to 6ms. Rcur offset to 6000 from 6300 in segment 1.
Dec 22 1997 11:56:53:820AM	971222015	Ian Hutchinson	Fizzle. rcur offset to 5800. ef4 to -1355.
Dec 22 1997 12:13:33:630PM	971222016	Ian Hutchinson	Plasma disrupts at .37s. 0.8MA. Vertical instability at about 100 Hz. This is well before any of the zcur changes. Not clear why. The OH2s are not in antiphase. OH2U seems to lead OH2L by about 3ms. Shut Mcpherson and Mo monitor. Because there seemed to be a gas puff. Reload shot 3 fiducial into segment 2.
Dec 22 1997 12:27:12:270PM	971222017	Ian Hutchinson	Fizzle. The gas puff was gone. Enable Mo monitor gate valve. rcur segment 1 offset to 5500.
Dec 22 1997 12:38:47:410PM	971222018	Ian Hutchinson	Fiducial plasma. FMIT 1 is back. H-modes with trips a voltage limits. OH2 V to 0V at .01s from 20V. zcur2 D to 1. from 1.5. The old ratio of D/P in physicsl units was 1ms.
Dec 22 1997 12:43:14:980PM	971222019	Ian Hutchinson	Fizzle. Br to 4.5mT in segment 1.
Dec 22 1997 01:03:33:160PM	971222020	Ian Hutchinson	Plasma. Big injection at .7s. RF got 2.6MW. 130 kJ. Import seg 2 from shot 11 to seg 2. Seg 1 rcur offset to 5800 from 5500. Slow zcur to D=1. from 1.5.
Dec 22 1997 01:13:01:610PM	971222021	Ian Hutchinson	Plasma. ELM-free H-modes. Still incipient instabilities. zcur 3 to 4 at .22s. and to 4.2 at .95s.
Dec 22 1997 01:23:19:340PM	971222022	Ian Hutchinson	Plasma disrupts at .83s. A brick. Repeat.
Dec 22 1997 01:42:52:730PM	971222023	Ian Hutchinson	Plasma till 1.4s. 2MW RF ELM-free. Accumulation. zcur 3 to P=3.6 at .95s. zcur 2 to D=.5 at .7s.
Dec 22 1997 01:58:08:590PM	971222024	Ian Hutchinson	Plasma. Disrupts at 1s. Vertical thrash as it drops out of H-mode. OH fuse blows. No, bad reading. Reduce zcur 2 gain to 1 from 1.5 at .65s.
Dec 22 1997 02:05:50:680PM	971222025	Ian Hutchinson	Fizzle. No-light current is now 34kA. CII to .006. Big excursion on Br. Repeat.
Dec 22 1997 02:17:37:370PM	971222026	Ian Hutchinson	Fizzle. Br and Bz seems to be rather erratic. Repeat.
Dec 22 1997 02:18:07:890PM	971222027	Ian Hutchinson	Mgnet resistance fault. No power supplies.
Dec 22 1997 02:40:24:800PM	971222028	Ian Hutchinson	Plasma. Nice current rise. Lower puff V to 35V. nl04 demand to 1e20 from 12.e20.
Dec 22 1997 02:52:37:270PM	971222029	Ian Hutchinson	Plasma. 3 H-modes, ELM free.
Dec 22 1997 03:05:08:100PM	971222030	Ian Hutchinson	Plasma. Slightly longer H phases. Fewer RF trips. 2MW RF. 178kJ. Disable argon.
Dec 22 1997 03:13:27:330PM	971222031	Ian Hutchinson	Fizzle. No-light current 35kA. Br offset to 5mT from 4.5mT
Dec 22 1997 03:28:15:750PM	971222032	Ian Hutchinson	Plasma. No EDA. Injection on RF trip. 180kJ. Lower Ip to 1MA. Reenable argon.
Dec 22 1997 03:35:06:580PM	971222033	Ian Hutchinson	Fizzle. Fill puff to 18ms.
Dec 22 1997 03:44:04:200PM	971222034	Ian Hutchinson	Fizzle. EF3 V to 1800 at 12 to 20 ms, from 2000V.
Dec 22 1997 03:50:54:240PM	971222035	Ian Hutchinson	Fizzle. EF3 V back to 2100-2000V. Rcur offset to 6000.
Dec 22 1997 04:03:20:660PM	971222036	Ian Hutchinson	Plasma for .325s. Hit by a brick. EF3 to 2300 at 12ms.
Dec 22 1997 04:18:00:590PM	971222037	Ian Hutchinson	Plasma. ELM free at 2MW RF, one trip. 150kJ. RXL, ZXL to 0, RXU to -.015 from -.025
Dec 22 1997 04:30:15:320PM	971222038	Ian Hutchinson	Plasma. EDA mode, but with some big injections. Tweak up EF3 at 7 to 10 ms. zxu to .045, rxu to .005.
Dec 22 1997 04:36:57:070PM	971222039	Ian Hutchinson	Fizzle. Repeat
Dec 22 1997 04:51:11:220PM	971222040	Ian Hutchinson	Plasma. EDA, but quite a lot of radiation. Import segment one from shot 2. This is where we started. nl04 to 14.e20.
Dec 22 1997 05:06:36:790PM	971222041	Ian Hutchinson	Dud. Clear verification of (1) 34 kA of no-plasma current. (2) Completely different (non)-startup. Load segment 1 from shot 40, the last that went.
Dec 22 1997 05:08:09:090PM	971222042	Ian Hutchinson	Plasma Disrupts at .36s. Growing vertical instability. Perhaps enhanced by the stronger gas puff for higher density.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:47:33:090AM	Test	Ok
2	08:56:45:100AM	Plasma	Ok
3	09:07:42:660AM	Plasma	Ok
4	09:26:01:670AM	Plasma	Ok
5	09:38:59:120AM	Plasma	Ok
6	09:53:37:590AM	Plasma	Ok
7	10:09:52:070AM	Plasma	Ok
8	10:18:30:880AM	Plasma	Ok
9	10:32:24:370AM	Plasma	Ok
10	10:49:34:150AM	Plasma	Ok
11	11:02:59:960AM	Plasma	Ok	no faults
12	11:14:42:450AM	Plasma	Ok	no faults fizzel
13	11:26:18:000AM	Plasma	Ok
14	11:36:39:530AM	Plasma	Ok
15	11:46:03:520AM	Plasma	Ok
16	11:54:59:330AM	Plasma	Ok
17	12:09:19:590PM	Plasma	Ok
18	12:25:00:370PM	Plasma	Ok
19	12:37:22:440PM	Plasma	Ok
20	12:45:26:770PM	Plasma	Ok
21	01:01:43:350PM	Plasma	Ok
22	01:14:23:200PM	Plasma	Ok
23	01:24:23:360PM	Plasma	Ok
24	01:41:08:180PM	Plasma	Ok
25	01:56:21:130PM	Plasma	Ok
26	02:06:12:390PM	Plasma	Ok
27	02:15:37:590PM	Plasma	Bad	mag resist fault
28	02:23:26:200PM	Plasma	Ok
29	02:38:26:990PM	Plasma	Ok
30	02:50:40:110PM	Plasma	Ok
31	03:03:35:870PM	Plasma	Ok
32	03:11:54:830PM	Plasma	Ok
33	03:25:07:000PM	Plasma	Ok
34	03:33:13:840PM	Plasma	Ok
35	03:42:33:440PM	Plasma	Ok
36	03:52:08:110PM	Plasma	Ok
37	04:01:42:670PM	Plasma	Ok
38	04:17:02:740PM	Plasma	Ok
39	04:28:36:110PM	Plasma	Ok
40	04:37:05:120PM	Plasma	Ok
41	04:49:40:780PM	Plasma	Ok
42	04:57:21:140PM	Plasma	Ok