Alcator C-Mod Run 1040323 Information

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Miniproposals
Miniproposal:341
Date Filed: 6/4/2003
Title:Power Absorption in ITBs
First Author:Catherine Fiore
Session Leader:Catherine Fiore (shots 1-38)

Operators
Session leader(s):Catherine Fiore
Physics operator(s):Joseph Snipes
Engineering operator(s):Bill Cochran,Ed Fitzgerald,Bill Byford

Engineering Operator Run Comment
MP#341 Power Absorption in ITB; SL: Fiore; PO: snipes; EO:Cochran/Fitz/B

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:03:757PM
Author: Catherine Fiore
SL Fiore
PO Snipes

In this run we hope to complete MP 341 which ended prematurely when we lost
the FMIT 4 output tube. We will start with shot 29 from 1040309 and
re-establish the ITB from that shot. We will start with somewhat lower
central ICRF power than on shot 29, and scan up until we lose the ITB.
Once this is done, we should change the off axis power and repeat the
central power scan. If time allows, we can try this at the higher field.

----------------------------------------------------------------------------

We obtained ITBs on at least 26 shots out of 31 plasma shots (1 early
disruption). However, we had difficulty getting central ICRF power into
the plasma until after shot 20 because of high neutral density, residual from
boronizing the previous night. On the last shot of the day, 36, we briefly
put 2 MW central power into the ITB, but a back transition quickly ensued.
Much of the time we had problems with back transitions coming too early before
we had a chance to turn on the central ICRF. On shot 26 we put in 1.4 MW
central ICRF and clamped the density rise, as we did with 1.5 MW on shot 33.
Also we added 1 MW central power on shot 22 without affecting the ITB at all.

There was some interesting MHD activity on a number of shots, #21 and #36
among them.

Some impressions about ITBs in general and MP341 in particular: ITBs are
easier to get and maintain in a cleaner machine. They benefit from having
target density of 0.9-1 10^20 /m^3 as opposed to lower values. Higher
triangularity plasmas seems to be more favorable. Off axis-ICRF power > 2MW
is also preferred. MP341 establishes that we have not yet found a limit for
adding central ICRF power to established ITBs under optimal conditions, and
the limits we have seen in the past are probably related to the amount of
radiated power in the plasma.
______________________________

Shot summary

1040323001-003 were data system tests.

1040323004 Good first shot, but no H-mode an less than 1 MW rf power.

1040323005 Again, no H-mode, intermittent rf power.

1040323006-007 data system problems

1040323008 Again, no H-mode, intermittent rf power.

1040323009 Good shot, H-mode with ITB. RF has 2 MW off axis, but we drop out
of Hmode when the power drops at 1.3 s. No central ICRF. We'll try again.

1040323010 No H-mode.

1040323011 H-mode with ITB, but still no central ICRF. The
neutral density is apparently too high. We'll keep
trying, possibly with lower triangularity.

1040323012 Early disruption.

1040323013 H-mode with ITB. Still no central ICRF

1040323014 H-mode with ITB. Still no central ICRF

1040323015 H-mode with ITB. Still no central ICRF

1040323016 H-mode with ITB. Still no central ICRF

1040323017 H-mode with ITB. Still no central ICRF

1040323018 H-mode with ITB. Still no central ICRF

1040323019 H-mode with ITB. Finally central rf (we lowered the target
density) but there was a back transition before J-port came on. We are going
to raise the target density a little higher, to 0.9 10^20

1040323020 H-mode with ITB. Finally a little central rf (we lowered the
target density) but there was a back transition before J-port came on.

1040323021 H-mode with ITB that self arrested for no apparent reason.
No central rf. Extremely unusual. There is apparently a lot of MHD activity.

1040323022 H-mode with ITB. 1. MW central rf. No arrest on the ITB. We will
try higher power.

1040323023 H-mode with ITB. 1.4 MW central rf. Premature back transition.
We will try to repeat the shot.


1040323024 H-mode with ITB. Disrupts near the time J-port is coming on.

1040323025 H-mode with ITB, but it back transitioned before J-port came
on. We will fire J-port earlier, at 1.1 s.

1040323026 H-mode with ITB, great shot.
1.4 MW central power into the ITB without clamping the rise. It disrupted,
however. We'll try going up on J port power some more.

1040323027 H-mode with ITB, 1.6 MW central power into the ITB which clamped
the ITB. The stored energy and neutron rate did not get as high as on
1040309029 however. We will change the J-port timing back to
1.2 s and hope for the best.

1040323028 H-mode with ITB, but it back transitioned before the
central power (1.5 MW comes in. We will try to increase the target density to
see if we can avoid the early back transition.

1040323029 H-mode with ITB, but it back transitioned before the central
power comes in. There are multiple trips on J.

1040323030 H-mode with ITB, but it disrupted before the central power comes
in. We will try to increase the target density to see if we can avoid
the early back transition.

1040323031 H-mode with ITB, but it back transitioned before the central
power comes in. We will try to back off on the D and E port power to see if
we can slow the impurity influx.

1040323032 H-mode with ITB, but it back transitioned before the central
power comes in. We will bring in the central ICRF earlier.

1040323033 H-mode with ITB. 1.5 MW central power clamps the density rise.
We will try to push the power up some more.

1040323034 H-mode with ITB. It back transitioned before the central ICRF
came on.

1040323035 H-mode with ITB. It back transitioned before the central
ICRF came on.

1040323036 H-mode with ITB. 2 MW central power came on for 50 ms before we
get a back transition. The neutron rate reached 2 10^13 before the transition.

Physics Operator Summaries
Entered: Jul 7 2004 04:36:49:583PM
Author: Joseph Snipes
Run Plan and Engineering Setup for Tuesday 23-Mar-2004

MP#341 Power Absorption in ITB
SL: Fiore
PO: snipes

Engineering setup:
------------------
Run begins at 09:00 (or as close as possible), ends at 17:00
Overnight boronization.

Power supplies as on 1040309013

Gas System Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
leave B-side upper with 15 psi He3 Hybrid DISABLED (PG2)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
fill NINJA (lower cap) with 8 psi D2

Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum problems

RF: Transmitters #1,2,3 and 4 in RUN-ON by 08:00

Run Plan:
---------

Finish off the MP begun on Tuesday, 1040309. Specifically, we still need to
determine the highest on-axis power we can use without destroying the
high-field side resonance ITB (4.5T), and document the confinement
properties. Then we can proceed to the low-field side resonance, using the
70MHz for off-axis heating at B~5.6T and 80MHz on-axis.

We will start with a shot like 1040309029, which had 1.5MW of on-axis
70MHz. We will revisit a few lower power cases, to verify reproducibility of
last week's results, in view of the fact that we are now one week after the
boronization. We will then increase the on-axis power until we get clear
indication of loss of the core barrier. We will also try varying the off-axis
power to see how that affects the amount of core heating allowed.

If we complete the 4.5 T experiments, we will continue the MP by going through
the same sequence for low-field side resonance at 5.6T.

Summary: There were 3 system test shots to start the day followed by two good plasma shots, but on the second
plasma shot, the data system hung and there were two more data system test shots. All plasma attempts had
successful current rises with no changes to the startup throughout the day and the machine ran very well.
Only one shot disrupted early, though there were a number of disruptions following long EDA H-modes. There was
difficulty coupling J-port power above 0.3 mTorr neutral pressure, so we reduced the density to lower the
neutral pressure and that allowed better J-port coupling. Most shots had long EDA H-modes with ITB's and a number
of shots arrested the ITB's with central RF power. One shot arrested the ITB without central RF power
(1040323021) apparently due to a 5 - 12 kHz MHD mode. The last shot of the day had somewhat higher density and
we returned to the triangularity of the previous good run and it had a large increase in the neutron rate during
the ITB up to 2.3 x 10^13 n/s.

Scorecard: 36 shots, 31 plasmas, 5 tests.

There were 3 system test shots to start the day.
Shot 4: Copied shot 1040309029. Good shot, but little RF and no H-mode.
Shot 5: Try again. Good shot. Reached 2 MW but there was no H-mode.
Shot 6: Data system failed, cooling system delay, RF delay. Finally, cycle test shot.
Shot 7: A second no power test shot.
Shot 8: One more time . . . Good shot. Got 2 MW intermittently but no H-mode. Wukitch claims that the
neutral pressure is too high to get the RF working well.
Shot 9: Try again. Good shot. Got H-mode with an ITB from 0.8 to nearly 1.3 s.
Shot 10: Steady L-mode. Very similar to shot 9 on the RF, but no H-mode.
Shot 11: Good shot. 2 MW nearly steady with an H-mode with an ITB.
Shot 12: Increased RXL from -2 cm to -1.5 cm to see if reducing the triangularity might reduce the plasma
surface interaction with the inner wall and reduce the neutral pressure to help get the RF working.
Disrupted at 0.18 s.
Shot 13: Noted that both the TF and Ip had a jump at segment switch. It may not be responsible for this
disruptive behavior, but I changed Ip to 0.45 MA at 0.1 s in segment 2 to match segment 1 and then
moved the flattop point at 0.8 MA from 0.15 s to 0.19 s to reduce the ramp rate a bit. Then, changed
the TF current in segment 2 to 149 kA from 150 kA to match segment 1. Try again. Good shot.
Shot 14: Repeat. Good shot with H-mode and ITB.
Shot 15: Set Ip to 0.62 MA at 0.1 s in segment 2 and moved the flattop value of 0.8 MA to 0.22 s.
Good shot. Nice long EDA H-mode with ITB.
Shot 16: Good shot. Nice long EDA H-mode with ITB.
Shot 17: Good shot. Nice long EDA H-mode with ITB. Still no J-port central RF.
Shot 18: Reduced nl04 from 1 x 10^20 m^-2 to 0.9 x 10^20 m^-2 to attempt to reduce the neutral pressure for
J-port to work better. Good shot. Long EDA H-mode with ITB. Still no J-port. Disrupted at 1.5 s.
Shot 19: Reduced nl04 to 8 x 10^19 m^-2. Good shot, but shorter H-mode with ITB. Neutral pressure now down
to 0.18 mTorr, well below Wukitch's 0.3 mTorr threshold for good J-port operation, but J-port still
did not stay on.
Shot 20: Increased nl04 to 9 x 10^19 m^-2. Good shot. Long EDA H-mode with ITB, still no J-port even
though the neutral pressure is below 0.3 mTorr.
Shot 21: Repeat with more RF power. Got 2.5 MW out of D and E and a long EDA H-mode but no ITB and no
J-port power. Arrested ITB without central J-port power.
Shot 22: Reduced nl04 to 8.5 x 10^19 m^-2 to keep the neutral pressure below 0.3 mTorr for J-port.
Good shot. D port tripped just before 1 s taking a bite out of the H-mode. J-port up to 0.8 MW.
Shot 23: Repeat. Good shot. Got 1.2 MW from J-port intermittently and 2.5 MW from D and E. Long EDA
H-mode with ITB.
Shot 24: Good shot. EDA H-mode with ITB. Disrupted at 1.25 s just after J-port turns on.
Shot 25: Good shot. Long EDA with ITB with 2.5 MW from D and E and 1.2 MW from J-port.
Shot 26: Good shot. Nice long EDA H-mode with ITB. Disrupted at 1.38 s.
Shot 27: Good shot. Nice long EDA H-mode with ITB. J-port up to 1.5 MW arrests ITB very clearly.
Shot 28: Repeat. RF trips out at the H-L transition just before 1.2 s.
Shot 29: Increased nl04 to 9 x 10^19 m^-2. Good shot. H-mode trips out at 1.15 s due to impurity
accumulation again.
Shot 30: Decreased nl04 to 8.5 x 10^19 m^-2. EDA H-mode with ITB but disrupted at 1.18 s.
Shot 31: Increased nl04 to 9.5 x 10^19 m^-2. Good shot. EDA with ITB from 0.6 to almost 1.2 s, then there
is an H-L transition before J-port comes on.
Shot 32: Good shot. H-L transition at 1.15 s again apparently from too much impurity accumulation.
Shot 33: Good shot with H-mode with ITB out to 1.35 s clamped by J-port ICRF.
Shot 34: Good shot. EDA with ITB ends at 1.12 s just before J-port comes on.
Shot 35: Good shot. Still getting H-L transition early though.
Shot 36: Raised nl04 to 1 x 10^20 m^-2 and returned RXL to -2 cm as it had been earlier in the day. Good shot.
Neutron rate reaches 2.3 x 10^13 n/s at the peak of the ITB.

Session Leader Comments
Mar 23 2004 08:16:57:027AMCatherine FioreSL Fiore
PO Snipes

In this run we hope to complete MP 341 which ended prematurely when we lost
the FMIT 4 output tube. We will start with shot 29 from 1040309 and
re-establish the ITB from that shot. We will start with somewhat lower
central ICRF power than on shot 29, and scan up until we lose the ITB.
Once this is done, we should change the off axis power and repeat the
central power scan. If time allows, we can try this at the higher field.

Mar 23 2004 09:08:18:900AM1040323004Catherine FioreGood first shot, but no H-mode an less than 1 MW rf power.
Mar 23 2004 09:26:35:150AM1040323005Catherine FioreAgain, no H-mode, intermittent rf power.
Mar 23 2004 10:30:48:013AM1040323008Catherine FioreAgain, no H-mode, intermittent rf power.
Mar 23 2004 10:47:44:163AM1040323009Catherine FioreGood shot, H-mode with ITB. RF has 2 MW off axis, but we drop out
of Hmode when the power drops at 1.3 s. No central ICRF. We'll
try again.
Mar 23 2004 11:00:22:980AM1040323010Catherine FioreNo H-mode.
Mar 23 2004 11:20:58:060AM1040323011Catherine FioreH-mode with ITB, but still no central ICRF. The
neutral density is apparently too high. We'll keep
trying, possibly with lower triangularity.
Mar 23 2004 11:35:39:970AM1040323012Catherine FioreEarly disruption
Mar 23 2004 11:45:54:223AM1040323013Catherine FioreH-mode with ITB. Still no central ICRF
Mar 23 2004 12:01:43:247PM1040323014Catherine FioreH-mode with ITB. Still no central ICRF
Mar 23 2004 12:19:38:367PM1040323015Catherine FioreH-mode with ITB. Still no central ICRF
Mar 23 2004 12:30:24:290PM1040323016Catherine FioreH-mode with ITB. Still no central ICRF
Mar 23 2004 12:42:00:510PM1040323017Catherine FioreH-mode with ITB. Still no central ICRF
Mar 23 2004 12:54:54:970PM1040323018Catherine FioreH-mode with ITB. Still no central ICRF
Mar 23 2004 01:18:44:880PM1040323019Catherine FioreH-mode with ITB. Still no central rf (we lowered the target density)
but there was a back transition. We are going
to raise the target density a little higher, to 0.9 10^20
Mar 23 2004 01:22:00:887PM1040323020Catherine FioreH-mode with ITB. Finally a little central rf (we lowered the target density)
but there was a back transition before J-port came on.
Mar 23 2004 01:42:13:510PM1040323021Catherine FioreH-mode with ITB that self arrested for no apparent reason. No central rf.
Extremely unusual.
Mar 23 2004 02:06:05:670PM1040323022Catherine FioreH-mode with ITB. 1. MW central rf. No arrest on the ITB
Mar 23 2004 02:04:08:463PM1040323023Catherine FioreH-mode with ITB. 1.4 MW central rf. Premature back transition.
We will try to repeat the shot.
Mar 23 2004 02:22:59:353PM1040323024Catherine FioreH-mode with ITB. Disrupts near the time J-port is coming on.
Mar 23 2004 02:35:03:637PM1040323025Catherine FioreH-mode with ITB, but it back transitioned before J-port came on. We
will fire J-port earlier, at 1.1 s.
Mar 23 2004 02:48:23:050PM1040323026Catherine FioreH-mode with ITB, great shot but no visible bremsstrahlung data. 1.3 MW
central power into the ITB without clamping the rise. It disrupted, however.
We'll try going up on J port power some more.
Mar 23 2004 03:01:33:337PM1040323027Catherine FioreH-mode with ITB, 1.6 MW
central power into the ITB which clamped the ITB. The stored energy and neutron rate
did not get as high as on 1040309029 however. We will change the J-port timing back to
1.2 s and hope for the best.
Mar 23 2004 03:17:17:687PM1040323028Catherine FioreH-mode with ITB, but it back transitioned before the central power (1.5 MW comes
in. We will try to increase the target density to see if we can avoid
the early back transition.
Mar 23 2004 03:31:42:820PM1040323029Catherine FioreH-mode with ITB, but it back transitioned before the central power comes
in. There are multiple trips on J.
Mar 23 2004 03:46:31:200PM1040323030Catherine FioreH-mode with ITB, but it disrupted before the central power comes
in. We will try to increase the target density to see if we can avoid
the early back transition.
Mar 23 2004 03:56:38:730PM1040323031Catherine FioreH-mode with ITB, but it back transitioned before the central power comes
in. We will try to back off on the D and E port power to see if we can slow
the impurity influx.
Mar 23 2004 04:11:06:880PM1040323032Catherine FioreH-mode with ITB, but it back transitioned before the central power comes
in. We will bring in the central ICRF earlier
Mar 23 2004 04:21:35:800PM1040323033Catherine FioreH-mode with ITB. 1.5 MW central power clamps the density rise.
We will try to push the power up some more.
Mar 23 2004 04:47:25:450PM1040323034Catherine FioreH-mode with ITB. It back transitioned before the central ICRF came on.
Mar 23 2004 04:48:27:000PM1040323035Catherine FioreH-mode with ITB. It back transitioned before the central ICRF came on.
Mar 23 2004 05:06:14:590PM1040323036Catherine Fiore H-mode with ITB. 2 MW central power came on for 50 ms before we
get a back transition. The neutron rate reached 2 10^13 before the transition.

Physics Operator Comments
Mar 23 2004 08:10:55:750AMJoseph SnipesRun Plan and Engineering Setup for Tuesday 23-Mar-2004

MP#341 Power Absorption in ITB
SL: Fiore
PO: snipes

Engineering setup:
------------------
Run begins at 09:00 (or as close as possible), ends at 17:00
Overnight boronization.

Power supplies as on 1040309013

Gas System Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
leave B-side upper with 15 psi He3 Hybrid DISABLED (PG2)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
fill NINJA (lower cap) with 8 psi D2

Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum problems

RF: Transmitters #1,2,3 and 4 in RUN-ON by 08:00

Run Plan:
---------

Finish off the MP begun on Tuesday, 1040309. Specifically, we still need to
determine the highest on-axis power we can use without destroying the
high-field side resonance ITB (4.5T), and document the confinement
properties. Then we can proceed to the low-field side resonance, using the
70MHz for off-axis heating at B~5.6T and 80MHz on-axis.

We will start with a shot like 1040309029, which had 1.5MW of on-axis
70MHz. We will revisit a few lower power cases, to verify reproducibility of
last week's results, in view of the fact that we are now one week after the
boronization. We will then increase the on-axis power until we get clear
indication of loss of the core barrier. We will also try varying the off-axis
power to see how that affects the amount of core heating allowed.

If we complete the 4.5 T experiments, we will continue the MP by going through
the same sequence for low-field side resonance at 5.6T.
Mar 23 2004 09:08:53:170AM1040323004Joseph SnipesShot 1: Copied shot 1040309029. Good shot, but little RF and no H-mode.
Mar 23 2004 09:27:17:040AM1040323005Joseph SnipesShot 5: Try again. Good shot. Reached 2 MW but there was no H-mode.
Mar 23 2004 10:12:52:453AM1040323006Joseph SnipesShot 6: Data system failed, cooling system delay, RF delay. Finally, cycle test shot.
Mar 23 2004 10:15:55:567AM1040323007Joseph SnipesShot 7: A second no power test shot.
Mar 23 2004 10:41:04:030AM1040323008Joseph SnipesShot 8: One more time . . . Good shot. Got 2 MW intermittently but no H-mode. Wukitch claims that the
neutral pressure is too high to get the RF working well.
Mar 23 2004 10:45:00:067AM1040323009Joseph SnipesShot 9: Try again. Good shot. Got H-mode with an ITB from 0.8 to nearly 1.3 s.
Mar 23 2004 11:01:36:013AM1040323010Joseph SnipesShot 10: Steady L-mode. Very similar to shot 9 on the RF, but no H-mode.
Mar 23 2004 11:20:33:277AM1040323011Joseph SnipesShot 11: Good shot. 2 MW nearly steady with an H-mode with an ITB.
Mar 23 2004 11:28:27:570AM1040323012Joseph SnipesShot 12: Increased RXL from -2 cm to -1.5 cm to see if reducing the triangularity might reduce the plasma
surface interaction with the inner wall and reduce the neutral pressure to help get the RF working.
Disrupted at 0.18 s.
Mar 23 2004 11:59:51:087AM1040323013Joseph SnipesShot 13: Noted that both the TF and Ip had a jump at segment switch. It may not be responsible for this
disruptive behavior, but I changed Ip to 0.45 MA at 0.1 s in segment 2 to match segment 1 and then
moved the flattop point at 0.8 MA from 0.15 s to 0.19 s to reduce the ramp rate a bit. Then, changed
the TF current in segment 2 to 149 kA from 150 kA to match segment 1. Try again. Good shot.
Mar 23 2004 12:01:55:060PM1040323014Joseph SnipesShot 14: Repeat. Good shot with H-mode and ITB.
Mar 23 2004 12:14:44:673PM1040323015Joseph SnipesShot 15: Set Ip to 0.62 MA at 0.1 s in segment 2 and moved the flattop value of 0.8 MA to 0.22 s.
Good shot. Nice long EDA H-mode with ITB.
Mar 23 2004 12:32:08:417PM1040323016Joseph SnipesShot 16: Good shot. Nice long EDA H-mode with ITB.
Mar 23 2004 12:42:54:107PM1040323017Joseph SnipesShot 17: Good shot. Nice long EDA H-mode with ITB. Still no J-port central RF.
Mar 23 2004 12:55:26:983PM1040323018Joseph SnipesShot 18: Reduced nl04 from 1 x 10^20 m^-2 to 0.9 x 10^20 m^-2 to attempt to reduce the neutral pressure for
J-port to work better. Good shot. Long EDA H-mode with ITB. Still no J-port. Disrupted at 1.5 s.
Mar 23 2004 01:12:42:247PM1040323019Joseph SnipesShot 19: Reduced nl04 to 8 x 10^19 m^-2. Good shot, but shorter H-mode with ITB. Neutral pressure now down
to 0.18 mTorr, well below Wukitch's 0.3 mTorr threshold for good J-port operation, but J-port still
did not stay on.
Mar 23 2004 01:20:32:383PM1040323020Joseph SnipesShot 20: Increased nl04 to 9 x 10^19 m^-2. Good shot. Long EDA H-mode with ITB, still no J-port even
though the neutral pressure is below 0.3 mTorr.
Mar 23 2004 01:40:51:523PM1040323021Joseph SnipesShot 21: Repeat with more RF power. Got 2.5 MW out of D and E and a long EDA H-mode but no ITB and no
J-port power. Arrested ITB without central J-port power.
Mar 23 2004 01:45:49:763PM1040323022Joseph SnipesShot 22: Reduced nl04 to 8.5 x 10^19 m^-2 to keep the neutral pressure below 0.3 mTorr for J-port.
Good shot. D port tripped just before 1 s taking a bite out of the H-mode. J-port up to 0.8 MW.
Mar 23 2004 02:03:11:433PM1040323023Joseph SnipesShot 23: Repeat. Good shot. Got 1.2 MW from J-port intermittently and 2.5 MW from D and E. Long EDA
H-mode with ITB.
Mar 23 2004 02:20:28:567PM1040323024Joseph SnipesShot 24: Good shot. EDA H-mode with ITB. Disrupted at 1.25 s just after J-port turns on.
Mar 23 2004 02:34:33:247PM1040323025Joseph SnipesShot 25: Good shot. Long EDA with ITB with 2.5 MW from D and E and 1.2 MW from J-port.
Mar 23 2004 02:45:33:390PM1040323026Joseph SnipesShot 26: Good shot. Nice long EDA H-mode with ITB. Disrupted at 1.38 s.
Mar 23 2004 02:58:10:750PM1040323027Joseph SnipesShot 27: Good shot. Nice long EDA H-mode with ITB. J-port up to 1.5 MW arrests ITB very clearly.
Mar 23 2004 03:21:57:007PM1040323028Joseph SnipesShot 28: Repeat. RF trips out at the H-L transition just before 1.2 s.
Mar 23 2004 03:29:22:360PM1040323029Joseph SnipesShot 29: Increased nl04 to 9 x 10^19 m^-2. Good shot. H-mode trips out at 1.15 s due to impurity
accumulation again.
Mar 23 2004 03:43:27:227PM1040323030Joseph SnipesShot 30: Decreased nl04 to 8.5 x 10^19 m^-2. EDA H-mode with ITB but disrupted at 1.18 s.
Mar 23 2004 03:57:12:640PM1040323031Joseph SnipesShot 31: Increased nl04 to 9.5 x 10^19 m^-2. Good shot. EDA with ITB from 0.6 to almost 1.2 s, then there
is an H-L transition before J-port comes on.
Mar 23 2004 04:13:02:803PM1040323032Joseph SnipesShot 32: Good shot. H-L transition at 1.15 s again apparently from too much impurity accumulation.
Mar 23 2004 04:21:44:287PM1040323033Joseph SnipesShot 33: Good shot with H-mode with ITB out to 1.35 s clamped by J-port ICRF.
Mar 23 2004 04:41:05:910PM1040323034Joseph SnipesShot 34: Good shot. EDA with ITB ends at 1.12 s just before J-port comes on.
Mar 23 2004 04:50:01:267PM1040323035Joseph SnipesShot 35: Good shot. Still getting H-L transition early though.
Mar 23 2004 05:03:56:240PM1040323036Joseph SnipesShot 36: Raised nl04 to 1 x 10^20 m^-2 and returned RXL to -2 cm as it had been earlier in the day. Good shot.
Neutron rate reaches 2.3 x 10^13 n/s at the peak of the ITB.
Mar 23 2004 07:37:58:493PM1040323036Joseph SnipesSummary: There were 3 system test shots to start the day followed by two good plasma shots, but on the second
plasma shot, the data system hung and there were two more data system test shots. All plasma attempts had
successful current rises with no changes to the startup throughout the day and the machine ran very well.
Only one shot disrupted early, though there were a number of disruptions following long EDA H-modes. There was
difficulty coupling J-port power above 0.3 mTorr neutral pressure, so we reduced the density to lower the
neutral pressure and that allowed better J-port coupling. Most shots had long EDA H-modes with ITB's and a number
of shots arrested the ITB's with central RF power. One shot arrested the ITB without central RF power
(1040323021) apparently due to a 5 - 12 kHz MHD mode. The last shot of the day had somewhat higher density and
we returned to the triangularity of the previous good run and it had a large increase in the neutron rate during
the ITB up to 2.3 x 10^13 n/s.

Scorecard: 36 shots, 31 plasmas, 5 tests.

Engineering Operator Comments
ShotTimeTypeStatusComment
107:03:38:007AMTestOk
207:26:57:230AMTestOk
307:45:18:557AMTestOk
409:01:28:873AMPlasmaOk
509:21:56:483AMPlasmaOk
710:15:03:300AMPlasmaBadshot cycle problem
810:27:07:367AMPlasmaOk
910:41:18:373AMPlasmaOk
1010:57:41:413AMPlasmaOk
1111:12:18:653AMPlasmaOk
1211:26:13:847AMPlasmaOk
1311:40:34:743AMPlasmaOk
1411:57:25:520AMPlasmaOk
1512:11:43:463PMPlasmaOk
1612:24:38:843PMPlasmaOk
1712:37:25:910PMTestBad
1812:50:17:053PMPlasmaOk
1901:03:18:980PMPlasmaOk
2001:15:58:843PMPlasmaOk
2101:28:33:427PMPlasmaOk
2201:41:19:727PMPlasmaOk
2301:54:57:200PMPlasmaOk
2402:14:18:263PMPlasmaOk
2502:27:22:987PMPlasmaOk
2602:40:35:723PMPlasmaOk
2702:53:52:900PMPlasmaOk
2803:07:23:670PMPlasmaOk
2903:23:15:807PMPlasmaOk
3003:37:51:937PMPlasmaOk
3103:50:35:490PMPlasmaOk
3204:03:13:900PMPlasmaOk
3304:15:43:137PMPlasmaOk
3404:28:28:187PMPlasmaOk
3504:42:04:957PMPlasmaOk
3604:54:54:010PMPlasmaOk
3706:43:11:817PMTestOk
3808:12:52:900PMTestOk