Alcator C-Mod Run 1020724 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Steve Wukitch (shots 1-22)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Steve Wolfe
Engineering operator(s):Gary Dekow,Ed Fitzgerald

Engineering Operator Run Comment
RF Conditioning; SL:Wukitch; PO:Wolfe; EO:Dekow/Fitzgerald

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:15:410PM
Author: To Be Determined
Physop Summary for Wednesday 1020724

RF Conditioning
SL: Wukitch
PO: wolfe
EO: Dekow,Fitzgerald

Run Plan and Engineering Setup:
--------------------------------
Run to begin at 9:00 AM
ECDC from 06:00-07:00 at 2e-4 T D2.

Power systems setup the same as for Shot 1020723001
Gas setup:

B-Top 6 psi D2 Hybrid Enabled (PG4)
B-side lower 1 psi Ar Hybrid Enabled (PG1)
B-side upper 10 psi D2 Hybrid DISABLED (PG2, for ECDC)
C-Side 30 psi D2 Hybrid Enabled (PG3)
J-Bottom leave as is, Hybrid DISABLED

Enable the following gate valves, assuming no vacuum problems:
ECE

RF Setup: All 4 transmitters in Run On by 07:00

Run Plan: Continue RF Conditioning of all antennas. We will start with
inner wall limiter shot, e.g. 1020723013, in order to avoid H-mode.
Depending on how things go, we may go back to lower null later in the
day; a lower null shot to try is 1020723008.

Results:
--------

We got a little further on D and E conditioning. Max power of 2MW from the two
running together was obtained, although E was not staying on very well. Some
progress may have been made on J, but there are still problems. Also, the
unexplained "fireworks" at J with no RF reappeared, and caused some
disruptions. Brian got some prep done for his divertor gas leakage experiment
tomorrow. Startup was problematic, and the run ended with a long series of
duds and fizzles for which there is no obvious explanation.

Details
========
G-bottom TS window had to be removed this morning to repair a leak at the
viton seal. This was the cause of the mass 14,28,40 peaks and high base
pressure observed during yesterday's run. During removal, the base pressure
went briefly to 5e-6 because the gate valve apparently has a through leak.
Pressure returned to the low -7 scale once the blank was installed and pumped
down.

The ratiomatic on g-side was found to have grid shorted to the filaments this
morning, after testing ok last night. This will need to be replaced (a
difficult but possible task).

The start of the run was delayed about a half hour by request of the RF group,
because J-port was not coming on at all.

D- and E-port antennas continued to come up in power, getting to 2MW on shot
6. After shot 6, Steve determined that the problem with J was the modification
made to the phase feedback this morning. This was undone, and vacuum
conditioning (followed by five minutes of ecdc) was done before shots 7 (which
fizzled) and 8, which disrupted at 0.2sec with fireworks in front of the
Jantenna. This was the first shot all day which had these sparks. Shot 9,
following the disruption fizzled, and 10 was a dud, despite the fact that I
raised the puff between 9 and 10.

Shot 11 ran into rampdown but 12 again disrupted at .37 sec, again with sparks
near the jantenna. Shots #13-16 ran into rampdown, with decent power on d&e,
and on 16 J seemed to be doing better. The sparking in front of J-port without
RF seemed to be decreasing in intensity, but was still present on those shots
for which the video worked.

Shot 17 fizzled, and, following another 2msec increase in the puff, shot#18-21
were all duds (#20 had no TF). I suspect that the sparker was not working,
based on the lack of response of the current to the gas puff at -0.5sec. Shot
#22, after 10 minutes of ecdc, was a late-breakdown fizzle. Again, there was
no deviation of the sparker current from a linear ramp until around 18msec. On
the other hand, there were a number of good shots that also show the same kind
of sparker current trace before t=0. Examples of shots for which the sparker
current DOES respond to the gas include shot 14 and 15; an example of a
successful startup that does not show a response to the gas is 16.

On shot #6 the chopper average current was very low, less than 1kA. The static
voltage was down to 600V, compared to the normal >800V. All three TMX supplies
were at lower voltage. The engineers put some instrumentation on the PLC limit
level in the TMX control. The problem did not reappear. Since these were lower
elongation limiter discharges, the shot ran fine with the lower current, but a
normal shot would probably have needed more dynamic range and gone vertically
unstable.

After the run, vacuum shop is going to put on a replacement Thomson window,
and replace the g-side ratiomatic. Base pressure rose to 8.5e-6 during the
window changeover. Dmitri has determined that the FERA problems in the core
Thomson CAMAC can be cured by replacing a fuse in the 24V line inside each
module. He expects to have the full set of FERA's back in service by
tomorrow. There may still be an issue with grounding in the Thomson data
system.

If the unexplained duds continue tomorrow, there is a second sparker installed
at k-port in the shit-shooter chamber. There is presently no cable going to
it, but Gary is going to look into the possibility that there is a second
cable available. Otherwise, the existing cable could be re-routed from C to
K-port, if the Physop wants to try that. The other possibility would be to
adjust the High Voltage on the C-sparker.

Scorecard:
----------

Tests 0
Duds 5 (1 from no TF)
Fizzles 5
Plasmas 12 (2 early disruptions)
======= ==
Shots 22











Session Leader Comments
Jul 24 2002 09:51:41:860AM1020724001Steve Wukitch001 plasma attempt after morning of RF vacuum conditioning

request: inner wall limited Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.5 MW ramp @[0.6-1.2]sec
E: 0.2 - 0.5 MW ramp @[0.6-1.2]sec
J: off

result: fizzle
Jul 24 2002 10:32:20:513AM1020724002Steve Wukitch002

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.6 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.6 MW ramp @[0.6-1.5]sec
J: off

result: plasma
D: ramped to 0.8 MW (DC1 and DC2) with 2 faults
E: ramped to 0.8 MW (DC1 and DC2) with 1 fault
~20 kV
no video

action: raise power on D and E by 200 kW each
Jul 24 2002 10:59:55:963AM1020724003Steve Wukitch003

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.8 MW ramp @[0.6-1.5]sec
J: off

result: plasma
D: ramped to 1.1 MW (DC1 and DC2)
E: ramped to 1.0 MW (DC1 and DC2) with 5 faults
~22 kV

action: raise power on D by 200 kW
Jul 24 2002 11:00:29:637AM1020724004Steve Wukitch004

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 1.0 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.8 MW ramp @[0.6-1.5]sec
J: off

result: plasma
D: ramped to 1.4 MW (DC1 and DC2) with max faults
E: ramped to 1.0 MW (DC1 and DC2) with 5 faults
~27 kV on D and 25 kV on E

action: lower power on D and E by 100 kW
Jul 24 2002 04:45:02:753PM1020724006Steve Wukitch006

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: off

result: plasma
D: 1.2 MW (DC1 and DC2) with a couple faults
E: couple of faults

identified problem with J-port: new mod was causing J3 to be off-frequency
few vacuum shots with J-port to condition to 25 kV
Jul 24 2002 04:44:08:830PM1020724007Steve Wukitch007

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: off

result: fizzle

vacuum condition J-port to ~28 kV
Jul 24 2002 04:43:12:720PM1020724008Steve Wukitch008

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: off

result: plasma - early disruption - J-port spark w/o power
Jul 24 2002 04:42:28:203PM1020724009Steve Wukitch009

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: 0.25 square pulse @[1.2-1.6]sec

result: fizzle
Jul 24 2002 04:41:35:827PM1020724010Steve Wukitch010

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: 0.25 square pulse @[1.2-1.6]sec

result: fizzle
Jul 24 2002 04:35:15:613PM1020724011Steve Wukitch011

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: 0.25 square pulse @[1.2-1.6]sec

result: plasma
D: max faulted late
E: 2 faults
J: 0.25 square pulse @[1.2-1.6]sec
Jul 24 2002 04:37:32:350PM1020724012Steve Wukitch012

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.5]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.5]sec
J: 0.25 square pulse @[1.2-1.6]sec

result: early disruption
Jul 24 2002 04:40:30:730PM1020724013Steve Wukitch013

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.9 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.25 square pulse @[1.4-1.6]sec

result: early disruption
D: still faulting
E: 2 faults
J: max faults
Jul 24 2002 03:07:42:010PM1020724014Steve Wukitch014

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.25 MW square @[1.4-1.6]sec

result: plasma
D: clean
E: faulted off late
J: faulted off

action: retune J4 and raise D by 100 kW

Jul 24 2002 03:20:11:763PM1020724015Steve Wukitch015

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.25 MW square @[1.4-1.6]sec

result: plasma
D: 1.2 MW max faults by end of pulse
E: 1.1 MW 4 faults
J: faulted off

action: retune J
Jul 24 2002 03:50:27:967PM1020724016Steve Wukitch016

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.1-0.25 MW square @[1.4-1.6]sec

result: plasma
D: 1.2 MW max faults by end of pulse
E: 1.1 MW 4 faults
J: 0.1-.25 MW ramp with a few faults - best shot yet

action: retune J
Jul 24 2002 03:52:29:720PM1020724017Steve Wukitch017

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.1-0.25 MW square @[1.4-1.6]sec

result: fizzle
Jul 24 2002 04:09:06:010PM1020724018Steve Wukitch018

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.1-0.25 MW square @[1.4-1.6]sec

result: dud
Jul 24 2002 04:09:34:260PM1020724019Steve Wukitch019

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.1-0.25 MW square @[1.4-1.6]sec

result: dud
Jul 24 2002 04:27:32:507PM1020724020Steve Wukitch020

request:inner wall limited
Ip~0.8 MA, BT~5.4 T, nl_04~1x10^20 m^-2
D: 0.2 - 0.8 MW ramp @[0.6-1.4]sec
E: 0.2 - 0.7 MW ramp @[0.6-1.4]sec
J: 0.1-0.25 MW square @[1.4-1.6]sec

result: dud

Physics Operator Comments
Jul 24 2002 07:33:16:427AMSteve WolfeSetting up for run 1020724

coldstart at 07:15 - all matrices respond ok.
Tommy Toland came in last night and found a leak on G-bottom;
G-bottom gate valve is now valved off, and Bob Childs will try
to repair the leak, probably at the window. The likely leak was
noted during the run, based on RGA readout and high base pressure (1e-6)
between shots, but Bob had been unable to isolate the problem in
post-run leak checking.

Last night W. Burke got the ratiomatic going again, with the
repaired new controller, but we could not determine what caused the
failure and damage to the controller yesterday. There may be an intermittant
problem in the gauge itself.

Run Plan:
Start from a limited equiilibrium and continue RF conditioning.
The problem with ejecta in front of the J-antenna early in the shot,
before any RF is on, is still a mystery, and if it continues we will
need to figure out what is going on.

Jul 24 2002 07:54:17:350AMSteve WolfeLoad from 1020723013 (limiter discharge)

Jul 24 2002 08:03:21:333AMSteve WolfeWilly now finds that the ratiomatic grid and filament are shorted (apparently again).
This means no ratiomatic today, and maybe not this campaign unless we can find a
gate valve location to install a new one.

Bob Childs finds a large leak on the window seal on the TS window; he will remove it
and blank off, and try to repair.
Jul 24 2002 08:19:34:950AMSteve WolfeWhen the TS window was removed the base pressure rose to 5e-6, and
large 14,28,40 peaks appeared on the RGA. The G-bottom gate valve apparently
has a through leak.
Once the flange was blanked off and pumped the base pressure returned to the low
e-7 scale.

We may need to do some extra ecdc this morning, but I'll wait until we have a
few shot attempts.
Jul 24 2002 09:53:15:033AM1020724001Steve WolfeECDC five minutes before first shot, after RF conditioning.
Wait until base pressure drops to 1.5e-6 before going to init.
fizzle.

next shot: drop fill from 22-18msec, raise br0 from .0015->.002

Jul 24 2002 10:23:53:750AM1020724002Steve Wolfeshot#2: drop fill from 22-18msec, raise br0 from .0015->.002
tci seems to have died on water flow too low. I'm going to take a shot with
no feedback on nl4 and draw a pg3 waveform and see what happens.

plasma inner wall discharge as requested.
TCI seems to have worked. I don't know why, since the PLC seems to be showing
no laser power. got 1e20, which is what we wanted.
traq2 data failed, have to re-run efit.

Jul 24 2002 10:36:34:897AM1020724003Steve Wolfeshot#3: reload seg 2 from 1020724001, which had nl4 feedback turned on.
plasma to 1.63sec
traq 2 failed again, need to re-run the efit when it recovers.
Up to 1.7MW from d&e antennas
Jul 24 2002 10:56:31:300AM1020724004Steve Wolfeshot#4: change nl4 programming to drop to zero after 1.45 sec, to
try to keep from disrupting in rampdown.

plasma to 1.58sec, if anything a little shorter.
traq2 is failing every time. Again need to re-run the EFIT when it gets restored.
It looks like the disruption may be related to ef4 swinging back through zero in
rampdown

next shot: slow down drop in ic_ef4 and rise of zxl in rampdown to try to
get rid of rampdown disruption

Jul 24 2002 11:13:42:557AM1020724005Steve Wolfeshot#5: slow down drop in ic_ef4 and rise of zxl in rampdown to try to
get rid of rampdown disruption

plasma to 1.5sec, everything I do makes it worse
ninja seems to be raising the density late in the pulse.
They will back off.

next shot: no PCS changes.

Jul 24 2002 11:35:57:870AM1020724006Steve Wolfeshot#6: no PCS changes. ninja backs off on their puff.

plasma to 1.72 sec.
traq2 failed again.
rf to 2MW (but they changed the calculation, so it may have been this much before).


Jul 24 2002 11:58:28:453AM1020724006Steve Wolfeshot#6: efc current was low on this shot. There seems to be a problem
with the efc tmx's; they are all putting out less voltage than on
shot 5, which explains why the staitc voltage is down from >800V
on shot 5 to 600V on shot 6.

Engineers are looking into this, while Wukitch tries to locate an arc
in the J transmission line.
Jul 24 2002 12:48:01:217PM1020724007Steve Wolfeshot#7: Engineers have instrumented the chopper tmx's
Steve determined that the modification to the phase feedback was responsible
for the J-port problem. Started vacuum conditioning on J.
5 minutes ecdc before shot. Wait until 1.5e-6 before init.

fizzle. Looks like another low current startup.
chopper static voltage looks like it was back at 800V, while it lasted.

nexy shot: drop the gas puff after ecdc. (vac conditioning on J-port again).


Jul 24 2002 01:34:46:023PM1020724008Steve Wolfeshot#8: short plasma .19sec
sparks from jport with no rf
Jul 24 2002 01:41:50:673PM1020724009Steve Wolfeshot#9: fizzle. looks like a bouncer.
next shot: back to 18msec.
Jul 24 2002 02:09:11:403PM1020724010Steve Wolfeshot 10: back to 18msec on the pre-puff.
dud. Fields look ok. Got gas.
Jul 24 2002 04:03:12:250PM1020724011Steve Wolfeshot 11: no changes.
plasma to 1.75 sec. late breakdown, 9msec.
No jantenna video this time.
traq time base problem again.
EFIT will be unrecoverable.

d&e ran off and on, j faulting

next shot: no changes, see if the startup will come back.
Jul 24 2002 02:29:18:810PM1020724012Steve Wolfeshot 12: no changes.
early disruption .37sec
breakdown back at 6msec.
Jul 24 2002 02:45:00:960PM1020724013Steve Wolfeshot 13: no changes.
plasma to 1.67sec
sparks early on jantenna, but survives.
Jul 24 2002 03:01:16:813PM1020724014Steve Wolfeshot 14: no changes.
plasma to 1.85sec
traq2 failed again, will re-run efit manually.
a few small sparks at J early, and one around 1.05 sec
Jul 24 2002 03:18:44:793PM1020724015Steve Wolfeshot 15: no changes.
plasma to 1.83sec, d&e on and off at 2MW, J trying harder,
still a few j sparkles. not as bad.
Jul 24 2002 03:33:58:220PM1020724016Steve Wolfeshot 16: no changes.
plasma to 1.75sec,
d trips out after .8sec
e still off and on. j doing better.

Jul 24 2002 03:45:02:893PM1020724017Steve Wolfeshot 17: no changes.
fizzle. bouncer, couldn't hold it.
Bz a little low.

next shot: raise pre-puff from 18 to 20msec
Jul 24 2002 04:01:17:890PM1020724018Steve Wolfeshot 18: raise pre-puff from 18 to 20msec
dud. That's the second time I raised the puff and got a dud.
The sparker may be misbehaving; on shot 17 it saw the gas puff
while on this shot it didn't seem to, although it looks like
it arced at about 35msec

next shot: repeat, since last time it came back on its own.
Jul 24 2002 04:17:08:880PM1020724019Steve Wolfeshot 19: repeat with raised pre-puff from 18 to 20msec
another dud. Again no sign that the sparker is responding to the
gas puff, but it also didn't on some good shots. On other good shots, there
is a clear puff signature in the sparker current though.

next shot: put gas back to 18msec and drop Br0 from .002 to .0015
Jul 24 2002 04:28:29:320PM1020724020Steve Wolfeshot 20: put gas back to 18msec and drop Br0 from .002 to .0015
No tf ! hybrid signal is there. Again no sign of the gas on the sparker current.

next shot: try again.
Jul 24 2002 04:40:40:653PM1020724021Steve Wolfeshot 21: put gas back to 18msec and drop Br0 from .002 to .0015
another dud.

next shot: try 10minutes of ecdc, and put the br0 back to .002
Jul 24 2002 05:47:24:710PM1020724022Steve Wolfeshot 22: try 10minutes of ecdc, and put the br0 back to .002
fizzle, very late breakdown, 10msec, with lots of CII.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:43:13:203AMPlasmaOk
210:12:52:953AMPlasmaOk
310:31:13:590AMPlasmaOk
410:45:43:177AMPlasmaOk
511:02:09:763AMPlasmaOk
611:30:28:427AMPlasmaOk
712:42:03:393PMPlasmaOk
801:21:59:847PMPlasmaOk
901:38:02:730PMPlasmaOk
1001:51:03:047PMPlasmaOk
1102:07:38:213PMPlasmaOk
1202:21:59:360PMPlasmaOk
1302:37:24:870PMPlasmaOk
1402:52:05:940PMPlasmaOk
1503:08:14:417PMPlasmaOk
1603:23:23:517PMPlasmaOk
1703:38:05:463PMPlasmaOk
1803:52:50:750PMPlasmaOk
1904:06:18:320PMPlasmaOk
2004:20:42:170PMPlasmaOkTF Didn't Fire
2104:34:55:893PMPlasmaOk
2204:57:24:320PMPlasmaOk