Alcator C-Mod Run 990427 Information

Back to runs

Miniproposals
Miniproposal:214
Date Filed: 1/5/1999
Title:D and E-port RF System Commissioning
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-24)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Robert Granetz
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
MP3214/Granetz/Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:01:003PM
Author: To Be Determined
Physics operator summary for run 990427.

MP 214 -- ICRF conditioning
(possible piggyback: MP 237 -- Plasma rotation vs Ip in EDA)

SL: S. Wukitch (piggyback: J. Rice)
PO: R. Granetz

The goal for today:

Continue improving performance of ICRF heating systems.

Summary: The tokamak ran well today, primarily at 1 MA, so the piggyback MP was
not addressed at all. See the session leader's report for information
on RF performance. I learned several technical physop things today,
mostly as a result of loading a relatively old shot. Because of a
change in a Bp coil during the past year, all of the estimators that
use the Bp's had to be re-'call'ed. However, I also happened to
recall EF2-by-EF4, which zeroes itself if you are not careful. This
resulted in two shots (3 and 4) with improper EF4 feedback. The other
problem concerned the 'factor' warning message. You get one of these
for every re-'call'ed wire, and I mistakenly okay'ed one of them
(CLEARIN) that was just slightly outside the proper range. This was
fixed after shot 10, thereby eliminating the current rampdown
disruption.

Scorecard: 18 plasmas
4 fizzles
0 duds (0 due to power supply faults)
2 tests (1 was actually a shot aborted in check)
----------
24 total

------------------------------------------------------------------------------
Engineering Setup for Tuesday, 990427

Load from 980213015 (note: this is a shot from last year)

1-2 hours ECDC in D2, stopping in time to begin run at 08:00.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
leave B-side upper as is Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV

-------------------------------------------------------------------------------
Run Plan for 990427:

MP 214 -- ICRF (possible piggyback: MP 237 -- Plasma rotation vs Ip in EDA)

SL: S. Wukitch (piggyback: J. Rice)
PO: R. Granetz

Start by loading 980213015, a 1 MA shot from last year on which the ICRF worked
well. However, set Btor = 5.4 T instead of 5.7 T. (The higher field was used
last year to prevent ECE cutoff from the core.) From there, we may want to
vary the plasma current, in which case, John Rice may be able to get some data
in piggyback mode.

Before the physics run, we will need to do a 'Tuesday' OH test.
------------------------------------------------------------------------------

Note: 1-2 hours of ECDC in D2 was done prior to this run.

Hybrid coldstart done; no errors found
($set default cmod$models:[hybrid.tcl]
$@hybinit_dispatch
$@show_bitbus_log
Use editor search to verify no occurrences of "error" nor
"not respond")
Load 980213015.
Re-call all estimators that use Bp coils (to update BP16_BC to
BP16_DE), but keep the same offsets.
Turn off bolo feedback gain (disable wire).
Reduce nl_04 from 2.4 to 1.2e20 m-2.
Reduce Btor from 5.7 to 5.4 T.
Confirm that RF feedback on RCUR is turned off (RF_LOAD_E = 0.0)

Shot 01 -- OH test. All OK.

Next shot: plasma, based on 980213015.

Shot 02 -- Fizzle.

Next shot: increase pre-puff from 20 to 22 ms. Decrease BR offset
from 0.0015 to 0.001 T

Shot 03 -- Plasma. 1 MA. Disrupted at 1.05 s. Went into H-mode with only
0.6 MW. EF4 doesn't look right.

Next shot: repeat

Shot 04 -- Plasma. 1 MA. Disrupted at 1.17 s. Similar problem with EF4 not
getting through crossover properly. I had inadvertently zeroed
the EF2-by-EF4 estimator when I loaded last year's shot. They have
now been set to 0.5 for EF2U and EF2L

Next shot: try again, with EF2-by-EF4 corrected.

Shot 05 -- Fizzle. Good null, but the pressure was down by almost 50% from
shot 3. It turns out the B-top plenum pressure has dropped from
6 psi to 3 psi during the past hour.

Next shot: refill B-top plenum to 6 psi of D2 and retry.

Shot 06 -- Plasma. VDE caused a disruption at 1.01 s. EF4 looks okay now, but
it was getting close to its 4 kA limit (8 kA total).

Next shot: increase EF4 PLC limit from 8.0 to 8.5 kA (4.25 kA/coil).
Also change inner and outer gap programming so that outer gap is
reduced from 2 to 1 cm, and inner gap is help more constant.

Shot 07 -- Fizzle.

Next shot: reduce Br another 0.5 mT.

Shot 08 -- Fizzle.

Next shot: reduce Br yet again. This time to 0.000 T

Shot 09 -- Plasma. 1 MA until VDE disruption at t=1.42 s. Outer gap is about
1.0 cm, but varies slowly from 0.5 to 1.4 over 0.8 s.

Next shot: program RCUR to ramp out slowly to try and keep the outer
gap constant. Also reduce Br offset again by another 0.5 mT.
Also start Ip rampdown at 1.25 instead of 1.5 s.

Shot 10 -- Plasma. 1 MA. Disrupted at 1.35 s. Outer gap was fairly constant,
but at 0.5 cm.

Next shot: tweaked the CLEARIN "factor" to get it within range
(Steve Wolfe found this problem).

Shot 11 -- Plasma. 1 MA, no disruption. Outer gap and inner gap ramped down
to almost zero.

Next shot: program CLEARIN to remain constant.

Shot 12 -- Plasma. 1 MA. Inner gap was constant at 1.3 cm, outer gap scanned
from 1.0 to 0.5 cm during the shot.

Next shot: tweak RCUR to keep outer gap at 1.0 cm.

Shot 13 -- Plasma. 1 MA. Both outer and inner gaps are drifting down with
time.

Next shot: more tweaking of CLEARIN.

Shot 14 -- Plasma. 1 MA. RF looked pretty good at 2.4 MW. Wp=150 kJ.

Next shot: more tweaking of CLEARIN and RCUR.

Shot 15 -- Plasma. 1 MA. Very good gap control. Outer gap=1.0 cm. Good
RF. Prf=2.1 MW. Wp=165 kJ.

Next shot: increase outer gap to 1.5 cm.

Shot 16 -- Plasma. 1 MA. Outer gap=1.5 +/- 0.1 cm. RF is not as good as on
the previous shots.

Next shot: no changes. RF needs to be re-tuned.

There was a delay between shots 16 and 17 to fix a heat scanner problem.

Shot 17 -- Aborted due to Heat subsystem failure during Check.

Shot 18 -- Plasma. 1 MA. Outer gap = 1.5 cm, good control.

Next shot: no changes.

Shot 19 -- Plasma. 1 MA. RF is not doing as well with this 1.5 cm gap
compared to the earlier 1 cm gap shots.

Next shot: Change outer gap to be 0.5 cm.

Shot 20 -- Plasma. 1 MA. Outer gap = 0.5 cm, good control. Very good RF
on this shot. It looks like the RF couples much better at smaller
gap.

Next shot: Change outer gap to be 1.0 cm, and raise ZCUR by 7 mm.

Shot 21 -- Plasma. 1 MA. Outer gap = 1.0 cm, good control. Xray centroid
went up by 6 mm (from -5 mm on previous shot to +1 mm on this shot).

Next shot: repeat, no changes

Shot 22 -- Plasma. 1 MA. RF didn't do too well on this shot.

Next shot: lower ZCUR back down by 7 mm (so it will be the same as
on shot 20). Also tweak outer gap from 11.5 to 10.0 mm.

Shot 23 -- Plasma. 1 MA.

Next shot: lower plasma current to 0.7 MA.

Shot 24 -- Plasma. 0.7 MA. Outer gap varied from 1.5 to 2.0 cm, even though
the programming remained unchanged.

End of run

Session Leader Comments
Apr 27 1999 09:16:32:560AM990427002Steve Wukitch002 fizzle

next shot: 0.5 MW/each staggered
Apr 27 1999 09:55:04:750AM990427003Steve Wukitch003 plasma - disruption
H-mode at 0.5 MW
Except one fault all faults were result of mismatch

next shot: retune and repeat
Apr 27 1999 09:55:21:047AM990427004Steve Wukitch0004 plasma - disruption
H-mode again
E-port had two MIT arc detection faults

next shot: raise power to 0.75 MW/each staggered
Apr 27 1999 12:39:41:640PM990427005Steve Wukitch005 fizzle

Apr 27 1999 12:39:53:450PM990427006Steve Wukitch006 plasma
no faults on D
no H-mode
E failed
Apr 27 1999 12:40:48:357PM990427007Steve Wukitch007 fizzle
Apr 27 1999 12:40:58:090PM990427008Steve Wukitch008 fizzle
Apr 27 1999 12:40:34:903PM990427009Steve Wukitch009 plasma
E faulted often

next shot: repeat with retune
Apr 27 1999 01:56:33:217PM990427011Steve Wukitch011 plasma
E-port failed
D-port power feedback started to oscillate
outer gap ->0

next shot: increase power to 1 MW/each
Apr 27 1999 01:56:48:200PM990427012Steve Wukitch012 plasma
D-port was at 250 kW - error in MW_coefficients
Apr 27 1999 01:56:58:700PM990427013Steve Wukitch013 plasma
good D port ramp
Apr 27 1999 01:57:18:060PM990427014Steve Wukitch014 plasma - good H-mode
NO FAULTS

next shot: try to keep outer gap at 1. cm and start outer gap scan
Apr 27 1999 01:57:30:420PM990427015Steve Wukitch015 plasma - good H-mode
NO FAULTS
outer gap at 1 cm

next shot: change outer gap to 1.5 cm
Apr 27 1999 02:43:03:700PM990427016Steve Wukitch016 plasma
faulting on E-port due to high reflected power

next shot: retune and repeat
Apr 27 1999 03:40:27:093PM990427018Steve Wukitch018 plasma
gap is steady at ~1.5 cm
faulting both due to mismatch in H-mode
overload on #1

next shot: repeat and complete overlap of D and E
Apr 27 1999 03:40:45:000PM990427019Steve Wukitch019 plasma
faulting on E is mismatch
faulting on D is voltage

next shot: change outer gap to 0.5 cm
retune based on 990427014
Apr 28 1999 07:32:03:373AM990427020Steve Wukitch020 plasma - good H-mode

next shot: raise plasma position
Apr 28 1999 07:32:28:980AM990427021Steve Wukitch021 plasma
faulting on D and E - phase balance
over load on #1 and #2
plasma position is Zpos~0.03
Apr 28 1999 07:32:55:327AM990427022Steve Wukitch022 plasma
overload on #1 and #2

next shot: lower plasma position
Apr 28 1999 07:33:18:733AM990427023Steve Wukitch023 plasma
screen overcurrent on #1
#2 ran with phase balance faults

next shot: lower plasma current to 0.7 MA
ramp #1 from 900 kW to 1.25 MW
Apr 28 1999 07:33:36:560AM990427024Steve Wukitch024 plasma
screen overcurrent on #1

Physics Operator Comments
Apr 27 1999 09:13:26:293AMRobert GranetzEngineering Setup for Tuesday, 990427

Load from 980213015 (note: this is a shot from last year)

1-2 hours ECDC in D2, stopping in time to begin run at 08:00.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
leave B-side upper as is Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV
Apr 27 1999 09:13:41:827AMRobert GranetzRun Plan for 990427:

MP 214 -- ICRF (possible piggyback: MP 237 -- Plasma rotation vs Ip in EDA)

SL: S. Wukitch (piggyback: J. Rice)
PO: R. Granetz

Start by loading 980213015, a 1 MA shot from last year on which the ICRF worked
well. However, set Btor = 5.4 T instead of 5.7 T. (The higher field was used
last year to prevent ECE cutoff from the core.) From there, we may want to
vary the plasma current, in which case, John Rice may be able to get some data
in piggyback mode.

Before the physics run, we will need to do a 'Tuesday' OH test.
Apr 27 1999 09:13:57:577AMRobert Granetz Note: 1-2 hours of ECDC in D2 was done prior to this run.

Hybrid coldstart done; no errors found
($set default cmod$models:[hybrid.tcl]
$@hybinit_dispatch
$@show_bitbus_log
Use editor search to verify no occurrences of "error" nor
"not respond")
Load 980213015.
Re-call all estimators that use Bp coils (to update BP16_BC to
BP16_DE), but keep the same offsets.
Turn off bolo feedback gain (disable wire).
Reduce nl_04 from 2.4 to 1.2e20 m-2.
Reduce Btor from 5.7 to 5.4 T.
Confirm that RF feedback on RCUR is turned off (RF_LOAD_E = 0.0)
Apr 27 1999 08:54:59:717AM990427001Robert GranetzShot 01 -- OH test. All OK.

Next shot: plasma, based on 980213015.
Apr 27 1999 09:11:04:437AM990427002Robert GranetzShot 02 -- Fizzle.

Next shot: increase pre-puff from 20 to 22 ms. Decrease BR offset
from 0.0015 to 0.001 T
Apr 27 1999 09:32:52:123AM990427003Robert GranetzShot 03 -- Plasma. 1 MA. Disrupted at 1.05 s. Went into H-mode with only
0.6 MW. EF4 doesn't look right.

Next shot: repeat
Apr 27 1999 10:22:25:157AM990427004Robert GranetzShot 04 -- Plasma. 1 MA. Disrupted at 1.17 s. Similar problem with EF4 not
getting through crossover properly. I had inadvertently zeroed
the EF2-by-EF4 estimator when I loaded last year's shot. They have
now been set to 0.5 for EF2U and EF2L

Next shot: try again, with EF2-by-EF4 corrected.
Apr 27 1999 10:35:31:233AM990427005Robert GranetzShot 05 -- Fizzle. Good null, but the pressure was down by almost 50% from
shot 3. It turns out the B-top plenum pressure has dropped from
6 psi to 3 psi during the past hour.

Next shot: refill B-top plenum to 6 psi of D2 and retry.
Apr 27 1999 11:08:28:717AM990427006Robert GranetzShot 06 -- Plasma. VDE caused a disruption at 1.01 s. EF4 looks okay now, but
it was getting close to its 4 kA limit (8 kA total).

Next shot: increase EF4 PLC limit from 8.0 to 8.5 kA (4.25 kA/coil).
Also change inner and outer gap programming so that outer gap is
reduced from 2 to 1 cm, and inner gap is help more constant.
Apr 27 1999 11:22:51:043AM990427007Robert GranetzShot 07 -- Fizzle.

Next shot: reduce Br another 0.5 mT.
Apr 27 1999 12:03:13:920PM990427008Robert GranetzShot 08 -- Fizzle.

Next shot: reduce Br yet again. This time to 0.000 T
Apr 27 1999 12:08:40:420PM990427009Robert GranetzShot 09 -- Plasma. 1 MA until VDE disruption at t=1.42 s. Outer gap is about
1.0 cm, but varies slowly from 0.5 to 1.4 over 0.8 s.

Next shot: program RCUR to ramp out slowly to try and keep the outer
gap constant. Also reduce Br offset again by another 0.5 mT
Also start Ip rampdown at 1.25 instead of 1.5 s.
Apr 27 1999 04:08:37:340PM990427010Robert GranetzShot 10 -- Plasma. 1 MA. Disrupted at 1.35 s. Outer gap was fairly constant,
but at 0.5 cm.

Next shot: tweaked the CLEARIN "factor" to get it within range (Steve
Wolfe found this problem).
Apr 27 1999 12:42:09:840PM990427011Robert GranetzShot 11 -- Plasma. 1 MA, no disruption. Outer gap and inner gap ramped down
to almost zero.

Next shot: program CLEARIN to remain constant.
Apr 27 1999 12:50:48:717PM990427012Robert GranetzShot 12 -- Plasma. 1 MA. Inner gap was constant at 1.3 cm, outer gap scanned
from 1.0 to 0.5 cm during the shot.

Next shot: tweak RCUR to keep outer gap at 1.0 cm.
Apr 27 1999 01:28:24:797PM990427014Robert GranetzShot 14 -- Plasma. 1 MA. RF looked pretty good at 2.4 MW. Wp=150 kJ.

Next shot: more tweaking of CLEARIN and RCUR.
Apr 27 1999 01:47:16:827PM990427015Robert GranetzShot 15 -- Plasma. 1 MA. Very good gap control. Outer gap=1.0 cm. Good
RF. Prf=2.1 MW. Wp=165 kJ.

Next shot: increase outer gap to 1.5 cm.
Apr 27 1999 02:01:52:700PM990427016Robert GranetzShot 16 -- Plasma. 1 MA. Outer gap=1.5 +/- 0.1 cm. RF is not as good as on
the previous shots.

Next shot: no changes. RF needs to be re-tuned.
Apr 27 1999 02:20:03:060PM990427016Robert GranetzThere was a delay between shots 16 and 17 to fix a heat scanner problem.
Apr 27 1999 02:46:03:733PM990427017Robert GranetzShot 17 -- Aborted due to Heat subsystem failure during Check.
Apr 27 1999 03:17:43:467PM990427018Robert GranetzShot 18 -- Plasma. 1 MA. Outer gap = 1.5 cm, good control.

Next shot: no changes.
Apr 27 1999 03:35:47:157PM990427019Robert GranetzShot 19 -- Plasma. 1 MA. RF is not doing as well with this 1.5 cm gap
compared to the earlier 1 cm gap shots.

Next shot: Change outer gap to be 0.5 cm.
Apr 27 1999 03:57:34:560PM990427020Robert GranetzShot 20 -- Plasma. 1 MA. Outer gap = 0.5 cm, good control. Very good RF
on this shot. It looks like the RF couples much better at smaller
gap.

Next shot: Change outer gap to be 1.0 cm, and raise ZCUR by 7 mm.
Apr 27 1999 04:13:54:623PM990427021Robert GranetzShot 21 -- Plasma. 1 MA. Outer gap = 1.0 cm, good control. Xray centroid
went up by 6 mm (from -5 mm on previous shot to +1 mm on this shot).

Next shot: repeat, no changes
Apr 27 1999 04:31:45:530PM990427022Robert GranetzShot 22 -- Plasma. 1 MA. RF didn't do too well on this shot.

Next shot: lower ZCUR back down by 7 mm (so it will be the same as
on shot 20). Also tweak outer gap from 11.5 to 10.0 mm.
Apr 27 1999 04:50:15:123PM990427023Robert GranetzShot 23 -- Plasma. 1 MA.

Next shot: lower plasma current to 0.7 MA.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:45:45:157AMTestOkOH CoAx test/AOK
209:02:16:060AMPlasmaOkno faults/fizzel
309:14:37:043AMPlasmaOkno faults/plasma
409:31:00:200AMPlasmaOkNo faults
510:28:56:437AMPlasmaOkno faults
610:42:44:717AMPlasmaOkno faults
711:09:21:157AMPlasmaOkno faults fizzle
811:22:34:857AMPlasmaOkno faults fizzle
911:35:28:810AMPlasmaOkno faults
1012:09:34:013PMPlasmaOkno faults
1112:26:59:407PMPlasmaOkno faults
1212:43:28:483PMPlasmaOkno faults
1301:02:33:390PMPlasmaOkNo Faults
1401:19:47:060PMPlasmaOkNo Faults
1501:37:49:513PMPlasmaOkNo Faults
1601:55:50:030PMPlasmaOkNo Faults
1702:31:59:763PMPlasmaBadNo Power Shot
1803:05:04:513PMPlasmaOkNo Faults
1903:27:08:857PMPlasmaBadFaults on OH1 and EF1
2003:45:17:450PMPlasmaOkno faults
2104:00:42:890PMPlasmaOkno faults
2204:20:03:170PMPlasmaOkNo Faults
2304:40:01:327PMPlasmaBadEF1 Fault
2404:57:51:797PMPlasmaOkNo Faults