Alcator C-Mod Run 1001020 Information

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Miniproposals
Miniproposal:268
Date Filed: 4/7/2000
Title:Conditioning of D-, E-, or J-Port ICRF Antenna
First Author:Gerd Schilling
Session Leader:John Goetz (shots 1-19)
Session Leader:Steve Wukitch (shots 1-19)

Operators
Session leader(s):John Goetz,Steve Wukitch
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Parkin,Gary Dekow

Engineering Operator Run Comment
MP#268 ICRF SL: Wukitch/Goetz PO: Wolfe EO: Dekow/Parkin

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:25:133PM
Author: To Be Determined
Run summary for 1001020

This run was to determine the maximum power available from the J-port
antenna. That answer today is 2.8MW. The antenna and transmitters ran
well today with very few faults.

The bad news is that the upper K-port corner of the J-port antenna
lights up and injects stuff. The plasma would enter H-mode and some time
later the injections would begin. The plasma would revert to L-mode with
most shots ending in an early disruption. The threshold for this phenomenon
happening was ~2.0 MW early in the run and slowly decreased to ~1.5 MW.
Many things were changed to try and get rid of the glow including an
outer gap scan (0.5 to 1.5 cm), a change in current, and a change in
target density. None of these changes made much of a difference. It appears
that this is neither a power nor a Joule heating problem. It is more than
likely a voltage problem as the glow begins shortly after the plasma enters
H-mode (when the voltage on the antenna is highest).

Upon investigating the history of this problem, it appears that the glow
begins on the upper K-side corner of the antenna beginning with shot
1001018021. Every shot today had a glow in that corner to varying degrees.

The shots are as follows:

Shot 001
cycle test

Shot 002
plasma
J-port tuned for L-mode; max faults early

Shot 003
plasma
J-port ran a little longer; tune was o.k.

Shot 004
fizzle

Shot 005
plasma
J3 - 0.8MW - one fault
J4 - 0.9MW - nine faults (mostly DC0)

Shot 006
data corrupted

Shot 007
plasma, H-mode at 1.3MW - early disruption
J3 - 1.0MW - no faults
J4 - 1.0MW - one fault

K-port top corner of the antenna is exploding to cause the disruption

Shot 008
plasma, H-mode at 1.3MW - early disruption
J3 - 1.0MW - no faults
J4 - 1.0MW - one fault

K-port top corner of the antenna is exploding to cause the disruption

Shot 009
plasma, H-mode at 1.1MW - early disruption
J3 - ramp from 0.4 to 0.9MW - no faults
J4 - ramp from 0.4 to 0.9MW - no faults

K-port top corner of the antenna is exploding to cause the disruption
injections begin to happen at about 1.8MW net power
power level for injections is decreasing as the shots go along

Shot 010
plasma, H-mode at 1.1MW - outer gap ~1.5cm
J3 - ramp from 0.4 to 1.3MW - one faults
J4 - ramp from 0.4 to 1.4MW - max faults at the high power

K-port top corner of the antenna has a "small" injection on this one

Shot 011
plasma, H-mode at 1.1MW - outer gap ~1.5cm
injection from K-port top causes a MARFE and an early
disruption
J3 - ramp from 0.4 to 1 MW - four faults during the MARFE
J4 - ramp from 0.4 to 1 MW - three faults during the MARFE

Shot 012
plasma, H-mode at 1.1MW - outer gap ~1.5cm - plasma moved down 0.5cm
no cameras to help find the injection
J3 - ramp from 0.4 to 1.1 MW - no faults
J4 - ramp from 0.4 to 1.1 MW - no faults

Shot 013
early disruption - RF didn't have a chance

Shot 014
plasma - all the way
right gap is about 0.5cm
many injections at 2 MW of power puts it into L-mode and then
it alternates
injections seem to be coming from the top K-port corner of the
antenna
J3 - 0.4 to 1.4 MW ramp - three faults
J4 - 0.4 to 1.4 MW ramp - three faults

Shot 015
plasma - H-mode
right gap is about 0.5cm
many injections at 2 MW of power puts it into L-mode and then
it alternates
injections seem to be coming from the top K-port corner of the
antenna
J3 - 0.4 to 1.4 MW ramp - one fault
J4 - 0.4 to 1.4 MW ramp - no faults

Shot 016
plasma - H-mode
right gap is about 0.5cm
many injections at 1.9 MW of power puts it into L-mode
injections seem to be coming from the top K-port corner of the
antenna
J3 - 0.95 MW ramp - no faults
J4 - 0.95 MW ramp - no faults

Shot 017
plasma - H-mode
many injection at 1.6 MW of power puts it into L-mode
injections from top K-port corner of antenna

J3 - 0.8 MW - no faults
J4 - 0.8 MW - no faults

Shot 018
plasma - H-mode - Ip = 1 MA
right gap is about 0.5cm
many injections at 1.6 MW (0.8 each) of power puts it into
L-mode
injections seem to be coming from the top K-port corner of the
antenna
J3 - 0.9 MW ramp - two faults
J4 - 0.9 MW ramp - two faults

Shot 019
plasma - H-mode - Ip = 1.1 MA - target ne = 0.8
right gap is about 0.5cm
many injections at 1.5 MW
injections seem to be coming from the top K-port corner of the
antenna

J3 - 0.9 MW ramp - no faults
J4 - 1.0 MW ramp - no faults

Physics Operator Summaries
Entered: Jul 7 2004 04:37:12:550PM
Author: To Be Determined
Physics Operator Summary for Friday, Oct 20, 2000


MP#268 ICRF
SL: Wukitch/Goetz
PO: Wolfe
EO: Dekow, Parkin

Engineering Setup
------------------

Overnight boronization, followed by ECDC in He until 2 hours before start of
run.

Power systems as on 1001018021
Note: EF4 current limit should be [-10,+4]ka
EFC start time should be -.035sec
Gas setup

fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
fill B-side upper with 35 psi of D2 Hybrid DISABLED, for ECDC
fill C-side with 30 psi of D2 Hybrid enabled
fill J-bot with 10 psi of N2 Hybrid DISABLED
fill Lower Div Cap with 10 psi of N2

The following gate valves should be enabled: ECE, VUV, Beast

Plan
--------------------

The idea is to investigate the power limit (voltage or heat load) for the
four-strap J-port antenna into H-modes, and then perhaps add additional power
from D and E. If possible, we would like to couple 2.5-3.0MW through the J
antenna. We will also try using nitrogen puffing, from either J-bottom or
NINJA or both, to cool the edge and reduce the impurity influx at high power.

Start from 1001018021 (1.1MA, 5.4T, nl04=1.1e20) target, slightly tweaked to
get rid of thrash at 0.5sec, using only J-port antenna. Try adjusting gap,
field, and perhaps current to reduce faulting on real or spurious arcs. We can
also change the outer plasma shape relative to the antenna by varying the
programmed IC_EF4 current; lowering IC_EF4 should result in a closer match at
the top and bottom of the antenna. Also try modifying the power feedback
circuit to reduce sawtooth-induced "faults".

We will also try using N2 puffing into the divertor to reduce Prad (cf MP#163,
run 980213). We can try both programmed puffs and even perhaps
bolo-feedback. Note that at the moment, only DIVBOLO1 seems to be hooked up to
the hybrid.

Results:
-----------

We got off to a late start, due to problems with the PLC/PC system. First the
PC's lost communication, apparently due to a flakey BNC connector on the
ethernet connection to either EF3 or TMX PC's. Then STATE refused to reboot,
and Joe had to swap in a new PC. Then it took quite a while to setup the new
one. Since the new unit did not include the card for communication with the
BigBoard, we ran without that today.

The first plasma shot was #2, which was based on 1001018021, as noted in the
run plan. I set up a bolofeed wire, but it was left off. J-port was the source
of the plasma terminating injections today, with the upper K-side corner
lighting up when the power got to ~2MW. It behaved basically the same all day,
perhaps getting a little worse later on, when the injections started happening
closer to 1.6MW. We were unable to find a plasma condition that improved the
injection situation. Outer gap was scanned from .5 to 1.5cm, zcur was lowered
to -.02 and raised to .013, current was dropped back to 1.0MA, density was
dropped from 1.1e20 to 0.8e20. Only a few shots made it through to rampdown,
and even those had injections from j-port that killed the h-mode when the
power got to the neighborhood of 2MW. This run was unsuccessful.

The offset on the bolofeed channel was determined to be -.07, for what it's
worth. We never tried the N2 puff because the injections were all local to the
antenna today, not from the divertor.

There were no startup problems associated with the boronization, as had been
feared. We had only one fizzle, and that was probably as much a disruption
effect as anything else. No startup tweaks were made. On the other hand, the
H/D ratio was not that great, getting up to 0.08 or so during RF.

Shot #3 disrupted at the beginning of rampdown, with the RF off.FOr the rest
of the run, I removed the RCUR and CLEARIN ramps after 1.5sec, and had no
further rampdown disruptions (of the shots that made it the far).

Scorecard
---------

Tests 1
Duds 0
Fizzles 1
Plasmas 17 (one pre-rf disruption)
------ --
Shots 19



Session Leader Comments
Oct 20 2000 11:41:55:357AM1001020001John Goetzcycle test
Oct 20 2000 11:20:28:560AM1001020002Steve Wukitch002

request: BT=5.4 T, Ip=1.1 MA
D: 0.75 MW [1.1,1.5]
E: 0.75 MW [1.1,1.5]
J3: 0.75 MW [0.6,1.5]
J4: 0.75 MW [0.6,1.5]

result: plasma, L-mode
D: 0. MW [1.1,1.5]
E: 0. MW [1.1,1.5]
J3: 0.75 MW [0.6,1.5] max faults
J4: 0.75 MW [0.6,1.5] max faults
Oct 20 2000 11:42:21:937AM1001020002John GoetzShot 002
plasma
J-port tuned for L-mode; max faults early
Oct 20 2000 11:46:05:607AM1001020003John GoetzShot 003
tune up J-port

plasma
J-port ran a little longer; tune was o.k.
Oct 20 2000 12:20:00:640PM1001020004John GoetzShot 004
fizzle
Oct 20 2000 12:25:13:670PM1001020005John GoetzShot 005
try again

plasma
J3 - 0.8MW - one fault
J4 - 0.9MW - nine faults (mostly DC0)
Oct 20 2000 02:08:34:360PM1001020006John GoetzShot 006
plasma, H-mode at 1.1MW - outer gap ~1.5cm
J3 - 1 MW
J4 - 1 MW
Oct 20 2000 01:17:02:327PM1001020007John GoetzShot 007
plasma, H-mode at 1.3MW - early disruption
J3 - 1.0MW - no faults
J4 - 1.0MW - one fault

K-port to corner of the antenna is exploding to cause the disruption
Oct 20 2000 01:27:30:360PM1001020008John GoetzShot 008
plasma, H-mode at 1.3MW - early disruption
J3 - 1.0MW - no faults
J4 - 1.0MW - one fault

K-port to corner of the antenna is exploding to cause the disruption
Oct 20 2000 01:45:13:263PM1001020009John GoetzShot 009
plasma, H-mode at 1.1MW - early disruption
J3 - ramp from 0.4 to 0.9MW - no faults
J4 - ramp from 0.4 to 0.9MW - no faults

K-port top corner of the antenna is exploding to cause the disruption
injections begin to happen at about 1.8MW net power
power level for injections is decreasing as the shots go along
Oct 20 2000 02:09:14:857PM1001020010John GoetzShot 010
plasma, H-mode at 1.1MW - outer gap ~1.5cm
J3 - ramp from 0.4 to 1.3MW - one faults
J4 - ramp from 0.4 to 1.4MW - max faults at the high power

K-port top corner of the antenna has a "small" injection on this one
Oct 20 2000 02:29:08:543PM1001020011John GoetzShot 011
plasma, H-mode at 1.1MW - outer gap ~1.5cm
injection from K-port top causes a MARFE and an early disruption
J3 - ramp from 0.4 to 1 MW - four faults during the MARFE
J4 - ramp from 0.4 to 1 MW - three faults during the MARFE
Oct 20 2000 02:47:14:200PM1001020012John GoetzShot 012
plasma, H-mode at 1.1MW - outer gap ~1.5cm - plasma moved down 0.5cm
no cameras to help find the injection
J3 - ramp from 0.4 to 1.1 MW - no faults
J4 - ramp from 0.4 to 1.1 MW - no faults
Oct 20 2000 03:11:27:030PM1001020013John GoetzShot 013
early disruption - RF didn't have a chance
Oct 20 2000 03:29:40:343PM1001020014John GoetzShot 014
plasma - all the way
right gap is about 0.5cm
many injections at 2 MW of power puts it into L-mode and then it alternates
injections seem to be coming from the top K-port corner of the antenna
J3 - 0.4 to 1.4 MW ramp - three faults
J4 - 0.4 to 1.4 MW ramp - three faults
Oct 20 2000 03:48:07:107PM1001020015John GoetzShot 015
plasma - H-mode
right gap is about 0.5cm
many injections at 2 MW of power puts it into L-mode and then it alternates
injections seem to be coming from the top K-port corner of the antenna
J3 - 0.4 to 1.4 MW ramp - one fault
J4 - 0.4 to 1.4 MW ramp - no faults
Oct 20 2000 04:10:57:357PM1001020016John GoetzShot 016
plasma - H-mode
right gap is about 0.5cm
many injections at 1.9 MW of power puts it into L-mode and then it alternates
injections seem to be coming from the top K-port corner of the antenna
J3 - 0.95 MW ramp - no faults
J4 - 0.95 MW ramp - no faults
Oct 20 2000 04:44:44:403PM1001020018John GoetzShot 018
plasma - H-mode - Ip = 1 MA
right gap is about 0.5cm
many injections at 1.6 MW (0.8 each) of power puts it into L-mode
injections seem to be coming from the top K-port corner of the antenna
J3 - 0.9 MW ramp - two faults
J4 - 0.9 MW ramp - two faults
Oct 20 2000 05:15:34:700PM1001020019John GoetzShot 019
plasma - H-mode - Ip = 1.1 MA - target ne = 0.8
right gap is about 0.5cm
many injections at 1.5 MW
injections seem to be coming from the top K-port corner of the antenna
J3 - 0.9 MW ramp - no faults
J4 - 1.0 MW ramp - no faults

Physics Operator Comments
Oct 19 2000 05:17:38:637PMSteve WolfeLoad starting shot, also stored in PCS$WOLFE:pcs_1001020000
Seg 1 from 1001019022
Seg 2 from 1001918021 with Ip gain switch delayed from .5 to .65sec
Oct 19 2000 05:18:55:200PMSteve WolfeRun Plan for Friday, Oct 20, 2000

MP#268 ICRF
SL: Wukitch/Goetz
PO: Wolfe

Engineering Setup
------------------

Overnight boronization, followed by ECDC in He until 2 hours before start of
run.

Power systems as on 1001018021
Note: EF4 current limit should be [-10,+4]ka
EFC start time should be -.035sec

Gas setup

fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
fill B-side upper with 35 psi of D2 Hybrid DISABLED, for ECDC
fill C-side with 30 psi of D2 Hybrid enabled
fill J-bot with 10 psi of N2 Hybrid DISABLED
fill Lower Div Cap with 10 psi of N2

The following gate valves should be enabled: ECE, VUV, Beast

Plan
--------------------

The idea is to investigate the power limit (voltage or heat load) for the
four-strap J-port antenna into H-modes, and then perhaps add additional power
from D and E. If possible, we would like to couple 2.5-3.0MW through the J
antenna. We will also try using nitrogen puffing, from either J-bottom or
NINJA or both, to cool the edge and reduce the impurity influx at high power.

Start from 1001018021 (1.1MA, 5.4T, nl04=1.1e20) target, slightly tweaked to
get rid of thrash at 0.5sec, using only J-port antenna. Try adjusting gap,
field, and perhaps current to reduce faulting on real or spurious arcs. We can
also change the outer plasma shape relative to the antenna by varying the
programmed IC_EF4 current; lowering IC_EF4 should result in a closer match at
the top and bottom of the antenna. Also try modifying the power feedback
circuit to reduce sawtooth-induced "faults".

We will also try using N2 puffing into the divertor to reduce Prad (cf MP#163,
run 980213). We can try both programmed puffs and even perhaps
bolo-feedback. Note that at the moment, only DIVBOLO1 seems to be hooked up to
the hybrid.
Oct 20 2000 07:18:49:827AMSteve Wolfecoldstart at 7:15AM
no errors, all matrices respond.

Oct 20 2000 10:59:59:733AM1001020001Steve Wolfeshot#1:in seg2, change ref#9-12 from Ip to 10V
change wire 9 to "bolofeed" with custom predictor: divbolo1=1.0,factor = 2.0
edit controler for pg5=10., algorithm left blank.
gains=0.0
zero_all for wires 10-12.
Also change title to 1.1MA..., and fix tf_current trace before 0.1sec to -150000.
Load at 20-Oct-2000 07:44:02.00

We will have a delay due to a PC/PLC problem: lost heartbeats on PC's, apparently due to
a flakey ethernet connection at EF3 or TMX system. State still won't reboot, claiming
CMOS not set. Joe swapped pc's, no bigboard but state should function.

Shot#1 will be a no-power cycle to test the new STATE machine, etc.
Seemed to go ok. Next shot, try for plasma.


Oct 20 2000 11:19:29:543AM1001020002Steve Wolfeshot#2: PCS setup as in entry for shot#1.
plasma, full length. multiple faulting on J-port.
Oct 20 2000 11:47:45:030AM1001020003Steve Wolfeshot#3: repeat, hopefully with rf.
plasma, disrupts at 1.5sec.
ELM-free h-mode, j still has faulting.
start-up is dicey; it hits something at 12msec, but keeps on
going.

next shot: leave rcur and clearin out during rampdown.
Oct 20 2000 12:07:05:610PM1001020004Steve Wolfeshot#4: leave rcur and clearin out during rampdown.
fizzle. probably just the disruption residue; fields look fine,
but it chokes.

next shot: repeat.
Oct 20 2000 12:28:07:937PM1001020005Steve Wolfeshot#5: leave rcur and clearin out during rampdown.
plasma, full length, h-modes; 115kJ, 1e13 neut/sec
J gives 1.7MW, a few faults. H/D~0.06
Oct 20 2000 01:00:04:827PM1001020006Steve Wolfeshot#6: repeat, try for more power.
plasma disrupted at ~1.2sec. during 2nd H-mode.
Oct 20 2000 01:11:22:530PM1001020007Steve Wolfeshot#7: repeat,

disrupted at 1.06sec.
RF gets to 1.9MW, one fault. eda h-mode, 1e13n/sec, 120kJ.
MPEG shows upper left corner of J-antenna as the source of the injections.

next shot: shorten the RF pulse.
Oct 20 2000 01:27:27:953PM1001020008Steve Wolfeshot#8: shorten the RF pulse.
disrupted at 0.75sec, at ~2MW from J corner again.
Oct 20 2000 01:46:19:340PM1001020009Steve Wolfeshot#9: long power ramp to 3MW, see where it dies.
disrupts at 1.02sec, 1.8MW on J

next shot: increase outer gap by 5mm.
Oct 20 2000 02:00:46:233PM1001020010Steve Wolfeshot#10: increase outer gap by 5mm. RCUR from .661 to .6585
plasma, full length. j-faulted at about the 2MW level.
lots of injections, three separate h-modes.
Oct 20 2000 02:26:15:840PM1001020011Steve Wolfeshot#11: repeat.
plasma disrupts at 1.06sec, right at 2MW.

next shot: lower the plasma by 5mm.
Oct 20 2000 02:49:46:233PM1001020012Steve Wolfeshot#12: lower the plasma by 5mm. (zcur to -.02)
plasma, disrupts at 1.13sec. It's not a bad EDA until it suicides.
136kJ, Rn>2e13, J gets right to 2MW.

No mpegs ahow up this time, so I can't tell if it comes from the
same place.

next shot: move it back up and out by 1cm
Oct 20 2000 03:07:52:437PM1001020013Steve Wolfeshot#13: move it back up and out by 1cm (rcur ->.6635, zcur->-.015)
disrupts very early, .39sec? I didn't change it that early.
Big injection at .35sec, maybe from the divertor in front of J again?

next shot: try that again,
Oct 20 2000 03:24:32:123PM1001020014Steve Wolfeshot#14: move it back up, and out by 1cm (rcur ->.6635, zcur->-.015)
plasma, full length, h-modes "here and there "
neuts to 2e13, 133kJ, lots of injections after 1.1sec, but rf stays on to 2.6MW
before tripping out. gap at 5mm.

next shot: up by 2mm
Oct 20 2000 03:44:42:467PM1001020015Steve Wolfeshot#15: up by 2mm (zcur-> -.013);
also change offset on bolofeed to .07

plasma, disrupts at 1.44sec, very similar injections.
It starts to spark when it gets to 2MW.

next shot: reduce power to 1.9 and see if it will stay quiet.
Oct 20 2000 04:05:21:030PM1001020016Steve Wolfeshot#16: reduce power to 1.9 and see if it will stay quiet.
also, change bolofeed offset to -.07 (went the wrong way)

plasma disrupts at .89 sec, out of h-mode at .8

next shot: drop power to 1.8MW

Oct 20 2000 04:20:03:577PM1001020017Steve Wolfeshot#17: : drop power to 1.8MW
disrupts at 0.9sec, RF at 1.65MW.

next shot: back to the long power ramp and drop current to 1.0MA
Oct 20 2000 04:43:17:560PM1001020018Steve Wolfeshot#18: back to the long power ramp and drop current to 1.0MA

disrupts at 1.05sec, out of H-mode at 0.92sec, P=1.6MW.
So it doesn't seem to be the q or the Ip.

next shot: back to 1.1MA, lower nl04 to .8e20
Oct 20 2000 05:05:03:827PM1001020019Steve Wolfeshot#19: back to 1.1MA, lower nl04 to .8e20
disrupts at 1.09sec, out of h-mode at .92sec, just the same.
g-side pressure down to 0.1mTorr; it doesn't care about that either.


Engineering Operator Comments
ShotTimeTypeStatusComment
110:53:52:590AMTestOkNo Power Test to Check State
211:12:50:780AMPlasmaOk
311:38:29:123AMPlasmaOk
412:02:12:420PMPlasmaOk
512:17:13:873PMPlasmaOk
612:37:11:840PMPlasmaOk
712:58:24:513PMPlasmaOk
801:20:31:623PMPlasmaOk
901:37:21:217PMPlasmaOk
1001:55:23:747PMPlasmaOk
1102:19:16:280PMPlasmaOk
1202:36:44:077PMPlasmaOk
1302:59:39:467PMPlasmaOk
1403:16:18:310PMPlasmaOk
1503:38:41:187PMPlasmaOk
1604:00:33:780PMPlasmaOk
1704:14:17:733PMPlasmaOk
1804:36:58:263PMPlasmaOk
1904:58:08:263PMPlasmaOk