Alcator C-Mod Run 1000428 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:Gerd Schilling (shots 1-22)

Operators
Session leader(s):Gerd Schilling
Physics operator(s):Earl Marmar
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
MP#268 ICRF Conditioning/Schilling, Marmer/Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:22:850PM
Author: To Be Determined
#31 of 34 OPS
Date: 29-APR-2000 11:19 Expires: 13-MAY-2000 00:00
From: RHONE::SCHILLING
Subj: Run Summary for Friday, April 28, 2000

Session Leader's Summary for Friday, April 28, 2000 (1000428)

SL: Schilling
PO: Marmar
EO: Silva

Objectives: bring up RF in E-Port (FMIT #2) and J-Port (FMIT #3,4) antennas
bring up RF in D-Port if FMIT #1 ready
continue DNB checkout
continue machine conditioning

Results:

On Thursday, the day before this run, an RF leakage survey of the Cell and the
Power Room was performed by exciting the J-Port antenna with very low power.
Randy Wilson discovered the greatest leakage signal on the cabling connected to
the glow discharge probe. Disconnecting this cabling reduced the leakage signal
by 40 dB. In addition, ferrites were added to the EF4 shunt cables. We had hoped
that this would eliminate EF4-induced disruptions, but did not have time to bring
up J-Port power consistently to the level giving problems on Wednesday. An
interlock on transmitter #4 monitoring FPA filament current started to fail early
in the run, leading to nuisance trips of the high voltage.

Shot 2 did disrupt with J-Port power at ~0.75 MW, but modifications to the
phase feedback loop for transmitters 3 and 4 resulted in amplitude oscillations
and hash. We then disabled the phase feedback and kept J-Port at low power
while we concentrated on D and E. Transmitter #1 was ready for use, and the
D-Port antenna had been vacuum conditioned up to ~22 kV Thursday evening.
We still had to find a plasma match following the resonant loop rebuild earlier
this year, and this took a number of shots.

Shots 3, 5, 6, and 7 were fizzles. On shots 4 and 8-14 we looked for a plasma
match for D, brought up the power in E to ~1.5 MW, and kept J at low power or
off. We obtained a match for D by shot 15, and in the following shots brought
its power up to 1.25 MW. By shot 18 we started to overlap the power from D and
E in order to raise the total power to the plasma, and added J at low power at
the end. A total power of ~2.3 MW was achieved.

Lithium pellets were added to several shots, and the DNB initiated injection into
plasma at low power.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:10:443PM
Author: To Be Determined
Physics Operator Run Summary 1000428

MP#268 ICRF Commissioning
SL: Schilling
PO: Marmar
EO: Silva

Engineering setup:
-------------------
ECDC overnight in D2, turn off 2 hours before run

Power system setup as on 1000426021

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
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


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

Start plasma operations from a reload of 1000426021 (800kA, nl4=8e19, TF=5.4T)
and proceed with conditioning. The main goal of the day is to condition all 4
RF systems.

The DNB may also fire into plasma.

The LPI is available for piggy-back service.



Results:

The run went reasonably well. All 4 antennas coupled power into the plasma,
with D and E combining for more than 2 MW on several shots at the end of the
day, giving brief transitions into ELM-free H-mode. The DNB fired into plasma
on several shots. It was being run in deuterium. There were no obvious effects
on the plasma, other than the pressure rise observed before initiation, which
typically caused a pre-fill pressure increase of about 20% relative to the PG_4
puff. The fizzle on shot 20 may have been caused by this pressure increase.

Lithium pellets were injected through the day, mostly at the beginning of
ramp-down. On shot 17, the pellet was injected at 1.3 seconds, resulting in a
long-lived P-mode, with sawtooth suppression lasting more than 150 ms and
neutron rate of 1e12/s. The Los Alamos camera very nicely shows the
bremsstrahlung torus that forms after the density peaks on each shot. Chris
Boswell reported that one of the slower cameras captured the pellet ablation on
one shot, when the event occurred right near the end of a frame integration
time.

After shot 2, the density programming was raised to nl_04=1.0e20.

H/D started the day at about 5% and crept up to 10% by the end of the run.

Problems:

Shot 1 was a dud because the TF voltage was too low (PLC setting), resulting in
only 3.9 tesla at t=0.

The RF caused EF4 to crowbar on shot 2, with symptoms similar to those of
Wednesday, 1000426. For the rest of the run, the J-port power was kept low (<.5
MW), and phase feedback on J was disabled; the EF4 problem did not recur.

We had 5 fizzles today (shots 3,5,6,7,and 20). On the early shots, we noticed
that the ratiomatic was reading about a factor of 4 low at t=0 as well as
between pulses. This problem disappeared for shot 7. Various wirehead tweaks
were undone for shots 8 and subsequent, and there was only one more fizzle
(shot 20).

There was a magnetics digitizer error on shot 8; EFIT could not be run.

Several signals were lost on the last shot (22) because of an inadvertent
disabling of the data acquisition during the store cycle.


Scorecard:

16 plasmas
5 fizzles
1 dud

22 cycles

Session Leader Comments
Apr 28 2000 01:21:48:483PM1000428001Gerd SchillingThe J-Port antenna was excited at low level yesterday, and an RF leakage survey of the power room and the cell was performed.
Randy Wilson discovered the greatest leakage signal on the cabling connected to the glow probe. Once this was disconnected,
the leakage signal dropped by 40 dB. In addition, ferrites were added to the EF4 shunt cables.

No TF, no plasma.





Apr 28 2000 01:22:17:560PM1000428002Gerd SchillingPlasma disrupted ~1.3 s. Attempted RF power from D+E+J, staggered in time. D~0, E=0.5 MW, J3=0.35 MW, J4=0.4 MW.
Turn off phase feedback on 3 and 4 to reduce hash (oscillation).




Apr 28 2000 10:28:59:263AM1000428003Gerd SchillingFizzle. No RF.



Apr 28 2000 10:37:06:420AM1000428004Gerd SchillingPlasma, RF. Attempted D+E+J again. D~0 MW (mismatch). E=0.5 MW. J3=0.1 MW, J4=0 MW.



Apr 28 2000 10:50:34:793AM1000428005Gerd SchillingFizzle.


Apr 28 2000 11:42:55:497AM1000428006Gerd SchillingFizzle.


Apr 28 2000 12:05:42:140PM1000428007Gerd SchillingFizzle.


Apr 28 2000 12:25:39:360PM1000428008Gerd SchillingPlasma, RF. Attempted D+E+J staggered. D still has mismatch, ~0 MW. E=0.78 MW. J3~0.15 MW, J4=0.2 MW


Apr 28 2000 12:47:34:043PM1000428009Gerd SchillingPlasma, RF. Attempted D+E+J staggered. D still has mismatch, ~0 MW. E=0.95 MW. J3~0.15 MW, J4=0 MW (HV dropped out).


Apr 28 2000 01:10:16:310PM1000428010Gerd SchillingPlasma, disrupted ~0.75 s. Attempted D+E+J staggered. D still has mismatch, ~0 MW. Never got to others.


Apr 28 2000 01:27:22:577PM1000428011Gerd SchillingPlasma, RF. Attempted D+E+J staggered. D still has mismatch, but getting better. E=1.1 MW. J3= 0.07 MW, J4=0.15 MW.


Apr 28 2000 01:50:19:170PM1000428012Gerd SchillingPlasma, RF. Attempted D+E staggered. Still trying to get better match on D. E=1.25 MW. Transmitters 3 and 4 off for the moment.


Apr 28 2000 02:10:13:000PM1000428013Gerd SchillingPlasma disrupted ~1.2 s, RF. Attempted D+E staggered. Still trying to get better match on D. E ramped up to 1.5 MW.
Transmitters 3 and 4 off for the moment.


Apr 28 2000 02:31:33:780PM1000428014Gerd SchillingPlasma, RF, and first injection of DNB into plasma. Attempted D+E staggered. Match on D improving very slowly. E ramped up to 1.4 MW.
Transmitters 3 and 4 off for the moment.


Apr 28 2000 03:14:14:467PM1000428016Gerd SchillingPlasma and RF, DNB off. D+E staggered. D up to 0.9 MW. E ramped up to 1.4 MW, extended in time but faulted at end.
Transmitters 3 and 4 off for the moment.


Apr 28 2000 03:30:09:310PM1000428017Gerd SchillingPlasma and RF, DNB off. D+E staggered. D up to 1.1 MW. E ramped up to 1.4 MW, extended in time but faulted at end.
Transmitters 3 and 4 off for the moment.


Apr 28 2000 03:53:17:827PM1000428018Gerd SchillingPlasma and RF, DNB off. D+E+J staggered, with slight D+E overlap. D up to 1.25 MW. E =1.3 MW. J3=0.14 MW, J4=0.23 MW.


Apr 28 2000 04:32:42:077PM1000428019Gerd SchillingPlasma, RF. Stagger D+E+J with partial D+E overlap. D=1.25 MW, E=1.3 MW, J3=0.13 MW, J4=0.23 MW.

Apr 28 2000 04:34:40:857PM1000428020Gerd SchillingFizzle.
Apr 28 2000 05:26:47:903PM1000428021Gerd SchillingPlasma, RF, DNB. Overlap D+E, followed by J. D=1.2 MW, E=1.07 MW with faults at end, J3=0.2 MW, J4=0.22 MW.
Apr 28 2000 05:10:24:170PM1000428022Gerd SchillingPlasma, RF, DNB. Partially overlap D+E, followed by J. D=1.2 MW with faults, E=0.96 MW, J3=0.2 MW, J4=0.35 MW.

Physics Operator Comments
Apr 28 2000 09:04:25:013AMEarl MarmarEngineering Setup and Run Plan for Friday, April 28, 2000

Run to start at 9:00AM and end at 5:00PM

MP#268 ICRF Commissioning
SL: Schilling
PO: Marmar

Engineering setup:
-------------------
ECDC overnight in D2, turn off 2 hours before run

Power system setup as on 1000426021

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
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:
VUV and ECE

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

Start plasma operations from a reload of 1000426021 (800kA, nl4=8e19, TF=5.4T)
and proceed with conditioning. The main goal of the day is to condition all 4
RF systems.

The DNB may also fire into plasma.

The LPI is available for piggy-back service.
Apr 28 2000 09:05:04:060AMEarl MarmarColdstart
all matrices respond

load from 1000426021
Apr 28 2000 09:13:18:000AM1000428001Earl Marmardud

TF voltage not set correctly on the PLC

Only had 3.9 Tesla at t=0.
Apr 28 2000 09:40:58:000AM1000428002Earl MarmarPlasma

Disrupt at 1.3 s

lost EF4 control at 1.2 seconds, when J-port came on (~.75 MW)

Apr 28 2000 10:17:44:843AM1000428003Earl MarmarRaise nl_04 program to 1e20

fizzle

B_R looks a tad negative

Ratiomatic pressure is a factor of 4 low at t=0; it's not clear if this is the guage or the real pressure.
Apr 28 2000 10:38:12:250AM1000428004Earl MarmarB_R offset to -.0005 T from -.001

plasma

got the higher density

some early hards
Apr 28 2000 11:01:26:547AM1000428005Earl Marmaradd some extra early PG3

move argon pulse 100 msec earlier

fizzle; B_R now looks a little too positive
Apr 28 2000 11:44:41:700AM1000428006Earl MarmarB_R offset to -.0015

call for Li pellet at 1.505 s

fizzle
Apr 28 2000 12:08:42:280PM1000428007Earl MarmarEF4 20 A less negative before t=0

(-1270 from -1290)

fizzle

Ratiomatic shows the normal fill pressure on this one.
Apr 28 2000 12:26:21:793PM1000428008Earl MarmarB_r offset to -.0005

EF4 back to -1290A

plasma

did not get the Li pellet

problem with traq digitizer; missing magnetics data; no EFIT
Apr 28 2000 12:50:02:140PM1000428009Earl Marmarno changes
plasma

Got the Li pellet at 1.5 s

EFIT ok this time
Apr 28 2000 01:14:24:717PM1000428010Earl Marmarremove TF jog after 1 second

LPI set for 0.5 seconds; got it

disrupt at 0.75 s
Apr 28 2000 01:25:06:950PM1000428011Earl Marmarmove argon puff 50 msec earlier

LPI to 1.5 s

plasma

got the pellet
Apr 28 2000 02:08:00:217PM1000428012Earl Marmarno PCS changes

plasma
Apr 28 2000 02:09:08:793PM1000428013Earl Marmarno PCS changes

plasma

disrupt at 1.19 s

1.5 MW from E port
Apr 28 2000 02:32:09:543PM1000428014Earl Marmarno PCS changes

DNB through open gate valve, asking for 50 ms pulse at 0.8 seconds

plasma
Apr 28 2000 03:05:15:793PM1000428015Earl Marmarno PCS changes

plasma

got >0.5 MW on D-port
Apr 28 2000 03:32:01:200PM1000428016Earl Marmarno PCS changes

plasma

disrupt at 1.59 s
Apr 28 2000 03:32:27:233PM1000428017Earl Marmarno PCS changes

Li pellet to 1.3 seconds

plasma
Apr 28 2000 03:50:23:483PM1000428018Earl MarmarNo PCS changes

plasma

short ELM-free H-mode, 0.92 to 0.98 seconds

disrupt at 1.6 s
Apr 28 2000 04:11:32:123PM1000428019Earl Marmarno PCS changes

plasma

ELM-free H-mode 0.82 to 0.92 seconds
Apr 28 2000 04:30:52:937PM1000428020Earl Marmarreduce clearin between 0.8 and 1.2 seconds

DNB firing into plasma (0.5 to 0.6 s)

fizzle (too much gas from DNB?)


Apr 28 2000 04:57:54:077PM1000428021Earl Marmardrop prepuff to 22 msec (from 28)

plasma
Apr 28 2000 05:11:27:060PM1000428022Earl Marmarreduce prepuff to 19 msec

Li pellet to 0.63

plasma

p-mode gone before RF turn-on (0.7 s)

Engineering Operator Comments
ShotTimeTypeStatusComment
109:06:39:123AMPlasmaBadTF voltage command was set to160v instead of 1600
209:19:44:640AMPlasmaOkEF4 IOC with RF. caused plasma to disrupt
309:56:04:200AMPlasmaOkno faults/dud
410:25:50:500AMPlasmaOkno faults/plasma
510:44:51:247AMPlasmaOkno faults/Dud
611:38:58:497AMPlasmaOkno faults/dud
712:02:30:920PMPlasmaOknofaults/dud
812:17:12:030PMPlasmaOkno faults/plasma
912:40:24:263PMPlasmaOkno faults/plasma
1001:01:45:983PMPlasmaOkno faults/plasma
1101:17:49:450PMPlasmaOkno faults/plasma
1201:41:50:047PMPlasmaOkno faults/plasma
1302:00:51:123PMPlasmaOkno faults/plasma
1402:20:41:890PMPlasmaOkno faults/plasma
1502:41:52:140PMPlasmaOkno faults/plasma
1603:02:49:483PMPlasmaOkno faults/plasma
1703:22:40:483PMPlasmaOkno faults/plasma
1803:43:36:797PMPlasmaOkno faults/plasma
1904:03:55:047PMPlasmaOkno faults/plasma
2004:24:31:687PMPlasmaOkno faults/????
2104:37:37:060PMPlasmaOkno faults/plasma
2204:58:48:657PMPlasmaOkno faults/plasma