Alcator C-Mod Run 1001206 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:Steve Wukitch (shots 1-15)
Session Leader:Rejean Boivin (shots 1-15)

Operators
Session leader(s):Steve Wukitch,Rejean Boivin
Physics operator(s):Robert Granetz
Engineering operator(s):Bill Parkin,Ed Fitzgerald

Engineering Operator Run Comment
MP #268 RF conditiong SL:Boivin/Wukitch PO:Granetz EO:Fitzgerald/Parkin

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:25:977PM
Author: To Be Determined
Dec. 6th 2000
MP #268 RF conditioning

Session leaders: R. Boivin/S. Wukitch
Physics operator: R. Granetz


We are continuing conditioning/bringing J to high power
for long pulse.

J antenna and systems came along right away at low
power, up to a total of 1.5 MW or so without
injections. When a total of 2 MW or more was injected,
more arcing/faulting was noted but conditioning
(more pulses) did not seem to help in that time span.

Shots 2 and 3 had a subtle problem on which
the phase was obviously wrong (in spite of
the feedback) which may point to some
glow discharge before the antenna. After changing
the ramp rate for the power it went away.

Shots 3-6 had reasonable/nice RF pulses for long
periods (up to 800 msec), with increasing power
levels. H-mode was obtained on shot 6 with 1.5 ish MW
of J alone. EDA was obtained although the confinement
was not the greatest overall.

Similar impurity generations coupled to control
issues resume after shot 007, while the RF power
was increased above 2ish MW. We eventually
revert the run to noise/pickup remedial in an
attempt to remove the pickup of RF on EF1 and EF2.



Physics Operator Summaries
Entered: Jul 7 2004 04:37:12:787PM
Author: To Be Determined
Physics operator summary for run 1001206:

MP #268 RF conditioning

Session leaders: R. Boivin/S. Wukitch
Physics operator: R. Granetz

Summary: Things were going pretty well from an RF standpoint, with J3+J4
delivering up to 2.6 MW, with H-modes, heating, and low radiated
power. But there was still a problem with RF pickup screwing up
some of the magnet supplies, particularly at the higher RF powers.
This problem results in VDE's. The run was stopped early so that
the RF leakage could be tracked down.

Other than the RF pickup problems, the machine ran very well today,
with excellent startup reliability (only one fizzle).

Scorecard: 13 plasmas
1 fizzles
0 duds
1 test
0 aborted and/or screwed up by computer problems
----------
15 total

-------------------------------------------------------------------------------
Engineering setup:

ECDC in D2 overnight, ending 2 hours before the run.

Power systems as on 1001205006.

Gas setup:
fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 35 psi of D2 Hybrid DISABLED, for ECDC
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bot as is Hybrid DISABLED

Enable the following gate valves: ECE, VUV, Beast, DNB

Run starts at 09:00 and ends at 17:00.

-------------------------------------------------------------------------------
RF Setup:

XMTRs 1,2,3, and 4 should be made ready by 8:00 (run-on).

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

Further tests of J-port performance as a four-strap.

Re-load a late shot from yesterday (0.8 MA, 5.3 T, NL_ZMETER). Fire J-port
into plasma. During the day we may raise the density, and if everything
works well, we may eventually the current.

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

Overnight ECDC in D2 was done.

Hybrid coldstart done; no errors found

PCS loaded from shot 1001205020 (using NL_ZMETER), except increased
pre-fill puff from 17 to 20 ms because the DNB will not be open on
the first shot. Also, I enabled the argon right from the first shot.

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

ECDC in D2 may be done between some shots today.

Shot 01 -- Plasma. Good shot. Ip=0.8 MA, Btor=5.2 T, nl_04=0.9e20 m-2 (Yes,
TCI worked on this shot, but we're using NL_ZMETER for density
control.) Max Prf=1.25 MW (J3+J4). No H-mode. Null was not too
good, and breakdown was real late. Gas pressure was low also.

Next shot: increase Br0 offset by 0.3 mT, increase IC_EF4 by 15 A,
and drop pre-fill to 18 ms (since DNB will open on the next shot).

Shot 02 -- Plasma. Good shot. Good startup. RF didn't work well. H/D is
down at 3.5%. Density is slowly rising during the shot for some
reason.

Next shot: no PCS changes. Jim Terry will not puff helium on this
shot (He puffed from the NINJA on shots 1 and 2.)

Shot 03 -- Plasma. Good shot. RF didn't work well. Density behavior didn't
change. H/D=4%.

Next shot: let JT turn the NINJA helium puff back on.

Shot 04 -- Plasma. Disrupted at t=0.98 s. There was a thermal quench, but it
began with a VDE. Steve doesn't see any evidence of pickup on any
of the power supplies. Max Prf=0.97 MW. H/D=4%.

Next shot: no PCS changes.

Shot 05 -- Plasma. Good shot. Good RF pulse. Max Prf=1.3 MW. Still no
H-mode. H/D=4-4.5%.

Next shot: no PCS changes.

Shot 06 -- Plasma. Good shot. Good RF pulse. Max Prf=1.8 MW. Still no
H-mode. nl_04=1.2e20 m-2 during the RF. H/D=4.5%.
STATE crashed while in RECOOL.

Next shot: no PCS changes.

Shot 07 -- Plasma. Good shot. Pretty good RF pulse. Max Prf=2.2 MW, all
from J-port. Finally got some H-modes, including a long EDA.
Breakdown pressure was pretty low (0.04 mTorr) due to shot-to-shot
changes being made with the DNB system. H/D=5%.

Next shot: no PCS changes.

Shot 08 -- Plasma. Disrupted at t=0.91 s, VDE. Prf=2.4 MW. EDA H-mode. This
is the second time today that the plasma went vertically unstable
immediately after the RF turned off (shot 04 also did this).
Breakdown pressure was still low. H/D=5%.

Next shot: increase pre-fill puff to 19 ms (from 18 ms). The DNB
will now fire at t=0.3 s (it was firing at t=1.4 s up until now.)

Shot 09 -- Plasma. Good shot. Prf=2.6 MW. EDA H-modes. Breakdown pressure
zoomed up to 0.07 mTorr, mostly due to much earlier DNB injection
time. H/D=5.5%, slowly creeping up shot-to-shot.

Next shot: reduce pre-fill by 2 ms (to 17 ms).

Shot 10 -- Plasma. Good shot. Almost no RF power.

Next shot: no PCS changes.

Shot 11 -- Plasma. Disrupted at t=1.25 s. Thermal quench disruption due to
a large impurity injection. Prf=2.4 MW. EDA H-mode. H/D=5.5%.

Next shot: lower nl_04 by 10%. Increase argon puff by 5 ms.

Shot 12 -- Plasma. Disrupted at t=0.95 s. Thermal quench disruption.
Prf=2.1 MW. H-modes. H/D=6%. Bill Cochran may have identified
something on the EF1 voltages that correlates with the RF.

Next shot: no PCS changes. J3 will fire into a dummy load, J4 will
be turned off. This is to see if there is some pickup
in the supplies.

Shot 13 -- Fizzle. Almost went. Null and pressure look fine.

Next shot: no changes.

Shot 14 -- Plasma. Disrupted at t=1.42 s. VDE. Pickup from J3 (into a dummy
load) was definitely seen on EF1 signals. No RF power was injected
into the plasma on this shot.

Next shot: no plasma shot, just fire EF1's under hybrid control with
pre-programmed currents (all in segment 1, with segment 2 turned
off) to check for J4 RF pickup.

Shot 15 -- Test. Due to a fault on the EF1's, this turned out to be a
no EF1 power shot. Max Prf=1.5 MW. RF pickup was seen on the EF1s.

Since the RF pickup can be detected on the supplies without any
magnet supplied on, we're going to end the run at this time and
continue looking for the RF leaks in a non-run mode.

End of run. Beginning of RF leakage tests.

Session Leader Comments

Physics Operator Comments
Dec 5 2000 05:13:59:343PMRobert GranetzEngineering setup:

ECDC in D2 overnight, ending 2 hours before the run.

Power systems as on 1001205006.

Gas setup:
fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 35 psi of D2 Hybrid DISABLED, for ECDC
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bot as is Hybrid DISABLED

Enable the following gate valves: ECE, VUV, Beast, DNB

Run starts at 09:00 and ends at 17:00.

-------------------------------------------------------------------------------
RF Setup:

XMTRs 1,2,3, and 4 should be made ready by 8:00 (run-on).

-------------------------------------------------------------------------------
Dec 5 2000 05:14:09:513PMRobert GranetzRun Plan:

Further tests of J-port performance as a four-strap.

Re-load a late shot from yesterday (0.8 MA, 5.3 T, NL_ZMETER). Fire J-port
into plasma. During the day we may raise the density, and if everything
works well, we may eventually the current.
Dec 6 2000 08:31:23:857AMRobert GranetzAfter the apparent RF pickup problems in the EF1's and EF2's, it was
noticed that the glow paddles were still connected, so on the off chance
that this might affect RF pickup, they were disconnected after the
run last evening.
Dec 6 2000 08:40:14:780AMRobert Granetz Overnight ECDC in D2 was done.

Hybrid coldstart done; no errors found

PCS loaded from shot 1001205020 (using NL_ZMETER), except increased
pre-fill puff from 17 to 20 ms because the DNB will not be open on
the first shot. Also, I enabled the argon right from the first shot.
Dec 6 2000 09:10:28:967AM1001206001Robert GranetzShot 01 -- Plasma. Good shot. Ip=0.8 MA, Btor=5.2 T, nl_04=0.9e20 m-2 (Yes,
TCI worked on this shot, but we're using NL_ZMETER for density
control.) Max Prf=1.25 MW (J3+J4). No H-mode. Null was not too
good, and breakdown was real late. Gas pressure was low also.

Next shot: increase Br0 offset by 0.3 mT, increase IC_EF4 by 15 A,
and drop pre-fill to 18 ms (since DNB will open on the next shot).
Dec 6 2000 09:35:44:250AM1001206002Robert GranetzShot 02 -- Plasma. Good shot. Good startup. RF didn't work well. H/D is
down at 3.5%. Density is slowly rising during the shot for some
reason.

Next shot: no PCS changes. Jim Terry will not puff helium on this
shot (He puffed from the NINJA on shots 1 and 2.)
Dec 6 2000 09:47:26:780AM1001206003Robert GranetzShot 03 -- Plasma. Good shot. RF didn't work well. Density behavior didn't
change. H/D=4%.

Next shot: let JT turn the NINJA helium puff back on.
Dec 6 2000 11:45:33:607AM1001206004Robert GranetzShot 04 -- Plasma. Disrupted at t=0.98 s. There was a thermal quench, but it
began with a VDE. Steve doesn't see any evidence of pickup on any
of the power supplies. Max Prf=0.97 MW. H/D=4%.

Next shot: no PCS changes.
Dec 6 2000 10:30:51:200AM1001206005Robert GranetzShot 05 -- Plasma. Good shot. Good RF pulse. Max Prf=1.3 MW. Still no
H-mode. H/D=4-4.5%.

Next shot: no PCS changes.
Dec 6 2000 10:51:38:873AM1001206006Robert GranetzShot 06 -- Plasma. Good shot. Good RF pulse. Max Prf=1.8 MW. Still no
H-mode. nl_04=1.2e20 m-2 during the RF. H/D=4.5%.
STATE crashed while in RECOOL.

Next shot: no PCS changes.
Dec 6 2000 11:22:56:297AM1001206007Robert GranetzShot 07 -- Plasma. Good shot. Pretty good RF pulse. Max Prf=2.2 MW, all
from J-port. Finally got some H-modes, including a long EDA.
Breakdown pressure was pretty low (0.04 mTorr) due to shot-to-shot
changes being made with the DNB system. H/D=5%.

Next shot: no PCS changes.
Dec 6 2000 11:44:52:590AM1001206008Robert GranetzShot 08 -- Plasma. Disrupted at t=0.91 s, VDE. Prf=2.4 MW. EDA H-mode. This
is the second time today that the plasma went vertically unstable
immediately after the RF turned off (shot 04 also did this).
Breakdown pressure was still low. H/D=5%.

Next shot: increase pre-fill puff to 19 ms (from 18 ms). The DNB
will now fire at t=0.3 s (it was firing at t=1.4 s up until now.)
Dec 6 2000 12:00:41:857PM1001206009Robert GranetzShot 09 -- Plasma. Good shot. Prf=2.6 MW. EDA H-modes. Breakdown pressure
zoomed up to 0.07 mTorr, mostly due to much earlier DNB injection
time. H/D=5.5%, slowly creeping up shot-to-shot.

Next shot: reduce pre-fill by 2 ms (to 17 ms).
Dec 6 2000 12:16:01:810PM1001206010Robert GranetzShot 10 -- Plasma. Good shot. Almost no RF power.

Next shot: no PCS changes.
Dec 6 2000 12:52:58:530PM1001206011Robert GranetzShot 11 -- Plasma. Disrupted at t=1.25 s. Thermal quench disruption due to
a large impurity injection. Prf=2.4 MW. EDA H-mode. H/D=5.5%.

Next shot: lower nl_04 by 10%. Increase argon puff by 5 ms.
Dec 6 2000 01:40:57:937PM1001206012Robert GranetzShot 12 -- Plasma. Disrupted at t=0.95 s. Thermal quench disruption.
Prf=2.1 MW. H-modes. H/D=6%. Bill Cochran may have identified something
on the EF1 voltages that correlates with the RF.

Next shot: no PCS changes. J3 will fire into a dummy load, J4 will
be turned off. This is to see if there is some pickup
in the supplies.
Dec 6 2000 01:36:56:750PM1001206013Robert GranetzShot 13 -- Fizzle. Almost went. Null and pressure look fine.

Next shot: no changes.
Dec 6 2000 01:58:06:483PM1001206014Robert GranetzShot 14 -- Plasma. Disrupted at t=1.42 s. VDE. Pickup from J3 (into a dummy
load) was definitely seen on EF1 signals. No RF power was injected
into the plasma on this shot.

Next shot: fire J4 into a dummy load, and turn off J3.
Dec 6 2000 02:26:39:310PM1001206014Robert GranetzShot 14 -- Plasma. Disrupted at t=1.42 s. VDE. Pickup from J3 (into a dummy
load) was definitely seen on EF1 signals. No RF power was injected
into the plasma on this shot.

Next shot: no plasma shot, just fire EF1's under hybrid control with
pre-programmed currents (all in segment 1, with segment 2 turned
off) to check for J4 RF pickup.
Dec 6 2000 02:39:57:950PM1001206015Robert GranetzShot 15 -- Test. Due to a fault on the EF1's, this turned out to be a
no EF1 power shot. Max Prf=1.5 MW. RF pickup was seen on the EF1s.

Since the RF pickup can be detected on the supplies without any
magnet supplied on, we're going to end the run at this time and
continue looking for the RF leaks in a non-run mode.

End of run. Beginning of RF leakage tests.
Dec 6 2000 02:40:19:500PM1001206015Robert GranetzSummary: Things were going pretty well from an RF standpoint, with J3+J4
delivering up to 2.6 MW, with H-modes, heating, and low radiated
power. But there was still a problem with RF pickup screwing up
some of the magnet supplies, particularly at the higher RF powers.
This problem results in VDE's. The run was stopped early so that
the RF leakage could be tracked down.

Other than the RF pickup problems, the machine ran very well today,
with excellent startup reliability (only one fizzle).

Engineering Operator Comments
ShotTimeTypeStatusComment
108:58:24:233AMPlasmaOk
209:17:37:750AMPlasmaOk
309:35:58:810AMPlasmaOk
409:53:49:763AMPlasmaOk
510:15:59:233AMPlasmaOk
610:37:24:577AMPlasmaOk
711:03:39:467AMPlasmaOk
811:25:06:357AMPlasmaOk
911:48:09:810AMPlasmaOk
1012:09:53:623PMPlasmaOk
1112:33:22:030PMPlasmaOk
1201:04:08:170PMPlasmaOk
1301:30:47:513PMPlasmaOk
1401:50:32:060PMPlasmaOk
1502:17:17:233PMTestBadEF1 Type 3 Fault was not reset before shot