Alcator C-Mod Run 950314 Information

Back to runs

Miniproposals
Miniproposal:081
Date Filed: 1/22/1995
Title:Li pellet + ICRF ``PEP\'\' Mode
First Author:Yuichi Takase
Session Leader:Bruce Lipschultz (shots 1-22)

Operators
Session leader(s):Bruce Lipschultz
Physics operator(s):Joseph Snipes
Engineering operator(s):Vinny Bertolino

Engineering Operator Run Comment
strike point

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:12:693PM
Author: To Be Determined
run 950314

Engineering operator: V. Bertolino
Physics operator J. Snipes
Session leader BLip

This run was supposed to be a continuation of mp #81 - 'effect of strike point position
on the extent of detachment'. However, the leak before the run put an end
to those plans. We then had 1.5 hours of ECDC and attempted to clean the
machine back up by making tokamak plasmas. This, in the end, was somewhat successful.
We were able to achieve consistent breakdown and current rise
after shot 15. 600 kA plasmas actually ran through inversion. We had
problems when we went back to 800kA with VDEs.
The other accomplishment from this run was to try out remote control
from California. Three shots (see physop summary) were run from there.
The detailed listing of shots follows:


shot 2-4: fizzle

shot 5: plasma current of 300 kA and plenty of hard x-rays.

shot 6-8: fizzle

shot 9: 'plasma current'

shot 10: 550 ms and full current (800 kA) but a mess.

shot 11: fizzle

shot 15: shot like 10 lasted to about 500 ms but was ugly. This one was
a reload of shot from California.

shot 16: again ugly plasma but it went.

shot 17: again ugly plasma like 16

shot 18: This shot went all the way! It barely made it past 600 ms but
after that things seemed to calm down. Not that the current was changed to 600
kA.

shot 19: Pretty much a repeat of shot 18, 600kA. The main difference was
an incredible MARFE early on that sweeps up the inner wall and back
causing a large density rise.

shot 20: Back to 800 kA but disrupted at around 550 ms due to VDE.

shot 21: Again a disruption due to VDE.

shot 22: fizzle



Physics Operator Summaries
Entered: Jul 7 2004 04:36:53:503PM
Author: To Be Determined
MP080 Strike Point Position Scan
Engineer in Charge: Vince Bertolino
Physicist in Charge: Joseph Snipes
Session Leader: Bruce Lipschultz

This run is intended to scan the density and modify the strike point
position with both a flat plate divertor configuration and a vertical plate
divertor configuration, both at the bottom of the vessel. We intend to
complete both density scans at 0.8 MA and, if time remains, to repeat the
vertical plate divertor scan at 1 MA. We copied shot 950202032, but raised
the current to 0.8 MA and lowered the density to 7 x 10^19 m^-2. Also,
RCUR was copied from shot 950202014. For shot 2, the startup segment was
copied from shot 950307002 and the main segment from 950202014 because of
the leak this morning. The run has been delayed for several reasons: 1) an
alternator problem, 2 vacuum leak that opened up on one of the bottom
flanges when the bottom heating tapes were raised to 80% of maximum to
remove some frost, 3) a server problem that made the HYBRID COLDSTART hang.

The program of strike point position scan was not attempted. Instead, some
progress was made at cleaning up the machine from the vacuum accident and
remote machine operation was successfully done for shots 16, 17, and 18 by
Steve Horne at LLNL.

Shot 1: OH test shot.
2: Fizzle
3: Fizzle
4: Fizzle
5: Short plasma to 0.4 sec
6: Fizzle
7: Test shot.
8: Fizzle
9: Short plasma to 0.35 sec
10: Short plasma to 0.55 sec
11: Fizzle
12: Fizzle
13: Fizzle
14: Fizzle
15: Fizzle
16: Horne's shots: short plasma to 0.45 sec
17: short plasma to 0.47 sec
18: long plasma to 1.6 sec
19: I took over again. Another long plasma.
20: Raised Ip to 0.8 MA, disrupted at 0.5 sec
21: Disrupted at 0.45 sec.
22: Fizzle

9 plasmas, 11 fizzles, 2 test shots.

Session Leader Comments
Mar 14 1995 10:34:50:980AMBruce Lipschultzrun 950314

Engineering operator: V. Bertolino
Physics operator J. Snipes
Session leader BLip

This run is a continuation of mp #81 - 'effect of strike point position
on the extent of detachment'. We intend to run a number of constant density
shots at 800kA with a flat-plate divertor; density varied shot by shot from
0.7 to 2 e20 (nl04). We then hope to finish the vertical plate scan that
was not completed on 950202. Data points at low and high density are needed as
well as trying to better diagnose the high plasma pressure found in the
divertor at the onset of detachment (Brian calls this the 'death ray'). WE
had intended to start this work at 1 MA as well today but given the problems
with a leak and the alternator forcing a late start we will be lucky if we
can get any data.
We will start the run by just trying to get a standard diverted
shot (normal strike point position on vertical plate).

Mar 14 1995 12:28:00:920PM950314005Bruce Lipschultzshot 1: test

shot 2-4: fizzle

shot 5: plasma current of 300 kA and plenty of hard x-rays.

Mar 14 1995 02:22:43:980PM950314009Bruce Lipschultzshot 6-8: fizzle
shot 9: 'plasma current'

Mar 14 1995 02:30:35:470PM950314010Bruce Lipschultzshot 10: 550 ms and full current (800 kA) but a mess.

Mar 14 1995 02:31:04:620PM950314010Bruce Lipschultzshot 10: 550 ms and full current (800 kA) but a mess.

Mar 14 1995 02:38:34:850PM950314011Bruce Lipschultzshot 11: fizzle

Mar 14 1995 03:47:52:500PM950314016Bruce Lipschultzshot 16: again ugly plasma but it went.

Mar 14 1995 04:04:17:780PM950314017Bruce Lipschultzshot 17: again ugly plasma like 16

Mar 14 1995 04:05:22:670PM950314018Bruce Lipschultzshot 18: This shot went all the way! It barely made it past 600 ms but
after that things seemed to calm down.

Mar 14 1995 04:22:49:310PM950314019Bruce Lipschultzshot 19: Pretty much a repeat of shot 18, 600kA. The main difference was
an incredible MARFE early on that sweeps up the inner wall and back
causing a large density rise.

Mar 14 1995 04:24:26:650PM950314019Bruce Lipschultzshot 19: Pretty much a repeat of shot 18, 600kA. The main difference was
an incredible MARFE early on that sweeps up the inner wall and back
causing a large density rise.

Mar 14 1995 04:38:52:740PM950314020Bruce Lipschultzshot 20: Back to 800 kA but disrupted at around 550 ms due to VDE.

Mar 14 1995 04:39:29:640PM950314021Bruce Lipschultzshot 21: Again a disruption due to VDE.

Mar 14 1995 05:13:19:570PM950314022Bruce Lipschultzshot 22: fizzle

Physics Operator Comments
Mar 10 1995 04:37:51:360PMJoseph SnipesThis run is intended to scan the density and modify the strike point
position with both a flat plate divertor configuration and a vertical plate
divertor configuration, both at the bottom of the vessel. We intend to
complete both density scans at 0.8 MA and, if time remains, to repeat the
vertical plate divertor scan at 1 MA. We copied shot 950202032, but raised
the current to 0.8 MA and lowered the density to 7 x 10^19 m^-2. Also, RCUR
was copied from shot 950202014.

Mar 14 1995 08:46:49:500AMJoseph SnipesThe run has been delayed for several reasons: 1) an alternator problem, 2) a
vacuum leak that opened up on one of the bottom flanges when the bottom heating
tapes were raised to 80% of maximum to remove some frost, 3) a server problem
that made the HYBRID COLDSTART hang. We will try to start by 10:30 am if we
can resolve these problems.

Mar 14 1995 10:54:05:620AMJoseph SnipesBecause the machine is dirty, we have decided to start a standard 800 kA
plasma copying segment 1 from 950307002 and segment 2 from 950202014 with the
density reduced to 7.3 x 10^19 m^-2. First, there will be the OH2 test shot.

Mar 14 1995 11:35:48:780AM950314001Joseph SnipesShot 1
OH test shot. O.K.

Mar 14 1995 11:46:48:100AM950314002Joseph SnipesShot 2
Attempt to get a standard SNB 0.8 MA discharge at 7.3 x 10^19 m^-2.
Fizzle!

Mar 14 1995 11:59:46:520AM950314003Joseph SnipesShot 3
Raised Br by 1 mT to 7 mT. Instrumentation problems in engineering slowing
us down a bit. Fizzle!

Mar 14 1995 12:16:36:110PM950314004Joseph SnipesShot 4
Lowered Br by 0.5 mT to 6.5 mT.
Fizzle!

Mar 14 1995 12:25:17:470PM950314005Joseph SnipesShot 5
Raised EF4 current by 20 A to 1105 A before t = 0. Got some plasma, but lots
of hard x rays.

Mar 14 1995 12:32:35:890PM950314006Joseph SnipesShot 6
Raised prefill to 2.3 x 10^-5 Torr. Fizzle!

Mar 14 1995 01:20:27:040PM950314006Joseph SnipesShot 6
DAQ3 problems slowing us down.


Mar 14 1995 01:31:55:000PM950314006Joseph SnipesShot 6
Turning on ECDC while we wait to resolve the DAQ3 CAMAC problem.

Mar 14 1995 01:55:35:890PM950314007Joseph SnipesShot 7
Test shot. O.K.

Mar 14 1995 02:10:10:340PM950314008Joseph SnipesShot 8
Lowered prefill to 1.9 x 10^-5 Torr. Fizzle!

Mar 14 1995 02:29:22:600PM950314009Joseph SnipesShot 9
Repeat. Short plasma to 0.35 sec.

Mar 14 1995 02:29:54:310PM950314010Joseph SnipesShot 10
Repeat. Short plasma to 0.55 sec. Reached 0.8 MA.

Mar 14 1995 02:34:31:890PM950314011Joseph SnipesShot 11
Repeat. Fizzle!

Mar 14 1995 02:51:51:570PM950314012Joseph SnipesShot 12
Repeat. Fizzle. Wolfe noticed that the EF2 start time was not what was
used for the 950307 run. I realized that I asked engineering to start with
parameters from shot 950202014, which is the segment 2 that I am using, but
I should have asked for shot 950307002, which is the segment 1 I am using.
Try the 950307003 parameters for shot 13 and see what happens.

Mar 14 1995 03:00:14:070PM950314013Joseph SnipesShot 13
Fizzle!

Mar 14 1995 03:09:46:370PM950314013Joseph SnipesShot 14
Returned to startup programming from 950307002 with Br = 6 mT, and EF4 at
1085 A before t = 0. Fizzle.

Mar 14 1995 03:29:23:670PM950314015Joseph SnipesShot 15
Repeat. Fizzle. Run turned over to Horne for two shots to see if he can do
it from LLNL and to see if he can improve things.

Mar 14 1995 03:39:49:650PM950314016Joseph SnipesShot 16
Horne set prefill to 1.6 x 10^-5 Torr, Br reset to 6.5 mT. Got plasma out to
0.45 sec. Horne had reduced the early gas puff a bit.

Mar 14 1995 04:01:40:630PM950314018Joseph SnipesShot 18
Horne reduced early gas a bit. Better shot lasted to 1.6 sec.

Mar 14 1995 04:16:39:180PM950314019Joseph SnipesShot 19
I'm taking control again. Reduced early gas a bit more. Raised prefill back
to 1.8 x 10^-5 Torr. Looked ok, but current dips at 0.4 sec.

Mar 14 1995 04:29:05:150PM950314020Joseph SnipesShot 20
Increased CLEARIN from -2 mm to +4 mm. Raised Ip to 0.8 MA. Disrupted at
0.5 sec.

Mar 14 1995 04:44:37:300PM950314021Joseph SnipesShot 21
Reduced proportional gain on slow ZCUR wire 2 from 3 to 1.5. Lowered prefill
to 1.6 x 10^-5 Torr after the disruption on shot 20. Expect a fizzle.
Got a plasma that disrupted at 0.45 sec.

Mar 14 1995 04:53:39:990PM950314022Joseph SnipesShot 22
Reduced early gas puff some more. Engineering changing some EF3 boards.
Proportional gain on fast ZCUR wire 3 extended to 0.6 sec at a value of 8,
then drops to 5 as before.
Fizzle.

Mar 14 1995 05:00:02:310PM950314022Joseph SnipesShot 22
Reduced early gas puff some more. Engineering changing some EF1 boards.
Proportional gain on fast ZCUR wire 3 extended to 0.6 sec at a value of 8,
then drops to 5 as before.
Fizzle.

Engineering Operator Comments
ShotTimeTypeStatusComment
111:19:20:260AMTestOkcoax test
211:39:02:110AMPlasmaOkno faults
311:57:13:790AMPlasmaOkno faults
412:09:17:590PMPlasmaOkno faults
512:20:10:940PMPlasmaOkno faults
612:30:08:930PMPlasmaOkno faults
701:53:25:290PMTestOkCAMAC TEST. O.K.
802:02:59:550PMPlasmaOkNO FAULTS.
902:11:30:170PMPlasmaOkCOMM FAULT OH2U
1002:20:48:840PMPlasmaOkCOMM FAULT EF1L, OH2 U&L
1102:31:32:260PMPlasmaOkNO FAULTS.
1202:44:02:830PMPlasmaOkNO FAULTS.
1302:53:56:340PMPlasmaOkNO FAULTS
1403:06:35:520PMPlasmaOkNO FAULTS.
1503:16:18:540PMPlasmaOkNO FAULTS.
1603:31:01:440PMPlasmaOkno faults
1703:43:36:250PMPlasmaOkEF1 L Comm Fault
1803:56:52:490PMPlasmaOkNo Faults.
1904:09:04:600PMPlasmaOkNo Faults.
2004:24:28:360PMPlasmaOkNo Faults.
2104:35:19:860PMPlasmaOkno faults
2204:50:09:110PMPlasmaOkNo Faults