Alcator C-Mod Run 1010601 Information

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Miniproposals
Miniproposal:215
Date Filed: 1/5/1999
Title:J-port RF System Commissioning
First Author:Steve Wukitch
Session Leader:Jim Irby (shots 1-12)

Operators
Session leader(s):Jim Irby
Physics operator(s):Dmitri Mossessian
Engineering operator(s):Bill Cochran,Bill Byford

Engineering Operator Run Comment
Plasma Conditioning/J-Port Conditioning/MP215 PO-Mossessian,SL-Irby,Wuki

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:26:303PM
Author: To Be Determined
Session Leader Run Report for Run 1010601

SS: Irby
PO: Mossessian
EO: Byford, Cochran


The goals of this run included a test of the j-bottom piezo valve,
continued plasma conditioning to recover from the up-to-helium,
j-port tuning, j-port instrumentation checkout, and continued DNB work.

Results:

We began the day testing the j-bottom gas puff. Looks like we still have
a problem with either the electronics or the piezo valve. No pressure
rise was seen on shot 2 in which we only enabled the j-bottom valve. On shot 3
we made a plasma attempt into a background basepressure of 2.7e-7 Torr
consisting mostly of H2O/D2O. We actually got plasma for 120 ms,
at 300 kA. Plasmas at this level were produced over the next few shots.
We eventually got plasmas lasting 280 ms and nearly 500 kA. ECDC and
a low temp bake over the weekend should get us back into full operation.
A fizzle on shot 8 was blamed on too low a gas puff causing the plasma
to move out too far. The rf group did some testing into a dummy load
today, but the plasmas were not good enough to try out the j-port antenna.


Note on Up-to-Helium:

During run 1010530, on shot 13, the visible brems array viewing
dump fell off the outer wall and into the divertor between B and C
ports. On shot 16 the melting, passivated, stainless steel, shim stock
dump was seen on the divertor TV camera. The vessel was warmed up
overnight and brought up to helium around 22:00. The gatevalve and
spool piece was removed at c-hor on the morning of 5/31 and the viewing
dump removed. After about 1.5 hours of being open, we pumped back down,
raised the vessel temp to 60C, and started ECDC. The low temp bake and
ECDC was continued until 07:30. This morning, the water vapor level is
still a factor of 10 or 20 higher than normal and the basepressure
is only 2.8e-7 Torr (mostly mass 18, 19, and 20) vs a more typical 3 to
5e-8 Torr.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:13:113PM
Author: To Be Determined
Physop summary for the run of June 1, 2001

PO Mossessian
SL Irby

_________________________________
Run plan for 1 June 2001

Engineering setup:

ECDC in D2 overnight prior to run.

Be prepared for ECDC in D2 between shots (using B-top valve).

Power systems as on 1010530008.

Gas setup:
fill B-top with 6 psi of D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi of Ar Hybrid enabled (PG1)
fill B-side upper with 6 psi of He Hybrid enabled (PG2)
fill C-side with 30 psi of D2 Hybrid enabled (PG3)
fill J-bottom with nothing Hybrid DISABLED (PG5)

Enable the following gate valves: ECE, DNB. Do NOT enable VUV !

Run starts at noon.

Run plan:

The run will be continuation of plasma conditioning (SL=IRBY) and, if the plasmas
are up to it, begin J-port conditioning, MP215 (SL=Wukitch).

If it can be accommodated without problems to the other
activities, it would be good to finish the shape development for MP287, ASDEX
comparison, that we began on Wednesday.

Start with 1010530003, which is 800kA, nl04=5e19

If that runs, then we could proceed
to 1010530016, which was higher density and part way to the ASDEX shape.

____________________


Summary:

J-bottom valve never worked.
We did only plasma conditionning with mild success. Maximum achieved current is 470 kA, and usually after
the current gets to this point plasma suffocates slowly to death. The longest discharge obtained was 250 msec.
No particular problems with startup was encountered. We had to step up the prepuff several times to
avoid bouncing off outer wall.

2 tests
1 fizzle
9 plasmas
12 shots

Details:

1010601001 mossessian PHYSICS_OPERATOR Jun 1 2001 12:25:17:296PM

Loaded 1010530003. Coldstart OK.

J-bottom test:

PCS: C-side upper HYBRID disabled to be able to see pulse from J
J-bottom programed at 80V from 0.5 to 1 sec.
Fizzle detector start moved to 1 sec

J-bottom doesn't work properly.
Will try another test shot with all valves disabled but J-bottom
-----------------------------------------------------------------------------
1010601002 mossessian PHYSICS_OPERATOR Jun 1 2001 12:38:15:346PM

J-bottom test shot

No gas puff observed.
The valve will be turned off for the rest of the day.

For next shot: Load 1010530007 (1010530003 wasn't the one
we actually wanted), disable J bottom and B side upper
-----------------------------------------------------------------------------
1010601003 mossessian PHYSICS_OPERATOR Jun 1 2001 12:58:52:940PM

130 msec of plasma.

For next shot - no changes
-----------------------------------------------------------------------------
1010601004 mossessian PHYSICS_OPERATOR Jun 1 2001 1:34:27:840PM
. . . . . . . . . . . . . . . . . . . .
153 msec of plasma.

For next shot - no changes
-----------------------------------------------------------------------------
1010601005 mossessian PHYSICS_OPERATOR Jun 1 2001 1:50:34:880PM
. . . . . . . . . . . . . . . . . . . .
147 msec of plasma.

For next shot - reprogram ip to 0.6 and slowed down ip rising rate
in segment 2
-----------------------------------------------------------------------------
1010601006 mossessian PHYSICS_OPERATOR Jun 1 2001 2:23:40:523PM
. . . . . . . . . . . . . . . . . . . .
Same kind of plasma. 430 kA now ( 20kA higher than shot 5).

For next shot: Try to get rid of hesitation at .015 sec - add 2 msec to prepuff
(Pulse_gas4 18 -> 20 msec in segment 1)
-----------------------------------------------------------------------------
1010601007 mossessian PHYSICS_OPERATOR Jun 1 2001 2:46:47:590PM
. . . . . . . . . . . . . . . . . . . .
Plasma 445 kA now , 170 msec.

For next shot: Pulse_gas4 20 -> 22 msec
-----------------------------------------------------------------------------
1010601008 mossessian PHYSICS_OPERATOR Jun 1 2001 3:06:59:683PM
. . . . . . . . . . . . . . . . . . . .
Fizzle.

For next shot: Pulse_gas4 back 22 -> 18 msec
-----------------------------------------------------------------------------
1010601008 mossessian PHYSICS_OPERATOR Jun 1 2001 3:11:48:346PM
. . . . . . . . . . . . . . . . . . . .
Change of story: it looks like the plasma is too far outside when it fizzles.
For next shot: add gas pulse_gas4 22 -> 24 msec
-----------------------------------------------------------------------------
1010601009 mossessian PHYSICS_OPERATOR Jun 1 2001 3:38:10:373PM
. . . . . . . . . . . . . . . . . . . .
Plasma, 480 kA, 174 msec long. Current rise is better

For next shot: no change
-----------------------------------------------------------------------------
1010601010 mossessian PHYSICS_OPERATOR Jun 1 2001 4:00:54:423PM
. . . . . . . . . . . . . . . . . . . .
Plasma, 450 kA, 225 msec long. Hesitation is worse at 0.015 sec

For next shot: add 2 msec of gas in pulse_gas4 (to 26 msec)
-----------------------------------------------------------------------------
1010601011 mossessian PHYSICS_OPERATOR Jun 1 2001 4:31:04:750PM
. . . . . . . . . . . . . . . . . . . .
Plasma, 470 kA, 240 msec long. Hesitation is slightly better at 0.015 sec

For next shot: no change
-----------------------------------------------------------------------------
1010601012 mossessian PHYSICS_OPERATOR Jun 1 2001 4:53:42:380PM
. . . . . . . . . . . . . . . . . . . .
Shorter plasma. 177 msec, 470 kA

Session Leader Comments
Jun 1 2001 12:25:55:187PM1010601001Jim IrbyFirst two shots will be tests of magnetics, j-bottom divertor
gas puff, and camac.

We see a smaller dP than expected from j-bottom. It may
barely be opening, but timing suggests it is responding
somewhat (g-side mks).
Jun 1 2001 12:41:41:303PM1010601002Jim IrbyOnly j-bottom high voltage enabled for this shot


No pressure rise. Looks like shot one pressure rise
was from b-side upper.
Jun 1 2001 12:53:43:573PM1010601003Jim IrbyPlasma attempt into H2O/DOH/D2O background gas at 2.4e-7 Torr.

Actually got plasma for 120 ms, 300 kA.

Starting ECDC between shots

Jun 1 2001 01:23:29:883PM1010601004Jim IrbyRepeat after 10 minutes of ECDC

Plasma to 160 ms, a little less plasma current

Will continue ECDC.
Jun 1 2001 02:09:13:720PM1010601005Jim IrbyPlasma ---- 150 ms



Jun 1 2001 02:37:56:890PM1010601006Jim IrbyPlasma for nearly 180 ms at 440 kA.




Jun 1 2001 03:04:31:743PM1010601007Jim IrbyPlasma for 175 ms, 440 kA.


Jun 1 2001 03:35:59:260PM1010601008Jim IrbyFizzle


Jun 1 2001 03:51:14:000PM1010601009Jim IrbyPlasma for 175 ms, 490 kA --- gas tweek improved bounce and hards


Jun 1 2001 04:22:24:613PM1010601010Jim IrbyPlasma for 230 ms, 450 kA --- hards are back



Jun 1 2001 04:31:32:860PM1010601011Jim IrbyPlasma to 238 ms, 470 kA

Physics Operator Comments
Jun 1 2001 11:53:27:573AMDmitri MossessianRun plan for 1 June 2001

Engineering setup:

ECDC in D2 overnight prior to run.

Be prepared for ECDC in D2 between shots (using B-top valve).

Power systems as on 1010530008.

Gas setup:
fill B-top with 6 psi of D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi of Ar Hybrid enabled (PG1)
fill B-side upper with 6 psi of He Hybrid enabled (PG2)
fill C-side with 30 psi of D2 Hybrid enabled (PG3)
fill J-bottom with nothing Hybrid DISABLED (PG5)

Enable the following gate valves: ECE, DNB. Do NOT enable VUV !

Run starts at noon.

Run plan:

The run will be continuation of plasma conditioning (SL=IRBY) and, if the plasmas
are up to it, begin J-port conditioning, MP215 (SL=Wukitch).

If it can be accommodated without problems to the other
activities, it would be good to finish the shape development for MP287, ASDEX
comparison, that we began on Wednesday.

Start with 1010530003, which is 800kA, nl04=5e19

If that runs, then we could proceed
to 1010530016, which was higher density and part way to the ASDEX shape.

____________________
Jun 1 2001 12:25:17:297PM1010601001Dmitri Mossessian11:50 AM

Loaded 1010530003. Coldstart OK.

J-bottom test:

PCS: C-side upper HYBRID disabled to be able to see pulse from J
J-bottom programed at 80V from 0.5 to 1 sec.
Fizzle detector start moved to 1 sec

J-bottom doesn't work properly.
Will try another test shot with all valves disabled but J-bottom
Jun 1 2001 12:38:15:347PM1010601002Dmitri MossessianJ-bottom test shot

No gas puff observed.
The valve will be turned off for the rest of the day.

For next shot: Load 1010530007 (1010530003 wasn't the one
we actually wanted), disable J bottom and B side upper
Jun 1 2001 12:58:52:940PM1010601003Dmitri Mossessian130 msec of plasma.

For next shot - no changes
Jun 1 2001 01:34:27:840PM1010601004Dmitri Mossessian153 msec of plasma.

For next shot - no changes
Jun 1 2001 01:50:34:880PM1010601005Dmitri Mossessian147 msec of plasma.

For next shot - reprogram ip to 0.6 and slowed down ip rising rate
in segment 2
Jun 1 2001 02:23:40:523PM1010601006Dmitri MossessianSame kind of plasma. 430 kA now ( 20kA higher than shot 5).

For next shot: Try to get rid of hesitation at .015 sec - add 2 msec to prepuff
(Pulse_gas4 18 -> 20 msec in segment 1)
Jun 1 2001 02:46:47:590PM1010601007Dmitri Mossessian Plasma 445 kA now , 170 msec.

For next shot: Pulse_gas4 20 -> 22 msec
Jun 1 2001 03:06:59:683PM1010601008Dmitri Mossessian Fizzle.

For next shot: Pulse_gas4 back 22 -> 18 msec
Jun 1 2001 03:11:48:347PM1010601008Dmitri Mossessian Change of story: it looks like the plasma is too far outside when it fizzles.
For next shot: add gas pulse_gas4 22 -> 24 msec
Jun 1 2001 03:38:10:373PM1010601009Dmitri Mossessian Plasma, 480 kA, 174 msec long. Current rise is better

For next shot: no change
Jun 1 2001 04:00:54:423PM1010601010Dmitri Mossessian Plasma, 450 kA, 225 msec long. Hesitation is worse at 0.015 sec

For next shot: add 2 msec of gas in pulse_gas4 (to 26 msec)
Jun 1 2001 04:31:04:750PM1010601011Dmitri Mossessian Plasma, 470 kA, 240 msec long. Hesitation is slightly better at 0.015 sec

For next shot: no change
Jun 1 2001 04:53:42:380PM1010601012Dmitri Mossessian Shorter plasma. 177 msec, 470 kA

Engineering Operator Comments
ShotTimeTypeStatusComment
112:11:53:117PMTestOk
212:26:52:923PMTestBadNo gas from J bottom
312:42:12:913PMPlasmaOk
401:13:52:650PMPlasmaOk
501:43:12:087PMPlasmaOk
602:13:36:117PMPlasmaOk
702:38:03:640PMPlasmaOk
803:02:59:083PMPlasmaOk
903:30:46:390PMPlasmaOk
1003:54:33:850PMPlasmaOk
1104:26:22:633PMPlasmaOk
1204:50:44:657PMPlasmaOk