Alcator C-Mod Run 970617 Information

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Miniproposals
Miniproposal:160
Date Filed: 7/23/1996
Title:Divertor Cryopump Prototype Commissioning
First Author:Jim Irby
Session Leader:Jim Irby (shots 1-34)
Miniproposal:177
Date Filed: 5/2/1997
Title:Exploration of the Prototype Cryopump on Impurity Transport
First Author:Bruce Lipschultz
Session Leader:Bruce Lipschultz (shots 1-34)

Operators
Session leader(s):Jim Irby,Bruce Lipschultz
Physics operator(s):Ian Hutchinson,Robert Granetz
Engineering operator(s):Frank Silva,Bill Cochran

Engineering Operator Run Comment
Same start as 97061616/Cochran/Silva/Terry/Hutchinson

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:16:930PM
Author: To Be Determined
Run Summary for 970617

SL: Irby/Blip
PO: Hutch/Grantez
EO: Silva, Bertolino

The major activities planned for the run were commissioning of the
divertor cryopump (finish mp160), and impurity injection in the
divertor to observe the effects of the new pump (mp177). The pump
was cooled down to LHe temps between shots 11 and 12. However, blow-by
through the LHe valve had already cooled the pump down to the 20
to 30K level during the early part of the run before we officially turned it
on. However, from shot 11 on we were pretty much in control of the
pump:

11-18 : pump on
19-20 : pump off (>100K)
21-31 : pump on
32-34 : pump partially off and dumping gas during/after shot

Below I have listed some pumping speeds from various gauges measured well
after the shot (7 to 12 seconds). These measurements should give a good
indication when the pump was pumping D2, though what its pumping speed
for other gases was is not clear for shots 1 to 10. Note that the pumping
speed calculations assume there is no gas source, so on shots where we
had just dumped the pump, or had disruptions that heated up the walls,
the quoted speeds can be very low. Note also that f-side ratiomatic
was not operating early (at least after the shot) early in the run.

Jim Terry reported that the pump reduced nitrogen levels both in the
core and in the divertor by a factor of two. This is pretty impressive
for what is supposed to be about 10% of our eventual pumping speed. A
first look at the late time behaviour of the plasma density also indicated
that the density was being reduced even as the gas valve demand was
going up when the pump was on.

I consider MP160 complete. The only part not done involved
looking at density rate of rise changes with and without the pump
during H-mode. We will certainly gather this data during future
runs without resorting to MP160.

Several hardware fixes for the pump/diag are required to make it easier
to use during the run:

. need to fix the leaky LHe valve

. need to be able to dump LHe cryostat pressure
from the control room

. reliability of the LHe valve control needs to be
improved

. Spencer is attempting to bring the divertor MKS
gauge back to life. Having pressure data in the
divertor would make understanding the pump operation
much easier.

. D2 puff rates need to be measured


970617001 B-bot MKS Pumping Speed: 195 l/s
970617001 B-bot Ratio Pumping Speed: 180 l/s
970617001 F-side Ratio Pumping Speed: 5 l/s

970617002 B-bot MKS Pumping Speed: 244 l/s
970617002 B-bot Ratio Pumping Speed: 210 l/s
970617002 F-side Ratio Pumping Speed: 7 l/s

970617003 B-bot MKS Pumping Speed: 153 l/s
970617003 B-bot Ratio Pumping Speed: 159 l/s
970617003 F-side Ratio Pumping Speed: 2 l/s

970617004 B-bot MKS Pumping Speed: 555 l/s
970617004 B-bot Ratio Pumping Speed: 449 l/s
970617004 F-side Ratio Pumping Speed: 484 l/s

970617005 B-bot MKS Pumping Speed: 206 l/s
970617005 B-bot Ratio Pumping Speed: 189 l/s
970617005 F-side Ratio Pumping Speed: 4 l/s

970617006 B-bot MKS Pumping Speed: 225 l/s
970617006 B-bot Ratio Pumping Speed: 198 l/s
970617006 F-side Ratio Pumping Speed: 0 l/s

970617007 B-bot MKS Pumping Speed: 197 l/s
970617007 B-bot Ratio Pumping Speed: 258 l/s
970617007 F-side Ratio Pumping Speed: 284 l/s

970617008 B-bot MKS Pumping Speed: 451 l/s
970617008 B-bot Ratio Pumping Speed: 488 l/s
970617008 F-side Ratio Pumping Speed: 535 l/s

970617009 B-bot MKS Pumping Speed: 504 l/s
970617009 B-bot Ratio Pumping Speed: 498 l/s
970617009 F-side Ratio Pumping Speed: 542 l/s

970617010 B-bot MKS Pumping Speed: 387 l/s
970617010 B-bot Ratio Pumping Speed: 485 l/s
970617010 F-side Ratio Pumping Speed: 528 l/s

970617011 B-bot MKS Pumping Speed: 269 l/s
970617011 B-bot Ratio Pumping Speed: 249 l/s
970617011 F-side Ratio Pumping Speed: 278 l/s

Cryopump turned on

970617012 B-bot MKS Pumping Speed: 385 l/s
970617012 B-bot Ratio Pumping Speed: 813 l/s
970617012 F-side Ratio Pumping Speed: 834 l/s

970617013 B-bot MKS Pumping Speed: 556 l/s
970617013 B-bot Ratio Pumping Speed: 862 l/s
970617013 F-side Ratio Pumping Speed: 1408 l/s

970617014 B-bot MKS Pumping Speed: 724 l/s
970617014 B-bot Ratio Pumping Speed: 874 l/s
970617014 F-side Ratio Pumping Speed: 1416 l/s

970617015 B-bot MKS Pumping Speed: 1277 l/s
970617015 B-bot Ratio Pumping Speed: 930 l/s
970617015 F-side Ratio Pumping Speed: 1472 l/s

970617016 B-bot MKS Pumping Speed: **** l/s
970617016 B-bot Ratio Pumping Speed: 822 l/s
970617016 F-side Ratio Pumping Speed: 1377 l/s

970617017 B-bot MKS Pumping Speed: **** l/s
970617017 B-bot Ratio Pumping Speed: 841 l/s
970617017 F-side Ratio Pumping Speed: 1400 l/s

970617018 B-bot MKS Pumping Speed: 533 l/s
970617018 B-bot Ratio Pumping Speed: 948 l/s
970617018 F-side Ratio Pumping Speed: 1497 l/s

Cryopump dumped, long cell access period

970617019 B-bot MKS Pumping Speed: 283 l/s
970617019 B-bot Ratio Pumping Speed: 256 l/s
970617019 F-side Ratio Pumping Speed: 271 l/s

970617020 B-bot MKS Pumping Speed: 189 l/s
970617020 B-bot Ratio Pumping Speed: 191 l/s
970617020 F-side Ratio Pumping Speed: 210 l/s

Cryopump on again

970617021 B-bot MKS Pumping Speed: 239 l/s
970617021 B-bot Ratio Pumping Speed: 828 l/s
970617021 F-side Ratio Pumping Speed: 873 l/s

970617022 B-bot MKS Pumping Speed: 1325 l/s
970617022 B-bot Ratio Pumping Speed: 976 l/s
970617022 F-side Ratio Pumping Speed: 1033 l/s

970617023 B-bot MKS Pumping Speed: 722 l/s
970617023 B-bot Ratio Pumping Speed: 840 l/s
970617023 F-side Ratio Pumping Speed: 915 l/s

970617024 B-bot MKS Pumping Speed: 505 l/s
970617024 B-bot Ratio Pumping Speed: 896 l/s
970617024 F-side Ratio Pumping Speed: 1044 l/s

970617025 B-bot MKS Pumping Speed: 885 l/s
970617025 B-bot Ratio Pumping Speed: 1187 l/s
970617025 F-side Ratio Pumping Speed: 0 l/s

970617026 B-bot MKS Pumping Speed: 810 l/s
970617026 B-bot Ratio Pumping Speed: 762 l/s
970617026 F-side Ratio Pumping Speed: 899 l/s

970617027 B-bot MKS Pumping Speed: 674 l/s
970617027 B-bot Ratio Pumping Speed: 849 l/s
970617027 F-side Ratio Pumping Speed: 1001 l/s

970617028 B-bot MKS Pumping Speed: 865 l/s
970617028 B-bot Ratio Pumping Speed: 748 l/s
970617028 F-side Ratio Pumping Speed: 899 l/s

970617029 B-bot MKS Pumping Speed: 638 l/s
970617029 B-bot Ratio Pumping Speed: 1181 l/s
970617029 F-side Ratio Pumping Speed: 5 l/s

970617030 B-bot MKS Pumping Speed: 714 l/s
970617030 B-bot Ratio Pumping Speed: 733 l/s
970617030 F-side Ratio Pumping Speed: 991 l/s

970617031 B-bot MKS Pumping Speed: 1457 l/s
970617031 B-bot Ratio Pumping Speed: 1105 l/s
970617031 F-side Ratio Pumping Speed: 1278 l/s

Cryopump warmup, pump dumps during/after next couple of shots

970617032 B-bot MKS Pumping Speed: 139 l/s
970617032 B-bot Ratio Pumping Speed: 134 l/s
970617032 F-side Ratio Pumping Speed: 0 l/s

970617033 B-bot MKS Pumping Speed: 80 l/s
970617033 B-bot Ratio Pumping Speed: 65 l/s
970617033 F-side Ratio Pumping Speed: 0 l/s

970617034 B-bot MKS Pumping Speed: 279 l/s
970617034 B-bot Ratio Pumping Speed: 438 l/s
970617034 F-side Ratio Pumping Speed: 488 l/s


Physics Operator Summaries
Entered: Jul 7 2004 04:36:57:740PM
Author: To Be Determined

970617 HUTCH PHYSICS_OPERATOR 17-JUN-1997 07:39:01.91
. . . . . . . . . . . . . . . . . . . .
Cryopump Conditioning, MP160, Cryopump and Impurities MP177
SL Irby/Blip
PO Hutch/Granetz

Plan:
Get the sparker-assisted breakdown going reliably.
Check out cryopump
Look at impurity injection effects.
Help complete RF conditioning process.
Fix the ramp-down
Chew gum
All at the same time.

Summary
_______

Most of the plan was accomplished at some level, except the gum.

Ninja puffs were observed with and without the cryopump.
The cryopump showed some evidence of ability to decrease the density
at the end of the shot.
The longest ramp-down coincided with the best density decrease.
The RF got to 1.5MW at 80 MHz. With a little H-mode seen.
The sparker was used routinely but did not give good immunity to
duds. Current about 150 uA.
Breakdown and current rise was erratic (to say the least) however, the
x-point laser demonstrated excellent correlation with non-duds. Thus
showing its superiority to the sparker as a preionization assist.

We have a breakdown problem even with the sparker.

Hydrogen stayed at about 10% all day.

Scorecard.
_________
Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax
1 0.611 1.091 2 1.519 1.009
3 1.123 1.071 4 0.000 0.016
5 1.420 1.014 6 1.349 1.009
7 1.500 1.014 8 0.000 0.016
9 0.000 0.037 10 0.000 0.027
11 1.484 1.009 12 0.000 0.037
13 0.000 0.037 14 0.000 0.037
15 0.000 0.037 16 0.000 0.037
17 0.000 0.042 18 0.000 0.047
19 1.509 1.009 20 1.524 1.009
21 0.000 0.027 22 1.654 1.014
23 1.585 1.014 24 0.000 0.021
25 1.198 1.050 26 0.000 0.037
27 0.000 0.016 28 0.000 0.016
29 0.913 1.071 30 0.000 0.027
31 1.494 1.019 32 0.624 1.071
33 0.990 1.076 34 0.000 0.032

Finished summary for 970617 Total of 34 shots.
34 shots. 16 plasmas. 14 fizzles. 4 duds.
Fizzle = gt 20 lt 50kA. [Actually there were a couple of duds > 20kA.]

For details see the logbook.

Session Leader Comments

Physics Operator Comments
Jun 17 1997 07:39:01:910AMIan HutchinsonCryopump Conditioning, MP160, Cryopump and Impurities MP177
SL Irby/Blip
PO Hutch/Granetz

Start From last shot of yesterday as set-up.
Plan:
Get the sparker-assisted breakdown going reliably.
Check out cryopump
Look at impurity injection effects.
Help RF conditioning process to be completed
Fix the ramp-down
Chew gum
All at the same time.
Jun 17 1997 08:38:32:170AMIan HutchinsonComments on the base shot.

Things that might be fixed.
Slight vertical instability at around .3s. Plasma is fairly far in while being diverted.
Plasma touches the outboard limiter (mfil) at 760 ms.
Ar pulse is at .300 to .318 s
Fill pulse is 21 ms.
OH2 startup voltages have been symmetrized.
OH2 currents at t=0: -26090,-27579. EF1 currents: -6330, -6150. EF1U is not reaching current.


Moved the penultimate EF1 points back to -.2s from -.1 s to make it top out earlier.
Jun 17 1997 08:52:09:560AMIan HutchinsonProblem with the interferometer to start with. Checked on the possibility of z-meter
feedback. It is channel 83 on the hybrid but does not have any signal yesterday.

Possibility of open loop operation:
Looked at phys M out. Trial paste into pg3. That worked. Jim reports we may be ready
so we remove that and try for feedback in standard mode.
Jun 17 1997 09:59:50:310AMIan HutchinsonComputers died and the whole cluster needed to be rebooted.
Redid cold start. Reload the model.
Jun 17 1997 10:25:12:080AM970617001Ian HutchinsonPlasma disrupted at 0.59s. Halo warning.
Breakdown at 6.7ms. Sparler on -20 to +20ms.
EF1U reaches flat section but still is 150A low.
Plasma still far out.

Move rcur in by 2 mm to .669m.
Jun 17 1997 10:37:36:050AM970617002Ian HutchinsonPlasma to 1.51s.

Neon Ninja enabled
Jun 17 1997 11:00:00:590AM970617003Ian HutchinsonPlasma disrupts at 1.1s. RF starts at 1.5kW at 0.9s. A big density rise and plasma cooling
starts at 1s. This seems to be divertor detachment. Probably caused by the neon ninja puff
being too much.

Start TF down ramp at 1.2s for decompression termination.
Lower ninja neon pressure to 2 psi from 4psi.
Add 3ms to fill puff, to slow the current rise.
Jun 17 1997 11:09:31:970AM970617004Ian HutchinsonDud. No obvious field problems. Sparker was on.

Repeat
Jun 17 1997 11:25:33:010AM970617005Ian HutchinsonPlasma till 1.42s. Breakdown at 4.5ms. Divertor detaches in ramp down.

Neon pressure to 3psi.
Jun 17 1997 11:39:07:940AM970617006Ian HutchinsonPlasma till 1.347s. Divertor Detachment at 1.2s.
Seems to be an interaction with the outboard limiter at .43 seconds caused by lurch at
OH1 cross-over.

Switch ninja to 4psi of Nitrogen.
Jun 17 1997 11:46:52:880AM970617007Ian HutchinsonPlasma till 1.5s.

Tweaked the position at .4s.
Increase of nitrogen by using a second capillary.
Jun 17 1997 11:55:11:950AM970617008Ian HutchinsonDud. Sparker was on. Fields look fine.

Repeat.
Jun 17 1997 11:58:54:820AM970617009Ian HutchinsonFizzle. Late breakdown at 10ms.

EF4 to -1295 from -1305.
Jun 17 1997 12:07:50:280PM970617010Ian HutchinsonFizzle. Breakdown even later.

EF4 to -1315.
Jun 17 1997 12:19:12:240PM970617011Ian HutchinsonPlasma till 1.5s. Breakdown at 7ms. 20 kW.

EF4 to -1320.
Cryopump on. It may have been somewhat cold before because of He valve leak.
TF rampdown end to 2s.
Jun 17 1997 12:29:15:730PM970617012Ian HutchinsonFizzle. Breakdown at 5ms. Bounces at 44kA.

Fill pulse to 28ms. (was 24).
Jun 17 1997 12:35:53:660PM970617013Ian HutchinsonFizzle. Breakdown at 4ms. Bounce at 44kA.

Rcur offset to 6800 from 6600. (Segment 1).
Jun 17 1997 12:45:25:550PM970617014Ian HutchinsonFizzle. Breakdown at 6ms.

Rcur offset to 6400.
Jun 17 1997 12:52:45:810PM970617015Ian HutchinsonFizzle. Bdwn at 6ms. 44kA. Plasma looks too far out, but it like this better than the higher
rcur offset, it seems.

Ef4 to -1330.
Jun 17 1997 02:39:30:970PM970617016Ian HutchinsonFizzle. Bounces slightly earier.

Fill puff to 20ms.
Jun 17 1997 01:07:17:830PM970617017Robert GranetzShot 17 -- Fizzle.

Granetz substitutes temporarily as physop for Ian.

 Next shot: reload segment 1 from shot 007 earlier today.
Jun 17 1997 01:12:47:790PM970617018Robert GranetzShot 18 -- Fizzle. 55 kA.

Next shot: turn off the cryopump. No other changes.
Jun 17 1997 02:04:50:730PM970617019Robert GranetzCell access required a very long delay (45 minutes) due to low oxygen levels in the cell.
Jun 17 1997 02:07:59:960PM970617019Robert GranetzShot 19 -- Plasma. Good shot. Terminates at1.51 s. The cryopump was turned off prior to
this shot. No NINJA puffing.

Next shot: Enable NINJA puffing of nitrogen.
Jun 17 1997 02:23:34:630PM970617020Robert GranetzShot 20 -- Plasma. Good shot. Terminates at 1.52 s. Nitrogen was puffed from the NINJA. There
was also 0.3 MW of 80 MHz ICRF.

Next shot: another nitrogen puff (identical to last shot), and
enable nitrogen puff from burbing FSP, and
start re-cooling the cryopump again (it will take a shot to get down to
operating temperature)
Jun 17 1997 02:26:30:180PM970617021Robert GranetzThe cryopump made it down to operating temperature before we took this shot.
Jun 17 1997 02:33:48:040PM970617021Robert GranetzShot 21 -- Fizzle. Cryopump was at operating temperature. Is there a correlation here? As it
turns out, the edge Thomson scattering laser was not firing on this shot, or on shot 18,
but was on for 19 and 20.

Next shot: repeat with no changes, except fire the edge TS laser. (NINJA nitrogen
puffing and B-FSP nitrogen puffing is enabled.)
Jun 17 1997 02:43:09:830PM970617022Robert GranetzShot 22-- Plasma. Good shot. Terminates at 1.65 s. Good rampdown. This is the first shot
which had the cryopump on. It may be pumping out the density during the rampdown,
resulting in a longer rampdown. The current rise of the last several plasmas was also
very good. This shot had nitrogen puffing from the NINJA and the B-FSP.

Ian has now returned and will take over as physop again.
Jun 17 1997 03:04:44:040PM970617023Ian HutchinsonPlasma. Ramp down to 1.58s. Got 0.9 MW and some heating. Still signs of possible pump-out.

Switch to 3psi Nitrogen.
Tweak the ramp down to stay at R=.65. (But with Neon, there probably is not much hope).
Jun 17 1997 03:11:44:590PM970617024Ian HutchinsonMany camac errors. No plasma. Dud. Ack fails on entering pulse.
Recovered magnetics look ok.

Repeat.
Jun 17 1997 03:23:41:160PM970617025Ian HutchinsonPlasma. till 1.19s. Neon causes divertor detachment. Big puff. RF gets 1.2MW brief burst.

Reduce neon puff duration by 2.
Increase nl04 to 1.5.
Jun 17 1997 03:34:30:920PM970617026Ian HutchinsonFizzle, Latish breakdown, CII up by a factor of 2. (.006).

Repeat.
Jun 17 1997 03:43:19:450PM970617027Ian HutchinsonDud. Laser was off. Sparker fails us! Bz looks rather high.

EF4 to -1315, from 1305.
Br offset to .007 from .008.
Jun 17 1997 03:51:28:030PM970617028Ian HutchinsonDud. No Laser.

Fill to 30ms. Br offset to 7.5mT.
Jun 17 1997 04:03:04:020PM970617029Ian HutchinsonPlasma till 0.91s. Bdwn at 5ms. Hesitation. Divertor detachment leads to cooling. Halo
warning. Gas puff is flat out.

Repeat without neon.
Jun 17 1997 04:10:34:380PM970617030Ian HutchinsonDud. No laser. Bz looks too positive.

ef4 to -1325.
Jun 17 1997 04:43:57:060PM970617031Ian HutchinsonPlasma till 1.5s. Laser fired briefly. Breakdown at 6ms. Tiny H-mode at 0.6s. 1.2MW RF.
Up to 1.5MW Prad.

Now to warm up the cryopump! A big dump up to 10 mtorr is seen but not all the pots
are getting warm. Jim pronounces that he thinks we are not pumping hydrogen. Pot
temperatures in the region of 10-15.
Jun 17 1997 04:56:02:000PM970617032Ian HutchinsonPlasma. Disrupts at 0.61s. Big injection.
CII is .008, slower current rise. Breakdown at 5.7ms. Got higher fill, .08mtorr.
Hydrocarbons stay very high on the RGA.

ef4 to -1330.
Jun 17 1997 05:06:45:840PM970617033Ian HutchinsonPlasma till 1s. No laser! Breakdown at 8ms. No hesitation. CII=.008. 1.5 MW.
Another big gas dump after this shot.

Density demand to nl04=1.
Jun 17 1997 05:08:51:640PM970617034Ian HutchinsonFizzle. late breakdown at 10ms. CII over .01.

Engineering Operator Comments
ShotTimeTypeStatusComment
110:11:12:310AMPlasmaOk
210:26:24:740AMPlasmaOk
310:46:00:000AMPlasmaOk
411:01:07:390AMPlasmaOk
511:08:58:710AMPlasmaOk
611:22:37:330AMPlasmaOk
711:37:22:840AMPlasmaOk
811:46:24:410AMPlasmaOk
911:53:22:780AMPlasmaOk
1012:00:57:580PMPlasmaOk
1112:07:48:090PMPlasmaOk
1212:19:18:520PMPlasmaOk
1312:28:08:630PMPlasmaOk
1412:36:04:200PMPlasmaOk
1512:43:58:520PMPlasmaOk
1612:51:23:880PMPlasmaOk
1701:00:00:350PMPlasmaOk
1801:09:15:060PMTestOk
1902:02:01:300PMPlasmaOkplasma ok
2002:14:01:150PMPlasmaOkplasma shot
2102:26:37:950PMPlasmaOk
2202:35:07:420PMPlasmaOk
2302:48:09:240PMPlasmaOk
2403:04:07:030PMPlasmaOk
2503:12:49:200PMPlasmaOk
2603:24:33:450PMPlasmaOk
2703:32:59:280PMPlasmaOk
2803:41:34:560PMPlasmaOk
2903:49:49:790PMPlasmaOk
3004:01:07:880PMPlasmaOk
3104:10:47:180PMPlasmaOk
3204:42:09:080PMPlasmaOk
3304:54:36:540PMPlasmaOk
3405:04:42:530PMPlasmaOk