Alcator C-Mod Run 990305 Information

Back to runs

Miniproposals
Miniproposal:217a
Date Filed: 1/13/1999
Title:Toroidal Rotation during Ohmic H-Modes
First Author:John Rice
Session Leader:Ian Hutchinson (shots 1-15)
Miniproposal:222
Date Filed: 1/13/1999
Title:Impurity Compression and Enrichment Studies
First Author:John Goetz
Session Leader:John Goetz (shots 16-25)

Operators
Session leader(s):Ian Hutchinson,John Goetz
Physics operator(s):Bill Rowan
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
MP217A,MP222/Rowan/Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:20:150PM
Author: To Be Determined
Summary of First Half of Run.

Nice rotation data was obtained at 1.1, 1.0MA, bricks killed us at 1.2MA.
Magnetics rotation was obtained at 0.8MA but the Argon line
intensity was very low. A He-like line may be needed for the
low current data.
Disruption was avoided in ramp-down by a reramp up of B_t
12 Plasmas were obtained, 7 with Ohmic H-modes.
Very useful.

Entered: Jul 7 2004 03:49:20:163PM
Author: To Be Determined
Run 990305B -- MP #222 Impurity Compression and Enrichment

This proposal is an attempt to extend the compression and enrichment database
to gases other than argon and investigate the effect of the divertor bypass on
impurity behavior. It was also hoped that that argon compression scaling
with density in Ohmic plasmas from the 1997-98 run campaign could be
reproduced.

The physics plan is to:
1. Perform a density scan with puffed argon and krypton in Ohmic
plasmas. Start with low density and increase until the
detachment threshold is passed.
2. Pick an intermediate density and do a divertor bypass scan, i.e.,
bypass closed, open, closed->open, and open->closed.

Physics Summary:
The run was successful in covering the above points. Argon and
krypton were puffed into Ohmic plasmas with nl04 ranging from 0.65 x 10^20
to 1.4 x 10^20 with Ip=0.8MA. The detachment threshold for these plasmas
is ~1.36 x 10^20.
The scaling of argon compression with density is similar to that
obtained in the previous run campaign. However, the compression values are
reduced by a factor of ~2. The krypton data is yet to be analyzed. The
core krypton levels are awaiting some modelling.
The divertor bypass does indeed have an effect on the impurity
behavior. The difference on the argon compression with the bypass open and
bypass closed is a factor of about two. The compression is higher with the
bypass closed. This is due to less argon in the core and more argon in the
divertor. Opening and closing the bypass during a discharge reproduces these
results dynamically (see shot 024 and 025).
This was a good beginning on MP222.

The detailed shot log follows:

Shot Result
---- ------
016 plasma - Ar puff; no Kr puff; flappers closed; strike points @ pr. 6
017 plasma - Ar and Kr puff; flappers closed; strike points betw. pr 5 & 6.
nl04=0.66e20 but drooping after 1.0s
018 plasma - 40ms Kr, 30ms Ar, nl04=0.67e20; strike points betw. 4 & 5
moving to 6; flappers closed
019 plasma - 50ms Kr, 30ms Ar, nl04=0.7e20; flappers closed; strike point
between 4 & 5; nl04=0.7e20
020 plasma - 50ms Kr, 30ms Ar, nl04=0.8->1e20; flappers closed; strike
point between 3 &4; 2.5x Kr in divertor
021 plasma - 50ms Kr, 30 ms Ar; nl04=1.0->1.1e20; flappers closed; strike
point between 4 & 6; inner divertor beginning to detach;
outer divertor down to 10eV
022 plasma - 50ms Kr, 30ms Ar, flappers closed;both divertors detach @ 1.0s
nl04=1.36e20 -> 1.45e20 after detachment; divertor Kr down
023 plasma - 50ms Kr; 30ms Ar; flappers open; nl04=1.1e20; more core Kr,
less core Kr, and reduced divertor argon compression compared
to the flappers closed
024 plasma - 50ms Kr, 30ms Ar, flappers open then closed @ 0.9s; core Kr
and Ar drop, divertor Ar up
025 plasma - 50ms Kr, 30ms Ar, flappers closed then open @ 0.9s; core Kr
and Ar rise, divertor Ar down

Physics Operator Summaries
Entered: Jul 7 2004 04:37:00:753PM
Author: To Be Determined
Physop Report for Friday, March 5, 1999


SL: J. Rice/J. Goetz
PO: W. Rowan
EO: F. Silva

This purpose of this run was to study Toroidal Rotation during Ohmic H-Modes (MP
217A) and Impurity Compression and Enrichment Studies (MP 222). Results will be
contained in the Session Leader Summaries.

Shot 990223021 was loaded to begin the Ohmic H-Mode work. Ohmic H-modes were
obtained. The toroidal field was ramped from 5.4 T to 3.5 T and then held
constant until the end of the shot. With the initial setup, the plasma
disrupted after the H-Mode, during the plateau in BT, and near 1 s. See shot
990305009, for example. The disruption was avoided by ramping the field back up
and increasing q. See shot 990305012, for example. The H-Mode still appeared.
In fact, there was an H-mode during the ramp up on shot 990305013.

Shot 990204018 was loaded for MP 217A. During this run, the various gaspuff
times were varied and density was varied. Straightforward operation.

Engineering setup
2 hours ECDC in deuterium on Friday morning before the run
Load from 990223021
TF under hybrid control
Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid ENABLED
fill B-side upper with 2 psi of Ne Hybrid DISABLED(yes, neon)
fill C-side with 30 psi of D2 Hybrid enabled
fill J-bottom with 2 psi of Kr Hybrid DISABLED

Shot 001. fizzle
Shot 002. plasma
Shot 003. Plasma. No H-mode.
Shot 004. Plasma. H-mode at 1.1s. Disrupted at 1.2s
Shot 005. Plasma. H-Mode as on previous shot.
Shot 006. Plasma. H-mode
Shot 007. Plasma. Disrupted at 0.35s.
Shot 008. Fizzle.
Shot 009. Plasma H-mode. Disruption at 0.884s.
Shot 010. Plasma. H-mode. Disruption at 0.9s.
Shot 11. Null shot.
Shot 12. Plasma. H-Mode.
Shot 13. Plasma. H-mode.
Shot 14. Disruption at 0.565s
Shot 15. Plasma. Disrupted at 0.66s
Shot 16. Plasma
Shot 17. Plasma.
Shot 18. Plasma.
Shot 19. Plasma
Shot 20. Plasma
Shot 21. Plasma
Shot 22. Plasma.
Shot 23. Plasma
Shot 24. Plasma
Shot 25. Plasma . Last shot.

Score Card
Plasmas 22
Fizzles 2
Dud 0
Total 24 (Note that there was null shot)

Session Leader Comments
Mar 5 1999 08:52:06:280AMIan HutchinsonMP 217A Toroidal Rotation in Ohmic H-modes

Completing the abbreviated run from 990223.
Plan to get some different currents.
Mar 5 1999 01:30:51:780PMIan HutchinsonSummary of First Half of Run.

Nice rotation data was obtained at 1.1, 1.0MA, bricks killed us at 1.2MA.
Magnetics rotation was obtained at 0.8MA but the Argon line
intensity was very low. A He-like line may be needed for the
low current data.
Disruption was avoided in ramp-down by a reramp up of B_t
12 Plasmas were obtained, 7 with Ohmic H-modes.
Very useful.
Mar 5 1999 09:01:47:170AM990305001Ian HutchinsonFizzle.
Mar 5 1999 09:25:20:483AM990305002Ian HutchinsonPlasma. Sawtooth rotation is clear in H-mode seems to reach 9kHz.
Not so clear in L-phase.
Mar 5 1999 09:33:08:500AM990305003Ian HutchinsonPlasma. No H-mode with this higher level of Argon. Some isolated "dithers".
During this time when it is trying to go into H-mode it looks as if the
sawtooth frequency is positive by maybe a couple of kHz.
Mar 5 1999 10:09:01:077AM990305004Ian HutchinsonPlasma. H-mode just before the disruption, 1.1 to 1.2s.
Sawtooth rotation about 5kHz co in H-mode.
q-value is becoming low only by about 0.9s. We prefer earlier, so ask for
the TF ramp to start at 10ms instead of 100ms.
Density might be a little low for optimal H-mode entry.
Mar 5 1999 10:33:20:640AM990305005Ian HutchinsonPlasma. Very similar.

Ask for 1e20 density next shot. Was set to 0.8e20.
Mar 5 1999 10:53:05:250AM990305006Ian HutchinsonPlasma. H-mode from 1.07 to 1.23s, makes it into ramp-down.
Co about 7.5kHz during H-mode.

Reload shot 990223012 and tweak Bt ramp raise nl04 to 1.

Mar 5 1999 11:07:02:530AM990305007Ian HutchinsonPlasma. Disrupts at 0.35s. A brick.
Mar 5 1999 11:13:44:340AM990305008Ian HutchinsonFizzle.
Mar 5 1999 12:03:23:327PM990305009Ian HutchinsonPlasma. Disrupts at .88s. 2 elm-free H-modes starting at 0.62 and 0.75s.
Digitization of the magnetics starts too late, 0.8s.
Mar 5 1999 12:13:27:153PM990305010Ian HutchinsonPlasma. Disrupts at .91s. Very similar to previous shot. But fast signals
set earlier so we have good data.
Mar 5 1999 12:23:38:060PM990305011Ian HutchinsonNull shot. We weren't ready.
Mar 5 1999 12:33:43:293PM990305012Ian HutchinsonPlasma. No disruption.
On this shot we had nl04 at 0.9 but mainly we installed a field ramp back
up starting about 0.75s.
The second H-mode is slightly shorter. It seems to
know that the field is ramping back up.
Mar 5 1999 12:55:05:983PM990305013Ian HutchinsonPlasma. No disruption. 3 H-modes in flat top. Plus one in ramp-down.
Raised Ip to 1.1MA and scale the flat low Bt level also by 10%.
Sawtooth frequencies about 8kHz on first two H-modes. Much less on the
third. Is confirmed by the Argon data. The field was going back up
there so q was nearly up to 3.
Mar 5 1999 01:13:27:937PM990305014Ian HutchinsonPlasma. Disrupts at 0.55s. Caused by OH1 coming out of cross-over and we
touch the inner limiter.

Try to fix by delaying the final Ip point and increasing clearin by 5mm
during the .4s time phase.
Mar 5 1999 01:18:59:653PM990305015Ian HutchinsonPlasma. Disrupts again at .66s. No H-mode. An brick even though we
avoided limiter contact.
Mar 5 1999 01:51:56:217PM990305016John GoetzShot 990305016
Ar puff and Kr puff attempted into a "long" plasma

Plasma
no Kr puff - J_Bottom valve waveform only 15V
strike points at probe 6; moving up late
nl04 = 0.66e20
Mar 5 1999 02:20:49:763PM990305017John GoetzShot 990305017
Ar puff and Kr puff attempted into a "long" plasma

Plasma
Kr puff thru B_side_upper; not enough for divertor RGA or spectroscopy
measurements
strike points between probe5 and probe 6
nl04 = 0.66e20 but drooping after 1.0s (ancient programming)
Mar 5 1999 02:41:45:123PM990305018John GoetzShot 990305018
30ms Ar puff and 40ms Kr puff attempted into a "long" plasma

Plasma
krypton seen on RGA, McPherson, and HIREX; but not quite enough
strike points between probe 4 and 5 but drifting up to probe 6
nl04 = 0.67e20 but drooping after 1.1s
Mar 5 1999 03:01:12:077PM990305019John GoetzShot 990305019
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
krypton seen on RGA, McPherson, and HIREX; better
strike points between probe 4 and 5
nl04 = 0.7e20; no drooping
Mar 5 1999 03:28:22:013PM990305020John GoetzShot 990305020
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
krypton seen on RGA, McPherson, and HIREX; slight "pump-out" on the Ar
and Kr core densities
strike points between probes 3 and 4 and moving to 6 late
nl04 = 0.8->1.0e20
Mar 5 1999 03:45:21:810PM990305021John GoetzShot 990305021
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
krypton seen on RGA, McPherson, and HIREX; slight "pump-out" on the Ar
and Kr core densities
strike points moves between probes 4 and 6
nl04 = 1.0->1.1e20
divertor cooling off; inner divertor nearing detachment
Mar 5 1999 04:08:55:263PM990305022John GoetzShot 990305022
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
krypton seen on RGA, McPherson, and HIREX; no "pump-out" on the Ar
and Kr core densities
detachment on both divertors to the "noses"
a lot of strike point movement
nl04 = 1.36 before detachment to 1.45 after detachment
much less Kr in the divertor
Kr core density up after detachment, Ar core density constant
Mar 5 1999 04:32:18:793PM990305023John GoetzShot 990305023
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
flappers open for the whole shot
krypton seen on RGA, McPherson, and HIREX; "pump-out" on the Ar
and Kr core densities
a lot of strike point movement
nl04 = 1.1
more Kr seen by HIREX and McP when compared to the flappers closed shot
divertor argon compression is reduced compared to the flappers closed shot
Mar 5 1999 04:52:42:013PM990305024John GoetzShot 990305024
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
flappers open and then close @ 0.9s
krypton seen on RGA, McPherson, and HIREX
krypton and argon signals are halved when the flappers close
a lot of strike point movement
nl04 = 1.1 - feedback keeps it stable through the flapper movement
radiated power drops, Dalpha rises after closure
Mar 5 1999 05:18:21:717PM990305025John GoetzShot 990305025
30ms Ar puff and 50ms Kr puff attempted into a "long" plasma

Plasma
flappers closed and then open @ 0.9s
krypton seen on RGA, McPherson, and HIREX
krypton and argon signals are doubled when the flappers open
a lot of strike point movement
nl04 = 1.1 - feedback keeps it stable through the flapper movement
radiated power rises, Dalpha drops, divertor pressure drops after closure

Physics Operator Comments
Mar 5 1999 07:47:25:060AMBill RowanSubj: Engineering setup and run plan for Friday, 990305

Engineering Setup for Friday, 990305

2 hours ECDC in deuterium on Friday morning before the run

Load from 990223021

TF under hybrid control

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 2 psi of Ne Hybrid DISABLED(yes, neon)
fill C-side with 30 psi of D2 Hybrid enabled
fill J-bottom with 2 psi of Kr Hybrid DISABLED


The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV

-------------------------------------------------------------------------------
Run Plan for 990305:

MP 217A -- Toroidal Rotation during Ohmic H-Modes
MP 222 -- Impurity Compression and Enrichment Studies

SL: J. Rice/J. Goetz
PO: W. Rowan

MP 217A

Start by reloading 990223021, .8 MA Ohmic H-mode. If successful run a few
shots, then attempt to obtain Ohmic H-modes at .6 MA. If .6 MA operation
doesn't work, reload 990223014 at 1.0 MA, and try to ramp Bt up while
maintaining the H-mode, hopefully avoiding disruptions. If this procedure
is successful, perhaps attempt 1.2 MA.


Miniproposal 222
Goals:
extend compression and enrichment measurements to gases other
than argon
determine what effect the divertor bypass has on impurity
compression and enrichment
Plan:
puff argon and krypton into Ohmic plasmas
density scan
divertor bypass open, closed, and dynami


Modification to run plan. B-side lower Ar hybrid enabled
Mar 5 1999 08:32:36:840AMBill Rowan
Started pcs and loaded from shot 9902230

Successful coldstart at 8.
Mar 5 1999 09:00:55:357AM990305001Bill RowanShot 001. fizzle

Next shot: Lowered BR from 0.002 to 0.001
Mar 5 1999 09:19:16:310AM990305002Bill RowanShot 002. plasma

Next shot: added an Ar puff at 0.8s. 30 ms.
Mar 5 1999 09:36:57:140AM990305003Bill RowanShot 003. Plasma. No H-mode. Attributed to additional Ar puff

Next shot: Moved Ar puff to 0.7s and reduced to 15 ms
Mar 5 1999 10:08:32:403AM990305004Bill RowanShot 004. Plasma. H-mode at 1.1s. Disrupted at 1.2s

Next shot: Moved the BT ramp down earlier
Mar 5 1999 10:32:05:560AM990305005Bill RowanShot 005. Plasma. H-Mode as on previous shot.

Next shot: Increase ne
Mar 5 1999 10:50:58:513AM990305006Bill RowanShot 006. Plasma. H-mode

Next shot:: Reloaded shot 990223012. This will increase the current to 1 MA. Increased ne. Reduced BR from 1.5 mT to 1 mT.
BT ramp down moved about 100 ms earlier.
Mar 5 1999 11:05:17:840AM990305007Bill RowanShot 007. Plasma. Disrupted at 0.35s.

Next shot: no changes
Mar 5 1999 11:19:33:903AM990305008Bill RowanShot 008. Fizzle.

Next shot: Reduced prefill by 2 ms. Reduced BZ.
Mar 5 1999 11:34:27:357AM990305009Bill RowanShot 009. Plasma H-mode. Disruption at 0.884s.

Next shot: Reduced BZ in an attempt to avoid a fizzle -- Granetz gambit
Mar 5 1999 12:18:48:983PM990305010Bill RowanShot 10. Shot 010. Plasma. H-mode. Disruption at 0.9s.
Mar 5 1999 12:17:30:700PM990305011Bill RowanShot 11. Null shot.

Next shot: Reduced density. Added a ramp up in BT at 0.75s. Increased outer gap
Mar 5 1999 12:34:00:937PM990305012Bill RowanShot 12. Plasma. H-Mode.

Next shot. Increase current to 1.1MA. Increase BT to maintain constant q
Mar 5 1999 12:52:48:187PM990305013Bill RowanShot 13. Plasma. H-mode.

Next shot: Increase current to 1.2MA. Increase BT to maintain constant q
Mar 5 1999 01:11:15:687PM990305014Bill RowanShot 14. Disruption at 0.565s

Next shot. Slowed IP and modified clearin
Mar 5 1999 01:31:56:483PM990305015Bill RowanShot 15. Plasma. Disrupted at 0.66s

Next shot. Start of MP 222. Reload segment 2 from 990204018

Kr puff at 0.375s
Mar 5 1999 01:52:45:937PM990305015Bill RowanShot 16. Plasma

Next shot: Pump neon out of B-side-upper and replace with 2 psi Kr

Mar 5 1999 02:19:38:920PM990305017Bill RowanShot 17. Plasma. Gas turned off hard at 1 s

Next shot. Gas turned off at the beginning of ramp down. That is, 1.4s.
Increased Kr puff from 25 ms to 40 ms by changing turn off time. Pulse still starts at 0.375s
Mar 5 1999 02:42:57:500PM990305018Bill RowanShot 18. Plasma.

Next shot: Increased Kr pulse from 40 ms to 50 ms

Mar 5 1999 03:02:17:607PM990305019Bill RowanShot 19. Plasma

Next shot: Increased NL_04 to 1e20. Increased outer gap.
Mar 5 1999 03:23:34:543PM990305020Bill RowanShot 20. Plasma

Next shot: Increased NL_04 ro 1.1e20. Increased gain from 4 to 9.
Mar 5 1999 03:50:56:483PM990305021Bill RowanShot 21. Plasma

Next shot: Increased NL_04 to 1.3e20. Increased maintenance gas.
Mar 5 1999 04:12:02:200PM990305022Bill RowanShot 22. Plasma.

Next shot: NL_04 changed to 1.0e+20

Mar 5 1999 04:28:43:170PM990305023Bill RowanShot 23. Plasma

Next shot: no changes

Mar 5 1999 04:48:40:873PM990305024Bill RowanShot 24. Plasma

Next shot: No changes
Mar 5 1999 05:03:12:590PM990305025Bill RowanShot 25. Plasma. Last shot

Engineering Operator Comments
ShotTimeTypeStatusComment
108:49:22:000AMPlasmaOkno faults/fizzel
209:03:34:543AMPlasmaOkno faults/1.16sec disruption
309:20:18:967AMPlasmaOkno faults/plasma
409:51:50:140AMPlasmaOkno faults/disruption
510:08:45:670AMPlasmaOkno faults/Disruption
610:29:36:170AMPlasmaOkno faults
710:52:35:590AMPlasmaOkno faults
811:05:22:280AMPlasmaOkno faults/fizzel
911:20:35:717AMPlasmaOkno faults/plasma
1011:40:45:717AMPlasmaOkno faults
1112:11:07:030PMPlasmaOkNo Power due to not physop not ready
1212:19:07:920PMPlasmaOkNo Faults / Plasma
1312:34:39:200PMPlasmaOkNo Faults / Plasma
1412:53:31:310PMPlasmaOkNo Faults / Plasma
1501:11:26:043PMPlasmaOkNo Faults / Plasma
1601:36:13:437PMPlasmaOkNo Faults / Plasma
1702:06:21:670PMPlasmaOkNo Faults / Plasma
1802:25:50:310PMPlasmaOkNo Faults / Plasma
1902:48:29:233PMPlasmaOkNO Faults / Plasma
2003:11:02:607PMPlasmaOkNo Faults / Plasma
2103:32:24:763PMPlasmaOkNo Faults / Plasma
2203:54:18:390PMPlasmaOkNo Faults / Plasma
2304:15:02:437PMPlasmaOkNo Faults / Plasma
2404:36:20:500PMPlasmaOkNo Faults / Plasma
2504:58:48:390PMPlasmaOkNo Faults / Plasma