Alcator C-Mod Run 951129 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Yuichi Takase (shots 1-26)

Operators
Session leader(s):Yuichi Takase
Physics operator(s):Joseph Snipes
Engineering operator(s):Vinny Bertolino

Engineering Operator Run Comment
RF Commissioning

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:14:210PM
Author: To Be Determined
Run plan for 951129:
MP102 RF Conditioning + D2 pellet piggy-back
Start from 951128033 (possibly with minor modification).
The goal is to obtain reliable power at 1.5 MW level from each antenna.

SL: Takase
PO: Snipes
EO: Bertolino

This run was continuation of yesterday's run.
The shot rep rate was very slow today (problem with TF cooling).

The goal of reliable 1.5MW power from each antenna was achieved.
Transmitter 1 has is operating near its power limit and has frequent
crowbars. E-port has larger excursions in the reflection coefficient
than D-port, and it is difficult to keep it from tripping on transitions
into EML-free H-mode. The reflection trip threshold probably needs to
be raised slightly. D-port can be tuned to handle both L and H-modes.
In addition to achieving the primary goal:

An official fiducial shot was established (shot 951129008). The RF power
was programmed to be 1MW from D port (.8 - .95sec) and 1MW from E port
(.85 - 1.00sec), so that there is a .1sec interval (.85 - .95) when
both antennas are on. However, 951129008 had only a short duration of
high power (2MW) RF because of H-mode.

We had a large number of H-modes. During the course of conditioning
(can also be considered to be a fine-step power scan) we have a few
instances in which the H-mode threshold was barely crossed. These
data can be useful.

On shots 15 (high density) and 21 (low density), outer gap scans were
performed, to obtain information on how much the outer gap needs to
be changed in order to gain a certain amount of loading.

D2 pellet was fired on shots 23 and 25. Shot 26 was an attemp to get
a PEP mode, but the plasma fizzled.

Shot
01 pla Repeat of 951128033, no RF
02 pla RF on D:1.2MW E:1.6MW (30 kV on both antennas)
Lots of spikes on density, D_alpha, etc., nel_04=1.6
03 fiz
04 pla RF on D:1.3MW E:1.6MW, still lots of density spikes, nel_04=1.5
05 pla RF pulses separated, D:0.9MW E:1.5MW, nel_04=1.2
Density feedback now on TCI (was on Z meter)
06 fiz Trying to take a fiducial, nel_04=1.0
07 pla Fiducial, got ELM-free H-modes, also got a few Mo injections
08 pla Reduced TF to 5.3T (was 5.5T), another fiducial, H-modes
09 pla asking for nel_04=1.2, reducing outer gap by 6mm (was 16mm)
got nel_04=1.1, R_gap=10mm, and H-modes, D:0.9MW E:1.5MW
10 pla add gas from B-top at 0.5sec, D:1.2MW, E:1.6MW
11 pla got H-mode with D-port, too (just above threshold), D:1.3MW, E:1.6MW
12 pla add gas from B-side-upper, D:1.3MW, E:1.7MW
13 pla add Ar from B-side-lower, asking for nel_04=1.4, D:1.5MW, E:0MW
14 pla R_gap scan (0.5 - 2cm) for E-port, D:1.6MW, E:0MW
didn't get R_gap scan
15 pla more Ar, larger R_gap swing, got R_gap scan (0.5 - 3cm)
disrupted after 1sec, D:1.6MW, E:0MW
16 fiz
17 dud
18 pla no R_gap scan, D:1.5MW, E:1.5MW
19 pla early disruption
20 pla Good shot, Mo injection @ .86sec, D:1.6MW, E:1.7MW
21 pla nel_04=1.2, R_gap scan
22 fiz reload shot 20, D and E on at the same time, D2 pellet at .65sec
23 pla D2 (#2) pellet @ .65sec, RF @ .7sec, E-port tripped on H-modes
24 fiz
25 pla D2 pellet @ .67sec, E-port still tripping on H-modes
26 fiz trying for larger (#3) D2 pellet @ .68sec, sharper RF turn-on

Physics Operator Summaries
Entered: Jul 7 2004 04:36:55:457PM
Author: To Be Determined
Run 951129 RF Commissioning
Engineer in Charge: Vince Bertolino
Physicist in Charge: Joseph Snipes
Session Leader: Yuichi Takase

Goal: To bring up both RF transmitters to 1.5 MW launched into the plasma
for reliable plasma operation. Start with shot 951128033 at 0.8 MA, 5.3 T.

Results: The run went rather well. Both antennas produced 1.5 MW and for
some periods, even together for more than 3 MW. Both ELMy and ELM-free
H-modes were produced with taue up to 75 msec, though the H factor still
did not exceed 1.5 (see shot 951129010). Deuterium pellets were injected
into a couple of discharges before the ICRF (shots 23 and 25). I noted
that extra gas was injected into the torus when the deuterium pellet
injector gate valve was open at about -1.6 sec, which increased the
pressure at breakdown from 0.05 mTorr to about 0.06 mTorr. This may have
contributed to the fizzles on shots 22, 24, and 26, but it may have also
been because the CII levels were higher on those shots. There were some
problems with cooling that led to 1/2 hour shot cycles for some of the run.
There was also one mysterious power supply failure on shot 17 caused by an
apparent magnetic resistance fault that disappeared for the next shot.
There were also a number of CAMAC problems that led to lost data for some
diagnostics and made it necessary to try to recover data before the next
shot. Otherwise, the systems ran reasonably well. Good run.

Scorecard: 26 shots, 19 plasmas, 6 fizzles, 1 power supply failure

Shot 1 : Start with shot 951128033 at 0.8 MA, 5.3 T. Good shot. Disrupted
at 1.2 sec.
Shot 2 : Moved CLEARIN ramp down time from 1.05 to 1.0 sec and increased
the rate of the ramp into the inner wall during rampdown. Turned
off the gas at 0.9 sec. O.K. Shot. Large oscillations on the H
alpha and electron density.
Shot 3 : Fizzle.
Shot 4 : Repeat. O.K. shot. Large oscillations in H alpha.
Shot 5 : Changed wire 14 to NL_04 density feedback. Requested 1.4 x 10^20 m^-2.
O.K. shot. Disrupted at 1.2 sec.
Shot 6 : Fiducial shot. nl04 requested at 1.0 x 10^20 m^-2. RF moved to
0.8 sec. Fizzle!
Shot 7 : Repeat. Fiducial with Moly injection at 0.777 sec, H-modes from
0.86 - 1.01 sec.
Shot 8 : Another fiducial. TF current set to 151 kA from 156 kA to get
down to 5.3 T. Good fiducial shot. ICRF H-modes from 0.86 - 1.01 sec.
Shot 9 : Raising nl04 to 1.2 x 10^20 m^-2. Increased RCUR by 3 mm to 0.669 m
to reduce the outer gap for RF coupling. Good shot. H-modes from
0.85 - 1.01 sec.
Shot 10: Added B top gas puff from 0.498 to 0.52 at 100 V, then 50 V until
0.7 sec. Good shot. ELMy H-mode from 0.78 - 0.8 sec, then ELMy and
ELM-free H-modes from 0.85 - 1.01 sec.
Shot 11: B top gas puff from 0.4 to 0.7 at 100 V. Good shot. ICRF H-modes
from 0.7 - 1.0 sec.
Shot 12: Late B top gas puff turned off. B side upper gas valve filled with
D to 20 psi. B side puff at 100 V from 0.4 to 0.5 sec and at 50 V
from 0.5 to 0.7 sec. Good shot. ICRF H-modes from 0.68 - 1.0 sec.
Shot 13: B side puff at 100 V from 0.4 to 0.7 sec. nl04 request set to 1.4
x 10^20 m^-2. Ar puff from 0.28 - 0.3 sec. Disrupted at 1.16 sec.
Short ELMy H-mode from 0.63 - 0.69 sec.
Shot 14: Changed RCUR programming to reduce outer gap to 5 mm between 0.7
and 0.8 sec, then increase the outer gap to 2 cm at 0.95 sec.
ELMy H-mode 0.64 - 0.74 sec.
Shot 15: Ar puff increased to 40 msec duration. RCUR changes doubled since
the gap scan did not work. Disrupted at 1 sec.
Shot 16: Ar puff reduced to 30 msec duration. RCUR programmed flat at 0.669 m.
Fizzle!
Shot 17: Magnet resistance fault. No TF.
Shot 18: Repeat. Decent shot. Disrupted at 1.16 sec.
Shot 19: Repeat. Lousy shot. Disrupted at 0.43 sec. Looks like a moly brick.
Shot 20: Repeat. Decent shot. Disrupted at 1.13 sec.
Shot 21: Reduced density to 1.2 x 10^20 m^-2. Disabled B side upper D gas.
Returned to RCUR programming from shot 15 but moved RCUR out 5 mm
at 1 sec. Good shot. Disrupted at 1.22 sec.
Shot 22: Return to shot 20. Reduce RCUR and CLEARIN in the rampdown to try
to prevent disruptions. Fizzle! Gas puff at -1.6 sec caused
breakdown conditions to be wrong. I suspect the deuterium pellet
injector may have let some gas into the torus.
Shot 23: Repeat. Good shot. Disrupted at 1.2 sec. D pellet at 0.65 sec.
H-modes from 0.74 - 0.91 sec. ICRF power up above 3 MW.
Shot 24: Repeat. Fizzle! Again, there is a gas puff at -1.6 sec that
increases the pressure at breakdown. However, the CII level was
also higher, so that may be why the plasma fizzled.
Shot 25: Repeat. D pellet requested at 0.69 sec. Good shot. H-modes from
0.75 to 0.92 sec.
Shot 26: Repeat. D pellet requested at 0.68 sec. Fizzle!

Session Leader Comments
Nov 29 1995 10:27:31:090AMYuichi TakaseRun plan for 951129:
MP102 RF Conditioning + D2 pellet piggy-back
Start from 951128033 (possibly with minor modification).
The goal is to obtain reliable power at 1.5 MW level from each antenna.

Nov 29 1995 10:28:27:090AM951129001Yuichi TakaseShot 01 plasma
Repeat of 951128033, no RF

Nov 29 1995 10:28:56:900AM951129002Yuichi TakaseShot 01 plasma
RF on D:1.2MW E:1.6MW (30 kV on both antennas)
Lots of spikes on density, D_alpha, etc., nel_04=1.6

Nov 29 1995 10:29:15:190AM951129002Yuichi TakaseShot 02 plasma
RF on D:1.2MW E:1.6MW (30 kV on both antennas)
Lots of spikes on density, D_alpha, etc., nel_04=1.6

Nov 29 1995 10:29:33:250AM951129003Yuichi TakaseShot 03 fizzle

Nov 29 1995 10:30:20:200AM951129004Yuichi TakaseShot 04 plasma
RF on D:1.3MW E:1.6MW, still lots of density spikes, nel_04=1.5

Nov 29 1995 10:30:47:580AM951129005Yuichi TakaseShot 05 plasma
RF pulses separated, D:0.9MW E:1.5MW, nel_04=1.2

Nov 29 1995 10:31:15:430AM951129006Yuichi TakaseShot 06 fizzle

Nov 29 1995 11:10:02:360AM951129007Yuichi TakaseShot 07 plasma
Fiducial, got ELM-free H-modes, also got a few Mo injections

Nov 29 1995 11:12:40:550AM951129008Yuichi TakaseShot 08 plasma
Another fiducial, got H-modes again (no ratiomatic data on this shot)

Nov 29 1995 12:41:25:970PM951129009Yuichi TakaseShot 09 plasma
asking for nel_04=1.2, reducing outer gap by 6mm (was 16mm)
got nel_04=1.1, R_gap=10mm, and H-modes, D:0.9MW E:1.5MW

Nov 29 1995 12:41:44:350PM951129010Yuichi TakaseShot 10 plasma
add gas from B-top at 0.5sec, D:1.2MW, E:1.6MW

Nov 29 1995 12:42:02:830PM951129011Yuichi TakaseShot 11 plasma
got H-mode with D-port, too (just above threshold), D:1.3MW, E:1.6MW

Nov 29 1995 12:42:19:730PM951129012Yuichi TakaseShot 12 plasma
add gas from B-side-upper, D:1.3MW, E:1.7MW

Nov 29 1995 03:06:42:610PM951129013Yuichi TakaseShot 13 plasma
add Ar from B-side-lower, asking for nel_04=1.4, D:1.5MW, E:0MW

Nov 29 1995 03:07:09:630PM951129014Yuichi TakaseShot 14 plasma
R_gap scan (0.5 - 2cm) for E-port, D:1.6MW, E:0MW
didn't get R_gap scan

Nov 29 1995 03:07:31:880PM951129015Yuichi TakaseShot 15 plasma
more Ar, larger R_gap swing, got R_gap scan (0.5 - 3cm)
disrupted after 1sec, D:1.6MW, E:0MW

Nov 29 1995 03:07:44:970PM951129016Yuichi TakaseShot 15 fizzle

Nov 29 1995 03:07:53:250PM951129016Yuichi TakaseShot 16 fizzle

Nov 29 1995 03:08:08:630PM951129017Yuichi TakaseShot 17 dud (power supply)

Nov 29 1995 03:08:36:780PM951129018Yuichi TakaseShot 18 plasma
no R_gap scan, D:1.5MW, E:1.5MW

Nov 29 1995 03:08:57:110PM951129019Yuichi TakaseShot 19 plasma
early disruption

Nov 29 1995 04:11:18:370PM951129020Yuichi TakaseShot 20 plasma
Good shot, Mo injection @ .86sec, D:1.6MW, E:1.7MW

Nov 29 1995 04:11:41:890PM951129021Yuichi TakaseShot 21 plasma
nel_04=1.2, R_gap scan

Nov 29 1995 04:12:25:520PM951129022Yuichi TakaseShot 22 fizzle
reload shot 20, D and E on at the same time, D2 pellet at .65sec

Nov 29 1995 04:31:55:910PM951129023Yuichi TakaseShot 23 plasma
Li pellet @ .65sec, RF .7 - .9sec, E-port tripped on H-modes

Nov 29 1995 04:55:06:900PM951129023Yuichi TakaseShot 23 plasma
D2 pellet @ .65sec, RF @ .7sec, E-port tripped on H-modes

Nov 29 1995 04:35:02:430PM951129024Yuichi TakaseShot 24 fizzle

Nov 29 1995 04:55:24:750PM951129025Yuichi TakaseShot 25 plasma
D2 pellet @ .67sec, E-port still tripping on H-modes

Nov 29 1995 05:03:43:550PM951129026Yuichi TakaseShot 26 fizzle
trying for larger (#3) D2 pellet @ .68sec, sharper RF turn-on

Physics Operator Comments
Nov 29 1995 09:05:36:360AMJoseph SnipesRun 951129 RF Commissioning
Engineer in Charge: Vince Bertolino
Physicist in Charge: Joseph Snipes
Session Leader: Yuichi Takase

Goal: To bring up both RF transmitters to 1.5 MW launched into the plasma for
reliable plasma operation. Start with shot 951128033 at 0.8 MA, 5.3 T.

Nov 29 1995 09:06:33:670AM951129001Joseph SnipesStart with shot 951128033 at 0.8 MA, 5.3 T. Good shot. Disrupted at 1.2 sec.

Nov 29 1995 09:31:51:090AM951129002Joseph SnipesShot 2
Moved CLEARIN ramp down time from 1.05 to 1.0 sec and increased the rate of
the ramp into the inner wall during rampdown. Turned off the gas at 0.9 sec.
O.K. Shot. Large oscillations on the H alpha and electron density.

Nov 29 1995 09:32:30:490AM951129003Joseph SnipesShot 3
Fizzle.

Nov 29 1995 09:45:37:430AM951129004Joseph SnipesShot 4
Repeat. O.K. shot. Large oscillations in H alpha.

Nov 29 1995 10:10:53:150AM951129005Joseph SnipesShot 5
Changed wire 14 to NL_04 density feedback. Requested 1.4 x 10^20 m^-2.
O.K. shot. Disrupted at 1.2 sec.

Nov 29 1995 10:23:52:830AM951129006Joseph SnipesShot 6
Fiducial shot. nl04 requested at 1.0 x 10^20 m^-2. RF moved to 0.8 sec.
Fizzle!

Nov 29 1995 10:38:47:690AM951129007Joseph SnipesShot 7
Repeat. Fiducial with Moly injection at 0.777 sec, H-modes from 0.86 - 1.01
sec.

Nov 29 1995 10:56:31:710AM951129008Joseph SnipesShot 8
Another fiducial. TF current set to 151 kA from 156 kA to get down to 5.3 T.
Good fiducial shot. ICRF H-modes from 0.86 - 1.01 sec.

Nov 29 1995 11:19:31:500AM951129009Joseph SnipesShot 9
Raising nl04 to 1.2 x 10^20 m^-2. Increased RCUR by 3 mm to 0.669 m to reduce
the outer gap for RF coupling. Good shot.

Nov 29 1995 11:33:57:400AM951129009Joseph SnipesShot 9
Raising nl04 to 1.2 x 10^20 m^-2. Increased RCUR by 3 mm to 0.669 m to reduce
the outer gap for RF coupling. Good shot. H-modes from 0.85 - 1.01 sec.

Nov 29 1995 11:49:31:110AM951129010Joseph SnipesShot 10
Added B top gas puff from 0.498 to 0.52 at 100 V, then 50 V until 0.7 sec.
Good shot. ELMy H-mode from 0.78 - 0.8 sec, then ELMy and ELM-free H-modes
from 0.85 - 1.01 sec.

Nov 29 1995 12:08:24:320PM951129011Joseph SnipesShot 11
B top gas puff from 0.4 to 0.7 at 100 V.
Good shot. ICRF H-modes from 0.7 - 1.0 sec.

Nov 29 1995 12:34:32:550PM951129012Joseph SnipesShot 12
Late B top gas puff turned off. B side upper gas valve filled with D to 20 psi.
B side puff at 100 V from 0.4 to 0.5 sec and at 50 V from 0.5 to 0.7 sec.
Good shot. ICRF H-modes from 0.68 - 1.0 sec.

Nov 29 1995 01:04:55:890PM951129013Joseph SnipesShot 13
B side puff at 100 V from 0.4 to 0.7 sec. nl04 request set to 1.4 x 10^20 m^-2.
Ar puff from 0.28 - 0.3 sec. Disrupted at 1.16 sec. Short ELMy H-mode from
0.63 - 0.69 sec.

Nov 29 1995 01:44:10:260PM951129014Joseph SnipesShot 14
Changed RCUR programming to reduce outer gap to 5 mm between 0.7 and 0.8 sec,
then increase the outer gap to 2 cm at 0.95 sec. ELMy H-mode 0.64 - 0.74 sec.

Nov 29 1995 02:28:46:210PM951129015Joseph SnipesShot 15
Ar puff increased to 40 msec duration. RCUR changes doubled since
the gap scan did not work. Disrupted at 1.0 sec.


Nov 29 1995 02:29:45:260PM951129016Joseph SnipesShot 16
Ar puff reduced to 30 msec duration. RCUR programmed flat at 0.669 m.
Fizzle!

Nov 29 1995 02:40:02:300PM951129017Joseph SnipesShot 17
Repeat. Magnet resistance fault. No TF.

Nov 29 1995 03:14:25:570PM951129018Joseph SnipesShot 18
Repeat. Decent shot. Disrupted at 1.16 sec.

Nov 29 1995 03:16:09:360PM951129019Joseph SnipesShot 19
Repeat. Lousy shot. Disrupted at 0.43 sec. Looks like a moly brick.

Nov 29 1995 03:25:19:440PM951129019Joseph SnipesShot 20
Repeat. Decent shot. Disrupted at 1.13 sec.

Nov 29 1995 03:25:30:900PM951129020Joseph SnipesShot 20
Repeat. Decent shot. Disrupted at 1.13 sec.

Nov 29 1995 03:39:12:370PM951129021Joseph SnipesShot 21
Reduced density to 1.2 x 10^20 m^-2. Disabled B side upper D gas.
Returned to RCUR programming from shot 15 but moved RCUR out 5 mm
at 1 sec. Good shot. Disrupted at 1.22 sec.

Nov 29 1995 04:13:04:150PM951129022Joseph SnipesShot 22
Return to shot 20. Reduce RCUR and CLEARIN in the rampdown to try to prevent
disruptions. D pellet requested at 0.65 sec (size 2 = 2 x 10^20 atoms).
Fizzle! Gas puff at -1.6 sec caused breakdown conditions to be wrong. I
suspect the deuterium pellet injector may have let some gas into the torus.

Nov 29 1995 04:26:18:330PM951129023Joseph SnipesShot 23
Repeat. Good shot. Disrupted at 1.2 sec. D pellet at 0.65 sec. H-modes from
0.74 - 0.91 sec. ICRF power up above 3 MW.

Nov 29 1995 04:41:12:450PM951129024Joseph SnipesShot 24
Repeat. Fizzle! Again, there is a gas puff at -1.6 sec that increases the
pressure at breakdown. However, the CII level was also higher, so that may be
why the plasma fizzled.

Nov 29 1995 04:56:22:800PM951129025Joseph SnipesShot 25
Repeat. D pellet requested at 0.69 sec. Good shot. H-modes from
0.75 to 0.92 sec.

Nov 29 1995 05:15:58:220PM951129026Joseph SnipesShot 26
Repeat. D pellet requested at 0.68 sec. Fizzle!

Engineering Operator Comments
ShotTimeTypeStatusComment
108:44:16:760AMPlasmaOk
209:03:24:570AMPlasmaOk
309:20:12:300AMPlasmaOk
409:33:02:160AMPlasmaOk
509:48:55:460AMPlasmaOk
610:17:56:450AMPlasmaOk
710:28:25:140AMPlasmaOk
810:51:19:650AMPlasmaOk
911:17:01:790AMPlasmaOk
1011:35:22:780AMPlasmaOk
1111:53:24:770AMPlasmaOk
1212:25:36:040PMPlasmaOk
1312:57:07:570PMPlasmaOk
1401:25:50:890PMPlasmaOk
1502:07:42:570PMPlasmaOk
1602:26:23:590PMPlasmaOk
1702:35:23:130PMPlasmaBadmag res fault
1802:44:29:270PMPlasmaOk
1903:01:45:230PMPlasmaOk
2003:18:50:380PMPlasmaOk
2103:35:11:230PMPlasmaOk
2203:59:01:010PMPlasmaOk
2304:19:24:010PMPlasmaOk
2404:31:02:540PMPlasmaOk
2504:41:32:600PMPlasmaOk
2605:01:29:930PMPlasmaOk