Alcator C-Mod Run 930608 Information

Miniproposals

Miniproposal:

Date Filed:

Title:

First Author:

Session Leader: Steve Horne (shots 1-25)

Operators
Session leader(s):	Steve Horne
Physics operator(s):	Steve Golovato
Engineering operator(s):	Joe Daigle

Engineering Operator Run Comment
Plasma run

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:07:867PM

Author: To Be Determined

Run 930608
Horne, Daigle, Golovato

Plan was to work on radial control. Instead we mostly had
power supply problems and startup ailments. We did use the new pressure diagnostic
(a Ratiomatic controller
with a nude gauge) to determine that the first signs of gas appear between 35 and 40 msec
after the puff. The gauge sees the plasma, so if there is a breakdown it can't be trusted.
The dud shots show reasonable signals.

Shots 1-3 had problems with power supplies, including that for the hybrid camac crate.

Shot 4 fizzled, shot 5 had horrendous runaways & hard x rays. A spot
on the RF limiter glowed brightly afterwards.

Shots 5-9 are a scan of gas puff timing. 5 had the inherited puff at + 12 msec.
Shot 6 we moved the puff back to -30 msec, then
advanced it to -20, (7,8) and -10 (9,10,11) We then moved it to -5 and left it there.

Good shots were 5,9,11,16,20,and 21.
They all broke down near +5 msec.
Most of the other broke down later.

duds (no fizzle) were 1,2,3,14,15. These are good to check the ratiomatic signal.

On shot 17 we adjusted the r_cur controller by reducing the EF3 weight and increasing
the PID to compensate partially. I haven't checked whether this changed plasma
behavior.

Current rise was too non-reproducible to make this sort of thing worthwhile.
Starting around shot 20 I turned over the first 50 msec of the shot to Ian to
try to improve current rise.

Physics Operator Summaries

Session Leader Comments

Jun 8 1993 09:28:59:470AM Steve Horne run 930608
comutation resistors: ef1l=118.8
ef1u=118.2
oh1=65.3
oh2l=12.8
oh2u=12.9
ef2u/l=45

run goals - improve radial control or if the shot reliability is poor (too many fizzles)
work on breakdown and initial current rise reproducibility.

Jun 8 1993 09:49:11:400AM 930608001 Steve Horne shot 930608001

same as shot 930604019 (last shot from last friday) except pulsed gas moved from 12-50ms
instead of 12-100ms.
pre-fill 6.e-5.
no plasma, tf crowbar at 55ka, -1.2sec. no ef3u/l.
no problem found. re-taking shot.

Jun 8 1993 10:21:42:440AM 930608001 Steve Horne shot 930608002

retake of first shot.
same problems.
also, hybrid camac crate not working correctly, all signals maxed out (this was also true
of first shot). hybrid problem corrected by replacing crate power supply.

tf problem is apparently interlock on one phase of one supply. appears to be a faulty
interlock, it was bypassed.

Jun 8 1993 10:38:40:770AM 930608001 Steve Horne shot 930608003

another retake of first shot.
same tf problem. disconnnected wrong interlock. try again.
hybrid camac worked.

Jun 8 1993 10:51:32:630AM 930608004 Steve Horne shot 930608004

breakdown, no current. nothing obviously wrong.

Jun 8 1993 11:06:16:940AM 930608005 Steve Horne shot 930608005

try it again.
worked but had runaways.
For next shot, shift gas programming earlier by 40 msec.

Jun 8 1993 11:16:47:880AM 930608006 Steve Horne shot 930608006

shifted gas programming earlier by 40 msec.
dud! probably too much gas. move forward 10ms (30ms earlier than shot 005).

Jun 8 1993 11:30:59:040AM 930608007 Steve Horne shot 930608007

moved pulsed gas forward 10ms, starts at -20ms.
re-take. some differences in the magnetics according to ian (bz early ion time).

Jun 8 1993 11:41:42:730AM 930608007 Steve Horne shot 930608007

breakdown seems to be delayed by moving pulsed gas earlier (comparing shots 5 and 6),
consistant with higher pressure as seen in pre-fill scan last friday. however
shot 7 broke down the same time as 5 but didn't go.

Jun 8 1993 11:47:53:020AM 930608008 Steve Horne shot 930608008

didn't go again. will move pulsed gas forward again by 10ms to -10ms.

Jun 8 1993 12:11:34:920PM 930608009 Steve Horne shot 930608009

moved pulsed gas forward again by 10ms to -10ms.
good shot, but hugged inner wall. slow current ramp (~2.5ma/ms), without
the early hesitation.

Jun 8 1993 12:11:42:930PM 930608009 Steve Horne shot 930608009

moved pulsed gas forward again by 10ms to -10ms.
good shot, but hugged inner wall. slow current ramp (~2.5ma/ms), without
the early hesitation.

Jun 8 1993 12:27:21:640PM 930608010 Steve Horne shot 930608010

repeat of shot 9. fizzled.

Jun 8 1993 12:37:57:930PM 930608011 Steve Horne shot 930608011

reduced bz (lowered ef4 by 30 amps to 670a for t=-.1 to 0) to reduce plasma motion
toward inner wall at breakdown.
good shot, almost identical to shot 9.

Jun 8 1993 12:51:31:960PM 930608012 Steve Horne shot 930608012

move pulsed gas forward again by 5ms to -5ms to try to increase current ramp rate,
to help keep plasma off of the inner wall.
fizzled.

Jun 8 1993 01:16:42:910PM 930608012 Steve Horne shot 930608013

further reduced ef4 current by 30a to 640a from -.1 to 0.
fizzled.

Jun 8 1993 01:37:09:570PM 930608014 Steve Horne shot 930608014

maybe we're going the wrong way. raise ef4 back to 700a. also move time
that it goes to 700a from -.1 to -.2 s to give feedback more time to get it there.

no plasma. ef4 and ef2l failed, faulty interlock indication.

Jun 8 1993 02:19:39:510PM 930608015 Steve Horne shot 930608015

retry last shot. granetz arrays show plasma is lost down when it doesn't work,
not to the inner wall. seems to be shot-to-shot variations in br, since we
are not changing anything that affects br.

no plasma, ef4 shut down at -1s. ef2l also didn't work.

Jun 8 1993 02:30:09:700PM 930608016 Steve Horne shot 930608015

worked, finally. plasma broke down low, then centered rather than diving down
as in shots that don't go.

Jun 8 1993 02:30:52:610PM 930608016 Steve Horne shot 930608016

previous log was for shot 16, not shot 15.

Jun 8 1993 02:55:36:570PM 930608017 Steve Horne shot 930608017

reduced rcur controller for ef3 to about half, making ratios of oh1, oh2, ef3 roughly
as suggested by wolfe, but about a factor of 10 higher.
rcur pid gain increased from .2 to .3.
previous shot was good but inside by about 5cm.

fizzled. hardly as flash.

marmar suggests that walls are loaded with gas by good shot which leads to several fizzles
which depletes them allowing a good shot, which reloads the walls...

Jun 8 1993 03:04:19:000PM 930608018 Steve Horne shot 930608018

ef4 voltage and current programming changed to make bz slightly lower.
fizzled.

Jun 8 1993 03:04:29:040PM 930608018 Steve Horne shot 930608018

ef4 voltage and current programming changed to make bz slightly lower.
fizzled.

Jun 8 1993 03:19:43:650PM 930608018 Steve Horne shot 930608019

drop pre-fill to 5.e-5.
fizzled. plasma dove down.

Jun 8 1993 03:28:53:550PM 930608020 Steve Horne shot 930608020

dropped oh2 demand from 20 to 10v for first 8ms to provide a more vertically
stable breakdown (at ian's suggestion).
pre-fill is 4.e-5 not 5.e-5 for last 2 shots.

worked but runaways (not as bad as previous runaway shot)

Jun 8 1993 04:04:48:170PM 930608021 Steve Horne shot 930608021

raised pre-fill to 5.e-5 to suppress runaways.
raised oh2 voltage programming back to 20v (added 10 v) and re-arranged oh1 voltage
roughly adding 50v. purpose is to get the voltages to be consistant with the turns
ratio. again this is ian's suggestion.

got plasma without runaways.

Jun 8 1993 04:18:08:400PM 930608022 Steve Horne shot 930608022

added 100a to ef2s at comuitation and a little (<0.1) derivative gain to rcur at 50 ms.
fizzled. broke down late, dove down.

Jun 8 1993 05:06:06:470PM 930608022 Steve Horne shot 930608023

reduce ef4 by 100a from 650 to 550. increase in ef2 gave too much bz at breakdown.

Jun 8 1993 05:06:18:650PM 930608022 Steve Horne shot 930608023

reduce ef4 by 100a from 650 to 550. increase in ef2 gave too much bz at breakdown.

fizzled.

Jun 8 1993 05:06:33:200PM 930608022 Steve Horne shot 930608024

fizzled.

Jun 8 1993 05:12:33:790PM 930608022 Steve Horne shot 930608025

better fizzle
Last shot..

Physics Operator Comments

Engineering Operator Comments

Shot Time Type Status Comment

1 09:34:26:070AM Plasma Bad TF supply faulted com Fail @ 55K amp.

2 09:52:55:060AM Plasma Bad camac & TF comm. fault.

3 10:22:15:770AM Plasma Ok power supply fault TF comm fault.

4 10:38:47:370AM Plasma Ok Plasma shot no faults

5 10:50:50:180AM Plasma Ok Good shot good plasma

6 11:06:59:640AM Plasma Ok No faults

7 11:20:54:110AM Plasma Ok No faults

8 11:37:19:170AM Plasma Ok Plasmas shot No faults.

9 11:53:39:010AM Plasma Ok Good shot

10 12:10:04:140PM Plasma Ok Good shot

11 12:27:45:010PM Plasma Ok Good shot

12 12:41:13:030PM Plasma Ok Good shot

13 01:02:52:980PM Plasma Ok Plasma shot no faults.

14 01:18:43:700PM Plasma Bad ef2 L ef4 faults no Plasma

15 01:57:17:700PM Plasma Bad Power supply fault ef2L & EF4

16 02:17:53:980PM Plasma Ok plasma shot no faults.

17 02:34:39:240PM Plasma Ok Plasma shot no faults.

18 02:45:47:240PM Plasma Ok Plasma shot no faults

19 03:07:38:630PM Plasma Ok Good shot

20 03:22:04:140PM Plasma Ok Plasma Shot no faults.

21 03:54:32:410PM Plasma Ok PLasma shot no faults.

22 04:10:17:020PM Plasma Ok Plasma shot No Faults.

23 04:22:31:190PM Plasma Ok Plasma shot No Faults

24 04:45:06:840PM Plasma Ok PLASMA SHOT NO FAULTS.

25 04:57:13:480PM Plasma Ok PLASMA SHOT NO FAULTS.

Session Leader Comments
Jun 8 1993 09:28:59:470AM		Steve Horne	run 930608 comutation resistors: ef1l=118.8 ef1u=118.2 oh1=65.3 oh2l=12.8 oh2u=12.9 ef2u/l=45 run goals - improve radial control or if the shot reliability is poor (too many fizzles) work on breakdown and initial current rise reproducibility.
Jun 8 1993 09:49:11:400AM	930608001	Steve Horne	shot 930608001 same as shot 930604019 (last shot from last friday) except pulsed gas moved from 12-50ms instead of 12-100ms. pre-fill 6.e-5. no plasma, tf crowbar at 55ka, -1.2sec. no ef3u/l. no problem found. re-taking shot.
Jun 8 1993 10:21:42:440AM	930608001	Steve Horne	shot 930608002 retake of first shot. same problems. also, hybrid camac crate not working correctly, all signals maxed out (this was also true of first shot). hybrid problem corrected by replacing crate power supply. tf problem is apparently interlock on one phase of one supply. appears to be a faulty interlock, it was bypassed.
Jun 8 1993 10:38:40:770AM	930608001	Steve Horne	shot 930608003 another retake of first shot. same tf problem. disconnnected wrong interlock. try again. hybrid camac worked.
Jun 8 1993 10:51:32:630AM	930608004	Steve Horne	shot 930608004 breakdown, no current. nothing obviously wrong.
Jun 8 1993 11:06:16:940AM	930608005	Steve Horne	shot 930608005 try it again. worked but had runaways. For next shot, shift gas programming earlier by 40 msec.
Jun 8 1993 11:16:47:880AM	930608006	Steve Horne	shot 930608006 shifted gas programming earlier by 40 msec. dud! probably too much gas. move forward 10ms (30ms earlier than shot 005).
Jun 8 1993 11:30:59:040AM	930608007	Steve Horne	shot 930608007 moved pulsed gas forward 10ms, starts at -20ms. re-take. some differences in the magnetics according to ian (bz early ion time).
Jun 8 1993 11:41:42:730AM	930608007	Steve Horne	shot 930608007 breakdown seems to be delayed by moving pulsed gas earlier (comparing shots 5 and 6), consistant with higher pressure as seen in pre-fill scan last friday. however shot 7 broke down the same time as 5 but didn't go.
Jun 8 1993 11:47:53:020AM	930608008	Steve Horne	shot 930608008 didn't go again. will move pulsed gas forward again by 10ms to -10ms.
Jun 8 1993 12:11:34:920PM	930608009	Steve Horne	shot 930608009 moved pulsed gas forward again by 10ms to -10ms. good shot, but hugged inner wall. slow current ramp (~2.5ma/ms), without the early hesitation.
Jun 8 1993 12:11:42:930PM	930608009	Steve Horne	shot 930608009 moved pulsed gas forward again by 10ms to -10ms. good shot, but hugged inner wall. slow current ramp (~2.5ma/ms), without the early hesitation.
Jun 8 1993 12:27:21:640PM	930608010	Steve Horne	shot 930608010 repeat of shot 9. fizzled.
Jun 8 1993 12:37:57:930PM	930608011	Steve Horne	shot 930608011 reduced bz (lowered ef4 by 30 amps to 670a for t=-.1 to 0) to reduce plasma motion toward inner wall at breakdown. good shot, almost identical to shot 9.
Jun 8 1993 12:51:31:960PM	930608012	Steve Horne	shot 930608012 move pulsed gas forward again by 5ms to -5ms to try to increase current ramp rate, to help keep plasma off of the inner wall. fizzled.
Jun 8 1993 01:16:42:910PM	930608012	Steve Horne	shot 930608013 further reduced ef4 current by 30a to 640a from -.1 to 0. fizzled.
Jun 8 1993 01:37:09:570PM	930608014	Steve Horne	shot 930608014 maybe we're going the wrong way. raise ef4 back to 700a. also move time that it goes to 700a from -.1 to -.2 s to give feedback more time to get it there. no plasma. ef4 and ef2l failed, faulty interlock indication.
Jun 8 1993 02:19:39:510PM	930608015	Steve Horne	shot 930608015 retry last shot. granetz arrays show plasma is lost down when it doesn't work, not to the inner wall. seems to be shot-to-shot variations in br, since we are not changing anything that affects br. no plasma, ef4 shut down at -1s. ef2l also didn't work.
Jun 8 1993 02:30:09:700PM	930608016	Steve Horne	shot 930608015 worked, finally. plasma broke down low, then centered rather than diving down as in shots that don't go.
Jun 8 1993 02:30:52:610PM	930608016	Steve Horne	shot 930608016 previous log was for shot 16, not shot 15.
Jun 8 1993 02:55:36:570PM	930608017	Steve Horne	shot 930608017 reduced rcur controller for ef3 to about half, making ratios of oh1, oh2, ef3 roughly as suggested by wolfe, but about a factor of 10 higher. rcur pid gain increased from .2 to .3. previous shot was good but inside by about 5cm. fizzled. hardly as flash. marmar suggests that walls are loaded with gas by good shot which leads to several fizzles which depletes them allowing a good shot, which reloads the walls...
Jun 8 1993 03:04:19:000PM	930608018	Steve Horne	shot 930608018 ef4 voltage and current programming changed to make bz slightly lower. fizzled.
Jun 8 1993 03:04:29:040PM	930608018	Steve Horne	shot 930608018 ef4 voltage and current programming changed to make bz slightly lower. fizzled.
Jun 8 1993 03:19:43:650PM	930608018	Steve Horne	shot 930608019 drop pre-fill to 5.e-5. fizzled. plasma dove down.
Jun 8 1993 03:28:53:550PM	930608020	Steve Horne	shot 930608020 dropped oh2 demand from 20 to 10v for first 8ms to provide a more vertically stable breakdown (at ian's suggestion). pre-fill is 4.e-5 not 5.e-5 for last 2 shots. worked but runaways (not as bad as previous runaway shot)
Jun 8 1993 04:04:48:170PM	930608021	Steve Horne	shot 930608021 raised pre-fill to 5.e-5 to suppress runaways. raised oh2 voltage programming back to 20v (added 10 v) and re-arranged oh1 voltage roughly adding 50v. purpose is to get the voltages to be consistant with the turns ratio. again this is ian's suggestion. got plasma without runaways.
Jun 8 1993 04:18:08:400PM	930608022	Steve Horne	shot 930608022 added 100a to ef2s at comuitation and a little (<0.1) derivative gain to rcur at 50 ms. fizzled. broke down late, dove down.
Jun 8 1993 05:06:06:470PM	930608022	Steve Horne	shot 930608023 reduce ef4 by 100a from 650 to 550. increase in ef2 gave too much bz at breakdown.
Jun 8 1993 05:06:18:650PM	930608022	Steve Horne	shot 930608023 reduce ef4 by 100a from 650 to 550. increase in ef2 gave too much bz at breakdown. fizzled.
Jun 8 1993 05:06:33:200PM	930608022	Steve Horne	shot 930608024 fizzled.
Jun 8 1993 05:12:33:790PM	930608022	Steve Horne	shot 930608025 better fizzle Last shot..

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:34:26:070AM	Plasma	Bad	TF supply faulted com Fail @ 55K amp.
2	09:52:55:060AM	Plasma	Bad	camac & TF comm. fault.
3	10:22:15:770AM	Plasma	Ok	power supply fault TF comm fault.
4	10:38:47:370AM	Plasma	Ok	Plasma shot no faults
5	10:50:50:180AM	Plasma	Ok	Good shot good plasma
6	11:06:59:640AM	Plasma	Ok	No faults
7	11:20:54:110AM	Plasma	Ok	No faults
8	11:37:19:170AM	Plasma	Ok	Plasmas shot No faults.
9	11:53:39:010AM	Plasma	Ok	Good shot
10	12:10:04:140PM	Plasma	Ok	Good shot
11	12:27:45:010PM	Plasma	Ok	Good shot
12	12:41:13:030PM	Plasma	Ok	Good shot
13	01:02:52:980PM	Plasma	Ok	Plasma shot no faults.
14	01:18:43:700PM	Plasma	Bad	ef2 L ef4 faults no Plasma
15	01:57:17:700PM	Plasma	Bad	Power supply fault ef2L & EF4
16	02:17:53:980PM	Plasma	Ok	plasma shot no faults.
17	02:34:39:240PM	Plasma	Ok	Plasma shot no faults.
18	02:45:47:240PM	Plasma	Ok	Plasma shot no faults
19	03:07:38:630PM	Plasma	Ok	Good shot
20	03:22:04:140PM	Plasma	Ok	Plasma Shot no faults.
21	03:54:32:410PM	Plasma	Ok	PLasma shot no faults.
22	04:10:17:020PM	Plasma	Ok	Plasma shot No Faults.
23	04:22:31:190PM	Plasma	Ok	Plasma shot No Faults
24	04:45:06:840PM	Plasma	Ok	PLASMA SHOT NO FAULTS.
25	04:57:13:480PM	Plasma	Ok	PLASMA SHOT NO FAULTS.