Alcator C-Mod Run 1050208 Information

Miniproposals

Miniproposal: 298a

Date Filed: 5/20/2002

Title: C-Mod Plasma Startup

First Author: Jim Irby

Session Leader: Jim Irby (shots 1-24)

Operators
Session leader(s):	Jim Irby
Physics operator(s):	Ian Hutchinson,Bill Rowan,Ian Hutchinson
Engineering operator(s):	Gary Dekow,Bill Byford

Engineering Operator Run Comment
MP 298a C-mod Plasma Startup

Session Leader Plans

Entered: Feb 8 2005 09:58:35:650AM

Author: Jim Irby

We will continue plasma conditioning today.

Start from 1050207022 (the 1.3s, 550 kA shot from 2/7)

We expect to be testing the density feedback system today.

Object is to get full length low density shots.

If any changes/mods have been done to the data system since the end of the run
we should do a cycle test

We should do a very complete cell check since lots of work has been going
on in the cell.

Physics Operators Plans

Entered: Feb 8 2005 11:28:55:790AM

Author: Ian Hutchinson

Settings all as yesterday.
Start with the last shot from yesterday. No changes.
Get some plasmas.

Session Leader Summaries

Entered: Feb 8 2005 07:23:26:010PM

Author: Jim Irby

Very good day from the standpoint of plasma production. Many full length shots. H/(H+D) was
much better than yesterday, but still 40 to 50 %. We had only a couple of Torr-liters of gas
puffed in before 100 ms, but never got to wall conditions that allowed the density to fall during the
shot. Ian attempted an upper divertor discharge on shot 22. It disrupted early and brought the
vessel pressure up to 20 mTorr (about 80 Torr-liters of gas, mostly mass 2,3,4 on RGA).

We were closing the pumping stack gatevalves in pulse and keeping them closed for 5 minutes after
the shot. A couple of settings of the bypass were tried today to keep the RGA in a linear range.
Shot 22 was definitely not linear.

Physics Operator Summaries

Entered: Feb 8 2005 07:40:32:337PM

Author: Ian Hutchinson

An excellent run with over 30s of plasma.

Brought the current up to 0.8kA without incident.

Got bored and tried to run an upper null shot.
However, the clearin settings were not properly constrained for
the offsets etc, and this led to excessive elongation and a VDE
disruption on shot 22. Thereafter a partial flux loop was found to
be broken. Probably that was part of the reason for the two closing
fizzles.

Scorecard:

Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 1.640 0.603 2 0.000 0.034 3 0.000 0.033 4 0.691 0.632 5 0.000 0.032 6 1.957 0.628 7 1.960 0.631 8 1.793 0.626 9 1.974 0.641 10 1.819 0.654 11 1.985 0.656 12 1.974 0.643 13 0.000 0.053 14 1.983 0.720 15 1.975 0.815 16 1.975 0.815 17 1.979 0.816 18 1.981 0.816 19 1.964 0.823 20 1.982 0.820 21 1.981 0.820 22 0.268 0.702 23 0.000 0.034 24 0.000 0.036 Finished summary for 1050208 Total of 24 shots. 24 shots. 19 plasmas. 4 fizzles. 1 ps dud.

Snapshots:

Session Leader Comments

Feb 8 2005 10:19:34:773AM Jim Irby In-rack cabling for neuts/hards has been replaced/repaired/checked. Frayed rg174 with loose shield
connection at BNC was found. Still mounted on diagnostic stand until mount to hirex jr is complete
(tomorrow morning). See clear x-ray pulses on scope, so the unit is operational. Have not done
a check into CAMAC, so there may still be problems.

Feb 8 2005 12:40:10:257PM 1050208001 Jim Irby plasma for 1.6 s

neuts/hards now producing more reasonable signal, but with offset

h/(h+d) 24% at 1.2 s

Feb 8 2005 02:46:46:150PM 1050208004 Jim Irby plasma for 0.68 s

h/(h+d) at 30%

Feb 8 2005 02:55:33:430PM 1050208009 Jim Irby h/(h+d) at 40 to 45%

Feb 8 2005 02:57:36:620PM 1050208010 Jim Irby full length plasma with good rampdown

Feb 8 2005 04:29:48:087PM 1050208014 Jim Irby h/(h+d) at 42%
plasma current at 700 kA

Feb 8 2005 06:04:08:447PM 1050208019 Jim Irby h/(h+d) around 48% --- very little change over the last few shots

ratios for 200 and 180 clicks:

mass2: 4.86/1.32 (e-6) = 3.68
mass3: 4.66/1.23 (e-6) = 3.78
mass4: 17.3/4.11 (e-7) = 4.21

Feb 8 2005 06:15:25:853PM 1050208021 Jim Irby the gatevalve toggle has been disabled

serious problem with drift on TCI

Feb 8 2005 06:35:41:930PM 1050208022 Jim Irby disruption brought vessel pressure to about 20 mTorr

Feb 8 2005 06:49:47:680PM 1050208023 Jim Irby bypass from 180 to 160 clicks

fizzle

TCI gatevalves were left closed from the last high pressure shot

Feb 8 2005 07:03:23:680PM 1050208024 Jim Irby fizzle

Physics Operator Comments

Feb 8 2005 12:40:06:490PM 1050208001 Ian Hutchinson Plasma to 1.7s.

Decrease the gas puff in segment 1.
Rcur offset in segment 1 to 1000 from 200A.
Take out the ramp of clearin from .01 at 1s to .003 at 1.5s..
Make it .01 throughout. We are getting .017 left gap for .01 drawn
which is about right. Load.

Feb 8 2005 12:41:51:040PM 1050208002 Ian Hutchinson Dud. TMX breaker was not in.

Feb 8 2005 01:06:53:507PM 1050208003 Bill Rowan Shot length 30 ms. Spike in CII and h-alpha at 10ms.

No changes for the next shot.

Feb 8 2005 01:21:30:930PM 1050208004 Bill Rowan Shot lasted for aproximately 0.7s.
Perhaps an injection. Soft x-ray increase leads loop volts and current changes prior to disruption

No changes for the next shot.

Feb 8 2005 01:42:30:447PM 1050208005 Bill Rowan Fizzle.

For the next shot, reduced BR_0 by 0.5 mT

Feb 8 2005 01:58:57:770PM 1050208006 Bill Rowan Discharge ran full length.

No changes for the next shot.

Feb 8 2005 02:12:01:180PM 1050208007 Bill Rowan Full length discharge.

No changes for the next shot.

Feb 8 2005 02:34:14:900PM 1050208008 Ian Hutchinson Plasma. Some injections during the flat top.
We are getting 550kA when the demand is 600kA.

Change seg 2 Ip offset to -50k from -30k.

Feb 8 2005 02:44:53:773PM 1050208009 Ian Hutchinson Plasma.

Make the drawn Vs for OHs flat in the flat top instead of sloping down.
Move Ip offset to -70k. Ought to be currently correct level. We think this
offset must be coming from the isoamps. Load

Feb 8 2005 03:05:48:337PM 1050208010 Ian Hutchinson Plasma

Increase the drawn Vs to slope slightly upward.

Feb 8 2005 03:39:16:463PM 1050208011 Ian Hutchinson Plasma

Feb 8 2005 04:02:15:947PM 1050208012 Ian Hutchinson Plasma

Raise current to 0.7MA.

Feb 8 2005 04:17:11:260PM 1050208013 Ian Hutchinson Fizzle.

Fill puff to 22ms from 19ms. Br to -.001 from -.0005T.

Feb 8 2005 04:49:16:807PM 1050208014 Ian Hutchinson Plasma. Neither gap had a substantial change.

Ip to .8MA. Increase V-demand on OH1.

Feb 8 2005 04:51:15:243PM 1050208015 Ian Hutchinson Plasma. Still some droop on the right gap.

Remove the Zxu ramp from end of flat top.

Feb 8 2005 05:03:59:900PM 1050208016 Ian Hutchinson Plasma

Remove ramp from RXU after 1s.

Feb 8 2005 05:20:02:540PM 1050208017 Ian Hutchinson Plasma.

Raise late OH2 Voltage.

Feb 8 2005 05:35:50:120PM 1050208018 Ian Hutchinson Plasma

Zxl to 0 from +1.5cm.
Remove unpleasant step from EF4 program at 1.5s.

Feb 8 2005 05:53:45:447PM 1050208019 Ian Hutchinson Plasma. The EF2s were in worse shape. I guess the unpleasant step
was there for a reason.

Put back the unpleasant step starting 1480.
Set Rxl to 0. Remove some spurious points from seg 2 all ps.

Feb 8 2005 06:05:11:837PM 1050208020 Ian Hutchinson Plasma. Shot well controlled. Strike point moved down.

Repeat with the pump gate valve open.

Feb 8 2005 06:30:38:430PM 1050208021 Ian Hutchinson Plasma. Interferometer does not seem to agree with TS.
It has dropped fringes, it seems.

Program in an upper null shot p-traces.
Call the clearin controller with zxa=+.3937
Move EF4 step to 1.46s. Close pumping gate valve.

Feb 8 2005 07:02:10:870PM 1050208022 Ian Hutchinson Plasma disrupts at .26s because of VDE induced by excessive elongation.
Forgot to flip zcur. Also it is trying too hard on clearin.
Big outgassing event.

Flip zcur
Slow clearin ramp and set to 0 (was +1)

Feb 8 2005 07:03:23:853PM 1050208023 Ian Hutchinson Fizzle. Br has jumped up a bit but then stays relatively low.
F27 partial flux loop appears to be broken.

Repeat (no changes).

Feb 8 2005 07:05:44:023PM 1050208024 Ian Hutchinson Fizzle. Rather repeatable.

Engineering Operator Comments

Shot Time Type Status Comment

1 12:06:46:477PM Plasma Ok

2 12:38:14:977PM Plasma Bad TMX Contactors not closed

3 12:51:05:350PM Plasma Ok

4 01:08:33:350PM Plasma Ok Disruption caused the OH1 crowbar self-power circuit to fired

5 01:35:49:490PM Plasma Ok

6 01:51:50:360PM Plasma Ok

7 02:04:48:107PM Plasma Ok

8 02:17:51:010PM Plasma Ok

9 02:32:08:807PM Plasma Ok

10 02:45:46:557PM Plasma Ok

11 03:01:41:040PM Plasma Ok

12 03:38:13:587PM Plasma Ok

13 03:58:01:837PM Plasma Ok

14 04:11:33:040PM Plasma Ok

15 04:37:34:243PM Plasma Ok

16 04:51:50:523PM Plasma Ok

17 05:06:16:040PM Plasma Ok

18 05:21:06:853PM Plasma Ok

19 05:34:12:133PM Plasma Ok

20 05:48:00:460PM Plasma Ok

21 06:04:50:040PM Plasma Ok

22 06:21:42:430PM Plasma Ok

23 06:44:13:510PM Plasma Ok

24 07:01:37:400PM Plasma Ok

Session Leader Comments
Feb 8 2005 10:19:34:773AM		Jim Irby	In-rack cabling for neuts/hards has been replaced/repaired/checked. Frayed rg174 with loose shield connection at BNC was found. Still mounted on diagnostic stand until mount to hirex jr is complete (tomorrow morning). See clear x-ray pulses on scope, so the unit is operational. Have not done a check into CAMAC, so there may still be problems.
Feb 8 2005 12:40:10:257PM	1050208001	Jim Irby	plasma for 1.6 s neuts/hards now producing more reasonable signal, but with offset h/(h+d) 24% at 1.2 s
Feb 8 2005 02:46:46:150PM	1050208004	Jim Irby	plasma for 0.68 s h/(h+d) at 30%
Feb 8 2005 02:55:33:430PM	1050208009	Jim Irby	h/(h+d) at 40 to 45%
Feb 8 2005 02:57:36:620PM	1050208010	Jim Irby	full length plasma with good rampdown
Feb 8 2005 04:29:48:087PM	1050208014	Jim Irby	h/(h+d) at 42% plasma current at 700 kA
Feb 8 2005 06:04:08:447PM	1050208019	Jim Irby	h/(h+d) around 48% --- very little change over the last few shots ratios for 200 and 180 clicks: mass2: 4.86/1.32 (e-6) = 3.68 mass3: 4.66/1.23 (e-6) = 3.78 mass4: 17.3/4.11 (e-7) = 4.21
Feb 8 2005 06:15:25:853PM	1050208021	Jim Irby	the gatevalve toggle has been disabled serious problem with drift on TCI
Feb 8 2005 06:35:41:930PM	1050208022	Jim Irby	disruption brought vessel pressure to about 20 mTorr
Feb 8 2005 06:49:47:680PM	1050208023	Jim Irby	bypass from 180 to 160 clicks fizzle TCI gatevalves were left closed from the last high pressure shot
Feb 8 2005 07:03:23:680PM	1050208024	Jim Irby	fizzle

Physics Operator Comments
Feb 8 2005 12:40:06:490PM	1050208001	Ian Hutchinson	Plasma to 1.7s. Decrease the gas puff in segment 1. Rcur offset in segment 1 to 1000 from 200A. Take out the ramp of clearin from .01 at 1s to .003 at 1.5s.. Make it .01 throughout. We are getting .017 left gap for .01 drawn which is about right. Load.
Feb 8 2005 12:41:51:040PM	1050208002	Ian Hutchinson	Dud. TMX breaker was not in.
Feb 8 2005 01:06:53:507PM	1050208003	Bill Rowan	Shot length 30 ms. Spike in CII and h-alpha at 10ms. No changes for the next shot.
Feb 8 2005 01:21:30:930PM	1050208004	Bill Rowan	Shot lasted for aproximately 0.7s. Perhaps an injection. Soft x-ray increase leads loop volts and current changes prior to disruption No changes for the next shot.
Feb 8 2005 01:42:30:447PM	1050208005	Bill Rowan	Fizzle. For the next shot, reduced BR_0 by 0.5 mT
Feb 8 2005 01:58:57:770PM	1050208006	Bill Rowan	Discharge ran full length. No changes for the next shot.
Feb 8 2005 02:12:01:180PM	1050208007	Bill Rowan	Full length discharge. No changes for the next shot.
Feb 8 2005 02:34:14:900PM	1050208008	Ian Hutchinson	Plasma. Some injections during the flat top. We are getting 550kA when the demand is 600kA. Change seg 2 Ip offset to -50k from -30k.
Feb 8 2005 02:44:53:773PM	1050208009	Ian Hutchinson	Plasma. Make the drawn Vs for OHs flat in the flat top instead of sloping down. Move Ip offset to -70k. Ought to be currently correct level. We think this offset must be coming from the isoamps. Load
Feb 8 2005 03:05:48:337PM	1050208010	Ian Hutchinson	Plasma Increase the drawn Vs to slope slightly upward.
Feb 8 2005 03:39:16:463PM	1050208011	Ian Hutchinson	Plasma
Feb 8 2005 04:02:15:947PM	1050208012	Ian Hutchinson	Plasma Raise current to 0.7MA.
Feb 8 2005 04:17:11:260PM	1050208013	Ian Hutchinson	Fizzle. Fill puff to 22ms from 19ms. Br to -.001 from -.0005T.
Feb 8 2005 04:49:16:807PM	1050208014	Ian Hutchinson	Plasma. Neither gap had a substantial change. Ip to .8MA. Increase V-demand on OH1.
Feb 8 2005 04:51:15:243PM	1050208015	Ian Hutchinson	Plasma. Still some droop on the right gap. Remove the Zxu ramp from end of flat top.
Feb 8 2005 05:03:59:900PM	1050208016	Ian Hutchinson	Plasma Remove ramp from RXU after 1s.
Feb 8 2005 05:20:02:540PM	1050208017	Ian Hutchinson	Plasma. Raise late OH2 Voltage.
Feb 8 2005 05:35:50:120PM	1050208018	Ian Hutchinson	Plasma Zxl to 0 from +1.5cm. Remove unpleasant step from EF4 program at 1.5s.
Feb 8 2005 05:53:45:447PM	1050208019	Ian Hutchinson	Plasma. The EF2s were in worse shape. I guess the unpleasant step was there for a reason. Put back the unpleasant step starting 1480. Set Rxl to 0. Remove some spurious points from seg 2 all ps.
Feb 8 2005 06:05:11:837PM	1050208020	Ian Hutchinson	Plasma. Shot well controlled. Strike point moved down. Repeat with the pump gate valve open.
Feb 8 2005 06:30:38:430PM	1050208021	Ian Hutchinson	Plasma. Interferometer does not seem to agree with TS. It has dropped fringes, it seems. Program in an upper null shot p-traces. Call the clearin controller with zxa=+.3937 Move EF4 step to 1.46s. Close pumping gate valve.
Feb 8 2005 07:02:10:870PM	1050208022	Ian Hutchinson	Plasma disrupts at .26s because of VDE induced by excessive elongation. Forgot to flip zcur. Also it is trying too hard on clearin. Big outgassing event. Flip zcur Slow clearin ramp and set to 0 (was +1)
Feb 8 2005 07:03:23:853PM	1050208023	Ian Hutchinson	Fizzle. Br has jumped up a bit but then stays relatively low. F27 partial flux loop appears to be broken. Repeat (no changes).
Feb 8 2005 07:05:44:023PM	1050208024	Ian Hutchinson	Fizzle. Rather repeatable.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	12:06:46:477PM	Plasma	Ok
2	12:38:14:977PM	Plasma	Bad	TMX Contactors not closed
3	12:51:05:350PM	Plasma	Ok
4	01:08:33:350PM	Plasma	Ok	Disruption caused the OH1 crowbar self-power circuit to fired
5	01:35:49:490PM	Plasma	Ok
6	01:51:50:360PM	Plasma	Ok
7	02:04:48:107PM	Plasma	Ok
8	02:17:51:010PM	Plasma	Ok
9	02:32:08:807PM	Plasma	Ok
10	02:45:46:557PM	Plasma	Ok
11	03:01:41:040PM	Plasma	Ok
12	03:38:13:587PM	Plasma	Ok
13	03:58:01:837PM	Plasma	Ok
14	04:11:33:040PM	Plasma	Ok
15	04:37:34:243PM	Plasma	Ok
16	04:51:50:523PM	Plasma	Ok
17	05:06:16:040PM	Plasma	Ok
18	05:21:06:853PM	Plasma	Ok
19	05:34:12:133PM	Plasma	Ok
20	05:48:00:460PM	Plasma	Ok
21	06:04:50:040PM	Plasma	Ok
22	06:21:42:430PM	Plasma	Ok
23	06:44:13:510PM	Plasma	Ok
24	07:01:37:400PM	Plasma	Ok