Alcator C-Mod Run 1040317 Information

Back to runs

Miniproposals
Miniproposal:386
Date Filed: 2/5/2004
Title:Locked Mode Threshold in Upper Null Configurations
First Author:Ian Hutchinson
Session Leader:Ian Hutchinson (shots 1-33)

Operators
Session leader(s):Ian Hutchinson
Physics operator(s):Bill Rowan
Engineering operator(s):Ed Fitzgerald

Engineering Operator Run Comment
MP 386: Locked Modes in Upper Null SL: Hutchinson PO: Rowen EO: Fitzgera

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:03:523PM
Author: Ian Hutchinson
MP 386 Upper and Lower null locked modes.

SL hutch

This run was quite successful. We got most of what was proposed done.
It seemed to be important to do upper/lower null comparisons in the
same run, which required more shots, but we used fewer bisections
in finding thresholds to compensate. Probably uncertainties were
dominated by irreproducibility more than convergence.
We lost 4 shots and a lot of time in the middle of the run because
of computer problems, but managed to recover.


Summary of shots for 1040317. Upper null locked mode.

HX1 is velocity at locking time. 9999 means no lock. -999 means no
data at lock.

A-coil current IA is for A configuration. Thus negative is destabilizing.

Shot Upper nl04 Bt Ip Hirex Hx1 IA

1 1 7 5.5 .8 -25 9999 -0
2 1 8.6 5.4 .97 -12 0 -0
4 1 8.8 5.4 .97 -15 0 -3500
5 1 8.5 5.4 .97 -16 0 -1230
6 1 7.7 5.4 .97 -14 0 -650
7 0 9.3 5.4 .97 0 9999 -0 (H-modes)
8 0 9 5.4 .97 9999 9999 -560 (No-hirex)
9 0 8.7 5.4 .97 +10 -999 -2650 (HVtrip)
10 0 8.7 5.4 .97 -7 -7 -1700
11 0 8.7 5.4 .97 -10 -10 -1100 (Dubious lock)
12 1 5.5 5.4 .97 -2 -999 0 (HVtrip)
17 1 5.0 5.4 .97 +20 9999 1700 (V-swing)
18 1 5.0 5.4 .97 +20 9999 1700 (V-swing)
19 1 5.0 5.4 .97 +21 9999 900 (V-swing)
20 1 5.0 5.4 .97 +15 9999 230 (V-swing)
22 1 5.0 5.4 .97 +6 0 0 (Injection)
23 0 5.9 5.4 .97 -13 0 0
24 0 5.0 5.4 .97 -10 9999 1100
25 0 4.6 5.4 .97 -5 -5 400
26 1 2.55 4.1 .6 -10 9999 400
27 1 2.4 4.1 .6 +15 +5 0 (V-swing)
28 0 3.0 4.1 .6 -20 9999 0
29 0 2.9 4.1 .6 -15 -3 -450
31 0 4.5 4.1 .6 -20 -7 -450
32 0 6.6 4.1 .6 0 9999 -450 (Noisy HR)
33 1 6.6 4.1 .6 -25 9999 -450

Obvious things discovered:

1. At 1 MA the effect of upper null on the velocity is opposite at low
density to what it is at high density. That is, at nl04=9, the
velocity is more negative in upper null, whereas at nl04=5 it is
more positive in upper null. The statistics on this are undeniable.

2. There is a suggestion that this effect is present also at 600kA.

3. By the time we lock, we generally have a velocity quite close to
zero.

4. There is locking that brings the velocity towards zero from both
positive and negative directions.

Further detailed analysis will be needed to see if there is a definite
result that can be attributed to velocity differences.

Physics Operator Summaries

Session Leader Comments
Mar 17 2004 09:10:37:770AMIan HutchinsonMP 386 Locked Mode Threshold in Upper Null Configurations.

SL Hutch
PO Rowan
Mar 17 2004 09:23:38:583AM1040317001Ian HutchinsonUpper null. 800kA. Changes to the recalled shot do not
seem to be present. nl04=7e19, hirex -25km/s
Mar 17 2004 09:45:38:960AM1040317002Ian HutchinsonGot 1MA, 8.6nl04, Perhaps locks at 1.52 sec in rampdown.
Hirex -12km/s.
Mar 17 2004 09:45:49:740AM1040317003Ian HutchinsonPS Dud
Mar 17 2004 04:18:44:890PM1040317004Ian HutchinsonA-coil configuration -A: adverse, causing locking.
A-coil current 3500A. Locked mode at .7-.75s.
Mar 17 2004 10:34:26:600AM1040317005Ian HutchinsonLocked mode at 1s. A-coil 1230A.
Nice slowing down from -20km/s
to lock when the velocity is zero.
Mar 17 2004 10:43:08:270AM1040317006Ian HutchinsonDisrupts at 1.6s.
Locked at 1.12s. A-coil 650A.
Rotation slows to zero again.
Mar 17 2004 10:59:06:257AM1040317007Ian HutchinsonSwitch to Lower Null. Got zero velocity early.
A-coil current 0.
Got H-modes, perhaps locks late, but hard to tell
because of the H-modes.
Mar 17 2004 11:15:15:567AM1040317008Ian HutchinsonNo hirex data. Got 560A A-coil.
H-mode only late 1.4s.
No locked mode. Slot divertor configuration.
Ask for 3000A A-coil. Ask for rxl +4mm.
Mar 17 2004 11:29:46:960AM1040317009Ian HutchinsonLocked mode at 1s. A-coil 2650A.
Hirex at +10, but trips at about .75s.
Big ne loss at locking.
Mar 17 2004 11:42:26:897AM1040317010Ian HutchinsonLocked mode at 1.1s. A-coil 1700A.

Mar 17 2004 11:53:04:257AM1040317011Ian HutchinsonA-coil 1100A.
Change in sawteeth at 1s, but locking somewhat uncertain.
Has an injection there, also it's coming out of slot divertor
around then.
Mar 17 2004 01:09:09:223PM1040317012Ian HutchinsonBack to Upper null.
A-coil off.
Lower density to 6e19.
Locked mode at 1.3s.
Hirex data only to .8s.
Mar 17 2004 01:21:47:100PM1040317017Ian HutchinsonA-coil polarity swapped:(correcting) 1700A.
Upper null. nl04=5 no locked mode
Hirex +10 to +30 km/s
Mar 17 2004 01:36:46:430PM1040317018Ian HutchinsonRepeat. Clear step in velocity from +10 to +30km/s
at 1s. It is not clear what might be causing it.
Mar 17 2004 01:52:05:913PM1040317019Ian HutchinsonA-coil 920A (compensating). No locked mode.
Hirex velocity step is very reproducible.
Not caused by mode locking.
Mar 17 2004 02:09:47:130PM1040317020Ian HutchinsonA-coil 230A. Hirex slightly lower. No locked mode.
Mar 17 2004 02:09:57:850PM1040317021Ian HutchinsonNo power shot.
Mar 17 2004 02:33:30:023PM1040317022Ian HutchinsonA-coil 0A. Big injection at .94s.
Plasma is cold after that. It seems locked.
Mar 17 2004 02:49:27:363PM1040317023Ian HutchinsonLower Null. A-coil 0A. Locks at 1.17s.
Hirex -12km/s.
Mar 17 2004 03:00:50:973PM1040317024Ian HutchinsonA-coil 1100A. No locked mode.
Hirex -10km/s flat.
Mar 17 2004 03:15:12:277PM1040317025Ian HutchinsonA-coil 400A. Locked mode at 1.26s
Hirex -5km/s
Mar 17 2004 03:37:09:187PM1040317026Ian HutchinsonChange to Bt=4T, Ip=.6MA, nl04=4, A-coil=400 (compensating)
Upper null. Runs ok. ECE is difficult because of lower Bt.
Using GPC2 channel 14. No evidence of locking.
Hirex -10 to 0 km/s.
Mar 17 2004 03:51:27:597PM1040317027Ian HutchinsonA-coil 0A. Locks at 1.325s.
Hirex swings from -10 to +15 then back to 0 on locking.
Mar 17 2004 04:16:42:683PM1040317028Ian HutchinsonLower null 4T, .6MA, 3e19nl04
A-coil =0A. No Lock.
Mar 17 2004 04:31:00:643PM1040317029Ian HutchinsonA-coil to -A configuration, causing locking. (Lower null)
Locks at 1.3s. nl04=2.9. Hirex -15km/s till lock.
Mar 17 2004 04:45:23:290PM1040317030Ian HutchinsonRaise nl04 to 5-6.
Fizzle because of an excess fill pressure.
Mar 17 2004 04:54:38:180PM1040317031Ian HutchinsonLocks at 1.27s. nl04=4.5 (lower null)
Mar 17 2004 05:12:19:800PM1040317032Ian Hutchinsonnl04=6.6, no locked mode (A-coil 400A)
Mar 17 2004 05:17:34:433PM1040317033Ian HutchinsonUpper null. No locked mode. nl04=6.6
(A-coil 450A.)
Hirex -25 noisy.

Physics Operator Comments
Mar 17 2004 07:24:30:210AMBill RowanEngineering setup for Wednesday, March 17, 2004

MP 386: Locked Modes in Upper Null

Session leader: Hutchinson
Physics operator: W. Rowan

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

Run begins at 09:00 and ends at 17:00.

Power systems the same as 1031125020.
Note: This is a guess for a starting point. Archived data not available.

A-coils should be enabled. There will be changes from the standard
configuration.

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

Disable NINJA

Enable the following gate valves, assuming no vacuum problems:
ECE, VUV, DNB

Necessary diagnostics:
Standard core profile diagnostics, specifically including Hirex (for Ti
profiles and rotation), core TS, VB, GPC 1 and 2, FRC ECE, neutrons
Desirable diagnostics:
DNB and all beam diagnostics

-------------------------------------------------------------------------------
RF Setup: No RF needed for this run.

-------------------------------------------------------------------------------
Run Plan. See MP386.

Before the run began. The A-coils were configured in this way
BTOP 0.00
BBOT 0.00
DTOP -1.00
DBOT +1.00
GTOP 0.00
GBOT 0.00
JTOP +1.00
JBOT -1.00

Alternator will be 15 to 30 minutes late

ECDC off at approximately 7am



Mar 17 2004 07:48:30:240AMBill RowanLoaded shot 1031125020
A-coil current demand is 2500A
nl_04 increased from 8e19 to 9e19
Mar 17 2004 07:54:55:460AMBill RowanIP = 1 MA
Mar 17 2004 08:11:55:507AMBill RowanStartup: loaded segment 1 from 1040316020. Next to last shot from yesterday.

Segment 3 on for the first shot. This is 1.0MA Upper Null
Mar 17 2004 08:22:51:350AMBill Rowan
Asked Steve to double check the a-coil hook up -- reports okay.
Mar 17 2004 08:47:28:740AMBill Rowan
Changed A-coil current demand to 4000kA
Mar 17 2004 08:50:45:473AMBill Rowan
Disabled the A-coils for the first shot.
Mar 17 2004 09:14:05:257AM1040317001Bill Rowan001.
IP is 0.8 MA approx
nl_04 = 7e+19
Changes before the start of the run were made in segment 02

For next shot.
IP = 1.0MA
nl_04 = 9e+19
Mar 17 2004 09:20:59:083AM1040317001Bill RowanBt changed from 5.5T to 5.4 T
150000 to 147000
Mar 17 2004 09:31:59:960AM1040317002Bill Rowan002.
BT = 5.4 T
IP = 0.96 MA
nl_04 = 8.5 e+19
Mar 17 2004 09:34:14:193AM1040317002Bill Rowan
For next shot.
A-coils enabled
Mar 17 2004 09:48:53:710AM1040317003Bill Rowan003. Nothing on this shot. Dud
I_square_t fault

After the shot:
Cell entry for TCI
Cell entry for LHCD
Mar 17 2004 10:04:02:537AM1040317003Bill Rowan
Engineering fault not understood. Will simply go again.

Next shot. No PCS changes.

Mar 17 2004 10:13:51:100AM1040317004Bill Rowan004.
Plasma.

Next shot.
A-coil demand reduced to 1700 A
Mar 17 2004 10:29:38:240AM1040317005Bill Rowan005.
Plasma
A coil current was 1250 A for 1700 demand

Next shot.
Reduce A-coil current to approximately half of current value
A coil current demand is 1100 A

Mar 17 2004 10:45:05:333AM1040317006Bill Rowan
006.
A coil current was 550 A for a demand of 1250 A

Next shot.
A-coils disabled for the next shot.
Switch to segment 02 which is a lower null.


Mar 17 2004 10:53:27:663AM1040317007Bill Rowan007. Plasma.
A-coils disabled.
H-modes appear after approximately 0.6 s
BT = 5.4 T
IP = 0.95 MA approx
nl_04 = 9e19 prior to H-mode
Mar 17 2004 11:09:21:803AM1040317007Bill RowanNext shot.
Enable A-coils.
A-coil demand of 1100 A
Mar 17 2004 11:06:19:317AM1040317008Bill Rowan008.
Plasma
A-Coil current = 550 A

Next shot.
A-coil demand 0f 3000 A
Mar 17 2004 11:08:22:677AM1040317008Bill RowanAdd approx 4 mm to rxl
Mar 17 2004 11:19:00:240AM1040317009Bill Rowan009.
Plasma
A-coil current = 2649

Next shot
A-coil current demand of 2100
Mar 17 2004 11:33:32:660AM1040317010Bill Rowan010.
Plasma
A-coil current = 1677

Next shot.
Add another 2 mm to rxl
A-coil demand is reduced to 1600
Mar 17 2004 11:49:43:600AM1040317011Bill Rowan011.
Plasma
A-coil current = 1155

Next shot.
Switch to segment 03. This is upper null.
Reduce the nl_04 to 0.6e+20
Disable the a-coils
Mar 17 2004 12:09:15:067PM1040317012Bill Rowan012.
Plasma
nl_04 reduced.
A-coils disabled
Upper null as requested

After this shot
Cell access to reverse the polarity of the A-coils
Cell access to look for camac problems. We are having intermittent data loss.

Next shot.
Reverse polarity of the A-coils
Enable the A-coils.
A-coil current demand to 2100 A and
expect this to produce a coil current of 1700 A
Mar 17 2004 12:37:28:537PM1040317013Bill Rowan013.
No power shot.
Computer hang in init
Mar 17 2004 12:37:45:977PM1040317014Bill Rowan014.
No power shot.
Computer problems.
Mar 17 2004 12:50:51:757PM1040317015Bill Rowan
015.
No power shot.
Computer problems.
uter problems.
Mar 17 2004 12:55:48:537PM1040317016Bill Rowan016. Dud. Power supply problem.
Supply remained disabled
Mar 17 2004 01:12:18:863PM1040317017Bill Rowan017.
Plasma.
A-coil current = 1700 A

Next shot
A-coil current demand reduced to 1400 A
Mar 17 2004 01:33:25:147PM1040317018Bill Rowan018,
Plasma


Next shot.
A-coil current demand = 1400 A
Mar 17 2004 01:42:15:600PM1040317019Bill Rowan019.
Plasma
A-coil current = 900 A

Next shot.
A-coil current demand = 800 A
Mar 17 2004 01:53:35:167PM1040317020Bill Rowan020.
Plasma
A-coil current = 245 A

Next shot.
Disable the a-coils.
Mar 17 2004 02:07:36:313PM1040317021Bill Rowan021.
No power shot.

Mar 17 2004 02:24:14:323PM1040317022Bill Rowan022.
Plasma
A-coils off

Next shot:
Change configuration: SNL, segment 2
Reduced nl_04 to 6E+19
Mar 17 2004 02:38:30:203PM1040317023Bill Rowan023.
Plasma
Lower null

Next shot.
Enable the A-coils
Increase the a coil current to 1000 A.
Set demand to 1600 A

Mar 17 2004 02:53:48:103PM1040317024Bill Rowan024.
Plasma
A-coil current is 1150 A

Next shot.
A-coil current = 500 A
Set demand to 950 A
Mar 17 2004 03:17:14:310PM1040317025Bill Rowan025. Plasma
A-coil current is 430 A

Next shot
Upper null
nl_04 = 4e+19
IP = 600 kA
BT = 4T
A-coils sto approximately 400 A
Demand set to 1000 A

Mar 17 2004 03:35:01:697PM1040317026Bill Rowan
026,
Plasma
IP = 0.58 MA
BT = 4.0T
nl_04 = 0.37e+20 at 0.8 s
A-coil = 490 A

Next shot.
Disable the a-coils
Mar 17 2004 03:44:18:557PM1040317027Bill Rowan027.
Plasma
A-coil is off.

Next shot.
lower null.
leave the A-coil off
nl_04 = 4e+19
IP = 600 kA
BT = 4T
Mar 17 2004 03:58:03:390PM1040317028Bill Rowan028.
Plasma
IP = 0.59 MA
BT = 4.0T
nl_04 = 4.2e+19 at 0.99s
A-coil = 0.0
Mar 17 2004 03:58:19:047PM1040317028Bill Rowan

Next shot.
Reverse the polarity of the A-coils
Mar 17 2004 04:05:32:853PM1040317028Bill Rowan
A-coil demand set for 1000 A
A-coil current intended to be 500 A
Mar 17 2004 04:08:09:623PM1040317028Bill RowanEnable the A-coils
Mar 17 2004 04:22:56:410PM1040317029Bill Rowan029.
Plasma
A-coil = 468 A

Next shot.
nl_04 = 5e+19.
Inserted a ramp to 6e+19 to compensate for the droop observed
on previous shot.
Mar 17 2004 04:38:50:483PM1040317030Bill Rowan030.
Fizzle
Prefill increased suddenly for this shot.

Next shot.
Disabled the DNB GV
This is an unlikely source for the problem as the beam is
at low pressure and the gas is not being puffed.
Mar 17 2004 04:52:37:833PM1040317031Bill Rowan031.
Plasma.

Next shot:
Removed negative bias from pg3 after 1s
nl_04 demand at 0.5 s increased to 6e+19
Ramped to 7e+19 at 1.5s
Mar 17 2004 05:02:41:253PM1040317032Bill Rowan032.
nl_04 = 6.4e+19 at 1s

Next shot:
Configuration changed to upper null (segment 3)
For segment 03
Removed negative bias from pg3 after 1s
nl_04 demand at 0.5 s increased to 6e+19
Ramped to 7e+19 at 1.5s
Mar 17 2004 05:22:08:130PM1040317033Bill Rowan033.
Plasma

Last shot.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:06:52:880AMPlasmaOk
209:21:48:177AMPlasmaOk
309:42:43:477AMPlasmaBadAll Power supply breakers opened
410:06:16:693AMPlasmaOk
510:20:05:990AMPlasmaOk
610:32:41:113AMPlasmaOk
710:45:11:977AMPlasmaOk
810:58:14:990AMPlasmaOk
911:12:06:803AMPlasmaOk
1011:26:02:727AMPlasmaOk
1111:38:32:460AMPlasmaOk
1211:51:02:147AMPlasmaOk
1312:22:55:473PMPlasmaBadNO Power Shot due to Actmon
1412:34:28:990PMPlasmaBadNo Power Shot Act
1512:42:58:070PMTestOk
1612:51:46:630PMPlasmaOk
1701:04:41:007PMPlasmaOk
1801:19:41:507PMPlasmaOk
1901:33:36:147PMPlasmaOk
2001:49:28:897PMPlasmaOk
2102:04:02:853PMPlasmaBadTCI lost before pulse, shot aborted
2202:18:40:503PMPlasmaOk
2302:31:37:757PMPlasmaOk
2402:47:10:217PMPlasmaOk
2503:02:38:490PMPlasmaOk
2603:20:13:987PMPlasmaOk
2703:37:27:390PMPlasmaOk
2803:50:43:783PMPlasmaOk
2904:16:49:620PMPlasmaOk
3004:30:08:533PMPlasmaOk
3104:43:31:770PMPlasmaOk
3204:56:11:260PMPlasmaOk
3305:10:33:080PMPlasmaOk