Alcator C-Mod Run 1051102 Information

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Miniproposals
Miniproposal:298a
Date Filed: 5/20/2002
Title:C-Mod Plasma Startup
First Author:Jim Irby
Session Leader:Steve Wolfe (shots 1-31)

Operators
Session leader(s):Steve Wolfe
Physics operator(s):Jim Irby,Steve Wolfe,Jim Irby
Engineering operator(s):Andy Pfeiffer,Sam Pierson,Ed Fitzgerald

Engineering Operator Run Comment
MP298A Plasma startup Session leader: Wolfe Physics operator: Irby

Session Leader Plans
Entered: Nov 2 2005 08:37:41:767AM
Author: Steve Wolfe
Continue bringing the machine back to "routine" operation.
Start from last shot from yesterday (1.2MA, 5.4T). Aim
for improved startup reliability, wall cleanup, reduced H/D.

Maybe run some upper null and/or limiter shots, back at lower
current to begin. 

Provide target for ICRF if requested by RF group.

Physics Operators Plans
Entered: Nov 1 2005 01:12:14:783PM
Author: Jim Irby
Engineering setup for Wednesday 2-Nov-2005

MP298A Plasma startup

Session leader: Wolfe
Physics operator: Irby

Overnight ECDC in D2, and bake at 60 C.

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

Power systems as on 1051031027 (1.0 MA fiducial, 5.4 T, lower single null)

A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
leave NINJA as is Leave DISABLED

Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters

Torvac setup: Gate valves open

No between-shot boronization.

Important Diagnostics: magnetics, standard impurity spectroscopy

-------------------------------------------------------------------------------
ICRF Setup: No RF required today, although it can be used at will.

-------------------------------------------------------------------------------
Run plan: Continue to improve startup reliability and reduce h/(h+d). Bring up ICRF and diagnostics as possible.

Session Leader Summaries
Entered: Nov 3 2005 07:15:06:650AM
Author: Steve Wolfe
Slow progress on cleanup today. Startup reliability may have taken 
a step backward.  We ended up with 11 plasmas out of 31 attempts. 

The RF is coming along nicely, with D&E combining for
over 2MW by shot 25, and close to 3MW by the end of the day.

After some early rampdown disruptions, with long recoveries,
we went back to 1MA from 1.2MA. We then spent much of the day in alternating fizzle/plasma/fizzle sequence (or worse). H/D was around 0.5 or higher, 
but there was a little bit of heating from the RF, despite rather high
radiated power fractions. 

The oh2u coax resistance was over 2.5uOhms after most of the fizzles.
Note that the oh2u current goes negative on a fizzle, which seems
to be the wrong way as far as the coax is concerned.  A digital fizzle
detector could remedy this. 

Physics Operator Summaries
Entered: Nov 2 2005 05:16:39:337PM
Author: Jim Irby
We had less than 50% startup reliability today. Lots of gas was
evolving from the walls, even w/o disruptions. I was probably not
agressive enough at reducing the fill pressure following the
disruptions, but doing so too much gave us a dud. On shot 10 we
reduced the Ip request from 1.2 to 1.0 MA. This change kept us from
having full current disruptions and decreased the recovery time and
the number of fizzles. Most of the day consisted of toggling between
plasma and fizzles. Tweaks were made to Bz0 a couple of times to take
care of mTesla drifts. Generally we had an acceptable startup if the
basepressure on entering CHECK was 1.2e-6 Torr or less.

The good news is that the D-Port antenna vacuum conditioned up to 40
kV and appears to have recovered from Ti contamination. It ran
cleanly at power levels of up to 1.2 MW. E-Port antenna was also
brought back online today at power levels up to 1.3 MW.


duds 01,22

fizzles 04,05,06,07,08,10,11,12,13,15,18,20,24,26,27,29,30

plasmas 02,03,09,14,16,19,21,23,25,28,31

glitches 17


problems:

Had to replace 13.8 kV PF breaker with a spare unit.

Opened up cell for a while to allow DNB guys to work on LHe dewer.

We may have had a dud on shot 01 because of a CAMAC issue.

On shot 17 we had no TF --- data system problem

Session Leader Comments
Nov 2 2005 09:10:08:017AM1051102001Steve Wolfe
Shot#1: repeat of 1051101026
Dud. There were INIT failures on magnetics camac, including
a decoder, but it must have been Joe's because we got all 
the cPCI data.

Nov 2 2005 09:28:58:423AM1051102002Steve Wolfe
Shot#2: repeat of 1051101026
Plasma full length, runaways. 
Some RF from D&E, ~300kW each. 
H/D rises from 0.1 to 0.3 during the pulse;
looking good. nl04~.9e20 with gas turning off 
(asking for 0.7e20).

Got an oh coax resistance warning 2.59uOhm; 
should come down next shot. 

Nov 2 2005 09:46:35:580AM1051102003Steve Wolfe
Shot#3: plasma to 1.6sec, disrupts at 900kA; some injections
Got rid of the runaways.
EF1U is railing, and efc is trying to floor 
before the disruption, but I think it was an injection 
that did it in. 
Actually, the oh1 rails at 1.4sec, and the plasma moves in
to the inner wall. It looks like the early injection, around
0.8sec, cost too much in V-sec, taking oh1 to the current rail
early.  

Nov 2 2005 09:59:51:203AM1051102003Steve Wolfe
The PF breaker has failed after the power room access
following shot 3. 
There will be about a one hour delay to rack it out
and install a spare. 

Nov 2 2005 10:12:43:140AM1051102003Steve Wolfe
The PF breaker has failed after the power room access
following shot 3. 
There will be about a one hour delay to rack it out
and install a spare. 

Nov 2 2005 10:34:50:720AM1051102004Steve Wolfe
Shot#4: fizzle


Nov 2 2005 10:46:18:907AM1051102005Steve Wolfe
Shot#5: fizzle


Nov 2 2005 11:27:53:127AM1051102007Steve Wolfe
Shot#7: fizzle, very late breakdown ~12msec



Nov 2 2005 11:29:10:110AM1051102008Steve Wolfe
Shot#8: fizzle, breakdown is back to 5.7msec



Nov 2 2005 11:49:00:220AM1051102009Steve Wolfe
Shot#9: plasma to 1.6sec, disrupts above 1MA
Still rails oh1 around 1.4sec; also EF1U
D&E at 0.55 and 0.4MW respectively
Little bit of power out of j4. 

next shot: back Ip down to 1MA

Nov 2 2005 12:17:41:493PM1051102010Steve Wolfe
Shot#10: back Ip down to 1MA
fizzle

Nov 2 2005 12:31:27:790PM1051102011Steve Wolfe
Shot#11: back Ip down to 1MA
another fizzle. Disruption recovery. 

Nov 2 2005 12:43:26:150PM1051102012Steve Wolfe
Shot#12: fizzle.  

Nov 2 2005 12:57:51:743PM1051102013Steve Wolfe
Shot#13: fizzle 

Nov 2 2005 01:16:53:477PM1051102014Steve Wolfe
Shot#14: 1MA plasma, full length
Some projectiles visible on F-side TV view
D=0.8MW, E=0.6MW; short J4 pulse at .15MW
H/D~0.5

Nov 2 2005 01:24:32:320PM1051102015Steve Wolfe
Shot#15: fizzle. Can't handle full length plasmas either. 


Nov 2 2005 01:43:18:070PM1051102016Steve Wolfe
Shot#16: 1MA plasma full length; no runaways
Possibly the best startup of the day, with CIII
peaking at .015 and then dropping. 
RF continues to fire:D~1MW, E~0.8MW. Some slight sign of heating,
along with small density increase, during D&E pulses.
Small injection at the start of the D pulse. 
H/D~0.5


Nov 2 2005 01:53:51:100PM1051102017Steve Wolfe
Shot#17: Hung in INIT on a DNB action.
INIT completed after 4 minutes
No TF. No plasma. 


Nov 2 2005 02:18:10:650PM1051102018Steve Wolfe
Shot#18: fizzle. 
I don't understand why that one didn't go; 
Bz may be drifting up a little. Pressure
and CIII are lower than on 16.


Nov 2 2005 02:26:39:413PM1051102019Steve Wolfe
Shot#19: plasma full length
D ran clean, E one trip, each around 1.3MW
H/D~ 0.4 to 0.55

Nov 2 2005 02:35:48:743PM1051102020Steve Wolfe
Shot#20: fizzle

Nov 2 2005 02:52:51:227PM1051102021Steve Wolfe
Shot#21: plasma full length
RF pulses overlapped, got over 2MW until
D-tripped. Actually got some neuts
during early part of rf pulse. Maybe even a 
tiny little h-mode or two, around 0.9sec,
with only E-port. 


Nov 2 2005 03:12:22:553PM1051102022Steve WolfeShot#22 - dud
Nov 2 2005 03:50:18:303PM1051102025Steve Wolfe
Shot#25: RF got 2.35MW flat, H/D rising from 0.4 to 0.65
Small amount of heating from RF, also some density rise
2pi foil over 1.5MW

Nov 2 2005 03:54:54:400PM1051102026Steve Wolfe
Shot#26: fizzle again. Very late breakdown

Nov 2 2005 04:28:10:180PM1051102028Steve Wolfe
Shot#28: plasma full length. 
breakdown at 11msec !
Up to 2.8MW for awhile, then D faults out.
H/D rises from .4 to .75 during flattop

Nov 2 2005 04:36:18:350PM1051102029Steve Wolfe
Shot#29: fizzle. 


Nov 2 2005 04:54:49:057PM1051102030Steve Wolfe
Shot#30: fizzle. 


Nov 2 2005 05:09:40:617PM1051102031Steve Wolfe
Shot#31: plasma full length. 
bd at 7.7msec, bz quite positive at breakdown but
no hesitation to speak of. 
Prf~2.7MW for over .5sec, nl rising through pulse
H/D rises from .4 to .8 


Physics Operator Comments
Nov 2 2005 12:07:45:367PM1051102001Jim IrbyNote that GV1 will be closed for the first few shots today as the pumping stack recovers from the RGA filament replacement.

Will start up from shot 1051101026, last shot from yesterday: 1.2 MA, 5.4T, SLN

If we have plasma we should have icrf: D-Port has been vacuum conditioned to 40 kV. Much better than during the last run campaign

Dud

CAMAC problems possibly with magnetics

Ratiomatic was not turned on --- not sure of pressure.


Nov 2 2005 09:27:14:127AM1051102002Jim Irbygas puff from 20 to 25 ms

plasma into rampdown

d and e antennas at about 300 kW

h/(h+d) 18% at 1 s --- not bad


Nov 2 2005 09:47:49:330AM1051102003Jim Irbywe got on OH warning on last shot --- oh2u

added a little gas with pg3 before 20 ms --- help runaways?

disruption in rampdown --- 1.6 s

injection starts around .82 s --- may have done us in

runaways fixed

injection bumps up h/(h+d) at 1 s to 25%

oh2u coax looks good

Nov 2 2005 10:38:58:390AM1051102004Jim Irbyno PCS changes

problems pulling in PF breaker --- into the power room we go...

cell open for diagnostic work

installed spare breaker --- looks good (10:15 AM)

fizzle

pressure and fields okay

Nov 2 2005 10:53:04:050AM1051102005Jim Irbydelayed onset of gas from pg3 until 10ms (from 5 ms)

fizzle --- drop gas next time
Nov 2 2005 11:02:51:627AM1051102006Jim Irbyprefill from 25 to 22 ms

dropped pg3 gas request after 10 ms.

ef4 from -1325 5o -1350 A

fizzle
Nov 2 2005 11:11:52:297AM1051102006Jim Irbyprefill from 25 to 22 ms

dropped pg3 gas request after 10 ms.

ef4 from -1325 to -1350 A

fizzle --- late breakdown


Nov 2 2005 11:23:21:017AM1051102007Jim Irbyput ef4 back to -1325 A

fizzle!
Nov 2 2005 11:31:26:313AM1051102008Jim Irbyef4 from -1325 to -1340 A
prefill from 22 to 24 ms

fizzle but at least it's earlier


Nov 2 2005 11:46:51:140AM1051102009Jim Irbyjust try again --- recovery from the disruption?

plasma for 1.55 s

no injection, but still railing oh1 and ef1u

h/(h+d) 34% at 1 s




Nov 2 2005 12:30:46:897PM1051102010Jim Irbydelay to enter cell and fix leak in DNB helium cryostat --- approx 20% of the LHe has been lost so far this morning

Ip request from 1.2 to 1.0 MA

entering INIT at 34 minutes

basepressure at CHECK: 1.4e-6 Torr

fizzle

pressure at breakdown still higher than on shot 9


Nov 2 2005 12:35:21:273PM1051102011Jim Irbyno PCS changes

fizzle --- pressure still high
Nov 2 2005 12:52:41:133PM1051102012Jim Irbyprefill from 24 to 23 ms

pressure at CHECK: 9.8e-7 Torr

fizzle
Nov 2 2005 01:01:14:150PM1051102013Jim Irbyno PCS changes

basepressure at CHECK: 8.1e-7 Torr

one more fizzle, but it almost went

carbon III signal beginning to look better (lower and extended longer)

Nov 2 2005 01:21:02:477PM1051102014Jim Irbyno PCS changes

plasma into rampdown (Ip 1 MA)

D and E antennas at about 0.8 and 0.6 MW

h/(h+d) 32% at 1 s

Nov 2 2005 01:28:20:210PM1051102015Jim Irbyno PCS changes

fizzle

fields okay, but carbon level very low again and no density rise


Nov 2 2005 01:44:50:803PM1051102016Jim Irbyprefill from 23 to 21 ms

pressure at CHECK: 1.3e-6 Torr

plasma into rampdown

took a little more gas to run this shot vs shot 14

1 MW on D-Port antenna --- evolving some gas
0.8 MW on E-Port

h/(h+d) 32% at 1 s

prad main .6 to .7 MW


Nov 2 2005 02:05:49:663PM1051102017Jim Irbyno PCS changes

data system fault: no TF


Nov 2 2005 02:17:00:133PM1051102018Jim Irbytry again

pressure at CHECK: 1.e-6 Torr

fizzle

fields okay
breakdown a little earlier than on 16

pressure about equal to shot 16 at breakdown

oh_coax resistances all went down: shot w/o TF?




Nov 2 2005 02:31:08:913PM1051102019Jim Irbyno PCS changes

pressure at CHECK: 1.0e-6 Torr

plasma into rampdown

d and e at about 1.3 MW each


Nov 2 2005 02:39:15:710PM1051102020Jim Irbyprefill to 19 ms from 21

basepressure at CHECK: 2.2e-6

fizzle


Nov 2 2005 02:55:41:647PM1051102021Jim Irbyno PCS changes

CHECK: 1.4e-6 Torr

plasma into rampdown

shot h-modes

2.1 MW from d and e


Nov 2 2005 03:17:26:243PM1051102023Steve Wolfe
Shot#23: Jim has gone to a meeting. Wolfe taking over as Physop

pg4 from 17 to 19msec
Br0 from 0 to -.0005
P0 = 1.5e-6 at check
plasma full length
late breakdown, around 9msec; almost crunched inside
but recovered. 

next shot: Br0 back to 0

Nov 2 2005 03:30:23:400PM1051102024Steve Wolfe
Shot#24: Br0 back to 0
rcur offset from 1600 to 1500 (shouldn't matter)
P0=2.8e-6 at check

fizzle. breakdown still late 9msec, so it probably
wasn't the Br0. 
next shot: add 1msec to pg4, get rid pf pg3 before 25msec

Nov 2 2005 03:42:21:243PM1051102025Steve Wolfe
Shot#25: pg4 from 19 to 20msec, get rid of pg3 before 30msec
plasma full length; breakdown back at 7msec,
some hesitation, but no inward motion. 

Irby is back and will take the next shot

Nov 2 2005 04:04:07:400PM1051102026Jim IrbyNo PCS changes

CHECK pressure: 2.6e-6 Torr

fizzle --- very late breakdown


Nov 2 2005 04:15:50:163PM1051102027Jim IrbyNo PCS changes

CHECK pressure: 1.6e-6 Torr

fizzle, but breakdown is early again

fields okay --- close to going



Nov 2 2005 04:32:28:570PM1051102028Jim Irbyno PCS changes

CHECK: 1.2e-6 Torr

plasma into rampdown

late breakdown, but it managed to run


Nov 2 2005 04:41:01:743PM1051102029Jim IrbyNo PCS changes

CHECK: 2.4e-6 Torr

fizzle and late

bz0 has drifted down a little


Nov 2 2005 04:56:41:663PM1051102030Jim Irbyef4 from -1340 to -1325 A

CHECK: 1.5e-6 Torr

fizzle --- very early injections or bounces


Nov 2 2005 05:12:43:803PM1051102031Jim Irbyno PCS changes

CHECK: 1.1e-6 Torr

plasma into rampdown --- breakdown a little late

h/(h+d) 36% at 1 s

2.7 MW of ICRF --- gas evolution and density rise


Engineering Operator Comments
ShotTimeTypeStatusComment
109:03:26:970AMPlasmaOk
209:17:33:393AMPlasmaOk
309:30:43:000AMPlasmaOk
410:30:49:703AMPlasmaOk
510:44:33:407AMPlasmaOk
610:57:54:673AMPlasmaOk
711:11:23:267AMPlasmaOk
811:24:47:767AMPlasmaOk
911:37:52:233AMPlasmaOk
1012:15:05:680PMPlasmaOk
1112:28:09:557PMPlasmaOk
1212:41:25:383PMPlasmaOk
1312:55:03:930PMPlasmaOk
1401:08:22:117PMPlasmaOk
1501:21:53:243PMPlasmaOk
1601:35:08:460PMPlasmaOk
1701:51:06:240PMPlasmaOkNo TF
1802:04:42:100PMPlasmaOk
1902:17:46:057PMPlasmaOk
2002:32:52:040PMPlasmaOk
2102:45:59:930PMPlasmaOk
2202:59:30:350PMPlasmaOk
2303:12:28:087PMPlasmaOk
2403:25:31:650PMPlasmaOk
2503:38:25:057PMPlasmaOk
2603:51:42:100PMPlasmaOk
2704:04:47:367PMPlasmaOk
2804:17:54:650PMPlasmaOk
2904:31:07:557PMPlasmaOk
3004:47:29:990PMPlasmaOk
3105:01:01:523PMPlasmaOk