Alcator C-Mod Run 1051103 Information

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Miniproposals
Miniproposal:355
Date Filed:11/12/2003
Title:ICRF Testing & Conditioning
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-33)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Parkin,Bill Byford,Ed Fitzgerald,Bill Byford,Ed Fitzgerald

Engineering Operator Run Comment
MP 298A Plasma Start up, MP 355 RF Conditionong. P.O. Wolfe

Session Leader Plans
Entered: Nov 4 2005 11:48:30:873AM
Author: Steve Wukitch
Engineering setup for Thursday 3-Nov-2005

MP298A Plasma startup and
MP355 RF Conditioning

Session leader: Wukitch
Physics operator: Wolfe

Overnight ECDC in D2, and bake at 60 C.

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

Power systems as on 1051102031 (1.0 MA fiducial, 5.4 T, lower single
null, right gap 2 cm)

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 DISABLED

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

Torvac setup: Gate valves open

ICRF Setup:

All transmitters to run-on by 8:30 am.

Important Diagnostics: magnetics, Cu and Mo impurity spectroscopy,
video monitors for antennas

Plan: Continue machine cleanup, ICRF conditioning
---------------------------------------------------------------------------

Physics Operators Plans
Entered: Nov 2 2005 04:01:02:383PM
Author: Steve Wolfe
Engineering setup for Thursday 3-Nov-2005

MP298A Plasma startup and
MP355 RF Conditioning

Session leader: ?
Physics operator: Wolfe

Overnight ECDC in D2, and bake at 60 C.

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

Power systems as on 1051102025 (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

ICRF Setup: YES

Important Diagnostics: magnetics, standard impurity spectroscopy

Plan: Continue machine cleanup, ICRF conditioning (maybe including Jport).
If we continue to have alternating fizzles, I may go back to the old
1050525002 startup and see if that's better than what Ian set up 
yesterday. 


Session Leader Summaries
Entered: Nov 4 2005 11:48:45:060AM
Author: Steve Wukitch
Run summary:

Using 1 MA, LSN, fiducial discharges, we began conditioning the ICRF
antennas into plasma. D antenna had reached ~1.3 MW yesterday but
suffered an event that set it back late in the day. It had
reconditioned to ~0.8 MW by the end of the day. E antenna continued
to operate well up to 1.2 MW and appears to be in good condition for
these discharges. E clearly causes D to fault and the situation
becomes worse as the H fraction increases. J antenna was slowed by a
malfunctioning stub tuner controller. The problem was ultimately
traced back to a bad relay. Once this was corrected, we found the
phase setting for 0,pi,0,pi to be near the last campaign value of
~320deg. Initial operation without a screen reached ~1.5 MW for short
pulse and has been uneventful with respect to injections thus far.

Physics Operator Summaries
Entered: Nov 3 2005 05:40:46:770PM
Author: Steve Wolfe
Some more progress today. The RF got J-port going, 
eventually J3 and J4 running together. 

Machine cleanup also progressed some, I suppose, although 
H/D rose through the day as we evolved more gas from plasma 
facing components and from the antennas.  Shot#1 started at 
about 10%, rose to 30% during RF, and got into H-mode. 
Later in the day we were running up to H/D~0.4 or so, which
is somewhat lower than yesterday. 

Startup reliability improved somewhat, but is still 
far from robust. We ended up with 19 plasmas in 33 attempts, all but 
one (#17) full length. Most were also free of runaways. I started
out by returning to our old startup (1050525002) with increased
pulsed gas, and modified it to higher oh1 voltage. Bz seemed to 
be drifting during the day and I made several tweaks to the IC_EF4U,
getting as low as -1355 and ending up at -1345. The reason for this
bad field behavior is not understood but it seems to be a fact. 
Some minor (<= .5mT) tweaks to Br0 may or may not have made any difference. Plasmas seemed most reproducible at high pre-puff, pg4 >= 25msec,
which put the ratiomatic pressure around .06mTorr, rather on the high 
side by historical standards. Pressures below .05 resulted in some
duds. After getting only two plasmas in the first 8 shots, I took 
30 minutes of ecdc, which seemed to help; we then got 6 successful out 
of the next 8 tries.   

Every fizzle and dud caused the oh2u coax to go into the warning
level above 2.5uOhm. Full length shots dropped the resistance
back below 2uOhm, but not by much. Note that it seems better to 
reduce the fizzle delay on the OH2's to at least 300msec, as we
had done yesterday. The engineers set this back to 500msec at the 
start of the day, which only resulted in higher dissipation and 
perhaps increased resistance readings. The point is that the
OH2U swings the wrong way (more positive) on fizzles, because
of the Zcur control, rather than double swinging which is 
the point of having the fizzle delay for oh1 and oh2l. 
While the joint dissipation never got above
about 2kJ, the joint resistance situation is cause for some concern, 
and the sooner we get past these fizzles, or implement a digital
fizzle detector algorithm that forces the currents to do the
right thing, the better. 

Scorecard:
-----------

  Tests     0
  Duds      5
  Fizzles   9
  Plasmas  19
  ======== ==
  Shots    33


Session Leader Comments

Physics Operator Comments
Nov 3 2005 07:43:34:153AMSteve Wolfe
RF has requested 2cm outer gap (compared to 1.5cm yesterday)
I want to change the startup back to the old "magic" 1050525002

PCS setup:
-----------
Seg1: Import 1050525002
  recalculate all mag preds (note RCUR offset=1500)
  pg4 from 21msec to 25msec
Seg2: RCUR from .6595 to .6570
Load/clean  - get timestamp errors on p05,p09 in seg1
Move end points and reload; except I moved them in seg2
 instead of seg1. Let's try that again.
Load/clean - no errors this time
Reset old values so PCS_compare doesn't squawk

Load at  3-Nov-2005 07:42:57.00
Open tree /home/wolfe/pcs_scratch      -1
Open tree done


Nov 3 2005 07:55:02:637AMSteve Wolfe
RF has requested 2cm outer gap (compared to 1.5cm yesterday)
I want to change the startup back to the old "magic" 1050525002

PCS setup:
-----------
Seg1: Import 1050525002
  recalculate all mag preds (note RCUR offset=1500)
  pg4 from 21msec to 25msec
Seg2: RCUR from .6595 to .6570
Load/clean  - get timestamp errors on p05,p09 in seg1
Move end points and reload; except I moved them in seg2
 instead of seg1. Let's try that again.
Load/clean - no errors this time
Reset old values so PCS_compare doesn't squawk

Load at  3-Nov-2005 07:42:57.00
Open tree /home/wolfe/pcs_scratch      -1
Open tree done


Nov 3 2005 09:29:09:073AM1051103001Steve Wolfe
Shot#1: startup as on 1050525002, except for PG4 to 25msec
I expect that the EF4 may be too positive (-1310) but will
evaluate after the shot. 

Seg2 same as 1051102031, except RCUR moved in by 2.5mm to 
increase outer gap, per RF request.

D&E (plus a little J4) will be tried on the first
shot; #3 tuner/phase shifter is still having a problem. 

Result: plasma full length
Nice breakdown time 6.5ms, good current rise, 
pressure is rather high at 55uTorr,
Bz is somewhat positive. Small runaways early.
Outer gap is 2cm as programmed,
got a little over 2MW, solid H-mode for 100ms
or so, then D faulted; E ran clean at 1.1MW 
till EOF. 
H/D 0.11 before RF, 0.2 to 0.3 during RF

next shot: reduce pg4 3ms

Nov 3 2005 09:25:28:667AM1051103002Steve Wolfe
Shot#2: PG4 from 25 to 22msec
p0 in check = 1.3e-6

Dud. I guess I shouldn't have dropped pg4
pressure was still .05mTorr, fields look fine
(and the same); should have gone?

next shot: pg4 back up

Nov 3 2005 09:44:05:793AM1051103003Steve Wolfe
Shot#3: PG4 from 22 to 25msec
Another dud? 
Br0 looks a little negative, Bz is ramping 
pretty fast. 

next shot: Pg4 to 28msec, OH1_Volt up by 50V

Nov 3 2005 09:54:27:417AM1051103004Steve Wolfe
Shot#4: PG4 from 25 to 28msec, 
OH1_Volt from 150 to 200V before .02sec (first point from 120->170)

fizzle. breakdown at 8.2msec. 
next shot: Br0 up .0003, EF4 down 15A

Nov 3 2005 10:14:47:793AM1051103005Steve Wolfe
Shot#5:  Br0 to .0003, EF4 from -1310 to -1325
plasma full length
breakdown is even later, at 10msec;
decent current rise. Halpha is burning out nicely,
CIII peaks around .011.
Br looks better, Bz a bit slower, still ramping and
rather positive at 10msec.

E ran ok at 1.25MW, D-faulted immediately,
J4 tried and failed.
H/D ~0.2 to 0.3

next shot: repeat and see what happens

Nov 3 2005 10:37:26:810AM1051103007Steve Wolfe
Shot#7:  Br0 to 0. from .0003
Dud? Br change is the only thing I see.

We've been getting oh resistance warnings on OH2U. 
The engineers had set the OH2 fizzle detector delay
to 500msec. We had changed this yesterday (per Irby)
to 300msec, since this coil goes the wrong way on a 
fizzle and having a longer delay just forces it further.
I have requested that it be set back to 300ms
and may ask to have it reduced further. 

Nov 3 2005 10:44:35:400AM1051103008Steve Wolfe
Shot#8: Br0 to .0005; I don't really think it's a Br issue,
but that's all that changed. 

Another dud 
It's not the fields. Try 30 minutes of ecdc before next shot.


Nov 3 2005 11:39:40:497AM1051103009Steve Wolfe
Shot#9: Br0 back to 0., PG4 to 25msec
30 minutes of ecdc before this shot. 
1.0e-6 at check
plasma full length
breakdown slightly late (~7msec)
slight hesitation, Br looks a little low
Got E at 1.25MW, J4 at .5MW, D faulting
H/D .15 to .25

next shot: repeat

Nov 3 2005 11:45:13:323AM1051103010Steve Wolfe
Shot#10:  repeat
fizzle. late breakdown @9msec

next shot: IC_EF4U to -1335 

Nov 3 2005 12:02:55:653PM1051103011Steve Wolfe
Shot#11: IC_EF4U to -1335 from -1325
Delay seg1 pg3 puff to after 30msec (wouldn't have mattered on 10)
plasma full length
bd at 6.7msec, nice burnout on H-alpha, no Ip hesitation.
D still faulting, E ok at 1.25MW, J ok at 0.6MW
Bolo almost as high on J pulse as E, despite half the power.

next shot: repeat
 DNB is firing into machine between shots.


Nov 3 2005 12:14:44:060PM1051103012Steve Wolfe
Shot#12: reduce outer gap back to 1.5cm (RCUR from .657 to .6595)
No startup changes
 DNB tried to fire into machine between shots, but gate valve 
wouldn't open.

plasma full length. Two in a row!
startup looks pretty much the same as 11; 
small runaway burst (1.5e12) early, otherwise ok.

D was better, still faulting but ramped up to 
0.5MW. E ran clean. J4 up to 0.7MW

next shot: repeat

Nov 3 2005 12:29:39:183PM1051103013Steve Wolfe
Shot#13: repeat
plasma full length
bd a little earlier, 5.8msec
Bz is down a tad. No runaways this time.
D still ratty, E clean at 1.3, J4 at 0.7MW

DNB will fire into the machine before next shot.
No PCS changes

Nov 3 2005 12:45:34:310PM1051103014Steve Wolfe
Shot#14: repeat
DNB gate valve opened between shots but beam did not fire,
according to RSG. Then he tried again and it did, raising 
the pressure to 1e-5 (gauge)
1.7e-6 in check

plasma full length
bd back to 6.5msec, still no runaways.
one injection ~0.9sec, during D pulse
D doing better, ramps to 0.6MW, E and J as before.
Also no neuts, the E port heating is now not visible.
H/D is up to 0.4 late in the flattop.


Nov 3 2005 12:55:44:870PM1051103015Steve Wolfe
Shot#15: repeat
plasma full length
bd later this time, 7.7msec
Br is a little more positive at t=0

D staggering up to 0.8MW, E and J as before.


Nov 3 2005 01:07:10:073PM1051103016Steve Wolfe
Shot#16: repeat
fizzle. Time to go back to work.
late breakdown 10msec and an injection (?) at .022sec

next: Br0 to -.0003, ef4 down another 10A

Nov 3 2005 01:23:58:730PM1051103017Steve Wolfe
Shot#17: Br0 to -.0003, ef4 to -1345 from -1335
plasma disrupted at 1.2sec. Injection from ?
bd at 7msec, no runaways.

next: I should probably drop pg4, but I'll just go again and see...

Nov 3 2005 01:34:19:230PM1051103018Steve Wolfe
Shot#18: No changes
fizzle, not robust to disruptions yet
breakdown at 6.5msec, almost made it; if I'd dropped the
pre-puff it probably would have gone through.

Next: no change

Nov 3 2005 01:47:29:433PM1051103019Steve Wolfe
Shot#19: No changes
another fizzle. Thought that one would be ok.
bd at 7.5msec, br is a bit too negative?
ratiomatic is actually down a little from the
shots that went. 
Here we go again.

Drop pg4 by 2ms, raise Br0 back to 0 

Nov 3 2005 02:11:26:247PM1051103020Steve Wolfe
Shot#20: pg4 from 25 to 23ms, Br0 back to 0 from -.0003
plasma full length. 
bd at 5.8ms, no hesitation, no runaways
J and E clean, D still faulting but getting there.
Bolo during J is now less than during E (though not 
by a factor of two)

H/D rising from .25 to .4 during pulse

The part for the J3 tuner has arrived. We will have a short
delay while they install it. 

Nov 3 2005 02:31:18:950PM1051103021Steve Wolfe
Shot#21: J3 is supposedly repaired.
DNB is down with a stuck calorimeter.
No PCS changes
plasma full length
bd at 6.7msec, ratiomatic .053mTorr
no runaways.

D and E look like they did on 20;
so does J4; not much from J3, but Steve claims it's "baby steps"

next: repeat

Nov 3 2005 02:44:26:980PM1051103022Steve Wolfe
Shot#22:repeat
plasma full length.
bd 6.5ms; startup looks the same as 21
D looks cleaner, one fault on the way up to 0.8
E clean at 1.3
J about the same.
Prad seems to be climbing a little during E pulse

next: repeat

Nov 3 2005 03:00:14:683PM1051103023Steve Wolfe
Shot#23:repeat
plasma full length
bd 7.3ms, a little later
Br drifting up, Bz a little down
D flat at 0.8MW, with a couple of trips
J3 ramping up to 0.5, clean; J4 at 0.7

next: no changes, see if it gets better or worse.

Nov 3 2005 03:08:42:277PM1051103024Steve Wolfe
Shot#24:repeat
base pressure seems to be up a little before this shot,
2.2e-6 at INIT, 1.8e-6 in check
fizzle. Well, I guess I should have tweaked it.
bd at 6.7ms, injection at 19ms, might have been 
sliding in at the time.

next: drop Br, drop pg4

Nov 3 2005 03:23:19:280PM1051103025Steve Wolfe
Shot#25:drop Br to -.0002, pg4 from 23 to 21ms
hope it doesn't dud.
oh2u resistance was down to 1.58uOhm on 24; 
it will probably be up over 3 this time.
1.0e-6 at check. Probably should have left pg4 alone.

plasma full length, lots of runaways, over 10^14 equivalent. 
This one definitely bounced outside.
bd at 5.8msec. 

D and E stacked, D faults out after 100ms or so
Got about 2MW for a while.
J3 faults at 0.7, J4 ok

next: pg4 back to 23msec

Nov 3 2005 03:36:27:207PM1051103026Steve Wolfe
Shot#26:pg4 back to 23msec from 21
1.8e-6 in check this time
Dud! Makes no sense. Br looks ok.

Next: back to 25msec

Nov 3 2005 03:51:08:643PM1051103027Steve Wolfe
Shot#27:pg4 to 25msec from 23
fizzle. late breakdown 9msec
looks like it chokes. Bz went up this time.

next: ef4 down by 10A

Nov 3 2005 04:02:38:800PM1051103028Steve Wolfe
Shot#28:ef4 from -1345 to -1355
Br0 back to 0
plasma full length
bd at 6ms, couple of small injections (or bounces?) 
but they don't affect the startup, no runaways.
J3 was not on this time, D and E separated again.

next: try for a repeat; J3 should be back on.

Nov 3 2005 04:15:59:160PM1051103029Steve Wolfe
Shot#29: repeat
plasma full length
bd at 7.1ms; Bz now a little negative.
J3 .4MW, J4 .3MW
D .8MW, E 1.1MW, very short overlap to get to ~2MW

next: ef4 positive by 5A


Nov 3 2005 04:31:01:143PM1051103030Steve Wolfe
Shot#30: ef4 from -1355 to -1350
plasma full length
early bd 5.5ms, no runaways. Bz still a little negative
D has lots of faulting, E clean around 1.1MW
J3 and J4 both faulting repeatedly
OH2U down to 1.5uOhm, ~1kJ dissipation this time,
hopefully down again next shot

next: no changes

Nov 3 2005 04:42:39:473PM1051103031Steve Wolfe
Shot#31:  no changes
plasma full length
bd 6.8ms, slight hesitation
bz again a little negative
D moved after 1sec, E off, D ratty at 0.8MW
J3 and J4 together total 1.5MW, not quite balanced

next: repeat 

Nov 3 2005 04:59:33:737PM1051103032Steve Wolfe
Shot#32:  no changes
fizzle. extremely late bd, >15msec
Bz went negative again, br maybe a little also
ratiomatic is around .06mTorr
Something is very screwed up with these fields.

next: ef4 to -1345

Nov 3 2005 05:12:16:190PM1051103033Steve Wolfe
Shot#33:  ef4 to -1345 from -1350
Plasma full length.
bd at 7msec, bounced outside, some runaways.
I suppose it could have stood more positive Bz, 
but I'll take it. 

D ran clean at .75MW, J faulted completely.
H/D starts around .2 and rises to .4

Engineering Operator Comments
ShotTimeTypeStatusComment
109:07:25:840AMPlasmaOk
209:21:43:823AMPlasmaOk
309:34:45:480AMPlasmaOk
409:47:35:760AMPlasmaOk
510:01:50:433AMPlasmaOk
610:15:00:543AMPlasmaOk
710:28:38:107AMPlasmaOk
810:41:48:607AMPlasmaOk
911:28:47:043AMPlasmaOk
1011:41:48:183AMPlasmaOk
1111:54:47:310AMPlasmaOk
1212:07:56:823PMPlasmaOk
1312:23:32:073PMPlasmaOk
1412:36:43:667PMPlasmaOk
1512:49:52:777PMPlasmaOk
1601:03:01:370PMPlasmaOk
1701:16:33:213PMPlasmaOk
1801:29:30:730PMPlasmaOk
1901:42:33:777PMPlasmaOk
2001:55:34:043PMPlasmaOk
2102:25:20:933PMPlasmaOk
2202:38:38:277PMPlasmaOk
2302:51:46:573PMPlasmaOk
2403:04:42:903PMPlasmaOk
2503:17:32:900PMPlasmaOk
2603:30:22:080PMPlasmaOk
2703:43:11:690PMPlasmaOk
2803:56:59:987PMPlasmaOk
2904:09:52:393PMPlasmaOk
3004:22:45:690PMPlasmaOk
3104:35:52:080PMPlasmaOk
3204:48:42:677PMPlasmaOk
3305:01:33:050PMPlasmaOk