Alcator C-Mod Run 951117 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Steve Golovato (shots 1-29)
Miniproposal:075
Date Filed: 1/8/1994
Title:\'q\' profile measurements using Lithium pellet ablation cloud imaging.
First Author:Darren Garnier
Session Leader:Darren Garnier (shots 1-29)

Operators
Session leader(s):Darren Garnier,Steve Golovato
Physics operator(s):John Goetz
Engineering operator(s):Frank Silva,Joe Daigle

Engineering Operator Run Comment
RF Conditioning

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:13:990PM
Author: To Be Determined
run summary - 951117
---------------------
SL: golovato
PO: goetz
EO: silva/daigle

The main goal of the run was to begin conditioning the rf antennas up to
full power with plasma. We had previously vacuum conditioned each system
up to 40kv for 10ms pulses. Both systems had been changed such that the
old tuning settings would not be correct. The D-port transmitter is now
tuned to 80.5mhz in order to allow discrimination of the signals from each
system, particularly when one picks up signal from the other. The E-port
coax system has always run at higher voltage than D-port so we changed
coax lengths so that E-port is now the same as D-port. We asked for plasmas
at about nl04=1.e20 with a 1-1.5cm outer gap so loading would be high and
voltages would not get close to 40kv until we were near full power. We
suffered every other shot syndrome for much of the run, but had one 5 shot
streak. D-port tuned up easily and we raised the power cautiously, getting
1.4mw at about 30kv on the last shot. E-port was more of a problem, with
the tuning apparently way off. When it was decided to make a big change
a look for a new operating point, using the difference in the vacuum tuning
as a guide, the tranmsmitter went down for some reason. It may be one of the
low power drivers went out, it didn't appear to be in the high power stages.
The outcome is that D-port is ready for experiments requiring heating, but
E-port needs more work. However, there is no reason to think E-port won't
come right up to power once the tuning is found.

Another goal of the run was to do lithium pellet injection after 750ms.
Darren informs me he got some good data. There are still some camac
highway problems that have to be worked out, although progress with
this was also made. For information on engineering problems and shot
statistics, see the physics operator summary. For shot-to-shot comments,
see the logbook under the session_leader topic.


Physics Operator Summaries
Entered: Jul 7 2004 04:36:55:427PM
Author: To Be Determined
Physics operator summary for 951117

EO: Silva/Daigle
PO: Goetz
SL: Golovato/Garnier

Run 951117 was in support of Mini-Proposals #75 - q-profiles and #102 - RF Conditioning
The goals of these mini-proposals are to check out diagnostics and systems.

Program for this run:
- Set up a shot acceptable to the various experimenters and repeat until everyone
is satisfied.

Some things discovered today:
1) Suitable plasmas were obtained to satisfy both the Li pelletiers and
the RF group. Large pellets (1e20 electrons) were successfully injected.
Up to 1.4MW of rf power was injected (shot 029)
2) Puffed prefill was used today. 13msec of puffed prefill gives 1.1e-5
on the ratiomatic for breakdown. A hint of hards early TCX was the
impetus to lengthen the puff to 14msec -> 1.3e-5 Torr.
3) Density feedback with the z_meter is reliable. A drawn waveform of
NL_ZMETER=0.7 gives an NL_04 equivalent of 1e20. Be careful with
using any shot from today (post-005) unless NL_ZMETER is necessary.
4) After a slow start, the machine went into a plasma/fizzle alternating
pattern (shot 008 to 019). It is suspected that the ramp-down
disruption was stirring up enough crud to keep the next shot from
burning out and having a good current rise. Shots 019-023 were
a set of nice plasmas, all of which will not make the disruption
database. This string may be due to the complete rampdowns.
The machine is definitely cleaner than 951116 but crud still
remains in reachable places.
5) Shot 027 is interesting in that the TF crowbars before breakdown.
This plasma broke down before .003sec and had a hesitation free
current rise. Further investigation is underway to determine if
anything can be gleaned from this set of circumstances to better
the breakdown/current rise phase.

Engineering, computing, and diagnostics today: Shots 024 - 027 had TF crowbars
caused by comm faults that weren't really there. Switching chips and
switching boards fixed whatever problem was there. Data acquisition
problems today include the RF crates causing the dreaded 'medium offline'
error. Moving the RF acquisition late in the cycle seemed to cure the
errors. The CO2 laser of TCI was having troubles early today. Repeated
trips to the cell for 'tuning' and switching to z_meter controlled density
feedback seemed to cure the problem. Dud caused today by the OH2L crapping
out and taking the rest of the PF supplies with it. This event remains
unexplained.

Scorecard: 29 shots = 14 plasmas + 14 fizzles + 1 p.s. dud

Shot summary for Run 951117:

Reload of 951116003:
no changes

Shot change result
____ _____ ______
1 puff pre-fill plasma - disr. @ 1.22
TCI problems - no gas in after 0.1sec

2 no changes fizzle - b.d. @ .005; Dalpha slow to burnout

3 NL_04 = 1.0e20 fizzle - b.d. @ .0045; Dalpha never burns out
base pressure still high after shot 1 disr.

4 cell access for TCI repair plasma - killed by Li pellet @ .76
fix blown fuse in OH1 TCI problems - no gas again

5 switch to z-meter for density fizzle - high carbon - Br = .0015
feedback; load wire 14, segment
2 from 950519005; draw 0.25

6 BR_0 offset = .007 (was .008) fizzle - Br better - high carbon
cell access for TCI repari

7 no changes fizzle - no burn-out

8 remove 1msec from pre-puff fizzle - no burn-out

9 remove 2msec from pre-puff plasma - disrupts early - requesting too
much NL_ZMETER too early

10 ramp NL_ZMETER to 0.7 @ 0.5sec fizzle - carbon too high (scatterplot)

11 no changes plasma - disr. @ 1.26

12 RCUR=0.668 fizzle

13 V_OH1 = 120V @ .01s (was 90V) plasma - disr. @ 1.22
30kW RF - small Li pellet

14 no changes fizzle

15 V_OH1=130V from .005 to .015s plasma - disr. @ 1.21
IC_EF4=-1125A

16 no changes fizzle - fields o.k. - carbon high

17 no changes plasma - disr. @ 1.38

18 1msec more prefill puff fizzle - fields o.k.

19 no changes plasma - big pellet - no RF

20 no changes plasma - big pellet - no RF

21 no changes plasma - big pellet - best RF (>.06MW)

22 no changes plasma - big pellet - RF < 0.2MW

23 no changes plasma - big pellet - RF < 0.7MW

24 add 1msec of prefill puff dud - OH2L pulled out the rest of the PF's

25 try again fizzle - Br a bit ratty - TF crowbar at 0.sec

26 no changes fizzle - Br wiggles - TF crowbar at -.005sec

27 try again plasma - killed by pellet @ 0.76
TF crowbar @ 0. -> EF3 to go @ 0.55

28 no changes fizzle - no burn out - post-disruption blues

29 no changes plasma - all the way down - Prf < 1.4MW

Session Leader Comments
Nov 17 1995 09:44:25:030AMSteve Golovatorun 951117 - goals

(1) tune antennas, bring power up
(2) shoot in lithium pellets later in shot after rf
(3) combine rf and pellets if power is high enough

Nov 17 1995 10:23:26:540AM951117005Steve Golovatoshot 951117005 -

problems with tci, going to visible bremstrahlung for nl feedback.

should be first shot with rf.

fizzle

Nov 17 1995 10:23:40:070AM951117006Steve Golovatoshot 951117006 -

fizzle

Nov 17 1995 11:42:30:600AM951117007Steve Golovatoshot 951117007 -

rf power set to a few 10s of kw.

tuning will be different, d-port is at 80.5mhz instead of 80mhz,
e-port coax circuit changed to be like d-port.

fizzle

Nov 17 1995 11:42:42:790AM951117008Steve Golovatoshot 951117008 -

fizzle

Nov 17 1995 11:43:06:410AM951117009Steve Golovatoshot 951117009 -

early disruption, .5s

Nov 17 1995 11:43:21:990AM951117010Steve Golovatoshot 951117010 -

fizzle

Nov 17 1995 11:53:03:100AM951117011Steve Golovatoshot 951117011 -

plasma. only d-port ran. outer gap 2cm, loading low. reduce to 1cm
for next shot.

Nov 17 1995 12:03:03:200PM951117012Steve Golovatoshot 951117012 -

fizzle.

Nov 17 1995 12:23:41:630PM951117013Steve Golovatoshot 951117013 -

plasma. d-port ran to 30 kw, is tuned.

e-port got a bit of rf, enough to start tuning.

Nov 17 1995 12:24:02:390PM951117014Steve Golovatoshot 951117014 -

fizzle

Nov 17 1995 12:47:37:530PM951117016Steve Golovatoshot 951117016 -

fizzle.

Nov 17 1995 01:15:27:950PM951117017Steve Golovatoshot 951117017 -

plasma. d-port interrupting. lower power, tune.
e-port still way off.

Nov 17 1995 01:17:43:770PM951117018Steve Golovatoshot 951117018 -

fizzle.

Nov 17 1995 02:03:02:140PM951117019Steve Golovatoshot 951117019 -

plasma. still tuning.

Nov 17 1995 03:46:43:990PM951117020Steve Golovatoshot 951117020 -

plasma. two in a row. tuning better, getting closer on d-port.
e-port still a problem.

Nov 17 1995 03:47:56:430PM951117021Steve Golovatoshot 951117021 -

plasma. 80kw. increasing power on d-port.

Nov 17 1995 03:48:31:860PM951117022Steve Golovatoshot 951117022 -

plasma. 200kw on d-port .

Nov 17 1995 03:49:02:790PM951117023Steve Golovatoshot 951117023 -

plasma. 600kw on d-port .

Nov 17 1995 03:49:30:090PM951117024Steve Golovatoshot 951117024 -

power supply fault.

Nov 17 1995 03:49:48:190PM951117025Steve Golovatoshot 951117025 -

fizzle. tf crowbar.

Nov 17 1995 04:12:34:220PM951117026Steve Golovatoshot 951117026 -

tf supply fault. third shot in row.

Nov 17 1995 04:36:00:060PM951117027Steve Golovatoshot 951117027 -

plasma. 800kw, no interrupts on d-port.
no e-port rf. try e-port with same st setting as for previous runs,
move ps to same difference relative to vacuum tune as before but
use new ps vacuum tune setting.

Nov 17 1995 04:55:39:210PM951117028Steve Golovatoshot 951117028 -

fizzle. no bt crowbar.

Nov 17 1995 05:04:35:870PM951117029Steve Golovatoshot 951117029 -

plasma, 1.4mw on d-port, no faults.
e-port seems to be broken, won't pulse even in manual mode.

Physics Operator Comments
Nov 17 1995 08:25:14:680AMJohn GoetzRun 951117
finish and/or start various checkout mini-proposals
#62 - Beast Commisioning
#75 - q-profiles
#102 - RF Conditioning

Begin from shot 951116003 and provide constant shots to those who
need them.

Nov 17 1995 08:48:27:450AM951117001John GoetzShot 951117001:
Start from 951116001 - no changes

Results:
plasma - disrupts @ 1.2sec
TCI problems - no gas input after 0.1sec

Nov 17 1995 08:58:36:990AM951117002John GoetzShot 951117002:
no changes

Results:
fizzle - breakdown @ .005
Dalpha slow to burn out

Nov 17 1995 09:10:59:820AM951117003John GoetzShot 951117003:
control passed to the RF group
NL_04 drawn to 1.0e20

Results:
fizzle - breakdown @ .045
base pressure still a bit high post-disruption
Dalpha never really burns out

Nov 17 1995 10:06:22:850AM951117004John GoetzShot 951117004:
cell access for TCI repair
fix blown fuse in OH1


Results:
plasma - killed by Li pellet at 0.76sec
TCI drops out again - density feedback shuts off gas

Nov 17 1995 10:07:58:320AM951117005John GoetzShot 951117005:
switch to z-meter for density feedback
load wire 14, segment2 from 950519005 into wire 14
draw NL_ZMETER to 0.25

Results:
fizzle
large carbon - CII > .04
positive radial field of .0015T

Nov 17 1995 10:44:36:470AM951117006John GoetzShot 951117006:
change BR_0 offset to .007 (was .008)
cell access to play with TCI

Results:
fizzle - breakdown @ .005 - no burnout
carbon levels ~ .002
radial field better

Nov 17 1995 10:45:13:340AM951117007John GoetzShot 951117007:
no changes

Results:
fizzle - breakdown at .005 - no burn out
carbon = .025

Nov 17 1995 11:17:47:860AM951117008John GoetzShot 951117008:
cell access for RF crate fiddling
remove 1msec from pre-puff

Results:
fizzle

Nov 17 1995 11:19:31:910AM951117009John GoetzShot 951117009:
remove 2msec from gas pre-puff (now 13msec)

Results:
plasma - disrupts early
way too much gas - NL_ZMETER drawn too high too early

Nov 17 1995 11:36:43:810AM951117010John GoetzShot 951117010:
ramp up NL_ZMETER demand - 0.7 @ 0.5sec

Results:
fizzle - no burn through on Dalpha
too much carbon light?

Nov 17 1995 11:51:42:470AM951117011John GoetzShot 951117011:
no changes

Results:
plasma - disrupts @ 1.26sec

Nov 17 1995 12:16:42:200PM951117012John GoetzShot 951117012:
RCUR = 0.668 (outer gap is too large)

Results:
fizzle

Nov 17 1995 12:17:33:380PM951117013John GoetzShot 951117013:
V_OH1 = 120V @ .01sec (was 90V)

Results:
plasma - disrupts @ 1.22
30kW of rF
small Li pellet

Nov 17 1995 12:37:42:900PM951117014John GoetzShot 951117014:
no changes

Results:
fizzle

Nov 17 1995 12:39:18:230PM951117015John GoetzShot 951117015:
V_OH1 = 130V from .005 to .015sec
IC_EF4 = -1125A

Results:
plasma - disr. @ 1.21

Nov 17 1995 12:53:20:270PM951117016John GoetzShot 951117016:
no changes

Results:
fizzle - fields look o.k. - carbon a bit high

Nov 17 1995 01:07:49:220PM951117017John GoetzShot 951117017:
no changes

Results:
plasma - disr. @ 1.38
another odd numbered shot
big pellet - no RF

Nov 17 1995 01:25:57:630PM951117018John GoetzShot 951117018:
1msec more prefill puff (indications of early hards from
HIREX & TCX)

Results:
fizzle

Nov 17 1995 01:41:29:820PM951117019John GoetzShot 951117019:
no changes

Results:
plasma - disr. @ 1.45 sec (Ip = .007MA)
big pellet
no RF

Nov 17 1995 01:59:08:070PM951117020John GoetzShot 951117020:
no changes

Results:
plasma - disr. @ 1.29
surprise, surprise, an even-numbered plasma
big pellet - no RF

Nov 17 1995 02:16:36:330PM951117021John GoetzShot 951117021:
no changes

Results:
plasma - all the way down
big pellet
best RF - .06-.08MW

Nov 17 1995 02:44:39:010PM951117022John GoetzShot 951117022:
no changes

Results:
plasma - all the way down
big pellet - RF < 0.2MW

Nov 17 1995 03:01:21:830PM951117023John GoetzShot 951117023:
no changes

Results:
plasma - all the way down
big pellet
Prf < 0.7MW - a little glitch on the stored energy

Nov 17 1995 03:29:42:890PM951117024John GoetzShot 951117024:
no changes

Results:
dud - OH2L pulled out @ -0.75 taking the rest of the
PF's along

Nov 17 1995 03:54:07:350PM951117025John GoetzShot 951117025:
no changes

Results:
fizzle - burnout but no current rise
TF crowbar at 0. sec

Nov 17 1995 04:23:07:340PM951117026John GoetzShot 951117026:
no changes

Results:
fizzle - TF crowbar @ -.005 - comm fault, but not really
induces some radial field wiggle

Nov 17 1995 04:32:48:540PM951117027John GoetzShot 951117027:
no changes

Results:
plasma - disr. @ 0.76 (pellet death)
TF crowbar @ -.02 -> EF3 begins to go @ 0.55
-> lose control of plasma
Prf < 0.8MW

Nov 17 1995 05:00:46:360PM951117028John GoetzShot 951117028:
no changes

Results:
fizzle - no burn out - high CII
probably post-disruption syndrome

Nov 17 1995 05:15:25:310PM951117029John GoetzShot 951117029:
no changes

Results:
plasma - all the way down
big pellet
Prf < 1.4MW

Engineering Operator Comments
ShotTimeTypeStatusComment
108:31:04:330AMPlasmaOk
208:48:33:530AMPlasmaOk
308:58:22:020AMPlasmaOk
409:26:03:450AMPlasmaOk
509:55:35:770AMPlasmaOk
610:15:18:560AMPlasmaOk
710:29:26:470AMPlasmaOk
810:48:30:850AMPlasmaOk
911:06:54:240AMPlasmaOk
1011:24:34:050AMPlasmaOk
1111:41:51:000AMPlasmaOk
1211:55:18:860AMPlasmaOk
1312:05:15:810PMPlasmaOk
1412:21:21:200PMPlasmaOk
1512:29:55:040PMPlasmaOk
1612:45:52:440PMPlasmaOk
1712:59:24:610PMPlasmaOk
1801:15:58:060PMPlasmaOk
1901:25:25:410PMPlasmaOk
2001:47:40:040PMPlasmaOk
2102:07:21:270PMPlasmaOk
2202:33:12:910PMPlasmaOk
2302:51:30:470PMPlasmaOk
2403:07:29:380PMPlasmaBadPower supply comm. faults.
2503:35:52:150PMPlasmaBadTF comm fault
2604:01:30:340PMPlasmaBadTf comm fault
2704:23:06:470PMPlasmaBadtf comm fault
2804:53:29:940PMPlasmaOk
2905:01:01:530PMPlasmaOk