Alcator C-Mod Run 990122 Information

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Miniproposals
Miniproposal:206
Date Filed:12/31/1998
Title:Restart Operation: January 1999
First Author:Steve Wolfe
Session Leader:Steve Wolfe (shots 1-28)

Operators
Session leader(s):Steve Wolfe
Physics operator(s):John Goetz
Engineering operator(s):Gary Dekow,Bill Cochran,Dave Terry

Engineering Operator Run Comment
MP 206/Wood/Goetz/Cochran/Silva/Dekow/D.Terry/

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:18:540PM
Author: To Be Determined
Run Summary for Friday, 990122

MP#206 Restart Operation 1999
SL wolfe
PO goetz
EO cochran,terry

Today's run continued the attempts to get plasma begun yesterday. We had 10-12
hours of ECDC last night, with the sweep adjusted to go further out and also
in to the inner wall. The goal today was to get plasma, as opposed to fizzles
and duds.

We were successful in getting plasma shots (defined as currents above 50kA) on
#12, 19, and 23. Maximum current was 300kA, and maximum pulse length was
0.11sec (just into the second segment, which was actually seg#4). Considering
where we are in the conditioning process, this was a very successful run,
though there is clearly a long way to go.

We started with a series of tests to try to determine the cause of the EF4
supply failures at the end of yesterday's run. We had one early invert, on
shot 3, but were unable to identify the cause, and the next test ran
successfully. We then proceeded with the run, with extra instrumentation in
the EF4.

We were successful in getting flashes, i.e. fizzles, from the first attempt
(loaded from yesterday's one flash 990121016). Aside from two duds due to EF4
failures, we had only one dud all day. This may be attributable to the use of
the sparker today to provide some pre-ionization, or it may be due to last
night's ECDC.

The first successful current rise was obtained after a couple of oh voltage
tweaks, and reached 300kA before choking on too much density and dirt. The
loop voltage was over 7V. All three of today's plasmas were very resistive and
came to early ends. CII levels after the plasmas were in the .02 to .03
mW/cm2/ster range, as compared to levels of .001 to .002 in a clean machine.

Earl and Teresa measured H/D ratios based on Balmer-alpha emission on the
fizzles and on the plasmas. The hydrogen fraction was observed to rise as we
pulsed, and H/D approached one during an h-alpha burst on shot 23.

John Rice reported that HIREX saw chlorine on shot 19.

Spencer Pitcher operated the flappers from his home in Toronto. All flappers
appear to open successfully. I propose we count this as an example of
international remote collaboration.

The H-port ECE diagnostics, including the Princeton GPC2 instrument, are
operational. Amanda was reporting temperatures in the 1keV range on the plasma
shots.

The EF4 forced invert problem recurred on shot 13 and 18. The problem was
traced to a DFOL signal derived from the fizzle detector, and a one-shot was
added to prevent a glitch on this line from causing a forced invert. There
were no further instances of spurious inverts today. The engineers will
continue to pursue this on Monday.

TCI was off-line at the start of the run due to a laser problem. The laser
power was low and unstable, leading to lots of fringe jumping on the
interferometer. This was apparently caused by a thermal problem. The laser
power drifted back up during the day, and useable signals were present for all
the plasmas shots. However, we turned off density feedback and left it off,
since Jim couldn't guarantee that the laser would stay on.

There were two hybrid-related problems today. Prior to the run, while trying
to understand the OH2 imbalance problem on shot 990121020 I discovered that
the V_OH2U waveform (output 19 from the WAVEGEN) was apparently dead. The
signal has in fact been dead for a long time, at least back to test shot #420
in October, 1998. However, after a lot of running back and forth and swapping
cables, and half a dozen test shots, it was determined that the problem is in
fact with the digitizer channel (or maybe the cable), rather than the actual
output. The proper waveform was observed on the M-out signals, and by using a
different digitizer. Shot 990121020 is still a mystery.

The second hybrid problem was related to the TCI failure. The NL04 input to
the hybrid was swinging wildly from -10V to +10V, causing big jumps in the PG3
output voltage. It was found that even with the gain turned to zero on the
NL04 wires, the saturating signals still came through the PID as spikes and
glitches that ended up on the Mout. This was fixed by setting the NL04
controllers to zero. NOTE: Anyone using today's shots must be aware that the
NL04 wires are doubly turned off, as just described. Copying a wire from one
of yesterday's shots, or from 980220003 segment 4, will put everything back
the way it was.

There was a minor power supply problem with EF1L that did not impact the run,
but should be fixed (again). Starting from shot 5 (the first shot on which it
was run), EF1L behaved as though there is an offset in the voltage
command. This phenomenon has been seen many times in the past, and is most
easily identified by the sudden jump up in negative voltage at supply turn-on,
while the hybrid demand is in fact swinging slightly positive. In the past,
this effect has vanished when instrumentation to track it down was installed.

Physics Operator Summaries
Entered: Jul 7 2004 04:36:59:850PM
Author: To Be Determined
Physics operator summary for 990122

EO: Cochran/Terry/Dekow
PO: Goetz
SL: Wolfe

Run 990122 was in support of Mini-Proposal #206 - Restart Operation: January
1999. This proposal is to resume plasma operations after the recent shutdown
and to provide suitable target plasmas for alignment, calibration, etc., of
main diagnostic systems.

The run today produced three plasmas. However, none were of research quality,
as was to be expected on the second day of operational restart. The run today
was much better than yesterday. Of all the attempts that had power supplies,
only one dud resulted. The overnight ECDC was swept in-and-out further and
some of today's success may be attributed to this.

Began with pre-puff widths of 26ms and ended at 16ms. It appears that the dud
on shot 25 was due to low prefill. The voltage on the OH stack after
commutation was raised to change the Bz ramp-rate. 100V was added to the
OH1 and 20V to the OH2. Future users of these shots should be aware of these
changes and remove them if current rise hesitation is observed. It was also
necessary to perform the usual tweaks in Br and Bz as warranted by the flux
plots. A Br offset of 2.5mT was used for most of the day, but was reduced to
2.0mT at the end.

Engineering, computing, and diagnostics today:
The EF4 power supply had problems today - shutting off before t=0 or
not even turning on. This was linked to a DFOL problem with the
fizzle detector input. A "filter" was added to the ladder logic of EF4
to smooth out any incoming noise. No trips occured after the fix. The
interferometer was not behaving well early today. Therefore, the
controller for NL_04 was zeroed in both segments 1 and 4. Future
users of today's shots must be aware of this if density feedback is
required. CAMAC errors happened with regularity today and involved
many different trees.

Scorecard: 28 shots = 3 plasmas + 18 fizzles + 1 dud + 2 eng. duds + 4 tests

Shot summary for Run 990122:

Load 990121016
coldstart hybrid - all matrices respond
- the V output of channel 3 of the hybrid is not
being digitized properly (see SL logbook
for detailed discussion)

Shot change result
____ _____ ______
1 cycle to reset CRYO PLC

2 EF4 PLC test -2000A; o.k.

3 EF4 PLC test +1500A; oscillation + early PLC invert

4 EF4 PLC test +1500A; o.k.

5 load 990121016; fizzle; b.d. @ .006; no current
turn off P gain on NL04;

6 no changes fizzle; b.d. @ .006; 5kA

7 PG4=22ms; zero NL4 controller fizzle; b.d. @ .006 5kA of current
in segs 1 & 4

8 Br_0 offset = .0025 fizzle; b.d. @ .0055; 7.5kA of current

9 ICEF4=-1330A fizzle; b.d. @ .0057; 7.5kA of current
some z-meter burn-out

10 PG4=20msec fizzle; b.d. @ .0065; same current

11 V_OH1=[150,110,70]V @ fizzle; b.d. @ .0065; a bit more current
[.005,.007,.008]s; V_OH2=
10V @ .007s

12 V_OH1=[200,160,120]V @ plasma; b.d. @ .006; Ip=0.3MA; Vloop=6V
[.005,.007,.008]s; V_OH2=
20V @ .007s

13 no changes dud; EF4 dead @ -0.68s (PLC invert)

14 less PG3 between .05 & .1s fizzle; b.d. @ .0065; few bits of Ip

15 no changes fizzle; b.d. @ .0065; less CII; some
burnout on z-meter

16 ICEF4 = -1340A fizzle; b.d. @ .0065; less CII

17 PG4=18ms fizzle; b.d. @ .006

18 V_OH1=[225,185,145]V @ dud; EF4 didn't turn on
[.005,.007,.008]s; V_OH2=
25V @ .007s

19 see above plasma; disr. @ .11; Ip=.24MA; rubs
something @ .082

20 PG3=30V in segment 1 fizzle; b.d. @ .011; 1 bit of current

21 no changes fizzle; b.d. @ .0062; Ip=7.5kA

22 no changes fizzle; b.d. @ .0065; Ip=10kA

23 no changes plasma; b.d. @ .0072; Ip=.24MA; disr.
@ .085; influx of H2 at .069

24 no changes fizzle; b.d. @ .0067; no z-meter burnout

25 V_OH1=[200,160,120]V at dud; Br oscillation?
[5,7,8]ms; V_OH2=20V at 7ms

26 PG4=18ms fizzle; b.d. @ .0065; Br oscillation
still there

27 no changes fizzle; b.d. @ .007; Ip=15kA; little
z-meter burn-out; Br too positive?

28 Br_0=.002 fizzle; b.d. @ .0055; Ip=15kA; almost!

Session Leader Comments
Jan 22 1999 10:06:34:767AM990122002Steve WolfeShot 2: EF4 PLC test -2000A. OK
There is about 50A difference current.

It looks like EFc_l rogowski may be fixed; it sees a bit or so of induced current (or pickup)
Jan 22 1999 10:23:26:450AM990122003Steve WolfeShot 3: EF4 PLC test +2000A.
Inverted early?

PG3 output looks funny.

TCI is gronked. Turn off nl_04 feedback and take a test shot.
453: looks reasonable now. V3 camac is still dead.
Jan 22 1999 10:45:58:517AM990122004Steve WolfeShot 4: Repeat to see why it inverted. Worked this time
Jan 22 1999 10:57:37:020AM990122005Steve WolfeShot 5: Full shot (plasma attempt)
flash. bd at 6msec, CII at .015

The Mout pg3 signal is screwed up . Lots of glitches and spikes.
I can't tell if they are actually going downstairs or just on digitizer output,
because the fd takes it out, and it's the duty cycle board anyway.
Jan 22 1999 11:17:18:460AM990122006Steve WolfeShot 6: No changes, another flash

The TCI output is going berserk. Even though the gain is off in on NL_04, the spikes show up
at the PID outputs. Wire 5 in Seg 1, Wire 13 in seg 4.

For next shot, zero the controllers on NL04 in both segments.
Jan 22 1999 11:31:42:240AM990122007Steve WolfeShot 7: Lower pre-puff.
Flash. A little better, CII=.02
Br develops a negative value after commutation.
Jan 22 1999 11:49:42:483AM990122008Steve WolfeShot 8: Br more positive by 0.5mT (risk the bd)
flash, looked brighter on the tv, but the traces are very similar.

Earl reports the last one was at 5.1T (just outside) based on Zeeman data!
Jan 22 1999 12:08:34:220PM990122009Steve WolfeShot 9: Make ef4 more positive by 15A.
flash - looks very similar, CII a little lower.

Sparker killed the oh bus camac, generating a spurious high oh resistance message.
Jan 22 1999 12:19:54:450PM990122010Steve WolfeShot 10: lower the pre-puff.
flash, bd at 6.3msec. CII=.018
Jan 22 1999 12:36:25:383PM990122011Steve WolfeShot 11: Try a V_OH tweak, +50V on OH1, +10V on OH2's.
This should make current rise faster, Bz rise slower; it's not obvious that's the right direction,
but can always go the other way.
flash, a bit more current, CII=.02.
TCI is coming back to life.

Next shot, try more of the same.
Jan 22 1999 01:00:23:923PM990122012Steve WolfeShot 12: Same OH tweaks again, for a net of 100V on OH1, 40V on OH2's
Spencer just asked permission to run the flapper from home (Toronto).

Plasma. lasted to 90msec, got to 300kA
CII=.016, Halpha burns out.
Loop voltage is around 6V the whole time.
ECE says about 1 Hubbard unit.
Jan 22 1999 01:10:04:057PM990122012Steve WolfeShot 12: Same OH tweaks again, for a net of 100V on OH1, 40V on OH2's
Spencer just asked permission to run the flapper from home (Toronto).

Plasma. lasted to 90msec, got to 300kA
CII=.016, Halpha burns out.
Loop voltage is around 6V the whole time.
ECE says about 1 Hubbard unit.

Jan 22 1999 01:40:55:010PM990122013Steve WolfeShot 13: No changes.
Dud. EF4 inverted early.

Jan 22 1999 01:40:30:573PM990122014Steve WolfeShot 14: PG3 change in seg 1 and 4.
fizzle, CII=0.03, z-meter climbs
Jan 22 1999 01:40:13:180PM990122015Steve WolfeShot 15: fizzle
Jan 22 1999 01:42:34:833PM990122015Steve WolfeShot 15: fizzle
CII=.026, hints of burnout on z-meter.
Jan 22 1999 02:01:01:213PM990122016Steve WolfeShot 16: EF4 10A more negative.
Flapper disabled (according to CSP)

fizzle. CII=.024
Bz definitely more negative this time.

Jan 22 1999 02:14:29:367PM990122017Steve WolfeShot 17: Drop gas to 18msec from 20msec

fizzle. CII=.023
Jan 22 1999 02:30:08:537PM990122018Steve WolfeShot 18: Drop gas to 16msec
Add another 25V to OH1, 5V to OH2's

EF4 dud.
Jan 22 1999 05:18:39:587PM990122019Steve WolfeShot 19: Repeat of 18, hopefully with EF4
(Drop gas to 16msec
Add another 25V to OH1, 5V to OH2's)

plasma. Bad hesitation at 40kA, got to 240ka, .11sec
TRAQ1 magnetics data was corrupted, so EFIT had a problem.
CII=.23

Jan 22 1999 03:13:11:150PM990122020Steve WolfeShot 20: Reduce seg pg3 to 30V
fizzle. bd at 11msec.
Jan 22 1999 03:27:42:033PM990122021Steve WolfeShot 21: no change
fizzle. bd back at 5.8msec, CII=.028
Jan 22 1999 03:42:44:110PM990122022Steve WolfeShot 22: fizzle
CII=.026
Jan 22 1999 04:07:37:137PM990122023Steve WolfeShot 23: no changes
plasma 220kA to 0.09sec
CII=.024
Earl & Teresa claim H/D is nearly 1
Jan 22 1999 04:12:13:613PM990122024Steve WolfeShot 24: no changes- get the fizzles out of the way
fizzle
CII=.030mW/cm2/ster
Jan 22 1999 04:28:14:527PM990122025Steve WolfeShot 25: changed V_oh's back like 12
dud
Br looks a litle positive.
Jan 22 1999 04:39:08:247PM990122026Steve WolfeShot 26: raise the gas
fizzle
CII=.026
Jan 22 1999 05:01:46:440PM990122028Steve WolfeShot 28:
fizzle - almost made it. Current got to 40kA, CII=.022
Z-meter almost burned out.
bd at 5msec

Physics Operator Comments
Jan 22 1999 08:21:35:350AMJohn GoetzRun Plan for 990122 -- MP#206 Restart Operation: January 1999

Engineering setup
-----------------
Overnight ECDC in D2 (as much as possible)
Gas setup:
B-top 6psi D2 Hybrid enabled
B-side lower 3psi Ar NOT enabled for 1st shot
"K-side" 30psi D2 Hybrid enabled

PF as on 990121015
TF under hybrid control, current limit set at 160kA, timing as on 990121015

Physics setup
-------------
PCS setup as on 990121015 for first try. Start from there and tweak up until
we get a flash or give up. If we get one, observe impurity signals, e.g. CII
signal and Z-meter to assess cleanliness. Also observe RGA after shots. If not
totally discouraged, try a limited number of shots for current rise. If it
looks dirty (as expected) resume ECDC.
Jan 22 1999 09:28:13:217AMJohn GoetzRun 990122

Hybrid problems - VOUT_3 (which is OH2_U) is not being digitized correctly.

The Ratiomatic in use today is a new gauge installed on G-side. It is currently reading
approximately 4x the torus gauge
Jan 22 1999 09:57:41:240AM990122001John GoetzFor shot 990122001:
cycle to reset the CRYO PLC
Jan 22 1999 10:00:13:620AM990122002John GoetzFor shot 990122002:
EF4 test under PLC control

Result:
-2000A -> o.k.
Jan 22 1999 10:16:48:560AM990122003John GoetzFor shot 990122003:
EF4 test under PLC control

Result:
1500A -> oscillation and an early invert from the PLC
Jan 22 1999 10:33:27:343AM990122004John GoetzFor shot 990122004:
EF4 test under PLC control

Result:
1500A -> smaller oscillation but otherwise o.k.
Jan 22 1999 10:56:01:143AM990122005John GoetzFor shot 990122005:
coldstart hybrid @ 0800 - all matrices respond
load 990121016
TCI laser problems - turn off P gain on NL_04 in segment 4 (was P=4)

Result:
fizzle
breakdown @ .006s
no current
Jan 22 1999 11:07:31:777AM990122006John GoetzFor shot 990122006:
no changes

Result:
fizzle
breakdown @ .006s
1 bit of current
Jan 22 1999 11:27:31:550AM990122007John GoetzFor shot 990122007:
zero NL_04 controller in segments 1 and 4 (because of spikes from the TCI input)
PG4 = 22ms (was 26)

Result:
fizzle
breakdown @ .006s
1 bit of current - 5kA
Session leader believes the ball o' plasma is moving vertically
Jan 22 1999 11:50:48:110AM990122008John GoetzFor shot 990122008:
BR_0 offset = .0025
spikes on PG3 output fixed by turning off NL_04 controller

Result:
fizzle
breakdown @ .0055s
2-3 bits of current - 7.5kA
H_alpha/D_alpha monitor indicates plasma at 5.1T
Jan 22 1999 12:02:03:210PM990122009John GoetzFor shot 990122009:
ICEF4 = -1330A (was -1345A)

Result:
fizzle
breakdown @ .0057s
2-3 bits of current - 7.5kA
some "burning out" evident on the z-meter signal
Jan 22 1999 12:22:56:060PM990122010John GoetzFor shot 990122010:
PG3 = 20ms

Result:
fizzle
breakdown @ .0065s
same current but a little less z-meter light
Jan 22 1999 12:37:30:047PM990122011John GoetzFor shot 990122011:
V_OH1: [150,110,70]V @ [.005,.007,.008]s
V_OH2: 10V @ .007s
these changes are for changing the Bz ramp rate

Result:
fizzle
breakdown @ .0065s
a bit more current and lots of CII light
Jan 22 1999 01:00:45:773PM990122012John GoetzFor shot 990122012:
V_OH1: [200,160,120]V @ [.005,.007,.008]s
V_OH2: 20V @ .007s
these changes are for changing the Bz ramp rate

Result:
plasma
breakdown @ .006s
disrupts @ 0.095s; 0.30MA
loop voltage of about 6V
Jan 22 1999 01:12:29:787PM990122013John GoetzFor shot 990122013:
no changes

Result:
dud
EF4 dead at -0.68s
Jan 22 1999 01:29:40:470PM990122014John GoetzFor shot 990122014:
less PG3 between 0.05 and 0.1s

Result:
fizzle; breakdown @ .0065
lot of CII light
few bits of current
Jan 22 1999 01:45:02:703PM990122015John GoetzFor shot 990122015:
no changes

Result:
fizzle - breakdown @ .0065
CII light coming down; a little burn-out on the z-meter
Jan 22 1999 02:00:44:900PM990122016John GoetzFor shot 990122016:
ICEF4 = -1340A (Bz is a touch positive now)

Result:
fizzle - breakdown @ .0065
Bz change is evident but doesn't drastically change the breakdown
CII decreasing shot-to-shot; z-meter burning out
Jan 22 1999 02:17:01:693PM990122017John GoetzFor shot 990122017:
PG4 = 18ms

Result:
fizzle - breakdown @ .006
not much change in the visible signals, but the CII is dropping slightly
Jan 22 1999 02:35:11:860PM990122018John GoetzFor shot 990122018:
PG4 = 16ms
V_OH1 = [225,185,145]V at [.005,.007,.008]s
V_OH2 = 25V at .007s

Result:
dud
EF4 did not turn on
Jan 22 1999 03:07:44:420PM990122019John GoetzFor shot 990122019:
PG4 = 16ms
V_OH1 = [225,185,145]V at [.005,.007,.008]s
V_OH2 = 25V at .007s

Result:
plasma - disrupts @ 0.11s; Ip = 0.24MA
breakdown @ .007s
plasma begins rubbing on something at .082s
nl04 = 1e20 before disruption
magnetics data problems on this shot
Jan 22 1999 03:16:16:007PM990122020John GoetzFor shot 990122020:
PG3 = 30V in segment 1

Result:
fizzle
breakdown @ .0106s?!?!?
only a bit or so of current
Jan 22 1999 03:27:52:987PM990122021John GoetzFor shot 990122021:
no changes

Result:
fizzle
breakdown @ .0062s
Ip = 7.5kA; slight burn-out on z-meter
Jan 22 1999 03:42:57:800PM990122022John GoetzFor shot 990122022:
no changes

Result:
fizzle
breakdown @ .0062s
Ip = 10kA; slightly more burn-out on z-meter
Jan 22 1999 04:10:44:823PM990122023John GoetzFor shot 990122023:
no changes

Result:
plasma
Ip = 0.24MA; disrupts @ .085; large influx of hydrogen at 0.69s
Jan 22 1999 04:12:47:943PM990122024John GoetzFor shot 990122024:
no changes

Result:
fizzle
breakdown @ .0067
no burn-out on the z-meter
Jan 22 1999 04:29:18:447PM990122025John GoetzFor shot 990122025:
V_OH1 = [200,160,120]V at [.005,.007,.008]s
V_OH2 = 20V at .007s
to get rid of the hesitation on the NEXT current rise

Result:
dud
Br oscillation at .005s - just the wrong time?
Jan 22 1999 04:42:07:533PM990122026John GoetzFor shot 990122026:
PG4 = 18ms

Result:
fizzle; breakdown @ .0065
z-meter level getting lower
Br oscillation still there; 025 dud must have been from lack of gas
Jan 22 1999 04:52:30:347PM990122027John GoetzFor shot 990122027:
no changes

Result:
fizzle; breakdown @ .007
Ip=15kA; slight burn-out on the z-meter signal
Jan 22 1999 05:02:28:710PM990122028John GoetzFor shot 990122028:
Br_0 offset = .002

Result:
fizzle; breakdown @ .005
Ip=15kA; almost went
radial field looks good

Engineering Operator Comments
ShotTimeTypeStatusComment
108:56:31:753AMTestOkross relay test
209:57:07:170AMTestOkef4 forward test
310:07:30:067AMTestOkef4 reverse test
410:27:40:017AMTestOkef4 reverse test
510:46:26:627AMPlasmaOkplasma shot
611:03:10:080AMPlasmaOkplasma shot
711:19:47:503AMPlasmaOkplasma shot
811:43:37:590AMPlasmaOkplasma shot
911:56:39:883AMPlasmaOkno faults
1012:13:10:400PMPlasmaOkno faults
1112:30:51:433PMPlasmaOkno faults
1212:46:56:523PMPlasmaOkno faults
1301:08:26:887PMPlasmaBadEarly Invert on EF4
1401:24:18:467PMPlasmaOkpower supplies ok
1501:38:30:170PMPlasmaOkpower supplies ok
1601:53:11:737PMPlasmaOkpower supplies ok
1702:09:28:433PMPlasmaOkpower supplies ok
1802:28:14:870PMTestBad
1902:52:31:857PMPlasmaOkplasma
2003:09:42:470PMPlasmaOkno faults
2103:23:36:327PMPlasmaOkno faults
2203:37:45:480PMPlasmaOkno faults
2303:54:28:100PMPlasmaOkNo Faults
2404:09:19:473PMPlasmaOkNo Faults
2504:22:36:820PMPlasmaOkNo Faults
2604:35:37:790PMPlasmaOkNo Faults
2704:46:21:227PMPlasmaOkNo Faults
2804:57:19:423PMPlasmaOkNo Fault