Alcator C-Mod Run 950324 Information

Back to runs

Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Steve Golovato (shots 1-36)

Operators
Session leader(s):Steve Golovato
Physics operator(s):Earl Marmar
Engineering operator(s):Vinny Bertolino

Engineering Operator Run Comment
G./Marmer

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:12:790PM
Author: To Be Determined
run summary - 950324
---------------------

SL: golovato
PO: marmar
EO: bertolino

This was a successful run. We re-established operation of the D-port antenna
at high power (this was the antenna that had a damaged feedthrough from
undetected arcing. Yesterday we had established that the new balance arc detector
worked. After the run we also vacuum conditioned D-port to 50kV for 15ms pulses.
Today we were able to run D-port up to 1.3 MW and E-port to a similar
power. We still had some interactions between the antennas which prevented
running them simultaneously. On the last shot we got a brief period with both
at 2.3 MW. We believe that the problem has to do with pickup between the antennas
confusing the balance detectors.

We spent the first 18 shots at low power wrestling with problems primarily
with the reflected power arc detection. We were being very cautious but
eventually just raised the threshold for reflected power by a large amount,
assuming that it was miscalibrated. We then increased the power slowly and
purposely mistuned to ensure that we got trips and to see at what level.
It turned out to be <~10%, which is about what we wanted in the first place.
We got to this point at shot 22. Shots 24-36 involved raising the power,
varying the balance detector thresholds, and varying the density to observe
loading changes. We had no problems going up to 1.3 MW on D-port. This was
the maximum we tried, not the power limit, We had about 10 Ohms of loading
at nl04=1.8e20, outer gap of 1.2 cm, and a voltage of 26 kV at 1.1 MW of power.

The session leader shot-to-shot summary can be found in the logbook under the
session_leader topic. Details on technical difficulties can be found in the
physics operator summary.

The shot summary was: 30 plasmas
3 fizzles
2 dud
1 power supply test shot



Physics Operator Summaries
Entered: Jul 7 2004 04:36:53:630PM
Author: To Be Determined
950324 RF tuning

PO Marmar
SL Golovato
EO Bertolino

ECDC was run in D2 overnight, stopped at 7:00 am

This was quite a successful run. RF power in excess of 1 MW was coupled
through each of the antennas, and on shot 36, over 2 MW was injected for a
short time. H-Modes occurred on many shots.

There were a couple of engineering problems:

A side would not fill the machine, so we switched to B side upper for fill and
pulse. It had had CH4 in the plenum; it was purged multiple times and filled
with D2 at 18.5 PSI. B side lower was used throughout the day.

On shot 14, there was a problem with an encoder not initializing properly,
which in turned appeared to be the cause of multiple difficulties. The
initialization problem did not recur, and Wolfe informed me that Fredian
modified software so that if this problem does recur, transition to Check will
be prevented.

See the Session Leader's summary for details of the progress on the RF front.

There were 3 bouncing fizzles, which were apparently cured by
progressively raising the fill pressure through the day.

1 OH1 problem (Vinnie says there was a switch fault), dud
2 Plasma. B side upper was not in the feedback loop, so the gas programming
came from the pre-programmed waveform. fill 2.0e-5
3 Put B side upper into the feedback loop. fill 2.0e-5; fizzle (bouncer)
4 fill 2.3e-5, moved zcur down by 4 mm, plasma, Irby reports a piece of
something fell onto the TCI window
5 enable argon, plasma, nasty injection at .77 s,
6 plasma, some vertical oscillation during rampdown
7 lower ZXL by 5 mm during flattop, start nl_04 rampdown at 0.8 s, plasma
8 repeat, plasma
9 Li pellet at 1.0 s, plasma, disrupt after pellet
10 no pellet, plasma, we are routinely going into ELMy H-Mode shortly after 1 s
11 repeat, plasma
12 repeat, plasma
13 Li pellet at 1.3 sec, plasma
14 dud, appears that magnetics did not initialize properly, which in turn may
have prevented the integrators from resetting; the data are missing because
the CAMAC was not initialized
15 test, EFC only
16 lower EFC voltage limit to 600 from 700, tweaked early gas, plasma
17 repeat, plasma
18 repeat, plasma
19 repeat, plasma
20 increase nl_04 programming to keep ramping up to 1.5e20, plasma
21 fiddle with zcur gains after 1.2 seconds, lower nl_04 to 0.5 during RF,
plasma
22 delay density rampdown to start at about 0.6 s, change clearin ramp after
1.0 s, plasma, density never came down
23 fizzle, bouncer
24 fill 2.4e-5, reload shot 19, plasma
25 repeat, plasma,
26 re-fill plenum to 19.5 psi (from 17), plasma, big burst of early MHD
27 repeat, plasma
28 tweak up early gas, plasma
29 increase density programming (1.3 ramping to 1.5) plasma
30 nl_04 to give flattop at 1.5e20, fizzle
31 fill to 2.6e-5, plasma, reached density later than programmed
32 keep density up until 1.0 s, plasma
33 repeat, higher RF power, plasma; h-mode during RF; magnetics data
acquisition problem, Ip, Bt bad data; plasma seems fine
34 repeat, magnetics ok, plasma
35 repeat plasma,
36 Li pellet at 1.03 s, did not see it on the fast TV, plasma


35 attempts, 2 duds, 3 fizzles, 30 plasmas; 1 test.

From: PHYSOP::MARMAR
Date: 24-MAR-1995 18:45:31
Description: Physop run summary 950324

950324 RF tuning

PO Marmar
SL Golovato
EO Bertolino/Daigle

ECDC was run in D2 overnight, stopped at 7:00 am

This was a successful run. RF power in excess of 1 MW was coupled through each
of the antennas, and on shot 36, 2.3 MW total was injected for a short
time. H-Modes occurred on many shots.

There were a couple of engineering problems:

A side would not fill the machine, so we switched to B side upper for fill and
pulse. It had had CH4 in the plenum; it was purged multiple times and filled
with D2 at 18.5 PSI. B side upper was used throughout the day. After the run,
John Goetz discovered that the hand valve for the A-side piezo had been
closed; opening this solved the problem.

On shot 14, there was a problem with an encoder not initializing properly,
which in turned appeared to be the cause of multiple difficulties: the
integrators did not reset, the hybrid thought there was a big B_R, OH2L was
jerked around at -0.8s and never reached appropriate current at breakdown, EFC
had a 4 KA spike. The initialization problem did not recur, and Wolfe informed
me that Fredian modified software so that if this problem does recur,
transition to Check will be prevented.

See the Session Leader's summary for details of the progress on the RF front.

There were 3 bouncing fizzles, which were apparently cured by
progressively raising the fill pressure through the day. These fizzles were
the only shots today which showed any evidence of hard x-rays.

1 OH1 problem (Vinnie says there was a switch fault), dud
2 Plasma. B side upper was not in the feedback loop, so the gas programming
came from the pre-programmed waveform. fill 2.0e-5
3 Put B side upper into the feedback loop. fill 2.0e-5; fizzle (bouncer)
4 fill 2.3e-5, moved zcur down by 4 mm, plasma, Irby reports a piece of
something fell onto the TCI window
5 enable argon, plasma, nasty injection at .77 s,
6 plasma, some vertical oscillation during rampdown
7 lower ZXL by 5 mm during flattop, start nl_04 rampdown at 0.8 s, plasma
8 repeat, plasma
9 Li pellet at 1.0 s, plasma, disrupt after pellet
10 no pellet, plasma, we are routinely going into ELMy H-Mode shortly after 1 s
11 repeat, plasma
12 repeat, plasma
13 Li pellet at 1.3 sec, plasma
14 dud, appears that magnetics did not initialize properly, which in turn may
have prevented the integrators from resetting; the data are missing because
the CAMAC was not initialized
15 test, EFC only
16 EFC voltage limit lowered to 600 from 700, tweaked early gas, plasma
17 repeat, plasma
18 repeat, plasma
19 repeat, plasma
20 increase nl_04 programming to keep ramping up to 1.5e20, plasma
21 fiddle with zcur gains after 1.2 seconds, lower nl_04 to 0.5 during RF,
plasma
22 delay density rampdown to start at about 0.6 s, change clearin ramp after
1.0 s, plasma, density never came down
23 fizzle, bouncer
24 fill 2.4e-5, reload shot 19, plasma
25 repeat, plasma,
26 re-fill plenum to 19.8 psi (from 17), plasma, big burst of early MHD
27 repeat, plasma
28 tweak up early gas, plasma
29 increase density programming (1.3 ramping to 1.5) plasma
30 nl_04 to give flattop at 1.5e20, fizzle
31 fill to 2.6e-5, plasma, reached density later than programmed
32 keep density up until 1.0 s, plasma
33 repeat, higher RF power, plasma; H-mode during RF; magnetics data
acquisition problem, Ip, Bt bad data, EFIT useless; plasma seems fine
34 repeat, magnetics ok, plasma
35 repeat plasma,
36 Li pellet at 1.03 s, did not see it on the fast TV, plasma


35 attempts, 2 duds, 3 fizzles, 30 plasmas; 1 test.

Session Leader Comments
Mar 24 1995 09:19:48:970AMSteve GolovatoGoals - Continuation of yesterday's run, that is, bring up power
on D-port antenna, evaluate new arc protection circuitry.

Yesterday we re-established the tuning for D-port and established
that the new balance arc detector worked. After the run we also
vacuum conditioned D-port to 50kV for 15ms pulses.

Mar 24 1995 09:20:32:000AM950324001Steve GolovatoShot 950324001 - dud. PS problem.

Mar 24 1995 09:24:56:920AM950324002Steve GolovatoShot 950324002 - plasma. A-side valve is not responding. went to
b-side-upper but forgot to put it in feedback loop. therefore we
got only programmed gas, density too low, rf not tuned.

running conditions - nl04=1.e20, o-gap=1.5cm, plasma up-down centered.
e-port at .3mw, .9-1.0sec. d-port varying from .3-.75sec.

Mar 24 1995 09:25:12:420AM950324003Steve GolovatoShot 950324003 - fizzle.

Mar 24 1995 09:43:37:030AM950324004Steve GolovatoShot 950324004 - plasma. less interrupts on d-port but still some.
not clear whether they are reflected power or balance. the changes
may indicate a too sensitive detector or true arcing, with progressive
improvement from conditoining.

Mar 24 1995 09:54:08:260AM950324005Steve GolovatoShot 950324005 - plasma. lowered power a little on d-port.
worked, no arcs at 30kw.

Mar 24 1995 10:03:44:210AM950324006Steve GolovatoShot 950324006 - plasma. stepped power to look for threshold for
arc detection. ran without arcs.

Mar 24 1995 10:39:43:560AM950324007Steve GolovatoShot 950324007 - moved e-port to .9-1.0sec. extened d-port
to .85sewc. have 5 steps in power to study threshold for arcing and
condition up in power.

plasma. no power steps, rf power camac screwed up.

Mar 24 1995 10:43:35:470AM950324008Steve GolovatoShot 950324008 - rf,power control fixed, have some steps.
plasma. trips started at about 40kw, around 4.1 volts on bira.

Mar 24 1995 11:02:10:680AM950324009Steve GolovatoShot 950324009 - finer steps, .05 v on bira instead of .1v.
threshold between 4.05 and 4.1 v.

Mar 24 1995 11:16:40:090AM950324010Steve GolovatoShot 950324010 - plasma. raised balance detector threshold.
tripped at 4.15v.

Mar 24 1995 11:18:10:560AM950324011Steve GolovatoShot 950324011 - plasma. made ramp instead of steps, went to higher
power. tripping starts about same place, 4.15v.

Mar 24 1995 11:30:31:260AM950324012Steve GolovatoShot 950324012 - making reflected power trip less sensitive, see
if rf runs longer. ran shorter.

Mar 24 1995 11:44:28:470AM950324013Steve GolovatoShot 950324013 - raised balance detector threshold.
plasma. no change in trippng behavior.

Mar 24 1995 12:28:13:650PM950324014Steve GolovatoShot 950324014 - removed power feedback from d-port transmitter.
lowered e-port power, was interrupting last shot.
dud, ps problems.

Mar 24 1995 12:30:26:710PM950324015Steve GolovatoShot 950324015 - test of chopper and magnetics.

Mar 24 1995 01:02:00:330PM950324016Steve GolovatoShot 950324016 - plasma. d-port power set too low without feedback.

Mar 24 1995 01:03:16:470PM950324017Steve GolovatoShot 950324017 - plasma. d-port still tripping at about the same
power level even without feedback circuit. reflected power very low,
rho_P < .01 .

Mar 24 1995 01:06:59:640PM950324018Steve GolovatoShot 950324018 - raised balance threshold to maximum.
plasma. still trips at same point. must be reflected power trip.

Mar 24 1995 01:25:53:910PM950324019Steve GolovatoShot 950324019 - raise threshold for reflected power trip by substantial
amount. plasma, no trips up to 100kw. must be problem with rho_P
calibration for arc detector.

Mar 24 1995 01:42:37:440PM950324020Steve GolovatoShot 950324020 - ramping density to change reflected power, make sure
we have arc detection, and at what rho_P, before raising power.
plasma. no trips.

Mar 24 1995 01:56:14:770PM950324021Steve GolovatoShot 950324021 - try ramping density dow and detuning a little to start.
didn't get much of a mismatch last shot.
plasma. interrupted thgroughout.

Mar 24 1995 02:13:46:250PM950324022Steve GolovatoShot 950324022 - adjust tuning, density ramp so we can see where
threshold rho_P is before we start raising power.
plasma. got interrupts at about rho_P=0.06

Mar 24 1995 02:14:48:120PM950324023Steve GolovatoShot 950324023 - back to constant density nl=1.e20, start ramping d-port
power.

Mar 24 1995 02:15:11:470PM950324023Steve GolovatoShot 950324023 - fizzle.

Mar 24 1995 02:32:15:090PM950324024Steve GolovatoShot 950324024 - plasma. 300kw, no arcs on d-port.

Mar 24 1995 02:59:58:440PM950324025Steve GolovatoShot 950324025 - plasma. 600kw on d-port!!!!!

Mar 24 1995 03:00:30:420PM950324026Steve GolovatoShot 950324026 - plasma. power feedback back on, power lowered to 280 kw.

Mar 24 1995 03:15:56:180PM950324027Steve GolovatoShot 950324027 - plasma. e-port back up, went back to earlier tune,
from shot 12. .680 mw on d-port..

Mar 24 1995 03:29:43:620PM950324028Steve GolovatoShot 950324028 - plasma. .96mw on d-port.

Mar 24 1995 03:42:13:090PM950324029Steve GolovatoShot 950324029 - ramp density 1.3-1.5e20, same power.
.925kw at higher density, voltage down from 23 (at 1.e20) to 18kv.

Mar 24 1995 03:45:33:200PM950324030Steve GolovatoShot 950324030 - tuned for 1.5e20 on both antennas, raised d-port power.
fizzle.

Mar 24 1995 04:07:23:220PM950324031Steve GolovatoShot 950324031 - 1.1mw on d-port. e-port tuned.

Mar 24 1995 04:09:13:170PM950324032Steve GolovatoShot 950324032 - raise power on d and e port.

Mar 24 1995 04:50:08:120PM950324032Steve GolovatoShot 950324032 - plasma, both ran,, but no overlap. 1.3mw on d,
.85 on e.

Mar 24 1995 04:51:41:370PM950324033Steve GolovatoShot 950324033 - plasma, e tripped during d power, no overlap.
h-mode at 1.3mw on d for 250ms, e picks it up when d turns off.

Mar 24 1995 04:52:42:480PM950324034Steve GolovatoShot 950324034 - plasma, same as shot 33 but changed d-port oscillator
power by 1db, lowered bira by 20%.

Mar 24 1995 04:57:03:770PM950324035Steve GolovatoShot 950324035 - plasma, still won't run together. 1.24 on d,
1.05 on e.

Mar 24 1995 05:05:31:920PM950324036Steve GolovatoShot 950324036 - try starting e port first then turning on d.
also raised d power a little more.
plasma. 1.1 form e, 1.2 from d, still won't run together.
had brief mooment at 2.3mw total power.

Physics Operator Comments

Engineering Operator Comments
ShotTimeTypeStatusComment
108:25:31:110AMPlasmaBadoh1 switch did not fire
209:01:48:540AMPlasmaOkno faults
309:22:10:040AMPlasmaOkno faults
409:31:14:860AMPlasmaOkno faults
509:41:50:590AMPlasmaOkno faults
609:55:13:940AMPlasmaOkno faults
710:12:26:700AMPlasmaOkno faults
810:36:25:860AMPlasmaOkno faults
910:47:56:740AMPlasmaOkno faults
1011:00:59:110AMPlasmaOkno faults
1111:11:44:540AMPlasmaOkno faults
1211:25:06:420AMPlasmaOkno faults
1311:38:05:150AMPlasmaOkno faults
1411:52:40:960AMPlasmaBadhybrid command problems
1512:28:48:150PMTestOkefc only
1612:40:46:420PMPlasmaOkno faults
1712:51:20:620PMPlasmaOkNo Faults.
1801:03:03:840PMPlasmaOkNo Faults.
1901:16:35:620PMPlasmaOkNo Faults.
2001:31:47:620PMPlasmaOkNo Faults.
2101:44:51:260PMPlasmaOkno faults
2201:57:33:070PMPlasmaOkNo Faults.
2302:09:31:750PMPlasmaOkNo Faults.
2402:22:35:600PMPlasmaOkNo Faults.
2502:34:08:800PMPlasmaOkNo Faults.
2602:47:42:210PMPlasmaOkNo Faults.
2703:02:52:630PMPlasmaOkNo faults.
2803:18:07:580PMPlasmaOkNo Faults.
2903:32:02:670PMPlasmaOkNo Faults.
3003:43:51:720PMPlasmaOkNo Faults.
3103:56:08:050PMPlasmaOkNo Faults.
3204:09:04:460PMPlasmaOkNo Faults
3304:21:41:330PMPlasmaOkNo Faults
3404:36:16:030PMPlasmaOkNo Faults.
3504:48:42:630PMPlasmaOkNo Faults.
3604:58:46:450PMPlasmaOkNo Faults.