Alcator C-Mod Run 1010703 Information

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Miniproposals
Miniproposal:246
Date Filed: 4/13/1999
Title:Toroidal Rotation Velocity Radial Profile
First Author:John Rice
Session Leader:John Rice (shots 1-8)

Operators
Session leader(s):John Rice
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Parkin,Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
MP246 Rotation Profiles; SL:Rice; PO:Wolfe; EO:Dekow/Fitzgerald/Parkin

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:26:773PM
Author: To Be Determined
Session Leader Run Summary for 1010703 MP246 Rotation Profiles

Is this son on 049A? Stay tuned. After alternater and transmitter 4
problems, the run began at 2:45. There were 6 plasmas, and given
the ICRF and HIREX high voltage trips, there was very little progress
toward measuring the velocity profile. The bright spot of the day
was shot 001, which may be the new EDA trophy shot, at least for 800 kA.
A beautifully steady EDA H-mode with 850 ms duration, betaN*H = 2.5
for over 15 tauE was achieved with 3 MW ICRF.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:13:583PM
Author: To Be Determined
MP#246 Rotation Profiles
SL: Rice
PO: wolfe
EO: Dekow,Fitzgerald

Engineering Setup:

ECDC in D2 at 2e-4 Torr overnight prior to run
We will require between shot ECDC (D2)

Power Systems as on 1010629021

Gas Setup:
fill B-top with 6 psi of D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi of Ar Hybrid enabled (PG1)
fill B-side upper with 30 psi of D2 Hybrid DISABLED (PG2)
fill C-side with 30 psi of D2 Hybrid enabled (PG3)
fill J-bottom with 30 psi of He Hybrid DISABLED (PG5)

Enable the following gate valves: ECE, DNB, VUV

RF setup:
XMTR 1,2,3,4 in RUN-ON by 8:00AM
RF Waveform:
-------------
square pulse on:.65sec, off: 1.45sec, Ptot=3MW (or higher)
Any combination of D, E, J antennas that works reliably is acceptable.

target plasma: 5.4T, 800kA, nl4~7e19m^-2, similar to 1010629012 but without
the current ramp.

Plan:
-----
1) Establish a reproducible EDA plasma at 800kA, with strong rotation.

2) Run constant shots while scanning the HIREX views to measure rotation
profiles out to r/a~0.6, or as far out as there is usable signal.

Results:
-------

The start was delayed because the RF had a problem getting FMIT#4 to turn on,
and the alternator had an overtemp indication. The combination of these
problems delayed the start of the run until 14:45. The transmitter problem was
traced to a mechanical problem in the switchgear, which required opening the
ALC2 breaker to access and repair. The alternator bearing overtemp was
apparently real, and was possibly due to a loading change due to the change in
ambient temperature. After dropping down in speed, which was necessary in any
case in order to open ALC2, and coming back up, the temperature returned to
normal.

We started from 1010629012, modified to remove the current ramp,
and the associated gain and voltage tweaks. Density feedback was changed from
zmeter to tci (nl4=7e19). Small tweaks were made to Br0 and pg4. At Amanda's
request, a tf waggle was added (.75-.90, 8Ka up).

Once we got going, the RF worked well, and we did get some good shots for
John's experiment. Shot 1 was at 3.0MW, all others at 3.5MW. The best shots at
3.5MW got to ~160kJ, beta_N~1.5, nd peak neutron rates around 4e13/sec. If we
can get rid of the injections these ought to be pretty impressive, for 800kA.

We had two disruptions due to injections (#2 and 8). The first started
coincident with the tf waggle, which had been moved to .8; just in case, the
waggle was removed for subsequent shots. H/D started around .05, but rose to
over .1 in some shots, particularly with injections. There seemed to be a
deleterious effect of high H/D on the heating. We ran between-shot ECDC after
shots #4 and 6, and in each case the next shot fizzled. This may have been a gas
pressure problem. We also had a couple of late breakdowns that survived. The
startup could probably use some minor tweaking. I made small tweaks to EF4,
pre-puff, and Br, not necessarily in the right direction.

The other problem encountered today was that the PLC interface to the torus
ion gauge failed, so that it was necessary to have a cell entry to restart the
filament after a disruption. Bob Childs and Joe Bosco determined that the
problem is probably in the i/o card in the controller, as the PLC voltages
were being sent and pusing the button on the controller worked. This should be
repaired/replaced Thursday morning.

Scorecard:
---------
Tests 0
Duds 0
Fizzles 2
Plasmas 6
------- -
Shots 8




Session Leader Comments
Jul 3 2001 03:09:20:967PMJohn Rice001
great shot, 850 ms EDA, steady RF at 3 MW
Jul 3 2001 03:34:17:390PMJohn Rice002
3.5 MW RF, disrupted at 0.84 s
Jul 3 2001 03:43:08:203PMJohn Rice003
lost J port at 1.12s
Jul 3 2001 04:19:06:710PMJohn Rice004
some RF trips,
Jul 3 2001 04:19:25:367PMJohn Rice005
fiz
Jul 3 2001 04:43:50:633PMJohn Rice006
some RF trips
Jul 3 2001 05:02:18:417PMJohn Rice007
fiz
Jul 3 2001 05:02:40:840PMJohn Rice008
disrupted at 0.89s

Physics Operator Comments
Jul 3 2001 07:43:11:400AMSteve WolfeProgram 800kA, nl4=7e19, based on 1010629012, but without the current
ramp. Tweak Br and increase the pre-puff to 20msec. Change NL feedback
from zmeter to tci.

coldstart at 07:38 - all respond ok.
Jul 3 2001 03:29:56:413PM1010703001Steve WolfeShot#1: plasma full length, with H-mode
RF at 3MW, clean except for one brief dropout (D-port).
Injection at .92, but it survives.

next shot: ask for .5MW more power
reduce Ar by 6msec, per JR request
Earl will shoot a pellet
Jul 3 2001 03:29:38:710PM1010703002Steve WolfeShot#2:ask for .5MW more power
reduce Ar by 6msec, per JR request
Earl will shoot a pellet
move tf waggle later by 50msec
breakdown was quite late

disruption at .84sec; injection. too much power?
injection starts at 0.8sec.
next shot: take out the tf waggle
Jul 3 2001 03:44:55:067PM1010703003Steve WolfeShot#3: take out the tf waggle; ef4 to -1300
plasma, full length, but an injection at 1.04 knocks it
out of the good EDA. E glitched off, then J turned off
at 1.128
breakdown is still late, 6.8msec this time.
pellet at ~1.5sec

next shot: raise pre-puff by 2msec.
Jul 3 2001 04:05:50:450PM1010703004Steve WolfeShot#4: raise pre-puff by 2msec. No pellet this time.
plasma, full length, J stayed on, D& E both glitch some
stored energy is lower. H/D is over 7% the whole time.
No injections this time.
breakdown still at 6.7msec.

next shot: ECDC for 5minutes; Earl is going to shoot another one.

Jul 3 2001 04:19:24:583PM1010703005Steve WolfeShot#5: ECDC for 5minutes; Earl is going to shoot another one.

fizzle; breakdown was actually earlier on this one, 5.4msec.
gas may have been too high after ecdc; p0=.09mtorr

next shot: no change.
Jul 3 2001 04:35:19:787PM1010703006Steve WolfeShot#6: no PCS changes.
plasma full length, but a couple of injections
give H-Ltransitions and knock out the RF briefly.
H/D rises from .05 to .11.
good breakdown this time. p0 back to .075, br0 drifted up a tad.

next shot: ecdc again.

Jul 3 2001 04:55:20:343PM1010703007Steve WolfeShot#7: ecdc again.
fizzle. p0 was .085mTorr. Should have been ok.
breakdown at 6.0msec.

next shot: Br to .0013

Jul 3 2001 05:06:20:113PM1010703008Steve WolfeShot#7: Br to .0013
disruption at .899; injection starts around .83
Got to 160kJ, beta_n to 1.5.

End of run.

Engineering Operator Comments
ShotTimeTypeStatusComment
102:45:25:513PMPlasmaOk
203:13:30:443PMPlasmaOk
303:33:48:437PMPlasmaOk
403:50:58:420PMPlasmaOk
504:11:49:430PMPlasmaOk
604:26:27:113PMPlasmaOk
704:48:28:873PMPlasmaOk
805:00:59:760PMPlasmaOk