Alcator C-Mod Run 990120 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 1-20)

Operators
Session leader(s):Steve Wolfe
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Cochran

Engineering Operator Run Comment
We will resume power systems testing and if successful we will move onto

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:36:59:647PM
Author: To Be Determined
Physop Summary for Wed, 990120

MP#206 Resume Operation 1999
SL/PO Wolfe
EO Cochran

Executive Summary:
-----------------
All power supplies have been tested. Some need additional testing at higher power,
and we still need some commutation tests, but so far everything seems to be
working. TF has been run to 5.3tesla. No plasma attempts were run today.

RUn Plan:
---------
The first part of the run will be devoted to power systems testing under the
direction of the Engineering Power Systems crew (Cochran, et al.)

If these are successful, and we can fix the magnetics problems discovered
Tuesday, we will try for plasma. Considering the lack of discharge cleaning,
we will be happy if we get a breakdown, indicating reasonable nulls and
allowing us to evaluate the magnetics patches, if any. Anything more than
fizzles is unlikely, and would be cause for celebration.

Setup:
-------
ECDC as much as possible overnight in D2
PF power supplies as on 980220003
TF under hybrid control, current limit set at 160kA, timing as on 980220003.

NOTE: Gas system must be baked out and ready to run.
Gas Setup for first plasma shot:
--------------------------------
B-top 6psi D2 Hybrid enabled
B-side lower 1psi Ar NOT enabled for 1st shot
"K-side"* 30psi D2 Hybrid enabled
* Note that this valve is physically on C-side now, but the PLC screen is
not updated yet.

Following or during the power tests, we will verify operation of the pulsed
gas system under hybrid control.

During the power tests, we will try to determine if the magnetics diagnostics
which were observed to be faulty yesterday are going to be useable. These are:

F21 full flux loop Seemed intermittant, ohmed out ok after reconnecting
cable, though not before.
F20 partial flux loop Appeared dead on tests 990119. ohmed out ok. May be
bad integrator.

BP20JK BP loop Seemed dead. Ohmed out ok after run. May be bad
integrator.

F21 is an essential loop. If it is not ok, we will have to modify predictor
algorithm routines before trying for plasma. Even if this is successful, there
will be a problem diagnosing and controlling he x-point location without this
coil. These problems will be worse if we have also lost F20.

We can probably live without f20 for awhile (startup struggles) if we have to,
as long as F21 and F19 are ok. It may be possible to interpolate this value
satisfactorily in the control algs even for x-point location.

BP20JK is redundant with BP20DE and BP20GH. We will just need to modify the
expression for processed BP19 in the tree, if it is not recovereable. This
loop is not used by the hybrid.

It may be necessary to go into the cell a few times during power tests to test
the hypothesis that the F20 (and perhaps Bp20_jk) integrators are bad, and
perhaps swap in new ones. It may also be necessary to re-check F21, if it
still isn't working.

Assuming we get this far, start from a successful fiducial from last year,
980220003. Tweak the null and try for a flash. 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.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Results:
--------

We got through most of the power supply testing. Everything looks good so
far. TF was tested at 50kA, 100ka, and 156kA (5.3T). The 5T shots are #14 and
15; both invert shortly after t=0, so the flattop is short. Shot 13 is 100kA
and has a reasonable flattop.

Still need to do commutation tests on OH2's (will do with OH1), and EF1's.

The flux loop signals F21 and F20 that were bad yesterday are now
fixed. BP20_JK is still bad (we didn't do anything to it), but the processed
node \MAGNETICS::MAG_PROCESSED_BP:SIGNALS:BP_19 has been changed to refer to
the BP20_DE loop instead. NOTE THAT THIS WAS DONE IN THE TRAVERSER, NOT IN THE
GRANETZ TCL FILE. Therefore, his file must be changed to include the new
pointer when he gets back from vacation.

Programmed but did not use double swing hybrid waveforms for OH1, OH2U, OH2L,
EF1U, EF1L, EF4. The waveforms look ok on shot 19,20. These still remain to be
done.

The run was paused after shot 18 to install the G-side ratiomatic and MKS
gauge. This was a serious error in judgment on my part. The gauge assembly
apparently has a leak and could not be pumped down. It was not opened to the
machine. While we were waiting, the alternator had a speed 1 fault indication
that caused it to ramp down in speed. It was determined that the fault was
spurious, but it was then too late to run the speed back up and accomplish
anything by the end of the day.

Only B-top and K-side gas lines were baked and ready to puff. We took two gas
puff tests (19,20) to test these. B-top seems to work ok under hybrid
control. K-side did not. The driver board output was good. After the run, Rice
and Goetz exercised the piezo and got gas into the machine. Will test this
again tomorrow.

On shot 15, a TF test, Spencer exercised the K-port flapper. He ran it at low
current and observed it to open, though not fully.

The EF3L bus rogowski was successfully inverted and now reads correctly. Bill
Parkin changed a chip on the EFCL bus rogowski integrator, but we did not get
a chance to test it.

for details, see entries in PHYSICS OPERATOR and MHD topics in logbook

Scorecard:
---------
20 test shots
0 duds
0 fizzles
0 plasmas
--
20 shots


Session Leader Comments

Physics Operator Comments
Jan 20 1999 07:13:02:000AMSteve WolfeColdstart at 07:10. All matrices responding.
LOAD FROM 980220003 - note segment 4 is active fiducial
LOAD/CLEAN at 20-Jan-1999 07:11:45.00
Jan 20 1999 01:52:21:450PM990120018Steve WolfeFor coil tests, set up double swings for OH1, OH2U, OH2L, EF1U, EF1L,EF4.
Had to make a new wire for OH2L, and re-do the predictor and controller on OH2U, since it was really
the average.

Drawn program is

OH1, OH2U, OH2L -5Ka to +5kA
EF1U, EF1L: -3kA to +3KA
EF4 -1.3kA to +3kA

Zero the rcur wire, turn off gains on zcur, BR_0, ip.
Turn off segment 4

Load at 20-Jan-1999 13:49:49.00 (before shot 19)
Jan 20 1999 02:22:37:103PM990120018Steve WolfeJohn Goetz has disconnected the divbolo fibers at the transmitter end. Will check on shot 19 to see
if this eliminates high levels at hybrid inputs 85 and 86.
Jan 20 1999 03:05:14:820PM990120018Steve WolfeWe have had a long access break to allow BLIP and BlaB to install the ratiomatic and MKS on G-side.
Bill Parkin has put a new chip in the integrator for EFCL bus rog.
Jan 20 1999 09:06:10:130AM990120019Steve WolfeJUst for the aesthetics, turn off the gain in segment 1 Ip wire, so it shows as lower case.
Load at 20-Jan-1999 09:05:08.00
Jan 20 1999 04:01:53:427PM990120019Steve WolfeShot 19: We've had an alternator fault while waiting. Probably won't be back up today.
Therefore, set up for a couple of gas tests.

Shot 19: Btop 15msec pre-puff. Using the coil test segment 1.
Base presure = 7.9e-8 (GV3 closed)
Reached 8e-6, so we got something. See D2 and maybe some O2??

Next shot K-side (PG3)
DIVbolo signals are ok.
Jan 20 1999 04:12:38:517PM990120020Steve WolfeShot 20: PG3 test, 30psi D2 in plenum
base pressure 8.1e-8
No gas. SIgnal at the output of the driver board looks ok,
Must be in the cable or the piezo.

End Run. Try again tomorrow.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:33:02:730AMTestOkef1L test only
209:43:02:290AMTestOkoh1 forward only
309:51:17:813AMTestOkoh1 reverse only
409:59:45:323AMTestOkoh2u forward only
510:06:22:877AMTestOkoh2u reverse only
610:21:08:750AMTestOkoh2L forward
710:38:03:810AMTestOkoh2L reverse only
810:52:40:520AMTestOkscanner test
911:02:41:253AMTestOkTF test only 50,000amps
1011:25:24:533AMTestOkef4 reverse test on
1111:35:00:833AMTestOkef3 rog test
1211:44:46:673AMTestOkefc chopper test only
1311:55:45:833AMTestOkTF test only 100,000amps
1412:10:04:960PMTestOkTF test only 156,000amps
1512:18:47:340PMTestOkTF test only 156,000amps
1612:30:12:313PMTestOkoh1 commutation test only
1712:47:18:990PMTestOkoh1 reverse 5000amps
1801:07:36:550PMTestOkoh1,oh2L,oh2U,no comm. 5000amps
1903:56:33:717PMTestOkgas test only
2004:03:18:760PMTestBadgas test only