Alcator C-Mod Run 1030717 Information

Back to runs

Miniproposals
Miniproposal:346
Date Filed: 6/24/2003
Title:PF Error Field Evaluation
First Author:Steve Wolfe
Session Leader:Steve Wolfe (shots 1-17)

Operators
Session leader(s):Steve Wolfe
Physics operator(s):Jim Irby
Engineering operator(s):Gary Dekow,Ed Fitzgerald,Bill Cochran

Engineering Operator Run Comment
MP 346, PF Error Field Evaluation; PO:Irby; SL:Wolfe; EO:Cochran/Dekow/F

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:34:257PM
Author: Steve Wolfe
Run Summary for Thurs. 7/17/2003

MP#346: PF Error Field Evaluation
SL: wolfe
PO: Irby
EO: Dekow/Cochran


The purpose of this run is to run single coil tests to look for
non-axisymmetric field errors due to misalignments of each of the PF coils. Of
particular importance are the first 4 shots, which test the EF4U, EF4L, EF3U,
and EF3L coils independently, rather than in their normal parallel or series
combinations. All shots except X3 will be run with flattop currents to
minimize induced current effects; X3 is an addition to the origninal MP to
test Dave Gwinn's suggestion that vessel currents flowing across the D and
E-port through the antenna boxes could be a significant source of
non-axisymmetry.

The last shot of the day will be an MSE beam-into-gas shot at 8T, which we did
not get to take yesterday because of a blown fuse in the TF cabinet.

We will be following the sequence in the MP except for a couple of
additions (marked by **):

1. 2sec EF4U pulse at +4kA (hybrid); EF3 aux power off.

2. 2sec EF3U pulse at +10kA (hybrid)

Reconfigure buss work to connect EF3L and EF4L coils to their respective supplies.

3. 2sec EF4L pulse at +4kA (hybrid); EF3 aux power off.

4. 2sec EF3L pulse at +10kA (hybrid)

** Reconfigure buss work to original configuration

** X1. EF4 test to confirm EF4 connection, EF3 aux power off
** X2. EF3 test to confirm EF3 connection

All remaining shots until **X4 to be carried out with EF3 aux power off

5. 2 sec OH1 pulse at +20kA

6. 2 sec OH2U pulse at +20kA

7. 2 sec OH2L pulse at +20kA

**X3. OH1 2sec ramp shot -20kA to +20kA and down

8. 2 sec EF1U pulse at +5kA

9. 2 sec EF1L pulse at +5kA

10. 2 sec EF2U pulse at -4kA

11. 2 sec EF2L pulse at -4kA

**X4. MSE test shot: Bt=8T, EF4 and EF3, gas as on 1030521014

Bob Granetz has set up several additional BPxx_GH coils for today's runs. The
list (from the logbook) is:

circuit signal now signal before today
59 BP08_GH upper halo Rog (
60 BP09_GH partial halo 13 (patch panel BP13_GH)
61 BP10_GH partial halo 11 (patch panel DCU1_HJ)
62 BP11_GH partial halo 12 (patch panel DCU2_HJ)
63 BP12_GH partial halo 14 (patch panel BP12_GH)
64 BP13_GH lower halo Rog (patch panel ROGL_KA)

Results
-------

The MP346 portion of the run came off as planned. Good difference signals were
obtained for analysis. The ramping oh1 shot did, at first glance, seem to
indicate a difference signal between the DE loops on the outboard wall and the
equivalent loops at other toroidal locations that looks proportional to the
loop voltage rather than the OH current; the magnitude is of order 1mT at
Vloop=1V. This is consistent with D.G.'s estimate, and a factor of five or so
smaller than other difference signals from the flattop coil tests (although
those may vanish when the gain errors and such are backed out).

Several of the other transient responses look puzzling, and need to be
examined. In particular, there seemed to be a long lasting transient on some
loop pairs due to EF2U that was not present for EF2L.

The 8T MSE calibration shot, however, was not successful. The fields behaved
as intended, but once again there was a vacuum incident which brought the
torus up to 5 Torr. This time, we think we have figured out what happened. The
gate valve on the pumping line to the shit shooter at K-side opened to air due
to the combined field of EF4 and EF3 on this test shot. The evidence is that
the Al foil which was covering the flange now has a hole in it the size of the
id of the pipe. This opeining needs to be blanked off or replaced with a
hand-valve, or else the solenoid needs to be moved away from the machine like
all the other gate valve solenoids.

The machine pumped back down successfully. As I write this the pressure is
3e-6 and falling. A bake and ecdc overnight would probably recover enough to
operate, but since we are warming up anyway there's no point in doing that.

This ends the 2003 Spring-Summer Campaign.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:18:957PM
Author: Jim Irby
Physop Summary for run 1030717 in support of
MiniProposal 346, PF Error Field Evaluation

EO: Cochran/Dekow/Parkin
SL: Wolfe
PO: Irby

This was a very successful run for Steve's error field search. Each
PF/OH magnet was run individually with an approximately 2 s long pulse
at relatively high currents. The EF3 and EF4 U and L magnets were run
independently and required considerable setup time, but the results
will be very useful. One physop thing to remember is that the ramp-up
and ramp-down times should be 100-200 ms to minimize induced voltages.
Open EF3 and EF4 leads were terminated with a varistor to limit these
voltages.

Another physop thing I wanted to mention was discovered in looking back
at the previous days 8T run. A short ramp-up on the TF, rather than
the hard turn on we usually use reduced the peak voltage on the TF
bus by 250-350 volts. Physops should include a ramp-up on the TF
request from now on.

The only down side to the run was that we came up to air during the last
shot and did not get the 8T MSE calibration shot. See the SL run
report for details.

----------------------------------------------------------------------
Run begins at 9:00 ends at 17:00,

Power system setup:

All PF/OH supplies ready to operate
Fizzle detector on at 2 s, off at 2.1 s for all shots

Some reconfiguration of the EF3/EF4 bus required (Bill Cochran
is prepared for these changes)

No plasmas will be produced during the run

The last shot of the run will be an 8T DNB calibration shot

The A-Coils will not be needed
No ECDC overnight will be needed
No gas setup is required
Diagnostic gatevalves and shutters may remain closed

**** We will begin warming up the machine following this run ****

Session Leader Comments
Jul 17 2003 08:57:17:150AMSteve WolfeWe will be following the sequence in the MP except for a couple of
additions (marked by **):

1. 2sec EF4U pulse at +4kA (hybrid); EF3 aux power off.

2. 2sec EF3U pulse at +10kA (hybrid)

Reconfigure buss work to connect EF3L and EF4L coils to their respective supplies.

3. 2sec EF4L pulse at +4kA (hybrid); EF3 aux power off.

4. 2sec EF3L pulse at +10kA (hybrid)

** Reconfigure buss work to original configuration

** X1. EF4 test to confirm EF4 connection, EF3 aux power off
** X2. EF3 test to confirm EF3 connection

All remaining shots until **X4 to be carried out with EF3 aux power off

5. 2 sec OH1 pulse at +20kA

6. 2 sec OH2U pulse at +20kA

7. 2 sec OH2L pulse at +20kA

**X3. OH1 2sec ramp shot -20kA to +20kA and down

8. 2 sec EF1U pulse at +5kA

9. 2 sec EF1L pulse at +5kA

10. 2 sec EF2U pulse at -4kA

11. 2 sec EF2L pulse at -4kA

**X4. MSE test shot: Bt=8T, EF4 and EF3, gas as on 1030521014
Jul 17 2003 09:58:45:680AMSteve WolfeThere is a delay to figure out how to convince the I2t circuit that
the disconnected coil is not out of range.
Jul 17 2003 10:23:23:733AM1030717001Steve Wolfeshot#1: EF4U +4ka pulse
good shot. Difference signals up to 5mT-10mT
Some outboard loops seem to have non-axi transients in first 1sec


next shot: ef3U +10kA pulse
Jul 17 2003 11:12:57:153AM1030717002Steve Wolfeshot#2: ef3U +10kA pulse
Good shot. NOTE that the EF3L rogowski shows current because it's on
the Al bus. Diffference signals at the .005T level; some of the new
gh loops seem to give larger diffs, up to 25mT.

The ramp down was at full inversion voltage, which ended up with 3000A in the
MOV. Need to change the waveform to ramp down gently earlier.

next shot: reconfigure bus for Lower EF4 and EF3 coils.
Jul 17 2003 11:44:07:717AM1030717003Steve Wolfeshot#3: Ef4L at +4kA
All invert times and fd settings moved 200msec later, redrawn waveforms
to ramp down slower. Change predictors on ef4 and ef3 to use lower rogowskis

good shot. difference signals up to .005T. My initial impression is that the difference signals
were larger on shot1, but I could be wrong.

next shot: Ef3L 10kA
Jul 17 2003 11:52:02:917AM1030717004Steve Wolfeshot#4: Ef3L 10kA

good shot: 5 to 10mT difference signals.
No varistor current

next shot: Reconfigure back to normal (parallel and series) connections
Then do the EF4 test
Jul 17 2003 12:20:10:600PM1030717005Steve Wolfeshot#5: EF4 (both) +4kA
Good shot: some difference signals up to 5mT
There is a small imbalance in the coil currents

next shot: EF3 (both) at +10kA

Jul 17 2003 12:25:42:170PM1030717006Steve Wolfeshot#6: EF3 (both) at +10kA

good shot- big differnce signals and lots of transients.

next shot: OH1 at +20kA, EF3 aux power off.
Jul 17 2003 12:35:42:483PM1030717007Steve Wolfeshot#7: OH1 at +20kA, EF3 aux power off, OH1 plc -27,+27

good shot: mostly small diff's but some quite large?

next shot: oh2U +20kA
Jul 17 2003 12:42:42:120PM1030717008Steve Wolfeshot#8: oh2U +20kA

looks like we got 22kA, good shot.
difference signals up to 15mT on inner wall

next shot: oh2l +20kA
Jul 17 2003 12:51:03:020PM1030717009Steve Wolfeshot#9: oh2l +20kA

good shot (reed relay didn't sound)
smaller diff signals in general, mostly<5mT

next shot: ramping oh1
Jul 17 2003 12:58:47:630PM1030717010Steve Wolfeshot#10: ramping oh1 -20 to +20

looks good, some difference signals ramp, some more constatnt.
In this case, the constant ones are presumably driven by the loop
voltage. get -.7V before crossover, -1V after.

next shot: EF1U 5ka
Jul 17 2003 01:08:12:877PM1030717011Steve Wolfeshot#11: EF1U 5ka 2sec pulse.
good shot
diff signals up to 10mT, not much transient

next shot: ef1L
Jul 17 2003 01:22:31:023PM1030717012Steve Wolfeshot#12: ef1L +5kA. Also enable Btop gas puff for DNB

good shot: mostly very small diffs

next shot: EF2U
short delay to put in the TMX breaker
Jul 17 2003 01:30:26:677PM1030717013Steve Wolfeshot#13: EF2U -4kA shot.

good shot. Lots of long transients in the diff signals

next shot: EF2L -4kA shot
Jul 17 2003 01:39:30:817PM1030717014Steve Wolfeshot#14: EF2L -4kA shot

good shot; transients and diffs seem smaller.

This completes the MP 346 portion of the run

Next shot: 50kA tf test (because they had to replace a fuse this AM)
Jul 17 2003 01:58:45:143PM1030717015Steve Wolfeshot#15: data system cycle (with gas and beam) to check whether tf scanner is
running properly.

seems to be working, but several turns look funny.

next shot: 50ka TF only PLC
Jul 17 2003 02:07:34:233PM1030717016Steve Wolfeshot#16: 50ka TF only PLC control (with gas, beam moved to t=0.)

looks ok to me.

next shot: MSE Cal shot at 8T
Jul 17 2003 02:20:28:690PM1030717017Steve Wolfeshot#17: MSE Cal shot at 8T (TF EF3 EF4 Btop gas DNB)

Torvac alarms. Machine is at 5Torr.

Physics Operator Comments
Jul 17 2003 07:35:13:943AMJim Irby Engineering setup for run 1030717 in support of
Miniproposal 346, PF Error Field Evaluation


Run begins at 9:00 ends at 17:00,

Power system setup:

All PF/OH supplies ready to operate
Fizzle detector on at 2 s, off at 2.1 s for all shots

Some reconfiguration of the EF3/EF4 bus required (Bill Cochran
is prepared for these changes)

No plasmas will be produced during the run

The last shot of the run will be an 8T DNB calibration shot

The A-Coils will not be needed
No ECDC overnight will be needed
No gas setup is required
Diagnostic gatevalves and shutters may remain closed

**** We will begin warming up the machine following this run ****
Jul 17 2003 10:21:08:683AM1030717001Jim IrbyFirst shot will be +4kA EF4U test, 2 second long pulse

Good first shot --- 3.9 kA
Jul 17 2003 10:56:52:410AM1030717002Jim IrbyEF3U at 10 kA for 2 s ---- note both Rogowskis are still in the circuit.

have 3 kA of ef3 varistor current --- shutdown at 2 s too fast --- reprogrammed
ramp down to start at 1.8 s

There will be a delay now to reconfigure the bus for the lower ef3 and ef4
coils
Jul 17 2003 11:41:31:900AM1030717003Jim IrbyAsked that inversion and fizzle be moved out to 2.3 s

This will be an EF4L test at 4kA, 2 s long.

Modified EF3 and EF4 predictors to look at the lower Rogowskis.

got it
Jul 17 2003 12:00:07:240PM1030717004Jim IrbyEF3L at 10kA for 2 s.

good shot

no varistor current

delay to put bus back to normal
Jul 17 2003 12:20:09:677PM1030717005Jim IrbyRemind EOs to put EF3 current limit back to 10 kA

Bus should be back to normal

modified EF3 and EF4 predictors to use upper and lower Rogowskis (weight = 0.5)

load/clean

EF4s in parallel: pulse to +4kA for 2 s

good shot --- ef4s were probably off in temp by 10C or so --- 150 A difference current
Jul 17 2003 12:26:07:937PM1030717006Jim IrbyEF3s in series at 10 kA for 2 s

good shot
Jul 17 2003 12:32:39:480PM1030717007Jim Irby2 s OH1 pulse at +20kA

good shot
Jul 17 2003 12:40:44:537PM1030717008Jim IrbyOH2U pulse at +20kA for 2 s

good shot
Jul 17 2003 12:51:20:867PM1030717009Jim IrbyOH2L at +20kA for 2 s

good shot --- note we had different gains on OH2L and OH2U for some reason

Jul 17 2003 01:02:11:617PM1030717010Jim IrbyLoaded OH1 swing from -20 to +20 kA from -1 to 1.5 s --- -20 kA at t=0.

looks good



Jul 17 2003 01:07:23:830PM1030717011Jim IrbyEF1U pulse at 5kA for 2 s

good shot
Jul 17 2003 01:16:20:467PM1030717012Jim IrbyEF1L at +5kA for 2 s

good shot
Jul 17 2003 01:29:54:643PM1030717013Jim IrbyEF2U at -4kA for 2 s

good shot
Jul 17 2003 01:37:19:797PM1030717014Jim IrbyEF2L at -4kA for 2 s

good shot
Jul 17 2003 01:58:55:470PM1030717015Jim Irby50 kA test of TF under PLC control ----- lost fuse yesterday at end of run that has been replaced

Make sure scanner is running

loaded shot 1030521014 in prep for Howard's DNB cal shot at 8T (no TF this shot)

this shot turned into a cycle test to check TF scanner ---- no TF current

TF scanner running okay now
Jul 17 2003 02:05:46:310PM1030717016Jim IrbyTry PLC controlled TF at 50 kA

gas enabled for DNB now firing at t=0.


got 50 kA in TF

scanner looks good
Jul 17 2003 02:33:40:510PM1030717017Jim IrbyReady for Howard's 8T shot

Fizzle and inverts to 1.0 s

TF made it okay to 8T --- scanner looks great

But..., vessel now a 4 Torr!

RGA indicates mostly mass 18 with some mass 4

We did not lose TORVAC as we did last week ---- Tommy had no problem starting us pumping
down again. Tommy is putting as much info a possible in the OPS logbook.

Some gatevalve convectrons indicate > 5 Torr.

Engineering Operator Comments
ShotTimeTypeStatusComment
110:17:26:067AMTestOkEF4 Field Test
210:29:04:320AMTestOkEF3U Field Test
311:38:44:223AMTestOkEF4L Field Test
411:47:11:707AMTestOkEF3L Field Test
512:15:04:530PMTestOkEF4U and L Field Test
612:22:22:697PMTestOkEF3U and L Field Test
712:29:55:960PMTestOkOH1 Field Test
812:38:10:893PMTestOk
912:46:11:500PMTestOk
1012:53:42:027PMTestOk
1101:04:33:370PMTestOk
1201:13:30:853PMTestOkEF1L Field Test
1301:26:41:547PMTestOk
1401:34:54:730PMTestOk
1501:45:37:980PMTestBadcamac scanner test
1602:00:12:677PMTestOk
1702:13:15:383PMTestOk