Alcator C-Mod Run 950315 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Brian Labombard (shots 1-35)

Operators
Session leader(s):Brian Labombard
Physics operator(s):Steve Wolfe
Engineering operator(s):Joe Daigle,Vinny Bertolino, Unknown

Engineering Operator Run Comment
scrape-off layer

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:12:710PM
Author: To Be Determined
Session Leader's summary of run 950315

MP# 084 Scrape_off Layer Characterization II

Physics Operator: Wolfe
Session Leader: LaBombard
Engineering Operator: Bertolino/Daigle/Paranay

The goal of this run was to continue the study of scrape-off
layer conditions in single null diverted plasmas, focussing on the lower
plasma currents of 0.4 and 0.6 MA. In the run of 950308, we managed to get
data at 0.8 and 1.0 MA but found it difficult to obtain vertically stable
plasmas at the lower currents. The challenge for Steve today was to
navigate around unstable equilibria at 0.4 and 0.6 MA, allowing us to
complete first half (diverted plasmas) of this miniproposal.
As usual, Steve was up to the task. He started with a successful
0.5 MA shot from 950202 and performed some extensive wire-head surgery on
it. By shot 10, we had a stable 0.4 MA shot with the desired gaps and
scanning probe target position.
Meanwhile, the first 10 shots were used also used to test the
response of the scanning probe during RF. The problem with the scanning
probe power supplies dropping out during RF seems to have been fixed.
However, there is still some pickup on the +15 volt supply which shows up
just noticably on the scanning probe's position signal. These tests where
performed at the 1 MW level. It remains to be seen if further problems show
up at higher powers. In any case, it looks like the probe will function at
the 1 MW RF level which is good news for the planned LLNL remote run.
Scanning probe data up to the LCFS was taken for a range of
densities for Ip = 0.4 MA over shots 14 to 19. The switch-over to 0.6 MA
went remarkably well and I figured that our luck had to run out soon.
Yet, we got a variety of densities on shots 21 to 26. We had some difficulty
with the LCFS shrinking away from the probe at high densities. Then shot 26
ended with a VDE disruption, directly hitting the scanning probe. The north
and south probes got melted and shorted to the probe body (sounds familiar?).
We changed the bias on these probes to "floating" mode and continued on.
By shot 29, we got the desired high density data point (NL_04 = 1.4e20).
To provide a comparison with results from the 950308 run, we
dialed up a 0.8 MA shot. No problem. We took probe data up to the LCFS
with the two standard density ramps, completing the diverted phase of this
miniproposal.
Shot 32 had a Sc injection (in preparation for tomorrow's
run). Shot 35 had a CH4 injection through NINJA capillaries B22-022 and
B31-086. Garry and Dave managed to see a directional CII "plume" from the
B22-022 capillary using the newly installed Culham camera system (exposure
time is feedback controlled).

The diverted plasma portion of this miniproposal is now complete.
The second half of MP#084 involves these same currents and densities, but in
limited plasmas.

See entries in the logbook under the physics operator and session
leader topics for shot-to-shot commentary.

Physics Operator Summaries
Entered: Jul 7 2004 04:36:53:520PM
Author: To Be Determined
Physics Operator Summary for 950315

MP#084 SOL Characterization II
SL: LaBombard
PO: Wolfe
EO: Bertolino/Daigle/Paranay


The run plan was as folllows:

5.3 Tesla deuterium plasmas, no impurity gas injection, maximum overnight wall
conditioning (D2 ECDC) to try and clean up from the recent leak.

Engineering set up should be as for shot #950307002 on supply timing,
A-side plenum filled to 19psi (D2). B-side lower plenum filled with argon to
4psi, but not enabled for first shot. Fill pressure will be determined in the
morning after ECDC.

Initial Segment 1 startup programming will be from 950314020, to be tweaked up
to taste.

(0) - Obtain a decent diverted shot at 0.4 MA vaguely related to the
equilibrium developed for the 0.5 MA shots (start from 950202020, lose the
sweeps, change the gains, recalculate the RCUR predictor, etc.). Tweak the
outer discharge shape to have a constant strike point location (probe 2 on
outer divertor), good scanning probe targeting, and good gaps. Ideally we
would use x-point control rather than strikepsi control. If we must sacrifice
constant strike point control in order to get a good probe target then so be
it. The challenge will be to get good plasmas back of any type, really. The
low current request is an additional complication. If we can not do 0.4 MA
then we could try 0.6 MA. (10 shots?)

Again, five key equilibrium shape parameters need to be watched during this
run: inner gap > 1.5 cm, outer gap > 1.5 cm, distance to second separatrix
(SSEP on EFIT scope) > 1.7 cm, constant outer divertor strike point location,
and constant scanning probe target flux surface location.

(1) - tune up a density ramp from NL_04 = 0.5e20 at 0.5 sec to 1.0e20 at 1
sec. Fire the scanning probe at 0.5, 0.75 and 1.0 sec. (3 shots)

(2) - density ramp from NL_04 = 0.8e20 at 0.5 sec to 1.5e20 at 1 sec, fire
probe (3 shots)

(2a) - optional at 1.0 MA: density ramp from NL_04 = 1.0e20 at 0.5 sec to
2.0e20 at 1 sec, fire probe (3 shots)

- repeat steps (1) and (2) for plasma currents of 0.6, and 0.8 MA. If all goes
well then repeat for 1.0 MA.

(3) - for last 2 shots, return to 0.8 MA with density ramp NL_04 = 0.5e20 at
0.5 sec to 1.0e20 at 1 sec, fire probe

We actually completed the work at the two lower currents (.4 and .6MA) and got
two density scans at 0.8MA to make contact with previous runs. We did not get
to the 1MA cases. We got extended periods with the density as low as 3e19
(NL4) with no problems. The RF was firing in the early part of the pulse (E-port
only) and seemed to be reliably getting around 1MW when the densities were
reasonable. CH4 injection from NINJA was tried on the last shot, and produced
a visible plume, as hoped. There was a Sc injection on the next to last shot.
For a blow-by-blow account, see the PHYSICS_OPERATOR topic in the
logbook.

The first task was to get the 0.4MA equilibrium. We started with a 500kA case
from 950202, seriously tweaked (see the logbook for details). On shot 3 we
dropped the programming to 384kA to get a nominal 400kA discharge. As I
expected, it turned out to be useful to move the OH1 and OH2 crowbar times to
.090 sec, from .120, in order to keep the current from overshooting and coming
back down. It was also helpful to increase the Ip gain, especially early.
There was some problem with hard xrays, which was dealt with by raising the
fill. The equilibrium was extablished by shot#10, on schedule, and we began
doing the density ramps. At 400kA the higher density led to shark fins and
some late disruptions, so we backed off the high end of the ramp. The 400kA
data shots were 11:19.

The 600kA shots were somewhat more problematic, particularly at the high
density end. The crowbar times were put back to .12, and we got a good looking
target by #22. It turned out that on the high density cases the EF1 supplies
were running out of voltage, leading to loss of target location and eventually
to vertical disruptions. We finally had to give up on the highest density for
this case. Data shots were from 22 : 31

To do the 800kA case, we reloaded Seg 2 from 950309009, which had used
STRKPSI control. The first try ran fine, but the second attempt, with the
probe going further in, disrupted early on a vertical problem early. This was
corrected by dropping the slow ZCUR P gain from 3 to 1.5, and the fast ZCUR P
gain from 5 to 4. The machine does not run well anymore with slow ZCUR P-gain
at 3. Future operators should be aware (and beware). Data shots were
32,34,35.

Startups were basically ok, 2 fizzles out of 35 attempts. There was one tweak
to Bz (IC_EF4). The Bz at t=0 had crept up over the first dozen shots, finally
leading to a late breakdown on 11 and a fizzle on 12. This may be a coil
cooling problem; there was a definite secular trend in the initial Bz. We
started with a fill of 1.8, and raised it to 2.2-2.5 later in the run; this
was the only anti-xray remedy taken today.

Problems:
--------
The EF1 supplies seem to be saturating on voltage late in the pulse,
especially on the ramps to high density. This may or may not be a consequence
of the new slew rate boards.

Cooling was slow today, held up by one upper TF arm. This probably cost us a
couple of shots, over the course of the day.

The last shot had an alternator problem in check and had to be ramped back up
a second time. The shot went ok, but the PF breaker pulled out after the
disruption (only time that happened all day).


Scorecard:
----------
Fizzles 2
Duds 0
Plasmas 33
------- --
Total 35

Session Leader Comments
Mar 15 1995 08:52:51:750AM950315001Brian LabombardShot 1:
Steve: "Loaded shot 950202020 with a bunch of changes"
Disrupted at 0.3 sec. Vertically unstable.

Mar 15 1995 09:13:52:900AM950315002Brian LabombardShot 2:
Amazing 0.5 MA plasma. Are we just lucky?
5 small moly injections.
Steve will reduce current on next shot and
reduce the gain on strikepsi control. RF pulsed three times
starting at .44 sec. FSP will fire on next shot to test interaction
with RF.

Mar 15 1995 09:28:48:470AM950315003Brian LabombardShot 3:
Another nice plasma. 0.4 MA as requested.
FSP firing at 0.5, .78, and .96 sec. Rest position is -20 mm
No problem with RF on probe position or on power supplies.

Mar 15 1995 09:42:19:720AM950315004Brian LabombardShot 4:
0.5 MA dropping to 0.4 MA. Disrupted at 0.76 sec.
Plasma bumps the inner wall at 0.6 sec which leads to
a large density rise.
FSP firing at 0.5, .78, and .96 sec. Rest position is -20 mm
No RF pulses.

Mar 15 1995 10:02:33:260AM950315005Brian LabombardShot 5:
Again 0.5 MA dropping to 0.4 MA.
FSP firing at 0.5, .78, and .96 sec. Rest position is -20 mm
Three RF pulses starting at .38 sec. Last pulse is 0.5 MW.
No effect on probe position trace. +15 volt supply shows
a fast spike down to 14 volts at the turn on of the 0.5 MW pulse.
Try to lower the density on the next shot to 0.5e20 on NL_04.
Also try to increase the inner gap and lower the outer strike point.

Mar 15 1995 10:17:34:060AM950315006Brian LabombardShot 6:
Again 0.42 MA.
FSP firing at 0.5, .78, and .96 sec. Rest position is -20 mm
Three RF pulses starting at .38 sec. Last pulse is 0.6 MW.
Some effect on probe position trace is now showing up.
+15 volt supply shows a fast spike down to 10 volts at the turn on
of the 0.6 MW pulse.
NL_04 is 0.5e20 as requested.
Inner gap needs to be increased.

Mar 15 1995 10:26:58:550AM950315007Brian LabombardShot 7:
0.42 MA. Disruption at .465 sec.
FSP firing at 0.5, .78, and .96 sec. Rest position is -5 mm

Mar 15 1995 10:27:42:240AM950315007Brian LabombardShot 7:
Sorry - Disruption was at .378 sec.

Mar 15 1995 11:04:15:750AM950315009Brian LabombardShot 9:
Good shot. Almost have the target plasma now.
Gaps are good. Tweaking SSEP again.
FSP firing at .6, .78, and .96 sec. Rest position is 0 mm.

Mar 15 1995 11:18:33:840AM950315010Brian LabombardShot 10:
FSP firing at .60, .76, and .96 sec. Rest position is 0 mm.
SSEP improved. Target is not as good. Add density ramp
on next shot.

Mar 15 1995 11:32:29:910AM950315011Brian LabombardShot 11:
FSP firing at .66, .81, and .96 sec. Rest position is 0 mm.
SSEP improved. Target is not as good. Add density ramp
on next shot.

Mar 15 1995 11:36:45:230AM950315011Brian LabombardShot 11:
Sorry. pressed the wrong button.
FSP firing at .66, .81, and .96 sec. Rest position is 0 mm.
Density ramp. Probe samples: .52, .71, 1.3 e20
Full plasma detachment at .94 sec?
Setting up 0.3e20 to 0.9e20 target for next shot.

Mar 15 1995 11:40:45:930AM950315012Brian LabombardShot 12:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is 10 mm.
Fizzle.

Mar 15 1995 11:57:14:550AM950315013Brian LabombardShot 13:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is 10 mm.
Divertor detaches at .87 sec.
FSP samples: .34, .6, .84 e20

Mar 15 1995 12:23:41:130PM950315014Brian LabombardShot 14:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is 15 mm.
Sampled: .38, .57, .79 e20
Increasing first density point on next shot.

Mar 15 1995 12:26:15:780PM950315015Brian LabombardShot 15:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is 15 mm.
Sampled: .61, .75, .87 e20
Target is 17 mm.

Mar 15 1995 12:51:14:760PM950315017Brian LabombardShot 17:
Argon is off on this shot.
Programmed 0.45e20 on start of ramp.
FSP firing at .66, .81, and .96 sec. Rest position is 17 mm.
Sampled: .43, .63, .77 e20
Target was 15 mm.

Mar 15 1995 12:59:34:490PM950315018Brian LabombardShot 18:
Argon is off on this shot.
Programmed 0.45e20 on start of ramp.
FSP firing at .66, .81, and .96 sec. Rest position is 15 mm.
Sampled: .73, .83, .96 e20
Target moved to 18 mm. We will retake this shot.

Mar 15 1995 01:18:58:300PM950315019Brian LabombardShot 19:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is 18 mm.
Sampled: .74, .84, .91 e20
Change to 0.6 MA on next shot.
MOve FSP out to -10 mm on next shot.

Mar 15 1995 01:34:12:020PM950315020Brian LabombardShot 20:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is -10 mm.
Nice 0.8 MA plasma.
Samples: .76, .84, .96 e20
Changing to 0.5e20 for start of ramp on next shot.
Target is 6 mm. Moving probe to 3 mm for next shot.

Mar 15 1995 01:45:46:580PM950315021Brian LabombardShot 21:
Argon is off on this shot.
FSP firing at .66, .81, and .96 sec. Rest position is 3 mm.
Samples: .65, .78, .91 e20
Target is moving: 4 mm to 10 mm
Try to fix RXL on next shot.

Mar 15 1995 02:07:17:260PM950315022Brian LabombardShot 22:
Disrupted at 0.962 sec.
FSP firing at .66, .81, and .96 sec. Rest position is 3 mm.
Samples: .67, .80, .90 e20
Target is moving: 4 mm to 15 mm

Mar 15 1995 02:20:13:780PM950315023Brian LabombardShot 22:
Nice target at 8 mm.
FSP firing at .66, .81, and .96 sec. Rest position is 3 mm.
Samples: .54, .72, .86 e20
Target is moving: 4 mm to 15 mm

Mar 15 1995 02:29:34:710PM950315024Brian LabombardShot 24:
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
Samples: .48, .60, .75 e20
Made it to LCFS on three scans.
Change to next density ramp.

Mar 15 1995 02:46:29:510PM950315025Brian LabombardShot 25:
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
Samples: .8, .9, 1.1 e20
First two scans go to LCFS. Last scan is 5 mm out.
Did not get the full density ramp. Try again with increased gain on
the density feedback.

Mar 15 1995 03:07:33:060PM950315026Brian LabombardShot 26:
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
Samples: 0.8, 1.1, 1.4 e20
First two scans make it to LCFS. Last scan is 10 mm out.
Next shot is a slower ramp starting 0.8e20 at .3 sec to 1.5 at 1.0 sec.

Mar 15 1995 03:19:05:900PM950315027Brian LabombardShot 27:
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
Samples: 1.0, 1.35, 1.46 e20
First scan makes it to LCFS. Second scan is 7 out.
Disrupts on third scan.

Mar 15 1995 03:46:35:870PM950315028Brian LabombardShot 28:
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
Samples: 1.4, 1.3 e20
Target moved up to 18 mm. Looks like the disruption on the
previous shot killed the north probe. It appears to be shorted
to the body.

Mar 15 1995 03:51:31:150PM950315029Brian LabombardShot 29:
FSP firing at .66, .81, and .96 sec. Rest position is 14 mm.
Samples: 1.3, 1.35 e20
First scan is 4 mm INSIDE LCFS. second scan is at LCFS
Last scan is at disruption.
North probe is shorted to body. Nex shot will have it floating.

Mar 15 1995 04:03:43:550PM950315030Brian LabombardShot 30:
FSP firing at .66, .81, and .96 sec. Rest position is 5 mm.
North probe is floating
Samples: .36, .58, .7 e20
South probe is also shorted to the body.

Retake the shot.

Mar 15 1995 04:11:26:810PM950315031Brian LabombardShot 31:
FSP firing at .66, .81, and .96 sec. Rest position is 5 mm.
North and South probes floating
All three scan make it LCFS.
Samples: .4, .59, .74 e20

Mar 15 1995 04:24:50:060PM950315032Brian LabombardShot 32:
0.8 MA shot.
FSP firing at .66, .81, and .96 sec. Rest position is 0 mm.
North and South probes floating

Samples: .5, .75, .9 e20
Sc injection at 1.05 sec.

Mar 15 1995 04:42:24:830PM950315033Brian LabombardShot 33:
0.8 MA shot.
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
North and South probes floating

Disruption at .452 sec.

Mar 15 1995 04:53:09:250PM950315034Brian LabombardShot 34:

0.8 MA shot.
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
North and South probes floating
Samples: .53, .74, .92 e20

Mar 15 1995 05:03:22:250PM950315035Brian LabombardShot 35:

0.8 MA shot.
FSP firing at .66, .81, and .96 sec. Rest position is 7 mm.
North and South probes floating
Samples: .7, .82, .9 e20
0, 0, 2 mm outside LCFS
CH4 NINJA injection from B22-022 and B31-086.

Physics Operator Comments
Mar 15 1995 07:34:21:380AMSteve WolfeThe run plan for Wednesday 15-MAR-1995 (MP# 084 Scrape-off Layer
Characterization II) is as follows:

5.3 Tesla deuterium plasmas, no impurity gas injection, maximum overnight wall
conditioning (D2 ECDC) to try and clean up from the recent leak.

Engineering set up should be as for shot #950307002 on supply timing,
A-side plenum filled to 19psi (D2). B-side lower plenum filled with argon to
4psi, but not enabled for first shot. Fill pressure will be determined in the
morning after ECDC.

Initial Segment 1 startup programming will be from 950314020, to be tweaked up
to taste.

Mar 15 1995 07:35:47:430AMSteve Wolfe(0) - Obtain a decent diverted shot at 0.4 MA vaguely related to the
equilibrium developed for the 0.5 MA shots (start from 950202020, lose the
sweeps, change the gains, recalculate the RCUR predictor, etc.). Tweak the
outer discharge shape to have a constant strike point location (probe 2 on
outer divertor), good scanning probe targeting, and good gaps. Ideally we
would use x-point control rather than strikepsi control. If we must sacrifice
constant strike point control in order to get a good probe target then so be
it. The challenge will be to get good plasmas back of any type, really. The
low current request is an additional complication. If we can not do 0.4 MA
then we could try 0.6 MA. (10 shots?)

Again, five key equilibrium shape parameters need to be watched during this
run: inner gap > 1.5 cm, outer gap > 1.5 cm, distance to second separatrix
(SSEP on EFIT scope) > 1.7 cm, constant outer divertor strike point location,
and constant scanning probe target flux surface location.

Mar 15 1995 07:36:38:110AMSteve Wolfe(1) - tune up a density ramp from NL_04 = 0.5e20 at 0.5 sec to 1.0e20 at 1
sec. Fire the scanning probe at 0.5, 0.75 and 1.0 sec. (3 shots)

(2) - density ramp from NL_04 = 0.8e20 at 0.5 sec to 1.5e20 at 1 sec, fire
probe (3 shots)

(2a) - optional at 1.0 MA: density ramp from NL_04 = 1.0e20 at 0.5 sec to
2.0e20 at 1 sec, fire probe (3 shots)

- repeat steps (1) and (2) for plasma currents of 0.6, and 0.8 MA. If all goes
well then repeat for 1.0 MA.

(3) - for last 2 shots, return to 0.8 MA with density ramp NL_04 = 0.5e20 at
0.5 sec to 1.0e20 at 1 sec, fire probe

Mar 15 1995 08:44:53:350AM950315001Steve WolfeShot #950315001

Use segment 1 from a successful shot from yesterday 950314020.
Use segment 2 based on 950202020 with lots of changes. (prepared shot
was in PCS$WOLFE:PCS_950315901). This is programmed for 500kA, we'll
start from here and drop it to 400 if possible.
Coldstart was run at 07:39
Note - among the changes, I noticed this morning that the Ip gain in
Seg 2 wasn't on until .127 sec, so the forst 27msec of the segment was
uncontrolled! I moved the initial point on the P-gain to .05sec

Also note that the new slew rate boards are in the EF1 supplies. These
were in yesterday for the last fizzle, but have not been tested double
swing.

At 08:25 base pressure is 3.4e-6
Fill set to 1.8e-5

Result:
Disrupts around 300msec.

Mar 15 1995 09:01:56:880AM950315002Steve WolfeShot #950315002

Decrease CLEARIN to -.005, reduce EF4 to 1500A

Ran full length.
Lots of injections, still thrashing early on EF2 and OH2's
It may be the strikepsi control, which we want to reduce anyway

Mar 15 1995 09:20:58:090AM950315003Steve WolfeShot #950315003

Reduce Ip programming to 384ka
Reduce physics P gain on strkpsi from 120 to 40
INcrease zxl gain to 32 (8 in H units)

Got xrays, but it ran; disrupts at 1.29
Current comes down to a flattop at 420kA

Mar 15 1995 09:37:40:520AM950315004Steve WolfeShot #950315004

Move OH crowbars from .120 to .090sec
At .5sec, increase RXL gain to 90/sec
decrease STRKPSI control from 3 to 1, then 0 at .5sec
Increase fill to 2.0e-5

Disrupted at .8sec - growing vertical oscillation
There is a big oscillation on the EF2's, in phase. May have too much
gain on RXL and/or CLEARIN

Mar 15 1995 09:52:37:730AM950315005Steve WolfeShot #950315005

Decrease RXL gain to 30/s throughout
INcrease early P-gain on Ip

Ran ok, disruption on ramp-down at 1.27sec
Multiple injections

Mar 15 1995 10:10:45:790AM950315006Steve WolfeShot #950315006

Reduce NL_04 program to be flat at 5e19
Increase CLEARIN to 0. at 0.5sec
Move RCUR from .662 to .664 at 0.5sec
Drop ZXL by 1cm to -1.29e-2, and further out on rampdown
Hold RXL out at rampdown
Maintain low RXL gain through rampdown
Raise Ip gain to constant level throughout shot

Ran, but disrupts at 1.18; I'll need to deal with the ramp-down soon
Current looks pretty flat.
Inner gap still a bit too small, strike still too high

Mar 15 1995 10:30:08:030AM950315007Steve WolfeShot #950315007

Get rid of STRKPSI control completely (including integral gain)
Increase CLEARIN to 0.004 from 0.5sec
Increase RCUR from .664 to .666, and don't swing in as fast on rampdown

Got hards again, early disruption
EF2L went to zero current at 180msec, disrupted at 390??

Mar 15 1995 10:41:20:730AM950315008Steve WolfeShot #950315008

Raise fill to 2.3e-4, everything else left the same as 7:
Get rid of STRKPSI control completely (including integral gain)
Increase CLEARIN to 0.004 from 0.5sec
Increase RCUR from .664 to .666, and don't swing in as fast on rampdown

That one ran ok, I still don't understand what happened to #7
ZXL is constant at +5000 a-m error, RXL is moving out, CLEARIN is pretty
constant
Left gap is 1.5 to 2 except for a glitch between .5 and .6 (crossover!)
right gap is around 2, strikes a bit high

Mar 15 1995 10:58:51:260AM950315009Steve WolfeShot #950315009

Lower ZXL to -.016 from -.0129
Raise ZXU from .03 to .04

Ran ok. Gaps are ok, strike still rides a little high
SSEP better, could stand a litle more

Mar 15 1995 11:18:42:300AM950315010Steve WolfeShot #950315010

Raise ZXU from .04 to .05
Drop EF4 to 940A
Ramp Clearin in faster at ramdown
Enable Ar puff

Ran ok. 2pi up slightly but still below 100kW in flattop.
SSEP is now out of the vessel
outer strike goes up above the mose at end of flattop

Mar 15 1995 11:33:06:090AM950315011Steve WolfeShot #950315011

Program density ramp from 0.5e20@.65 to 1.e0 at 1sec
Program EF4 ramp from 920 at .6 to 1900 at 1sec
Bring Ip down faster
Raise fill to 2.5e-5

Disrupted at 1sec
Looks like a shark fin
Detaches from divertor around .7

Mar 15 1995 11:56:02:020AM950315013Steve WolfeShot #950315013

INcrease EF4 from 1085 to 1100a (it's that or a V_OH1 tweak)
Program density ramp from 0.3e20@.65 to .9e20 at 1sec
Argon puff off

Got it back, Disrupts at 1.1sec
Nice early breakdown, current rise
Density starts REALLY LOW, as programmed
Still looks like its detaching early
Growing vertical instability on early rampdown

Mar 15 1995 12:13:48:860PM950315014Steve WolfeShot #950315014

Only rampdown changes, ramp CLEARIN in faster, Ip down a little faster
For next shot, narrow the Ar pulse to 13msec, still leave valve disabled

Made it further into rampdown
Brian got good data, detaching during ramp

Mar 15 1995 12:25:22:690PM950315015Steve WolfeShot #950315015

Raise initial density to 6e19, leave ramp to 0.8 after .65
Ran ok. Brian likes the data

Mar 15 1995 12:40:58:110PM950315016Steve WolfeShot #950315016

Lower initial density to 4.5e19, leave ramp to 0.8 after .65
Cooling is slow today, there's one upper TF arm that's lagging

Fizzle. Why? Fields look better than 15, which went ok.

Mar 15 1995 12:49:27:350PM950315017Steve WolfeShot #950315017

Drop fill to 2.2e-5 and repeat:
Lower initial density to 4.5e19, leave ramp to 0.8 after .65

Ran ok. Some ECE data lost (CAMAC error)

Mar 15 1995 12:57:20:410PM950315018Steve WolfeShot #950315018

Raise initial density to 7e19, ramp to 1.e20 after .65
Try to see the shark fin come back (or not)

Disrupts at 1sec, similar to before.
This completes the data for 400kA

Mar 15 1995 12:59:28:940PM950315018Steve WolfeShot #950315018

Raise initial density to 7e19, ramp to 1.e20 after .65
Try to see the shark fin come back (or not)

Disrupts at 1sec, similar to before.
Brian's target moved away. Need to redo this point.

Mar 15 1995 01:15:30:470PM950315019Steve WolfeShot #950315019

Repeat with deeper probe insertion:
Raise initial density to 7e19, ramp to 1.e20 after .65
Try to see the shark fin come back (or not)

This one ramped on down, vertical problem at 1.0, but made it through
Longer RF pulse at .43 to .53 sec, 1.1MW

Mar 15 1995 01:29:37:280PM950315020Steve WolfeShot #950315020

Raise Ip programing to 570kA, EF4 initial level to 1400a
Leave crowbar settings the same (.090 on OH's)

Ran through
Current turns around a little after crowbar, need to increase the
programmed value.
Gaps look ok

Mar 15 1995 01:45:00:580PM950315021Steve WolfeShot #950315021

Move 400kA point earlier on Ip programming to match the real rise
Start NL_04 at 5e19 and ramp to 1.0 between .65 and 1.0
Flatten EF4 at 1435a

Ran fine. See how the target looks
Density has three early wobbles?
X-point is now too far outside

Mar 15 1995 02:00:19:180PM950315022Steve WolfeShot #950315022

Move RXL from -.005 to -.01
Increase integral gain on CLEARIN from 4 to 8
Turn on NL_04 derivative gain at 0.4 sec to 2.0

Disrupted at about 0.9 sec, looks like a vertical problem again
EF2 U railed early and stayed up. Last time it also railed.
The CLEARIN tweak was the WRONG thing to do.

Mar 15 1995 02:16:06:180PM950315023Steve WolfeShot #950315023

Move crowbar times back to 0.120
Drop CLEARIN Integral gain back to 4
Slow down the current rise program .1sec to .4 sec: Ip from 400kA->600kA

Ran through, we'll see how the target looks
EF2's now well off the rail
Target looks ok

Mar 15 1995 02:29:09:200PM950315024Steve WolfeShot #950315024

Change P gain on NL_04 from 8 to 3 at .4sec to try to reduce density
wobble.
No equilibrium changes

Ran fine. Still a little drop in density following the RF.
Target looks good, on to the next ramp

Mar 15 1995 02:39:08:220PM950315025Steve WolfeShot #950315025

Change density ramp: 0.8 to 1.5e20

Ran through ok.Looks like a bit of a vertical problem at EOF
Didn't get the high density.

Mar 15 1995 03:05:04:770PM950315026Steve WolfeShot #950315026

Raise both P and D gains on NL_04 at 0.65sec

Ran ok, but got some hard xrays early.
Breakdown almost doesn't make it.
Disrupted at EOF.
Got to 1.5 at 1sec
EF1's seem to stop following demand at around .75 sec (flat out?)

Mar 15 1995 03:18:09:290PM950315027Steve WolfeShot #950315027

Raise fill to 2.4e-5 (to try to hold down xrays)
Slow down density ramp, starting at .3 sec instead of .65
The idea is to require less voltage out of EF1 by slowing things down

No xrays, still disrupts just before EOF
No improvement

Mar 15 1995 03:34:29:670PM950315028Steve WolfeShot #950315028

Program flat density at 1.3e20
Ramp EF4 to 2000A late

Disrupted again, before EOF
Looks like a vertical problem
Density goes way high early.

Mar 15 1995 03:44:48:560PM950315029Steve WolfeShot #950315029

Slow down density ramp, reach 1.3e20 at .6sec
Ramp EF4 to 2000A late

Still disrpting before EOF.
Brian has a shorted probe from disruption two or three shots ago.
Got the density this time, and EF2's are off the rail.
Still losing control of the EF1's at about the same time
Done with this density at 600kA

Mar 15 1995 03:59:26:410PM950315030Steve WolfeShot #950315030

Density ramp from 0.3e20 to 0.8e20
Brian re-configuring his probes because N is shorted

Ran ok. Got the density we asked for
Looks like S probe is also shorted.

Mar 15 1995 04:05:34:560PM950315031Steve WolfeShot #950315031

Repeat with S probe floating as well
Looks ok.

Mar 15 1995 04:23:06:550PM950315032Steve WolfeShot #950315032

Load seg 2 from 950309009, an 800kA shot,
program NL_04 from .5 to 1.0e20
Fill NINJA plenum to 8psi CH4
Enable shitshooter gate valve; will fire Sc at 1.sec

Ran fine. Note that this one is using strkpsi control.

Mar 15 1995 04:32:02:360PM950315033Steve WolfeShot #950315033

Repeat to get probe scans

Disrupted early. Damn, it had the old bad gains.
Must have just made it through last time

Mar 15 1995 04:45:42:540PM950315034Steve WolfeShot #950315034

Drop slow Zcur gain to 1.5, fast P gain to 4
Enable NINJA puff (CH4 at .35 sec)
There was some problem writing to the tree to set up the NINJA

Got it!

Mar 15 1995 05:02:47:050PM950315035Steve WolfeShot #950315035

NL_04 ramp from .8 to 1.5 e20
Turn on NL_4 D gain at 2.0 from 0.5sec
NINJA system was not enabled at PC on lasr shot; will be this shot

Alternator had to ramp up twice.
Shot ran ok, disrupted at 1.25
got a PF fault late
EF1 may have lost control (saturated) again

Engineering Operator Comments
ShotTimeTypeStatusComment
108:33:14:240AMPlasmaOkno faults
208:53:28:460AMPlasmaOkNo Faults.
309:13:08:370AMPlasmaOkno faults
409:30:19:360AMPlasmaOkno faults
509:45:38:430AMPlasmaOkno faults
610:02:23:440AMPlasmaOkno faults
710:17:09:720AMPlasmaOkno faults
810:31:27:760AMPlasmaOkno faults
910:48:06:660AMPlasmaOkno faults
1011:06:11:070AMPlasmaOkno faults
1111:23:43:040AMPlasmaOkno faults
1211:39:12:110AMPlasmaOkno faults
1311:47:12:180AMPlasmaOk no faults
1412:05:20:500PMPlasmaOkno faults
1512:16:26:240PMPlasmaOkno faults
1612:32:38:990PMPlasmaOkno faults
1712:42:07:550PMPlasmaOkno faults
1812:52:05:680PMPlasmaOkno faults
1901:09:39:920PMPlasmaOkNo Faults.
2001:20:58:270PMPlasmaOkNo Faults.
2101:34:06:450PMPlasmaOkNo Faults.
2201:56:07:210PMPlasmaOkno faults
2302:08:29:550PMPlasmaOkNo Faults.
2402:20:51:760PMPlasmaOkNo Faults.
2502:33:00:450PMPlasmaOkNo Faults.
2602:51:41:330PMPlasmaOkNo Faults
2703:08:00:360PMPlasmaOkno faults
2803:22:40:320PMPlasmaOkno faults
2903:35:59:840PMPlasmaOkno faults
3003:49:57:490PMPlasmaOkno faults
3104:01:45:030PMPlasmaOkno faults
3204:15:41:950PMPlasmaOkno faults
3304:28:41:420PMPlasmaOkno faults
3404:41:57:570PMPlasmaOkno faults
3504:52:57:570PMPlasmaOkcomm fail oh2u, oh1