Alcator C-Mod Run 1000925 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Bruce Lipschultz (shots 1-26)
Miniproposal:228
Date Filed: 1/15/1999
Title:Scrape-off Layer Transport Studies
First Author:Brian Labombard
Session Leader:Brian Labombard (shots 1-26)

Operators
Session leader(s):Brian Labombard,Bruce Lipschultz
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Parkin,Gary Dekow,Bill Cochran

Engineering Operator Run Comment
Evaluation of Machine Conditioning, MP 228 Scape off Layer Transport Stu

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:24:930PM
Author: To Be Determined
#38 of 43 CMOD
Date: 25-SEP-2000 18:19 Expires: 9-OCT-2000 00:00
From: RHONE::BLIP
Subj: run summary 1000925

Run 1000925

Physop: Steve Wolfe
Session leader: B. Lipschultz/B. LaBombard for MP228
Eng. operator: Bill Cochrane

Primary goal: Get the machine running discharges. Evaluate cleanliness and best
options for recovery.

Secondary goal: We hope to eke out a gap scan. The need is for a well-defined
scan of the outer gap and density, keeping other conditions constant
(inner gap, outer divertor conditions...). We will be taking data with the
2 scanning probes, the limiter flux probes, pressure gauges and so on.
With this data we will not only be able to evaluate the effect of outer gap on
the midplane pressure, but also understand if there are any effect on the
transport in the SOL that correspond (assuming changes in the midplane
pressure).

The first goal was certainly achieved. We got plasma on the first shot (#2
I believe) and continued on from there. There was a hiatus to take care of the
Ratiomatic gauge at G-side which was not operating. That was fixed.
When a new gauge is installed the gauge pressure tends to vary for the next
4-8 hours. We tried to compensate for this by recalibrating as we went
along through the day.

Regarding the effect of the outer gap: We found that the midplane pressure
did NOT seem to be affected by the outer gap! In addition, it appeared that
the plasma parameters at the plate were unaffected as well! The flux to the
limiter increased by ~x10 in going from 2.4 cm gap to 0. We are not sure how
to reconcile all of this at the moment. Is the outer limiter really acting as
a proper limiter? If not this would explain the lack of gap effect on the
divertor plasma (We have not looked at the general SOL profile from the
F-scanning probe yet),

In the final several shots we limited the plasma on the inner wall (24-25)
and made the outer gap -6 mm (shot 26). Looking at shots 25, 26, 18 and 10,
where the outer gap was 12 (but inner wall limited), -5, 0, and 24 did seem
to indicate that there was a variation of midplane pressure with gap, but
it was small - factor of 2. In the case where the outer gap was -6 mm
we did see the divertor pressure drop and some effect density in the
divertor, but not large.

In summary, alot of interesting data, but no obvious meaning.

Shot summary:

shot 4: Ratiomatic now working. Calibrated after shot 3. Gaps look good until
current inversion. Unfortunately the gaps increase then and the plasma
disrupts during inversion. Strike point position ~ probe 3.

shot 5: midplane pressure .06 mT. Outer gap 2.3 cm. Inner gap 1.5 cm.
nl04 varying from 7.2 to 8.3e19.

shot 6: outer gap 2.2 cm. nl04 = 6-8e19 over the shot. Midplane
pressure .04 - .05 mT over the shot.

shot 7: disrupted early on.

shot 8: disrupted again.

shot 9: 0.55-0.6e20. Outer gap ~ 2.4 cm. midplane pressure ~ .03 mT.

shot 10: 0.95e20. Outer gap ~ 2.5-2.6 cm. midplane pressure .1-.2 mT.
injection at .827 sec raises the midplane pressure from .13 - .18 mT.

shot 11: 1.2-1.35e20. Outer gap ~ 2.5-2.7 cm. midplane pressure .5-1.36 mT.
Brian's probe scan (FSP) poor, try again.

shot 12: no plasma

shot 13: 1.3-1.6e20. Outer gap ~ 2.7 cm. midplane pressure .6-2.2 mT.
For some reason the midplane presure, and the G/H flux stop rising
after divertor detachment?

shot 14: interferometer died causing the gas valve to be wide open and
a disruption. Comparison of the Thomson ne this shot to last indicates that
nl04 similar - 1.5-1.6e20. midplane pressure 1.7 m

shot 15: no plasma.

shot 16: outer gap .6 cm. nl04 =1.5-1.7. Midplane pressure 1.3-2.2 mT.

shot 17: outer gap 0 cm. nl04 =1.5-1.6. Midplane pressure 1.0-1.6 mT.

shot 18: outer gap 0 cm. nl04 =1.09e20. Midplane pressure .3-.36 mT.

shot 19: outer gap 0 cm. nl04 =.7-.85e20. Midplane pressure .08-.12 mT.

shot 20: outer gap 0 cm. nl04 =.65-0.8e20. Midplane pressure .06-.11 mT.

shot 21: outer gap 1.2 cm. nl04 =.6e20. Midplane pressure .035 mT.

shot 22: outer gap 1.2 cm. nl04 =1.0e20. Midplane pressure .2-.3 mT.

shot 23: outer gap 1.2 cm. nl04 =1.5e20. Midplane pressure .9-2. mT.

shot 24: INNER GAP CHANGE to 0 cm. outer gap 2.0 cm. nl04 =1.0e20.
Midplane pressure .16-.19 mT.

shot 25: INNER GAP CHANGE to 0 cm. outer gap 2.0 cm. nl04 =1.1e20.
Midplane pressure .19-.27 mT.

shot 26: INNER GAP CHANGE to 1.5 cm. outer gap -0.6 cm. nl04 =1.1-1.17e20.
Midplane pressure .3-.45 mT.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:12:100PM
Author: To Be Determined
Physics Operator Summary for Monday, Sept 25

MP#228 Scrape-off Layer Transport Studies/Outer gap scan
SL: B. Labombard/B. Lipschultz
PO: S. Wolfe
EO: Cochran, Parkin, Dekow

Run plan
---------

Experiments:
1. Evaluation of Machine Conditioning
2. If feasible, MP 228 -- Scrape-off Layer Transport Studies/Outer gap scan


Engineering setup:
-------------------
Over the weekend ECDC in D2, stopping 1-2 hours prior to run

Run begins at 9:30 (earlier if possible), and ends at 17:00

Power System as on 1000831021 except EFc voltage to 900V.
*Note EFc start time should be -.03 sec (Ian's early zcur control).
Also, note that the EF2 ballast resistors have been changed; they should
now be entered as
EF2U RComm/Ballast=42.08
EF2L RComm/Ballast=42.49

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 35 psi of D2 Hybrid DISABLED, available ECDC
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:
ECE, VUV

DNB is out of commission. Do NOT Enable its gate valve!


Run Plan:
----------
The first priority will be to evaluate how well the machine has recovered from
the vacuum incident last week. Key indicators are plasma cleanliness, ability
to run low and moderate-high density, and H/D ratio. Depending on
results, boronization may be scheduled for Monday night. Assuming that the
cleanliness and density range are suitable, we will attempt to complete the
experiments on recycling vs gaps and density called for in the following plan.
Otherwise, we'll either run clean-up shots, or go to ECDC.

MP228 Goals: Use FSP, ASP, and limiter flux probes to record profiles into the
limiter shadow, studying the movement of recycling from the top of
the divertor to the midplane limiter surfaces as the outer gap is
changed.

All shots are 1 MA, 5.3 T, lower single null (or outboard limited) with
inboard gap of ~15mm. Flattop will be shortened to t=1.2 s.

Shot sequence:

1) Load a 1MA, 5.3T shot, with outer gap about 20mm, inner gap ~15mm.
Lower plasma center and increase upper x-point height to reduce
elongation, then increase outer gap to ~24mm.
It will take several shots to tune up gaps, probe positions,
strike points, density.

2) Outer gap = 2.4 cm, NL_04=0.6, 0.9, 1.3, 1.7e20 m-2

3) Outer gap = "0" cm, NL_04=1.7, 1.3, 0.9, 0.6e20 m-2

4) Outer gap = 1.2 cm, NL_04=0.6, 0.9, 1.3, 1.7e20 m-2

-------------------------------------------------------------------------------
PCS setup for first shot:

Load seg 2 from 1000914020, a 1MA, nl4=6e19 shot, and tweak as follows:

Rcur from .661->.656
IP ramp down from 1.2 to 1.7sec.
density ramp-down to 1.2
zcur to -.02, ramp back up slowly after 1.2sec
zxu from 0.048 -> .058
ic_ef4 ramp down at 1.2sec
tf from -151ka->-150kA, ramp down at 1.2sec
reduce pg3 maint level to 0 after .35 sec
change strkpsi waveform to 0.0; do not turn on.
change fsp waveform to 0.0; do not turn on.

Load seg 1 from 1000831021, change BR0 offset to 0.001,
IC_EF4 to -1290
PG4 to 17msec
--------------------------------------------------------------------

Results:
--------

The alternator was actually ready at 9:00, but we had some delays to work on
the ratiomatic before and after the first shots. The ratiomatic gauge, which
had failed following the loss of vacuum last week, was necessary for the
midplane pressure measurements for the MP228 experiment; it was fixed for shot
#3, and calibrated during the run. It is still not clear what was wrong with
it.

The run was reasonably successful; we ended up with only three densities at
each gap, rather than four, but we did an inner limiter case as well. The
results were not what was expected by the proposers, but the data look
good. Brian claims "Out of confusion come deeper understanding."

The H/D ratio never got significantly below 0.2, even for the highest
density. Therefore, the boronization was postponed until at least Tuesday
night.

Details:
-------
Shot#1 was a TF test, since work had been done in the TF supplies since
the last run. This was successful.

Shots #2-8 were used for setting up a satisfactory target, including
density, FSP target and strike point, with an outer gap of ~25mm.

Shots #9-14 were a density scan at large outer gap, ~25mm

Shots #16-20 scanned density down with "0" outer gap

Shots #21-23 scanned density up with 12mm outer gap.

Shots #24-25 were back at nl4=1.0e20 run on the inboard limiter

Shot #26 was a repeat of shot 18, but pushed 6mm further out to make sure it
is hard limited on the outside.

Aside for the high H/D ratio, and a somewhat more restricted range of density
than desired (we only got .7 - 1.5e20, rather than .6-1.7), the machine ran
pretty well today, considering it was the first run after last week's vacuum
accident. There was one power system induced dud when the OH2 commutation
switches failed to close (shot#12), and one fizzle (shot#15) foloowing a full
current disruption. There were also a couple of early disruptions, which
seemed to be due to moly injections. There were also a number of vertical
position thrashes which I was unable to eliminate, and the high density shots
tended to disrupt in rampdown.

Some tweaking of RXL and ZXL was required during the day to maintain the
strikepoints and FSP target. The specialized controllers STRKPSI and FSP were
not turned on.

The RF group was able to do a little bit of piggybacking at the tail end of
the last group of shots, in preparation for tomorrow's run.

Scorecard:
---------

Tests 1
Duds 1
Fizzles 1
Plasmas 23
------- --
Shots 26

Session Leader Comments
Sep 25 2000 09:42:58:373AMBruce LipschultzRun 1000925

Physop: Steve Wolfe
Session leader: B. Lipschultz/B. LaBombard for MP228
Eng. operator: Bill Cochrane

Primary goal: Get the machine running discharges. Evaluate cleanliness and best options
for recovery.

Secondary goal: We hope to eke out a gap scan. The need is for a well-defined scan of the
outer gap and density, keeping other conditions constant (inner gap, outer divertor conditions...).
We will be taking data with the 2 scanning probes, the limiter flux probes, pressure gauges and so on.
With this data we will not only be able to evaluate the effect of outer gap on the midplane
pressure, but also understand if there are any effect on the transport in the SOL that
correspond (assuming changes in the midplane pressure).
Sep 25 2000 10:45:41:873AM1000925004Bruce Lipschultzshot 4: Ratiomatic now working. Calibrated after shot 3. Gaps look good until
current inversion. Unfortunately the gaps increase then and the plasma
disrupts during inversion. Strike point position ~ probe 3.
Sep 25 2000 05:28:19:483PM1000925005Bruce Lipschultzshot 5: midplane pressure .06 mT. Outer gap 2.3 cm. Inner gap 1.5 cm.
nl04 varying from 7.2 to 8.3e19.
Sep 25 2000 05:28:49:013PM1000925006Bruce Lipschultzshot 6: outer gap 2.2 cm. nl04 = 6-8e19 over the shot. Midplane
pressure .04 - .05 mT over the shot.
Sep 25 2000 03:32:03:373PM1000925007Bruce Lipschultzshot 7: disrupted early on.
Sep 25 2000 03:31:47:293PM1000925008Bruce Lipschultzshot 8: disrupted again.
Sep 25 2000 03:31:28:827PM1000925009Bruce Lipschultzshot 9: 0.55-0.6e20. Outer gap ~ 2.4 cm. midplane pressure ~ .03 mT.
Sep 25 2000 03:31:15:793PM1000925010Bruce Lipschultzshot 10: 0.95e20. Outer gap ~ 2.5-2.6 cm. midplane pressure .1-.2 mT.
injection at .827 sec raises the midplane pressure from .13 - .18 mT.
Sep 25 2000 03:31:01:140PM1000925011Bruce Lipschultzshot 11: 1.2-1.35e20. Outer gap ~ 2.5-2.7 cm. midplane pressure .5-1.36 mT.
Brian's probe scan (FSP) poor, try again.
Sep 25 2000 03:30:27:890PM1000925012Bruce Lipschultzshot 12: no plasma
Sep 25 2000 03:30:11:920PM1000925013Bruce Lipschultzshot 13: 1.3-1.6e20. Outer gap ~ 2.7 cm. midplane pressure .6-2.2 mT.
For some reason the midplane presure, and the G/H flux stop rising
after divertor detachment?
Sep 25 2000 03:28:28:793PM1000925014Bruce Lipschultzshot 14: interferometer died causing the gas valve to be wide open and
a disruption. Comparison of the Thomson ne this shot to last indicates that
nl04 similar - 1.5-1.6e20. midplane pressure 1.7 mT.
Sep 25 2000 03:27:40:250PM1000925015Bruce Lipschultzshot 15: no plasma.
Sep 25 2000 02:15:42:403PM1000925016Bruce Lipschultzshot 16: outer gap .6 cm. nl04 =1.5-1.7. Midplane pressure 1.3-2.2 mT.
Sep 25 2000 02:33:27:280PM1000925017Bruce Lipschultzshot 17: outer gap 0 cm. nl04 =1.5-1.6. Midplane pressure 1.0-1.6 mT.
Sep 25 2000 02:58:26:373PM1000925018Bruce Lipschultzshot 18: outer gap 0 cm. nl04 =1.09e20. Midplane pressure .3-.36 mT.
Sep 25 2000 03:16:28:530PM1000925019Bruce Lipschultzshot 19: outer gap 0 cm. nl04 =.7-.85e20. Midplane pressure .08-.12 mT.
Sep 25 2000 03:34:23:250PM1000925020Bruce Lipschultzshot 20: outer gap 0 cm. nl04 =.65-0.8e20. Midplane pressure .06-.11 mT.
Sep 25 2000 04:04:05:840PM1000925021Bruce Lipschultzshot 21: outer gap 1.2 cm. nl04 =.6e20. Midplane pressure .035 mT.
Sep 25 2000 04:23:23:827PM1000925022Bruce Lipschultzshot 22: outer gap 1.2 cm. nl04 =1.0e20. Midplane pressure .2-.3 mT.
Sep 25 2000 04:41:00:140PM1000925023Bruce Lipschultzshot 23: outer gap 1.2 cm. nl04 =1.5e20. Midplane pressure .9-2. mT.
Sep 25 2000 05:11:42:450PM1000925024Bruce Lipschultzshot 24: INNER GAP CHANGE to 0 cm. outer gap 2.0 cm. nl04 =1.0e20.
Midplane pressure .16-.19 mT.
Sep 25 2000 05:27:28:890PM1000925025Bruce Lipschultzshot 25: INNER GAP CHANGE to 0 cm. outer gap 2.0 cm. nl04 =1.1e20.
Midplane pressure .19-.27 mT.
Sep 25 2000 05:53:16:937PM1000925026Bruce Lipschultzshot 26: INNER GAP CHANGE to 1.5 cm. outer gap -0.6 cm. nl04 =1.1-1.17e20.
Midplane pressure .3-.45 mT.

Physics Operator Comments
Sep 25 2000 07:39:07:450AMSteve Wolfeload previously prepared starting shot from pcs$wolfe:pcs_1000925000
do a remcam (just in case)
coldstart 07:38
All matrices responding
Sep 25 2000 08:18:21:950AMSteve WolfeRun plan for Monday, 25 September 2000:

Experiments:
1. Evaluation of Machine Conditioning
2. If feasible, MP 228 -- Scrape-off Layer Transport Studies/Outer gap scan

Session leaders: B. Labombard/B. Lipschultz
Physics operator: S. Wolfe

Engineering setup:
-------------------
Over the weekend ECDC in D2, stopping 1-2 hours prior to run

Run begins at 9:30 (earlier if possible), and ends at 17:00

Power System as on 1000831021 except EFc voltage to 900V.
*Note EFc start time should be -.03 sec (Ian's early zcur control).
Also, note that the EF2 ballast resistors have been changed; they should
now be entered as
EF2U RComm/Ballast=42.08
EF2L RComm/Ballast=42.49

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 35 psi of D2 Hybrid DISABLED, available ECDC
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:
ECE, VUV

DNB is out of commission. Do NOT Enable its gate valve!
Sep 25 2000 09:31:00:000AM1000925001Steve Wolfeshot#1: TF 50kA test
Looks good.

There is a problem with the ratiomatic, which unfortunately
is needed for the MP#228 experiment. However, we will proceed to
try to get plasma before continuing with repair efforts.
Sep 25 2000 10:03:57:280AM1000925002Steve Wolfeshot#2: plasma attempt. Should be 1MA, 6e19, 2cm outer gap.

plasma, full length. density is a bit high, at 7-8e19.
A few runaways early.
z-meter signal shows nothing, hesitation in startup.
Br and Bz perhaps both a little negative, early current rise
is slow.
H/D ~ 20-30%

right gap is 18-20mm, left 16-18mm, n/nc=1.1

Next shot:
decrease rcur by 3mm, to .653; clearin .005->.003
BR0 from .001->.0015
Ratiomatic is being worked on in the cell.
Z-meter camera was bumped; Earl has fixed it for next shot.
Sep 25 2000 10:27:22:310AM1000925003Steve Wolfeshot#3: decrease rcur by 3mm, to .653; clearin .005->.003
BR0 from .001->.0015
Ratiomatic is now working again; although it may be a few hours
for it to read correctly.
Z-meter camera was bumped; Earl has fixed it for next shot.

plasma, some vertical thrashes, but it survives.
current rise is a little better, 45kA at 15msec.
density is still at 7 - 8e19
H/D at 30%, over .5 after ijection at .96sec.
right gap 22mm, left gap 15mm, n/nc=1.16
strike point is high, according to Blip.

Next shot:
rcur to .652, ramp EF4 down slowly at 1.2 (seems to be affecting
EF2, clearin?)
rxl in by 5mm.
drop the pg3 early voltage a little.
Sep 25 2000 10:45:38:577AM1000925004Steve Wolfeshot#4: rcur to .652, ramp EF4 down slowly at 1.2 (seems to be affecting
EF2, clearin?)
rxl in by 5mm.

plasma, disrupted with a vertical instability at 1.33sec.
Need to fix the rampdown.
dithers from 1 sec on.
n/nc=1.2
gaps look good.

Next shot: ramp clearin in at inversion
drop zcur by 5mm to -.025, move rxl in by 3mm
Sep 25 2000 11:04:54:890AM1000925005Steve Wolfeshot#5: ramp clearin in at inversion
drop zcur by 5mm to -.025, move rxl in by 3mm, faster after .8sec

plasma, full length, there is a thrash at .26sec, otherwise ok.
density is still running a bit high.

next shot: Try dropping nl4 program, although the valve is already turning off at .5sec
drop icef4 gain at 0.2 sec.


Sep 25 2000 11:18:53:030AM1000925006Steve Wolfeshot#6: Try dropping nl4 program, although the valve is already turning off at .5sec
drop icef4 gain at 0.2 sec to try to affect early thrash.

plasma, full length. thrash is still there at .25 or so.
nl4 still rising during pulse to 0.8e20; it's just coming in from the walls.

next shot: move rcur in by 1.5mm, to .6505; gap had shrunk to 22mm, probably
when I dropped zcur again.



Sep 25 2000 11:35:54:590AM1000925007Steve Wolfeshot#7: move rcur in by 1.5mm, to .6505; gap had shrunk to 22mm, probably
when I dropped zcur again.

plasma disrupts at .35, the early thrash got it.
JR says there was a moly injection then.

next shot: try letting rcur swing out further, then back in by .5sec


Sep 25 2000 11:52:28:403AM1000925008Steve Wolfeshot#8: try letting rcur swing out to .654, then back in by .5sec to .6505

Another early disruption. Let's not do this again!
This one made it to .48, and had an injection; disrupts at .52.
I don't see anything in programming or shape that could be causing it,
but JR says this Mo injection has been there all day.

next shot: repeat and cross your fingers




Sep 25 2000 12:08:09:543PM1000925009Steve Wolfeshot#9: try again letting rcur swing out to .654, then back in by .5sec to .6505

plasma, full length. there are thrashes at .26, .41, and 1.36, but it makes it through
injections at .537, 1.0, 1.35.

Blip and Brian are relatively happy, go on to 0.97e20



Sep 25 2000 12:28:04:263PM1000925010Steve Wolfeshot#10: go on to nl4=0.97e20

plasma, to 1.58sec, some vertical thrashes in rampdown.
injections at .69 and .82sec
gap is a little bigger, and grows some in rampdown
H/D ~.4 to .6

next shot: nl4=1.4 or so, maybe a little more agressive rampin
on clearin in rampdown


Sep 25 2000 12:49:04:793PM1000925011Steve Wolfeshot#11: nl4=1.4 or so, a little more faster ramp on clearin in rampdown

disrupts at 1.4sec, got the density ok, need to work on the rampdown.

next shot: ramp zxu down in ramp down
also ramp zxl down to -.01 (was -.006) at 1.2sec, to try to stabilize fsp
target. raise nl4 to 1.5e20

Sep 25 2000 01:06:29:107PM1000925012Steve Wolfeshot#12: ramp zxu down in ramp down
also ramp zxl down to -.01 (was -.006) at 1.2sec, to try to stabilize fsp
target. raise nl4 to 1.5e20

dud! Power supply problem on OH2U? Switches never closed on the OH2's.
Sep 25 2000 01:25:40:500PM1000925013Steve Wolfeshot#13: ramp zxu down in ramp down
also ramp zxl down to -.01 (was -.006) at 1.2sec, to try to stabilize fsp
target. raise nl4 to 1.5e20, and raise pg3 maint level back to ~20V.

plasma, disrupts at 1.23 sec, vertical instability growing from 1 sec
looks like a poloidal detachment. Gas valve is wide open to .9 sec
H/D is around .2

next shpt: repeat, ramp clearin harder in rampdown.


Sep 25 2000 01:37:23:013PM1000925014Steve Wolfeshot#14: repeat, ramp clearin harder in rampdown.
another disruption, at 1.0 sec this time.
TCI failed, probably lost nl4 feedback very early.
Gas valve is full open from .16sec on.

Move on to the "zero gap" case.



Sep 25 2000 01:55:31:733PM1000925015Steve Wolfeshot#15: Move on to the "zero gap" case. rcur from .6505 to .664,
hold CLEARIN at 0.003 through rampdown

fizzle. fields don't look bad, gas is ok, looks like it doesn't burn through.

next shot: repeat



Sep 25 2000 02:19:40:840PM1000925016Steve Wolfeshot#16: Move on to the "zero gap" case. rcur from .6505 to .664,
hold CLEARIN at 0.003 through rampdown

plasma, to 1.4sec. Gap shows .6cm, according to EFIT.

next shot: add 3mm to RCUR
Sep 25 2000 02:28:45:640PM1000925017Steve Wolfeshot#17: add 3mm to RCUR to .667
plasma to 1.4sec. this time got the right gap at 0.

next shot: drop density to .97e20
Sep 25 2000 02:54:43:810PM1000925018Steve Wolfeshot#18:: drop density to .97e20

plasma to 1.59sec, nl4=1.0-1.1e20
H/D ~.3 to .4

next shot: .6e20
Sep 25 2000 03:11:30:590PM1000925019Steve Wolfeshot#19: drop density to .6e20

plasma, full length. nl4 rising from .7 to .9

next shot: drop demand to 0.5e20
Sep 25 2000 03:29:53:090PM1000925020Steve Wolfeshot#20: drop demand to 0.5e20. Brian will puff from FSP this shot.

plasma, full length. nl4=6 - 8e19.

next shot: go to 12mm outer gap.
Sep 25 2000 03:52:38:750PM1000925021Steve Wolfeshot#21: go for 12mm outer gap. rcur from .667 to .660

plasma, full length. nl4=0.6e20, gap=12-13mm.

next shot: nl4=9.7e19
Sep 25 2000 04:24:15:640PM1000925022Steve Wolfeshot#22: nl4=9.7e19, move rxl out by 4mm

plasma, 1.56 sec, nl=1e20, 12mm gap.

next shot, nl4=1.5e20
Sep 25 2000 04:36:23:090PM1000925023Steve Wolfeshot#23: nl4=1.5e20, increase pg3 pre-prog, keep rcur in a little at crossover.

plasma to 1.4sec, bad thrashes at .32 and .45 sec
nl4 is ramping continuously through the shot, reaches 1.5 at 0.9

next shot: nl4=1.0, inner gap to "0"

Sep 25 2000 05:00:59:107PM1000925024Steve Wolfeshot#24: nl4=1.0, inner gap to "0", so clearin from .003 -> -.017,
rcur from .660->.650

plasma, 1.64sec, nl4-=1.1e20, outer gap 18-20mm instead of 12.

next shot: try for outer gapback at 12mm
Sep 25 2000 05:18:43:437PM1000925025Steve Wolfeshot#25: try for outer gap back at 12mm; rcur to .654 from .650

plasma, full length, looked good.

next shot: Go back to shot 18, and move 4mm further out.


Engineering Operator Comments
ShotTimeTypeStatusComment
109:27:23:920AMTestOkTF Test only, Looks Good
209:40:49:983AMPlasmaOk
310:08:04:140AMPlasmaOk
410:28:57:590AMPlasmaOk
510:50:18:217AMPlasmaOk
611:06:14:810AMPlasmaOk
711:24:28:623AMPlasmaOk
811:40:33:780AMPlasmaOk
911:56:54:060AMPlasmaOk
1012:13:54:233PMPlasmaOk
1112:33:51:857PMPlasmaOk
1212:53:29:700PMPlasmaBadOH-2 commutation switches did not fire.
1301:12:23:500PMPlasmaOk
1401:29:42:060PMPlasmaOk
1501:49:36:090PMPlasmaOk
1602:02:48:060PMPlasmaOk
1702:23:23:000PMPlasmaOk
1802:45:36:153PMPlasmaOk
1903:04:39:607PMPlasmaOk
2003:25:30:750PMPlasmaOk
2103:46:29:890PMPlasmaOk
2204:17:06:560PMPlasmaOk
2304:31:03:607PMPlasmaOk
2404:54:54:577PMPlasmaOk
2505:15:58:233PMPlasmaOk
2605:37:55:733PMPlasmaOk