Alcator C-Mod Run 951215 Information

Miniproposals

Miniproposal: 130a

Date Filed: 12/5/1995

Title: Effect of Helium Plasmas on Divertor Operation

First Author: Bruce Lipschultz

Session Leader: Bruce Lipschultz (shots 1-40)

Operators
Session leader(s):	Bruce Lipschultz
Physics operator(s):	Steve Wolfe
Engineering operator(s):	Vinny Bertolino,Frank Silva

Engineering Operator Run Comment
divertor op

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:14:837PM

Author: To Be Determined

Run # 951215

Engineering operator: F. Silva
Physics operator S. Wolfe
Session leader B. Lipschultz

The aim of today's run was to compare the operation of helium and
deuterium plasmas. Through that comparison we hope to better understand
various aspects of SOL transport, recycling, impurity transport and detachment.
Note that even though charge exchange is much reduced as a momentum-loss
mechanism, ion-neutral elastic collisions still remain. I believe that these
crossections have similar magnitudes for D2.
We saw significant differences:

- The SOL was hotter
- detachment appears to be at higher density (about 50% higher than w/D2)
- The transition was slower than recent D2 discharges (as a function of nl04).
- The pressure drop observed was small (upstream pressure over downstream of
order 4-5). The corresponding Te at the plate was slightly higher. This
may be consistent.
- no death ray. Is this related to the reduction in CX which results in
momentum-carrying neutrals directed along a flux surface? Elastic collisions
would result in a 'spray' of neutrals in all directions.
- The main plasma radiated power not particularly down but Prad/Pin down.
This meant higher powers flowing into the SOL. The divertor radiated power
was lower than equivalent densities with D2. This is consistent with the
story that cx is a big contributor to radiation. The 2 methods of measuring
central radiated power (2Pi bolo which only 'sees' radiation and ASDEX
bolos which 'see' neutrals and photons) seemed to agree on most shots. This
implied that cx was a contributor to main plasma radiation as well.
- Measured XUV radiation at the x-point low for all impurities and
decreases with density! He dominates the XUV emission spectrum.
Recombination edge in hydrogen-like He very strong. The moly source as
measured by the Chromex was quite significant but decreased with increasing density.
- The neutral pressure at the edge (and divertor) was lower than with
D2 by a factor of 5 at nl04=1; smaller factors at higher densities.
- Measurements with FSP as Mach probe indicate flows in edge similar to
D2; they exist at low density and disappear as the density is increased.

Rf coupling not unusual. We did not achieve H-modes (but power was low).
This is true even though the neutral densities
at the midplane were lower and the edge temperature higer (probes and ECE).
We are well prepared for higher power heating
with mp # 131.
Garry used the Chromex to study the He lines around 700 nm. These have
been used to determine density and temperature through line ratios from He
beam measurements. Over a
number of shots he found that the line ratio density increased with
nel04 and the Te determined decreased. The actual values are reasonable and
make this diagnostic worth pursuing.
Spectra were obtained with the Chromex from 200 nm to 1 micron at the 3 different
densities. A number of different spectra were also abtained with the McPherson
looking at the x-point. At the end of the
run the McPherson was scanned poloidally up from the x-point for further comparisons
with D2 plasmas.

A run summary follows:

shot #1: disruption @ 200 ms

shot #2: This shot ok. No probe data because DAQ1 down.
H_alpha at H-port =.4 (compared to ~ 2 normally).
Mo signal ~ 1e15. 2 injections at .57 and .69 seconds.

shot #3: Fine shot. Daq1 still off meaning no edge probes and no
Chromex spectrograph. RF went fine for 1 MW at .9 seconds

shot #4: Same shot; DAQ1 still down.

shot #5: shot fine.

shot #6: DAQ1 is back! All data except for Chromex. Next shot it
will be fixed. RF faulting.

shot #7: FSP scan accomplished. RF tripping continuously (D-port).
E-port not Pressure in the divertor is low (1-2 mTorr). The midplane
pressure is also low (of order several mTorr). The neutral compression
is of order 100 still! The divertor plsama is not detached even though
nl04 is higher than that required to detach D2 plasmas.
Still problems with Chromex.

shot #8: FSP scan accomplished. RF ok at 1. MW (D-port).

shot #9: FSP scan accomplished. RF ok at 1. MW (D-port).

shot #10: FSP scan accomplished. RF ok at 1. MW (D-port). H_alpha
getting lower - .2 (au). Radiated power before RF ~ 250 kW even
though the input power is 1.15 MW. It appears that C and possibly even
Mo levels in the core are lower.
shot #10: FSP scan accomplished. RF ok at 1. MW (D-port). H_alpha
getting lower - .2 (au). Radiated power before RF ~ 250 kW even
though the input power is 1.15 MW. It appears that C and possibly even
Mo levels in the core are lower.

shot #11: same shot, JT still scanning spectrum. FSP scan fine.

shot #12: same shot, JT lost spectrum.

shot #13: fizzle + break for FEAC visitor

shot #14: Back on track with program.

shot #15: Continue to take spectra

shot #16: should be last shot at this density but one more for Ar screening
measurement.

shot #17: Ar puff (standard 20 ms) but John Rice does not 'see' it.
Either there was a problem with the valve (yes this is true).

shot #18: fizzle.

shot #19: Shot went fine at nl04=1.5e20. FSP scan and Ar went in.

shot #20: Ar puff ok. Doing spectral scan over next several shots.

shot #21: nl04 = 1.6e20 again. Very high compression of gas into the
divertor for these shots. With the ratiomatic calibration for D2 we
get compression of 600. The conversion for He is ~ 2 bringing the
compression down to ~ 300.
The divertor appears to be detaching at this density.

shot #22: same shot, nl04=1.6e20.

shot #23: disruption @0.9 seconds. nl04 slightly lower as well - 1.45.
This is true even though the density feedback is trying hard to make it
to 1.5-1.5e20. The other oddity is that the radiated power continues
to rise throughout the shot reaching 1 MW before the disruption.

shot #24: fizzle

shot #25: shot is back. nl04=1.55.

shot #26: shot is fine

shot #27: same shot

shot #28: same shot, next goto nl04=2.e20

shot #29: fizzle

shot #30: nl04=2. but barely escapes disruption during curent flattop.
no FSP scan. starting spectral scan.

shot #31: this shot very similar

shot #32: disruption at .7 seconds.

shot #33: also disrupts. Let's give up on the high density and go to
a density ramp.

shot #34: density ramp from nl04 = 1.2 - 1.7e20. still no FSP

shot #35: fizzle

shot #36: fine shot, FSP scan ok.

shot #37: fine shot FSP scan ok. JT is scanning McPherson in space
rather than wavelength from shot to shot.

shot #38: fine shot again. FSP scan ok. Next shot fiducial.

shot #39: fizzle

shot #40: fiducial went fine with D2 puff.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:55:630PM

Author: To Be Determined

Physics Operator Summary for 951215

MP 130A Effect of Helium on divertor characteristics
SL Blip
PO wolfe
EO Silva/Bertolino

The object was to get data with He4 plasmas at several densities to determine
differences in divertor characteristics, do a spectroscopic survey of the
x-point region, and look at ICRF heating. Most of the goals were successfully
accomplished.

The plan was to start from a fiducial setup, but use He4 in the K-side valve
for density feedback and main fueling; the B-top pre-puff was left as D2 to
facilitate breakdown. The shot would then be adjusted to make a good target
for the FSP, extend the length so the RF could fire at 0.9sec, and do a density
scan.

There was considerable worry that the machine would not be recovered from
yesterday's vacuum accident, but this proved not to be the case. Overnight
ECDC in D2, switching to He at around 6AM, was sufficient to give good
breakdowns with some of the lowest CII levels so far this campaign (.006
mW/cm2/ster on the first shot, down to .002mW/cm2/ster later in the run).
The run was started early (8:10).

We were visited during the run by Dr. Knotek, chair of the FEAC panel on
Strategy for the Future of the Fusion Program; he was hosted by Bruce
Montgomery and Miklos Porkolab. After observing operation for a while, and
discussing the program with several individuals, he was given a brief tour of
the cell and power room between shot 13 and 14.

Shots 1-2 used the fiducial programming. Shot 1 disrupted early because EFC
failed to go. After resetting the 32V supply, it worked fine and shot 2 looked
good.

Shot 3-6 were involved in setting up the shot for the first condition. During
this time there was a problem with no data from the DAQ1 highway, including
ECDC and the Edge probes. JAS fixed this for shot 6.

Shot 7-17 were spent doing a careful spectroscopic scan at the first density,
around 1.2e20. These plasmas were attached, so the low density point was not
investigated.

Shot 18-28 were at a density of nl4=1.5e20. The pre-puff was changed from D2
to H2 because the RF team was complaining of low minority fraction. There
seems to be some debate as to whether these were detached or not. Some playing
with the early density to get the Moly down. These typically disrupted at
1.25-1.3 sec, as the density did not come down in rampdown.

Shot 29-33 were at 2.0e20 . A scan was begun but after two disruptive shots at
around 0.6 sec this was abandoned in favor of a density ramp to somewhat lower
density (1.7e20). The disruptions were due to a growing vertical mode; the
non-disruptive shots also showed evidence of being close to vertical
instability. n/n_crit was getting close to 1.2, probably due to a relatively
high li. I think reducing the elongation by reducing the outer gap would have
cured this, but Blip decided to back off the density anyway.

Shot 34-38 used a density ramp. 34 went from 1.2e20 at .45 to 1.7e20 at .9,
#35 fizzled, and the rest used an initial value of 1.0e20. All had 2mm larger
RCUR than previous shots, and exhibited no signs of vertical instability.

Shot 39 was an attempt to do a true fiducial in D2, by re-loading 951213001.
It fizzled. Shot 40 was the same except I tweaked the Br down by 1.5mT to
match what I had been using on shot 36-38. This went.

Problems and observations:
---------
On the first 5 shots there were no data from any of the CAMAC on the DAQ1
highway. The error message said Invalid Logname, and it looked like the DAQ1
was not part of the cluster. This was fixed by Josh when he came in.

The Chopper failed on the first shot, with no output and no dynamic voltage,
although the on and off pulses were there. This was fixed by Sam and Vinnie,
who found the 32V supply had tripped, although it was on before the run.

Bob Granetz discovered that the timebase for his fast halo data has been
screwed up since APS. The times were off by 4.000sec, apparently due to a
software change. Josh found and fixed this problem.

One of the ICRF transmitters died early in the run. The rest of the run was
done with D-port only.

After the disruption on shot 23, the stray light signal on the YAG went
through the roof. See Watterson's bulletin.

Jim Irby's program was generating spurious halo current warnings on shots
which ramped all the way down successfully. He apparently found and fixed this
bug during the run.

PCS had a bug which resulted in changes to linked waveforms on the ALL-P's
screen not being properly made to all the linked wires. Josh fixed this by the
end of the day, according to the bulletin he posted. I did not test this fix.

The Br offset value required to avoid fizzles decreased throughout the day,
from .007 to .0055T. The first attempt at a D2 fiducial (39) fizzled because
it had reverted to the original .007 value.

Helium operation apparently allows and prefers faster early density rise. I
gradually increased the density requested and reached at 0.225 sec to 1.0e20.
This seemed helpful in lowering the early Mo level, which tended to climb
during fixed density programming.

I tried playing with the derivative gain in the first 40msec, to reduce the
observed thrash on the OH supplies. While the thrash was reduced initially,
the current rises with lowered D-gain had hesitations or even turnarounds
around 25-30msec, at the 120+ kA level. I eventually put the D-gain back to 6.

Carbon levels, as indicated both by the CII signal and by JT's UV lines, were
greatly reduced. Whether this is due to He operation, the short He ECDC, or
just the effects of ongoing cleanup of the machine, is unclear.

Summary:
-------
FOr a shot by shot description, see the logbook under Physics_operator.

Plasmas 34 (including one that died at 190 msec due to EFC failure)
Fizzles 6 (including one at 60kA that Ian would count as a plasma)
Duds 0
---------- --
Total 40

Session Leader Comments

Dec 15 1995 08:17:47:370AM Bruce Lipschultz Run # 951215

Engineering operator: F. Silva
Physics operator S. Wolfe
Session leader B. Lipschultz

The aim of today's run is to compare the operation of helium and
deuterium plasmas. Through that comparison we hope to better understand
various aspects of SOL transport, recycling, impurity transport and detachment.

AAn additional hidden agenda is to start investigating the effect of
helium on RF-heated discharges.

Plan:

(1) Obtain 800 kA fiducial equilibrium with He. It may be necessary to use a $D
breakdown after which the puff is all He. After that take 5 shots for
scan of spectrographs in wavelength and space (McPherson), FSP scan of
the SOL and impurity injection.

(2) Lower nl04 to .7e20 to make sure divertor plasma is not detached.
Repeat step 1 (5 shots)

(3) Raise the density to nl04=1.5 and 2.0e20 and repeat step 1.(10 shots)

Dec 15 1995 08:22:25:040AM 951215001 Bruce Lipschultz shot #1: disruption @ 200 ms

Dec 15 1995 08:47:27:480AM 951215002 Bruce Lipschultz shot #2: This shot ok. No probe data because DAQ1 down.
H_alpha at H-port =.4 (compared to ~ 2 normally).
Mo signal ~ 1e15. 2 injections at .57 and .69 seconds.

Dec 15 1995 09:13:22:970AM 951215003 Bruce Lipschultz shot #3: Fine shot. Daq1 still off meaning no edge probes and no
Chromex spectrograph. RF went fine for 1 MW at .9 seconds

Dec 15 1995 09:13:25:100AM 951215003 Bruce Lipschultz shot #3: Fine shot. Daq1 still off meaning no edge probes and no
Chromex spectrograph. RF went fine for 1 MW at .9 seconds

Dec 15 1995 09:24:08:200AM 951215004 Bruce Lipschultz shot #4: Same shot; DAQ1 still down.

Dec 15 1995 09:57:29:720AM 951215005 Bruce Lipschultz shot #5: shot fine.

Dec 15 1995 09:58:29:940AM 951215006 Bruce Lipschultz shot #6: DAQ1 is back! All data except for Chromex. Next shot it
will be fixed. RF faulting.

Dec 15 1995 10:16:33:770AM 951215007 Bruce Lipschultz shot #7: FSP scan accomplished. RF tripping continuously (D-port).
E-port not Pressure in the divertor is low (1-2 mTorr). The midplane
pressure is also low (of order several mTorr). The neutral compression
is of order 100 still! The divertor plsama is not detached even though
nl04 is higher than that required to detach D2 plasmas.
Still problems with Chromex.

Dec 15 1995 10:17:42:940AM 951215008 Bruce Lipschultz shot #8: FSP scan accomplished. RF ok at 1. MW (D-port).

Dec 15 1995 10:18:28:900AM 951215008 Bruce Lipschultz shot #8: FSP scan accomplished. RF ok at 1. MW (D-port).

Dec 15 1995 11:42:08:550AM 951215009 Bruce Lipschultz shot #9: FSP scan accomplished. RF ok at 1. MW (D-port).

Dec 15 1995 11:47:37:300AM 951215010 Bruce Lipschultz shot #10: FSP scan accomplished. RF ok at 1. MW (D-port). H_alpha
getting lower - .2 (au). Radiated power before RF ~ 250 kW even
though the input power is 1.15 MW. It appears that C and possibly even
Mo levels in the core are lower.

Dec 15 1995 11:51:20:040AM 951215011 Bruce Lipschultz shot #11: same shot, JT still scanning spectrum. FSP scan fine.

Dec 15 1995 11:53:42:700AM 951215012 Bruce Lipschultz shot #12: same shot, JT lost spectrum.

Dec 15 1995 11:56:15:700AM 951215012 Bruce Lipschultz shot #12: same shot, JT lost spectrum.

Dec 15 1995 11:57:40:960AM 951215013 Bruce Lipschultz shot #13: fizzle + break for FEAC visitor

Dec 15 1995 11:58:11:590AM 951215014 Bruce Lipschultz shot #14: Back on track with program.

Dec 15 1995 11:59:46:220AM 951215015 Bruce Lipschultz shot #15: Continue to take spectra

Dec 15 1995 12:02:44:770PM 951215016 Bruce Lipschultz shot #16: should be last shot at this density but one more for Ar screening
measurement.

Dec 15 1995 12:13:29:950PM 951215017 Bruce Lipschultz shot #17: Ar puff (standard 20 ms) but John Rice does not 'see' it.
Either there was a problem with the valve or the screening is better.

Dec 15 1995 12:36:39:120PM 951215018 Bruce Lipschultz shot #18: fizzle

Dec 15 1995 12:37:57:460PM 951215019 Bruce Lipschultz shot #19: Shot went fine at nl04=1.5e20. FSP scan and Ar went in.

Dec 15 1995 12:54:55:780PM 951215020 Bruce Lipschultz shot #20: Ar puff ok. Doing spectral scan over next several shots.

Dec 15 1995 01:03:33:200PM 951215021 Bruce Lipschultz shot #21: nl04 = 1.6e20 again. Very high compression of gas into the
divertor for these shots. With the ratiomatic calibration for D2 we
get compression of 600. The conversion for He is ~ 2 bringing the
compression down to ~ 300.
The divertor appears to be detaching at this density.

Dec 15 1995 01:18:17:600PM 951215022 Bruce Lipschultz shot #22: same shot, nl04=1.6e20.

Dec 15 1995 01:31:21:860PM 951215023 Bruce Lipschultz shot #23: disruption @0.9 seconds. nl04 slightly lower as well - 1.45.
This is true even though the density feedback is trying hard to make it
to 1.5-1.5e20. The other oddity is that the radiated power continues
to rise throughout the shot reaching 1 MW before the disruption.

Dec 15 1995 01:44:29:870PM 951215024 Bruce Lipschultz shot #24: fizzle

Dec 15 1995 02:04:03:500PM 951215025 Bruce Lipschultz shot #25: shot is back. nl04=1.55.

Dec 15 1995 02:14:24:220PM 951215026 Bruce Lipschultz shot #26: shot is fine

Dec 15 1995 02:30:30:680PM 951215027 Bruce Lipschultz shot #27: same shot

Dec 15 1995 02:37:25:880PM 951215028 Bruce Lipschultz shot #28: same shot, next goto nl04=2.e20

Dec 15 1995 03:15:49:910PM 951215030 Bruce Lipschultz shot #30: nl04=2. but barely escapes disruption during curent flattop.
no FSP scan. starting spectral scan.

Dec 15 1995 03:56:48:800PM 951215031 Bruce Lipschultz shot #31: this shot very similar

Dec 15 1995 04:07:03:170PM 951215032 Bruce Lipschultz shot #32: disruption at .7 seconds.

Dec 15 1995 04:13:37:150PM 951215033 Bruce Lipschultz shot #33: also disrupts. Let's give up on the high density and go to
a density ramp.

Dec 15 1995 04:14:24:870PM 951215034 Bruce Lipschultz shot #34: density ramp from nl04 = 1.2 - 1.7e20. still no FSP

Dec 15 1995 04:15:51:840PM 951215035 Bruce Lipschultz shot #35: fizzle

Dec 15 1995 04:35:45:390PM 951215036 Bruce Lipschultz shot #36: fine shot, FSP scan ok.

Dec 15 1995 04:45:03:970PM 951215037 Bruce Lipschultz shot #37: fine shot FSP scan ok. JT is scanning McPherson in space
rather than wavelength from shot to shot.

Dec 15 1995 04:45:57:180PM 951215037 Bruce Lipschultz shot #37: fine shot FSP scan ok. JT is scanning McPherson in space
rather than wavelength from shot to shot.

Dec 15 1995 04:55:27:020PM 951215038 Bruce Lipschultz shot #38: fine shot again. FSP scan ok. Next shot fiducial.

Dec 15 1995 04:55:47:150PM 951215038 Bruce Lipschultz shot #38: fine shot again. FSP scan ok. Next shot fiducial.

Dec 15 1995 05:04:04:850PM 951215039 Bruce Lipschultz shot #39: fizzle

Dec 15 1995 05:16:36:120PM 951215040 Bruce Lipschultz shot #40: fiducial went fine with D2 puff.

Physics Operator Comments

Dec 15 1995 06:46:37:490AM Steve Wolfe Run plan for Friday, 951215

MP 130A Effect of He plasmas on divertor operation
SL Blip
PO wolfe

Setup:
-----
Overnight ECDC in D2, change to He4 for 2-3 hours in the morning before run
Power system setup as for 951213001
Gas setup:
B-top 5psi D2 (as usual) Hybrid enable
"A-side" 20psi He4 Hybrid enable

Dec 15 1995 06:47:21:350AM Steve Wolfe Run plan:

Start from 800kA fiducial equilibrium (load from 951213001), D2 puff from
B-top for breakdown, He4 from A-side for density feedback.

Check equilibrium for suitability for FSP target. If necessary, turn
on FSP control. Extend pulse length to 1.1sec flattop. Try to get the x-point
to its final position earlier, by around 0.4sec.

Take 5shots for spectral scan, FSP scan, and impurity injection. RF can fire
at 0.9 sec.

Lower nl04 to 0.7e20 to make sure divertor is attached. 5 shots for scans at
this condition.

Raise nl04 to 1.5 and 2.0e20 (may need NINJA puff for higher density). Repeat
scans (5shots each).

Dec 15 1995 06:49:33:910AM Steve Wolfe Special notes:
--------------
We are expecting a visit from the FEAC sub-panel on strategy for the fusion
program. There will be a walk-through tour including cell and power room at
some point during the run, probably in the morning. If there are not too many
people involved, we will try to do this under controlled access; we will need
to open the big door.

Dec 15 1995 06:56:46:580AM Steve Wolfe Yesterday's run terminated early with a vacuum accident. We have run
overnight ECDC in D2 and started He4 ECDC at 6:30. A short He4 ECDC was
begun earlier using the A-side valve for the fill, but this was stopped
when I pointed out to Frank that this valve is now on Willy's chopper
circuit. Re-started ECDC using B-top for He4 at 6:30.

28 peak looks a little higher than two days ago, 20 looks similar. We'll
have to see how the breakdowns look. If they are very ratty we'll punt
and continue ECDC.

Dec 15 1995 07:46:51:910AM Steve Wolfe 07:43 Coldstart done and ok.

Dec 15 1995 08:20:48:950AM 951215001 Steve Wolfe Shot 951215001

First shot: fiducial setup but with He4 in A-side.

Result:
Short plasma.
No EFC.
Breakdown looks good. CII is at 0.006mW/cm2/ster. Slight hesitation
at the 60kA.

Dec 15 1995 08:38:52:980AM 951215002 Steve Wolfe Shot 951215002

DAQ1 seems to be out of communication. Let TWF deal with it when he
gets in.
The 32V supply on the chopper was down. Maybe it will work this time.

PLasma - all the way down. Chopper loks fine.
Beautiful breakdown. CII at 0.004

Dec 15 1995 09:05:09:110AM 951215003 Steve Wolfe Shot 951215003

Extend shot to 1.1sec.

Plasma - all the way down.

Dec 15 1995 09:22:02:170AM 951215004 Steve Wolfe Shot 951215004

Try moving ZXL and ZCUR to their final values by 0.4 sec.

Plasma - all the way down.
Still no ECE or Edge signals because of the DAQ1 lossage.
We are (and have been) getting a dip in the density because the early
gas puff overshoots the programming. For next shot reprogram the density
to be higher early.

Dec 15 1995 09:27:29:320AM 951215005 Steve Wolfe Shot 951215005

reprogram the density to be higher early to eliminate dip.

Plasma - all the way down. Density looks better.
Br is creeping up.

Dec 15 1995 09:50:08:060AM 951215006 Steve Wolfe Shot 951215006

Josh has arrived and is dealing with the DAQ1 problem.
Mike is out on the floor looking at a transmitter problem

This shot should be a repeat. I'm holding off on the Br tweak for now.
Shot disrupts at 1.4 sec. Burst of vertical at around 0.6.

Dec 15 1995 10:01:17:210AM 951215007 Steve Wolfe Shot 951215007

Repeat: start of scans at this density.
Got ECE, probes, etc, data on shot 6.
We are getting spurious garbage from the halo current monitor, and
Granetz's timing is screwed up for his A14 that triggers on fizzle
detector.

Plasma - all the way down.
One RF transmitter is down. D-port is faulting, but less than
last shot. There is a drop in density when the RF turns on.

Dec 15 1995 10:09:49:730AM 951215008 Steve Wolfe Shot 951215008

Repeat. doing scans.

Plasma - all the way down.
JT reports unusually low Carbon levels in the main plasma.
Brian says these divertors are attached.

Dec 15 1995 10:26:44:600AM 951215009 Steve Wolfe Shot 951215009

Repeat. doing scans.

Plasma - all the way down.
H-alpha during the pulse seems to be dropping, so we may still be
unloading the walls.

The density is dropping at RF. I'll extend the pre-programmed puff for
next shot.

Dec 15 1995 10:35:22:350AM 951215010 Steve Wolfe Shot 951215010

Extend pre-programmed gas puff past 1 sec; had been shutting off at 1sec

PLasma - all the way.
Density stays up with RF this time.

Dec 15 1995 10:48:54:130AM 951215011 Steve Wolfe Shot 951215011

Repeat. still doing scan.

PLasma- all the way down

Dec 15 1995 10:54:58:360AM 951215012 Steve Wolfe Shot 951215012

Repeat. still doing scan.

Plasma - all the way.

Dec 15 1995 11:08:50:660AM 951215013 Steve Wolfe Shot 951215013

Repeat. still doing scan.
JT says two more shots like this.

fizzle. Maybe time for a Br tweak.

Dec 15 1995 11:37:35:860AM 951215014 Steve Wolfe Shot 951215014

Br reduced by 0.5mT
We've taken our break for access to allow the visitor in to see
the facilities.

Got it back. Breakdown looks good. CII at .002mW/cm2/ster
Disrupts at 1.35 sec. could be density limit. [G] says earlier
ones were.

Dec 15 1995 11:46:26:100AM 951215015 Steve Wolfe Shot 951215015

Repeat.

Lasted till 1.45.
This one finned.
JT now says one more.

Dec 15 1995 11:55:22:340AM 951215016 Steve Wolfe Shot 951215016

Repeat.

PLasma. To 1.55sec
WE'll do one more here.

Dec 15 1995 12:05:31:160PM 951215017 Steve Wolfe Shot 951215017

Repeat with Argon enabled (20msec).
Moly has been coming up the last few shots.

Plasma - all the way down.
This will be the last shot of this scan.
Next go to nl4=1.5 and change pre-puff to H2

Dec 15 1995 12:21:29:870PM 951215018 Steve Wolfe Shot 951215018

Increase NL_04 to 1.5e20
Increase Ar puff to 25msec
INcrease pre-pulse by 5msec to 23msec and change plenum to H2 (6psi)

Fizzle. 40kA. Bd is a little late 6.7msec
May be too much gas. I got 3.1e-5 Torr (gage)
Ar had not pulsed last time. Don't know why.

Dec 15 1995 12:35:50:120PM 951215019 Steve Wolfe Shot 951215019

Back pre-puff back down by 5msec.
Ar still programmed for 25msec. DOn't know why it didn't go on 17

Disrupts at 1.25 sec.
Got 1.5e20 ok.
breakdown still late, but runs ok.
Br still high. Got the Ar puff that time. and it looks normal.
Not detached yet.

Dec 15 1995 12:47:27:450PM 951215020 Steve Wolfe Shot 951215020

Ar back to 20msec
INcrease early gas puff from 25 to 30V (10msec and next point.)
INcrease density rate of rise to reach 1.5 at .45sec

Plasma to 1.25 again.
Densty still not up to value early enough

Dec 15 1995 01:00:51:200PM 951215021 Steve Wolfe Shot 951215021

INcrease NL_04 at .225 from .65 to .75e20
Moly was still high on last shot.

Density rise is a little faster. Same length.
BLIP and BLAB are in disagreement as to whether it is detached.

Dec 15 1995 01:05:32:330PM 951215022 Steve Wolfe Shot 951215022

Repeat. Doing the scan.

Plasma - looks same.

Dec 15 1995 01:32:24:160PM 951215023 Steve Wolfe Shot 951215023

GO back to NL_04 program as on 19 (flattop from 0.6sec instead of .45)
Brian likes to see the early sheath-limited regime before the detach?

Disrupted early - 0.9sec.
Radiated power is much higher, plasma more resistive.
Mo early is higher 1.5e16. Gas is on hard but doesn't get to density.

Dec 15 1995 01:43:07:530PM 951215024 Steve Wolfe Shot 951215024

Raise .225 density point from .65 to .85e20
fizzle - 35kA, CII gets up to .007 (from .002!)
Br is also still high. Fill is 2.4e-5
No sign of it on ECE.

Dec 15 1995 02:00:38:610PM 951215025 Steve Wolfe Shot 951215025

Stairstep the derivative gain on RCUR.

Plasma to 1.25. Density as programmed more or less.
Mo down to 5e15
Current almost turns around at 25msec (over 100kA)
plasma moving in during breakdown.

Dec 15 1995 02:11:13:860PM 951215026 Steve Wolfe Shot 951215026

Change earliest D-gain point on RCUR from 2 to 4.
Put early gas puff points back from 30 to 25V

Plasma - lasts to 1.25sec
breakdown phase looks better

Dec 15 1995 02:24:49:120PM 951215027 Steve Wolfe Shot 951215027

Extend Ip rampdown to try to delay disruption at 1.25 sec

PLasma - Lasted a little longer, but still disrupts at around 500kA.

Dec 15 1995 02:32:10:100PM 951215028 Steve Wolfe Shot 951215028

Extend clearin and RCUR ramp in at end of shot; still trying to get rid
of 1.25sec disruption.

Plasma - no change in end disruption.

Dec 15 1995 02:56:14:840PM 951215029 Steve Wolfe Shot 951215029

Raise nl_04 to 2.e20 at 0.6sec. For now, don't touch the .225 point,
although the Mo is growing again.

fizzle. 40kA (at 15msec). It hits someplace.
Probably vertically, Br has quite a thrash.

Dec 15 1995 03:13:35:300PM 951215030 Steve Wolfe Shot 951215030

Drop Br by 0.5 mT to 0.006
Drop RCUR D-gain first point from 4 to 1.

PLasma - About the same length, disrupts at 1.2 (600kA)
Big burst of vertical instability at around .5sec
Breakdown shows high current hesitation again.
Loop voltage is up to 2V throughout the shot.
EF1's are on there voltage rails.

Dec 15 1995 03:25:42:670PM 951215031 Steve Wolfe Shot 951215031

Raise .225 NL4 point to 1.0e20
Turn Pre-prog gas off at .9 again.

Plasma - similar to 30, gets to 1e20 at .25 ok

Dec 15 1995 03:40:35:460PM 951215032 Steve Wolfe Shot 951215032

Repeat.

Disrupted early, around 0.7sec
Growing vertical oscillation.
I don't understand why this one went except we already were
pretty marginal.

Dec 15 1995 03:43:52:350PM 951215033 Steve Wolfe Shot 951215033

No changes. Get the fizzle out of the way.

Didn't fizzle. Similar disruption.
Need to deal with this.

Dec 15 1995 04:18:33:720PM 951215035 Steve Wolfe Shot 951215035

Repeat.
Fizzle. 60kA!
had long wait for cooling, I don't know if that mattered.
Br has a big thrash. I still don't know if D-gain helps or hurts.

Dec 15 1995 04:27:20:010PM 951215036 Steve Wolfe Shot 951215036

Drop Br by .5mT to .0055
Change NL04 program to start ramp at 1.0 instead of 1.2e20

Plasma - runs to 1.3 sec.
Breakdown still has a high current hesitation.
I guess I'd better put back the D-gain.

Dec 15 1995 04:37:13:060PM 951215037 Steve Wolfe Shot 951215037

RCUR D-gain back to 6 from 10msec on.
Otherwise a repeat.

Plasma - same length.
Much better current rise in breakdown phase.

Dec 15 1995 04:46:01:790PM 951215038 Steve Wolfe Shot 951215038

Repeat.

Plasma - looks good.

Dec 15 1995 05:01:33:240PM 951215039 Steve Wolfe Shot 951215039

Back to D2 fiducial shot.
Reload of 951213001

Fizzle. got to 40kA.
Breakdown on time. Br is high

Dec 15 1995 05:13:04:420PM 951215040 Steve Wolfe Shot 951215040

Try again D2 fiducial shot.
Drop Br to 5.5mT (from 7)

Successful fiducial shot.
End of run.

Engineering Operator Comments

Shot Time Type Status Comment

1 08:14:51:260AM Plasma Ok efc fault

2 08:35:25:290AM Plasma Ok

3 08:55:12:290AM Plasma Ok

4 09:06:58:310AM Plasma Ok

5 09:21:31:450AM Plasma Ok

6 09:41:42:700AM Plasma Ok

7 09:53:22:910AM Plasma Ok

8 10:06:14:730AM Plasma Ok

9 10:20:13:660AM Plasma Ok

10 10:30:52:720AM Plasma Ok

11 10:41:34:420AM Plasma Ok

12 10:50:32:630AM Plasma Ok

13 11:02:03:300AM Plasma Ok

14 11:30:21:810AM Plasma Ok

15 11:41:20:240AM Plasma Ok

16 11:52:16:300AM Plasma Ok

17 12:02:05:150PM Plasma Ok

18 12:14:30:080PM Plasma Ok

19 12:25:21:750PM Plasma Ok

20 12:40:43:470PM Plasma Ok

21 12:51:27:060PM Plasma Ok

22 01:02:36:490PM Plasma Ok

23 01:17:40:960PM Plasma Ok

24 01:37:48:350PM Plasma Ok

25 01:50:14:770PM Plasma Ok

26 02:04:56:040PM Plasma Ok

27 02:15:45:450PM Plasma Ok

28 02:28:18:110PM Plasma Ok

29 02:49:14:280PM Plasma Ok

30 03:00:05:280PM Plasma Ok

31 03:17:22:790PM Plasma Ok

32 03:28:29:160PM Plasma Ok

33 03:40:50:050PM Plasma Ok

34 03:51:08:880PM Plasma Ok

35 04:10:18:470PM Plasma Ok

36 04:22:30:840PM Plasma Ok

37 04:32:41:940PM Plasma Ok

38 04:43:16:810PM Plasma Ok

39 04:57:16:610PM Plasma Ok

40 05:10:50:560PM Plasma Ok

Session Leader Comments
Dec 15 1995 08:17:47:370AM		Bruce Lipschultz	Run # 951215 Engineering operator: F. Silva Physics operator S. Wolfe Session leader B. Lipschultz The aim of today's run is to compare the operation of helium and deuterium plasmas. Through that comparison we hope to better understand various aspects of SOL transport, recycling, impurity transport and detachment. AAn additional hidden agenda is to start investigating the effect of helium on RF-heated discharges. Plan: (1) Obtain 800 kA fiducial equilibrium with He. It may be necessary to use a $D breakdown after which the puff is all He. After that take 5 shots for scan of spectrographs in wavelength and space (McPherson), FSP scan of the SOL and impurity injection. (2) Lower nl04 to .7e20 to make sure divertor plasma is not detached. Repeat step 1 (5 shots) (3) Raise the density to nl04=1.5 and 2.0e20 and repeat step 1.(10 shots)
Dec 15 1995 08:22:25:040AM	951215001	Bruce Lipschultz	shot #1: disruption @ 200 ms
Dec 15 1995 08:47:27:480AM	951215002	Bruce Lipschultz	shot #2: This shot ok. No probe data because DAQ1 down. H_alpha at H-port =.4 (compared to ~ 2 normally). Mo signal ~ 1e15. 2 injections at .57 and .69 seconds.
Dec 15 1995 09:13:22:970AM	951215003	Bruce Lipschultz	shot #3: Fine shot. Daq1 still off meaning no edge probes and no Chromex spectrograph. RF went fine for 1 MW at .9 seconds
Dec 15 1995 09:13:25:100AM	951215003	Bruce Lipschultz	shot #3: Fine shot. Daq1 still off meaning no edge probes and no Chromex spectrograph. RF went fine for 1 MW at .9 seconds
Dec 15 1995 09:24:08:200AM	951215004	Bruce Lipschultz	shot #4: Same shot; DAQ1 still down.
Dec 15 1995 09:57:29:720AM	951215005	Bruce Lipschultz	shot #5: shot fine.
Dec 15 1995 09:58:29:940AM	951215006	Bruce Lipschultz	shot #6: DAQ1 is back! All data except for Chromex. Next shot it will be fixed. RF faulting.
Dec 15 1995 10:16:33:770AM	951215007	Bruce Lipschultz	shot #7: FSP scan accomplished. RF tripping continuously (D-port). E-port not Pressure in the divertor is low (1-2 mTorr). The midplane pressure is also low (of order several mTorr). The neutral compression is of order 100 still! The divertor plsama is not detached even though nl04 is higher than that required to detach D2 plasmas. Still problems with Chromex.
Dec 15 1995 10:17:42:940AM	951215008	Bruce Lipschultz	shot #8: FSP scan accomplished. RF ok at 1. MW (D-port).
Dec 15 1995 10:18:28:900AM	951215008	Bruce Lipschultz	shot #8: FSP scan accomplished. RF ok at 1. MW (D-port).
Dec 15 1995 11:42:08:550AM	951215009	Bruce Lipschultz	shot #9: FSP scan accomplished. RF ok at 1. MW (D-port).
Dec 15 1995 11:47:37:300AM	951215010	Bruce Lipschultz	shot #10: FSP scan accomplished. RF ok at 1. MW (D-port). H_alpha getting lower - .2 (au). Radiated power before RF ~ 250 kW even though the input power is 1.15 MW. It appears that C and possibly even Mo levels in the core are lower.
Dec 15 1995 11:51:20:040AM	951215011	Bruce Lipschultz	shot #11: same shot, JT still scanning spectrum. FSP scan fine.
Dec 15 1995 11:53:42:700AM	951215012	Bruce Lipschultz	shot #12: same shot, JT lost spectrum.
Dec 15 1995 11:56:15:700AM	951215012	Bruce Lipschultz	shot #12: same shot, JT lost spectrum.
Dec 15 1995 11:57:40:960AM	951215013	Bruce Lipschultz	shot #13: fizzle + break for FEAC visitor
Dec 15 1995 11:58:11:590AM	951215014	Bruce Lipschultz	shot #14: Back on track with program.
Dec 15 1995 11:59:46:220AM	951215015	Bruce Lipschultz	shot #15: Continue to take spectra
Dec 15 1995 12:02:44:770PM	951215016	Bruce Lipschultz	shot #16: should be last shot at this density but one more for Ar screening measurement.
Dec 15 1995 12:13:29:950PM	951215017	Bruce Lipschultz	shot #17: Ar puff (standard 20 ms) but John Rice does not 'see' it. Either there was a problem with the valve or the screening is better.
Dec 15 1995 12:36:39:120PM	951215018	Bruce Lipschultz	shot #18: fizzle
Dec 15 1995 12:37:57:460PM	951215019	Bruce Lipschultz	shot #19: Shot went fine at nl04=1.5e20. FSP scan and Ar went in.
Dec 15 1995 12:54:55:780PM	951215020	Bruce Lipschultz	shot #20: Ar puff ok. Doing spectral scan over next several shots.
Dec 15 1995 01:03:33:200PM	951215021	Bruce Lipschultz	shot #21: nl04 = 1.6e20 again. Very high compression of gas into the divertor for these shots. With the ratiomatic calibration for D2 we get compression of 600. The conversion for He is ~ 2 bringing the compression down to ~ 300. The divertor appears to be detaching at this density.
Dec 15 1995 01:18:17:600PM	951215022	Bruce Lipschultz	shot #22: same shot, nl04=1.6e20.
Dec 15 1995 01:31:21:860PM	951215023	Bruce Lipschultz	shot #23: disruption @0.9 seconds. nl04 slightly lower as well - 1.45. This is true even though the density feedback is trying hard to make it to 1.5-1.5e20. The other oddity is that the radiated power continues to rise throughout the shot reaching 1 MW before the disruption.
Dec 15 1995 01:44:29:870PM	951215024	Bruce Lipschultz	shot #24: fizzle
Dec 15 1995 02:04:03:500PM	951215025	Bruce Lipschultz	shot #25: shot is back. nl04=1.55.
Dec 15 1995 02:14:24:220PM	951215026	Bruce Lipschultz	shot #26: shot is fine
Dec 15 1995 02:30:30:680PM	951215027	Bruce Lipschultz	shot #27: same shot
Dec 15 1995 02:37:25:880PM	951215028	Bruce Lipschultz	shot #28: same shot, next goto nl04=2.e20
Dec 15 1995 03:15:49:910PM	951215030	Bruce Lipschultz	shot #30: nl04=2. but barely escapes disruption during curent flattop. no FSP scan. starting spectral scan.
Dec 15 1995 03:56:48:800PM	951215031	Bruce Lipschultz	shot #31: this shot very similar
Dec 15 1995 04:07:03:170PM	951215032	Bruce Lipschultz	shot #32: disruption at .7 seconds.
Dec 15 1995 04:13:37:150PM	951215033	Bruce Lipschultz	shot #33: also disrupts. Let's give up on the high density and go to a density ramp.
Dec 15 1995 04:14:24:870PM	951215034	Bruce Lipschultz	shot #34: density ramp from nl04 = 1.2 - 1.7e20. still no FSP
Dec 15 1995 04:15:51:840PM	951215035	Bruce Lipschultz	shot #35: fizzle
Dec 15 1995 04:35:45:390PM	951215036	Bruce Lipschultz	shot #36: fine shot, FSP scan ok.
Dec 15 1995 04:45:03:970PM	951215037	Bruce Lipschultz	shot #37: fine shot FSP scan ok. JT is scanning McPherson in space rather than wavelength from shot to shot.
Dec 15 1995 04:45:57:180PM	951215037	Bruce Lipschultz	shot #37: fine shot FSP scan ok. JT is scanning McPherson in space rather than wavelength from shot to shot.
Dec 15 1995 04:55:27:020PM	951215038	Bruce Lipschultz	shot #38: fine shot again. FSP scan ok. Next shot fiducial.
Dec 15 1995 04:55:47:150PM	951215038	Bruce Lipschultz	shot #38: fine shot again. FSP scan ok. Next shot fiducial.
Dec 15 1995 05:04:04:850PM	951215039	Bruce Lipschultz	shot #39: fizzle
Dec 15 1995 05:16:36:120PM	951215040	Bruce Lipschultz	shot #40: fiducial went fine with D2 puff.

Physics Operator Comments
Dec 15 1995 06:46:37:490AM		Steve Wolfe	Run plan for Friday, 951215 MP 130A Effect of He plasmas on divertor operation SL Blip PO wolfe Setup: ----- Overnight ECDC in D2, change to He4 for 2-3 hours in the morning before run Power system setup as for 951213001 Gas setup: B-top 5psi D2 (as usual) Hybrid enable "A-side" 20psi He4 Hybrid enable
Dec 15 1995 06:47:21:350AM		Steve Wolfe	Run plan: Start from 800kA fiducial equilibrium (load from 951213001), D2 puff from B-top for breakdown, He4 from A-side for density feedback. Check equilibrium for suitability for FSP target. If necessary, turn on FSP control. Extend pulse length to 1.1sec flattop. Try to get the x-point to its final position earlier, by around 0.4sec. Take 5shots for spectral scan, FSP scan, and impurity injection. RF can fire at 0.9 sec. Lower nl04 to 0.7e20 to make sure divertor is attached. 5 shots for scans at this condition. Raise nl04 to 1.5 and 2.0e20 (may need NINJA puff for higher density). Repeat scans (5shots each).
Dec 15 1995 06:49:33:910AM		Steve Wolfe	Special notes: -------------- We are expecting a visit from the FEAC sub-panel on strategy for the fusion program. There will be a walk-through tour including cell and power room at some point during the run, probably in the morning. If there are not too many people involved, we will try to do this under controlled access; we will need to open the big door.
Dec 15 1995 06:56:46:580AM		Steve Wolfe	Yesterday's run terminated early with a vacuum accident. We have run overnight ECDC in D2 and started He4 ECDC at 6:30. A short He4 ECDC was begun earlier using the A-side valve for the fill, but this was stopped when I pointed out to Frank that this valve is now on Willy's chopper circuit. Re-started ECDC using B-top for He4 at 6:30. 28 peak looks a little higher than two days ago, 20 looks similar. We'll have to see how the breakdowns look. If they are very ratty we'll punt and continue ECDC.
Dec 15 1995 07:46:51:910AM		Steve Wolfe	07:43 Coldstart done and ok.
Dec 15 1995 08:20:48:950AM	951215001	Steve Wolfe	Shot 951215001 First shot: fiducial setup but with He4 in A-side. Result: Short plasma. No EFC. Breakdown looks good. CII is at 0.006mW/cm2/ster. Slight hesitation at the 60kA.
Dec 15 1995 08:38:52:980AM	951215002	Steve Wolfe	Shot 951215002 DAQ1 seems to be out of communication. Let TWF deal with it when he gets in. The 32V supply on the chopper was down. Maybe it will work this time. PLasma - all the way down. Chopper loks fine. Beautiful breakdown. CII at 0.004
Dec 15 1995 09:05:09:110AM	951215003	Steve Wolfe	Shot 951215003 Extend shot to 1.1sec. Plasma - all the way down.
Dec 15 1995 09:22:02:170AM	951215004	Steve Wolfe	Shot 951215004 Try moving ZXL and ZCUR to their final values by 0.4 sec. Plasma - all the way down. Still no ECE or Edge signals because of the DAQ1 lossage. We are (and have been) getting a dip in the density because the early gas puff overshoots the programming. For next shot reprogram the density to be higher early.
Dec 15 1995 09:27:29:320AM	951215005	Steve Wolfe	Shot 951215005 reprogram the density to be higher early to eliminate dip. Plasma - all the way down. Density looks better. Br is creeping up.
Dec 15 1995 09:50:08:060AM	951215006	Steve Wolfe	Shot 951215006 Josh has arrived and is dealing with the DAQ1 problem. Mike is out on the floor looking at a transmitter problem This shot should be a repeat. I'm holding off on the Br tweak for now. Shot disrupts at 1.4 sec. Burst of vertical at around 0.6.
Dec 15 1995 10:01:17:210AM	951215007	Steve Wolfe	Shot 951215007 Repeat: start of scans at this density. Got ECE, probes, etc, data on shot 6. We are getting spurious garbage from the halo current monitor, and Granetz's timing is screwed up for his A14 that triggers on fizzle detector. Plasma - all the way down. One RF transmitter is down. D-port is faulting, but less than last shot. There is a drop in density when the RF turns on.
Dec 15 1995 10:09:49:730AM	951215008	Steve Wolfe	Shot 951215008 Repeat. doing scans. Plasma - all the way down. JT reports unusually low Carbon levels in the main plasma. Brian says these divertors are attached.
Dec 15 1995 10:26:44:600AM	951215009	Steve Wolfe	Shot 951215009 Repeat. doing scans. Plasma - all the way down. H-alpha during the pulse seems to be dropping, so we may still be unloading the walls. The density is dropping at RF. I'll extend the pre-programmed puff for next shot.
Dec 15 1995 10:35:22:350AM	951215010	Steve Wolfe	Shot 951215010 Extend pre-programmed gas puff past 1 sec; had been shutting off at 1sec PLasma - all the way. Density stays up with RF this time.
Dec 15 1995 10:48:54:130AM	951215011	Steve Wolfe	Shot 951215011 Repeat. still doing scan. PLasma- all the way down
Dec 15 1995 10:54:58:360AM	951215012	Steve Wolfe	Shot 951215012 Repeat. still doing scan. Plasma - all the way.
Dec 15 1995 11:08:50:660AM	951215013	Steve Wolfe	Shot 951215013 Repeat. still doing scan. JT says two more shots like this. fizzle. Maybe time for a Br tweak.
Dec 15 1995 11:37:35:860AM	951215014	Steve Wolfe	Shot 951215014 Br reduced by 0.5mT We've taken our break for access to allow the visitor in to see the facilities. Got it back. Breakdown looks good. CII at .002mW/cm2/ster Disrupts at 1.35 sec. could be density limit. [G] says earlier ones were.
Dec 15 1995 11:46:26:100AM	951215015	Steve Wolfe	Shot 951215015 Repeat. Lasted till 1.45. This one finned. JT now says one more.
Dec 15 1995 11:55:22:340AM	951215016	Steve Wolfe	Shot 951215016 Repeat. PLasma. To 1.55sec WE'll do one more here.
Dec 15 1995 12:05:31:160PM	951215017	Steve Wolfe	Shot 951215017 Repeat with Argon enabled (20msec). Moly has been coming up the last few shots. Plasma - all the way down. This will be the last shot of this scan. Next go to nl4=1.5 and change pre-puff to H2
Dec 15 1995 12:21:29:870PM	951215018	Steve Wolfe	Shot 951215018 Increase NL_04 to 1.5e20 Increase Ar puff to 25msec INcrease pre-pulse by 5msec to 23msec and change plenum to H2 (6psi) Fizzle. 40kA. Bd is a little late 6.7msec May be too much gas. I got 3.1e-5 Torr (gage) Ar had not pulsed last time. Don't know why.
Dec 15 1995 12:35:50:120PM	951215019	Steve Wolfe	Shot 951215019 Back pre-puff back down by 5msec. Ar still programmed for 25msec. DOn't know why it didn't go on 17 Disrupts at 1.25 sec. Got 1.5e20 ok. breakdown still late, but runs ok. Br still high. Got the Ar puff that time. and it looks normal. Not detached yet.
Dec 15 1995 12:47:27:450PM	951215020	Steve Wolfe	Shot 951215020 Ar back to 20msec INcrease early gas puff from 25 to 30V (10msec and next point.) INcrease density rate of rise to reach 1.5 at .45sec Plasma to 1.25 again. Densty still not up to value early enough
Dec 15 1995 01:00:51:200PM	951215021	Steve Wolfe	Shot 951215021 INcrease NL_04 at .225 from .65 to .75e20 Moly was still high on last shot. Density rise is a little faster. Same length. BLIP and BLAB are in disagreement as to whether it is detached.
Dec 15 1995 01:05:32:330PM	951215022	Steve Wolfe	Shot 951215022 Repeat. Doing the scan. Plasma - looks same.
Dec 15 1995 01:32:24:160PM	951215023	Steve Wolfe	Shot 951215023 GO back to NL_04 program as on 19 (flattop from 0.6sec instead of .45) Brian likes to see the early sheath-limited regime before the detach? Disrupted early - 0.9sec. Radiated power is much higher, plasma more resistive. Mo early is higher 1.5e16. Gas is on hard but doesn't get to density.
Dec 15 1995 01:43:07:530PM	951215024	Steve Wolfe	Shot 951215024 Raise .225 density point from .65 to .85e20 fizzle - 35kA, CII gets up to .007 (from .002!) Br is also still high. Fill is 2.4e-5 No sign of it on ECE.
Dec 15 1995 02:00:38:610PM	951215025	Steve Wolfe	Shot 951215025 Stairstep the derivative gain on RCUR. Plasma to 1.25. Density as programmed more or less. Mo down to 5e15 Current almost turns around at 25msec (over 100kA) plasma moving in during breakdown.
Dec 15 1995 02:11:13:860PM	951215026	Steve Wolfe	Shot 951215026 Change earliest D-gain point on RCUR from 2 to 4. Put early gas puff points back from 30 to 25V Plasma - lasts to 1.25sec breakdown phase looks better
Dec 15 1995 02:24:49:120PM	951215027	Steve Wolfe	Shot 951215027 Extend Ip rampdown to try to delay disruption at 1.25 sec PLasma - Lasted a little longer, but still disrupts at around 500kA.
Dec 15 1995 02:32:10:100PM	951215028	Steve Wolfe	Shot 951215028 Extend clearin and RCUR ramp in at end of shot; still trying to get rid of 1.25sec disruption. Plasma - no change in end disruption.
Dec 15 1995 02:56:14:840PM	951215029	Steve Wolfe	Shot 951215029 Raise nl_04 to 2.e20 at 0.6sec. For now, don't touch the .225 point, although the Mo is growing again. fizzle. 40kA (at 15msec). It hits someplace. Probably vertically, Br has quite a thrash.
Dec 15 1995 03:13:35:300PM	951215030	Steve Wolfe	Shot 951215030 Drop Br by 0.5 mT to 0.006 Drop RCUR D-gain first point from 4 to 1. PLasma - About the same length, disrupts at 1.2 (600kA) Big burst of vertical instability at around .5sec Breakdown shows high current hesitation again. Loop voltage is up to 2V throughout the shot. EF1's are on there voltage rails.
Dec 15 1995 03:25:42:670PM	951215031	Steve Wolfe	Shot 951215031 Raise .225 NL4 point to 1.0e20 Turn Pre-prog gas off at .9 again. Plasma - similar to 30, gets to 1e20 at .25 ok
Dec 15 1995 03:40:35:460PM	951215032	Steve Wolfe	Shot 951215032 Repeat. Disrupted early, around 0.7sec Growing vertical oscillation. I don't understand why this one went except we already were pretty marginal.
Dec 15 1995 03:43:52:350PM	951215033	Steve Wolfe	Shot 951215033 No changes. Get the fizzle out of the way. Didn't fizzle. Similar disruption. Need to deal with this.
Dec 15 1995 04:18:33:720PM	951215035	Steve Wolfe	Shot 951215035 Repeat. Fizzle. 60kA! had long wait for cooling, I don't know if that mattered. Br has a big thrash. I still don't know if D-gain helps or hurts.
Dec 15 1995 04:27:20:010PM	951215036	Steve Wolfe	Shot 951215036 Drop Br by .5mT to .0055 Change NL04 program to start ramp at 1.0 instead of 1.2e20 Plasma - runs to 1.3 sec. Breakdown still has a high current hesitation. I guess I'd better put back the D-gain.
Dec 15 1995 04:37:13:060PM	951215037	Steve Wolfe	Shot 951215037 RCUR D-gain back to 6 from 10msec on. Otherwise a repeat. Plasma - same length. Much better current rise in breakdown phase.
Dec 15 1995 04:46:01:790PM	951215038	Steve Wolfe	Shot 951215038 Repeat. Plasma - looks good.
Dec 15 1995 05:01:33:240PM	951215039	Steve Wolfe	Shot 951215039 Back to D2 fiducial shot. Reload of 951213001 Fizzle. got to 40kA. Breakdown on time. Br is high
Dec 15 1995 05:13:04:420PM	951215040	Steve Wolfe	Shot 951215040 Try again D2 fiducial shot. Drop Br to 5.5mT (from 7) Successful fiducial shot. End of run.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:14:51:260AM	Plasma	Ok	efc fault
2	08:35:25:290AM	Plasma	Ok
3	08:55:12:290AM	Plasma	Ok
4	09:06:58:310AM	Plasma	Ok
5	09:21:31:450AM	Plasma	Ok
6	09:41:42:700AM	Plasma	Ok
7	09:53:22:910AM	Plasma	Ok
8	10:06:14:730AM	Plasma	Ok
9	10:20:13:660AM	Plasma	Ok
10	10:30:52:720AM	Plasma	Ok
11	10:41:34:420AM	Plasma	Ok
12	10:50:32:630AM	Plasma	Ok
13	11:02:03:300AM	Plasma	Ok
14	11:30:21:810AM	Plasma	Ok
15	11:41:20:240AM	Plasma	Ok
16	11:52:16:300AM	Plasma	Ok
17	12:02:05:150PM	Plasma	Ok
18	12:14:30:080PM	Plasma	Ok
19	12:25:21:750PM	Plasma	Ok
20	12:40:43:470PM	Plasma	Ok
21	12:51:27:060PM	Plasma	Ok
22	01:02:36:490PM	Plasma	Ok
23	01:17:40:960PM	Plasma	Ok
24	01:37:48:350PM	Plasma	Ok
25	01:50:14:770PM	Plasma	Ok
26	02:04:56:040PM	Plasma	Ok
27	02:15:45:450PM	Plasma	Ok
28	02:28:18:110PM	Plasma	Ok
29	02:49:14:280PM	Plasma	Ok
30	03:00:05:280PM	Plasma	Ok
31	03:17:22:790PM	Plasma	Ok
32	03:28:29:160PM	Plasma	Ok
33	03:40:50:050PM	Plasma	Ok
34	03:51:08:880PM	Plasma	Ok
35	04:10:18:470PM	Plasma	Ok
36	04:22:30:840PM	Plasma	Ok
37	04:32:41:940PM	Plasma	Ok
38	04:43:16:810PM	Plasma	Ok
39	04:57:16:610PM	Plasma	Ok
40	05:10:50:560PM	Plasma	Ok