Alcator C-Mod Run 950425 Information

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Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader:Jim Terry (shots 1-34)

Operators
Session leader(s):Jim Terry
Physics operator(s):Steve Wolfe
Engineering operator(s):Vinny Bertolino,Joe Daigle

Engineering Operator Run Comment
Terry X-pt

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:13:553PM
Author: To Be Determined
Run Summary for 950425

MP#109 (x-point studies)
SL: Terry
PO: Wolfe
EO: Bertolino,Daigle

The goals of this X-pt run (scheduled for 950425 and 950426) were:

a) determine what impurities are responsible for the radiation coming
from the X-pt region
b) try to determine the reason for the location of the peak in emissivity
near the X-pt
c) obtain profiles of electron density from below the strike pts to above the
X-pt using stark-broadened Balmer lines and the views of the K and A
bottom arrays
d) document the presence or absence of H_2 lines in the visible and/or in the VUV.
This is the reason for beginning the run in H_2. The literature on H_2 spectra
is more extensive than on D_2.
e) measure the optical thickness of The n=3 to n=1 line (Lyman_beta) in H
for views through or below the X-pt

Overall this was a very sucessful run. We believe we have accomplished
goals a), c), and d). We have comprehensive VUV (75 A - 1130 A) and visible/IR
(3200 A - ~10000 A) spectra. In addition, we think that we have observed
Stark broadened lines of the H Paschen series (lower state n=3).
These line widths are of order 100 A!

We observed the Xpt in three regimes on each shot:
sheath-limited - with NL04 = 0.6e20 from .4 to .56 s
ramp NL04 to ~1.4e20, where the divertor is detacthed
Turn on RF (P>0.8 MW) at this density and re-attach the divertor
(on shots 31-34 we have short H-modes during the RF)

We discharge-cleaned on Monday April 24 in H_2 and began the run in H_2

We loaded shot 950317024 which had Ip=800 kA, Z_XL=-37.75 cm, R_XL=56.0 cm.
STRIKEPSI is turned off and X-pt control was in use.
We have tried to keep the the outer strike point at or lower than Probe 7.

We ran essentially 100% H_2 thru shot 15 at which time we switched to D_2, by shot 20
H/(H+D) was ~15%. The H_2 was used for easier identification of the molecular spectra.

The following is a blow-by-blow account:

shot 001 - Tues. morning test

shot 002 - loaded shot 950317024 - Good shot for first attempt
Hard x-rays early - disrupted at 1.0 sec.

shot 003 - Short plasma lasting 0.14 s.

shot 004 - reduced the early hard x-ray problem - good shot but disrupted at 1.02 s
X-pt at R=55.9 cm, Z=-37.6 cm. The outer strike pt at Probe 7 most of the
time, although it is above Probe 7 for a short time.

shot 005 - plasma, not pretty, disrupted at .91 - many Mo injections.

shot 006 - Plasma OK, disrupted at 1.34 during rampdown

shot 007 Plasma OK, disrupted at same time (1.34 s) during rampdown.
Xpt moving in and up after .9 s.

shot 008 Plasma OK, disrupted at 1.0 s. Xpt staying more const. after 0.8 s

shot 009 Plasma OK, disrupted at 1.08 s. Upper Xpt now close to LCFS.

shot 010 fizzle

shot 011 Plasma OK, disrupted at 1.02 s.

shot 012 Ugly plasma, disrupted at .418 s.

shot 013 Plasma OK, disrupted at 1.02 s. RF generating alot of edge stuff at .9 s.

shot 014 Plasma OK, disrupted at 1.02 s.

shot 015 Plasma OK, disrupted at 1.20 s during rampdown.

shot 016 Switched to D_2 on this shot. Plasma OK, disrupted at 1.20 s
during rampdown. CX shows H/(H+D)~60%

shot 017 Plasma OK, disrupted at 1.24 s. Starting spectral scans
with 1 MW of RF. CX shows H/(H+D)~35-40%

shot 018 Plasma OK, disrupted at 1.24 s. RF tripped very quickly
CX shows H/(H+D)~30%

shot 019 Plasma OK, disrupted at 1.26 s. RF power 1.5 and 1.0 MW
with trips.

shot 020 Plasma OK, disrupted at 1.25 s. RF power 1.5 and 1.0 MW.
CX shows H/(H+D)~15%

shot 021 Plasma OK, disrupted at 1.29 s. RF power 1.0 MW.

shot 022 Plasma OK, disrupted at 1.30 s. RF power 1.0 MW.
RF reattaches the divertor. CX shows H/(H+D)~12%.

shot 023 Plasma OK, disrupted at 1.29 s. RF power 1.0 MW to 1.16 MW.

shot 024 fizzle

shot 025 Plasma OK, disrupted at 1.30 s. RF power 1.0 MW to 1.16 MW.

shot 026 Plasma OK, disrupted at 1.30 s. RF power at 1.17 MW.
CX shows H/(H+D)~10%.

shot 027 Plasma OK, disrupted at 1.30 s. RF power at 1.17 MW.

shot 028 Plasma OK, disrupted at 1.31 s. RF power at 1.35 MW.

shot 029 Plasma OK, disrupted at 1.32 s. RF power from 1.35 to 1.0 MW.

shot 030 Plasma OK, disrupted at 1.32 s. RF power from 1.38 to 1.0 MW.

shot 031 Plasma OK, disrupted at 1.32 s. RF power 1.36, 2.3 and 1.0 MW.
Short H-mode from 1.00 to 1.025 s

shot 032 Plasma OK, disrupted at 1.32 s. RF power 1.36, 2.3 and 1.0 MW.
Short H-mode from 1.00 to 1.05 s

shot 033 Plasma OK, disrupted at 1.29 s. RF power 1.15, 2.5 and 1.35 MW.
Short H-mode from 1.00 to 1.015 s

shot 034 Plasma OK, disrupted at 1.31 s. RF power 1.13, 2.46 and 1.35 MW.
Very short H-mode at 1.00 s

Scorecard:
_________
1 test
2 fizzles
2 short, ugly plasmas
29 usable plasmas
TOTAL=34


Physics Operator Summaries
Entered: Jul 7 2004 04:36:54:020PM
Author: To Be Determined
Physics Operator Summary for 950425

MP#109 (x-point studies); piggyback MP102 (RF debugging)
SL: Terry
PO: Wolfe
EO: Bertolino,Daigle

This was the first day of a planned 1.5 day effort at studying the x-point
region. From the operations point of view, the issues involved a high x-point
location (to be in the field of view of the spectroscopic instruments) and a
density ramp from a low density flattop (NL_04=0.6e20) to a high one
(NL_04=1.4e20). An additional complication is that the run was to be begun in
H2 and changed over to D2 after obtaining data on molecular H2 radiation. Once
a satisfactory shot was obtained, constant shots were required for a scans of
the various spectroscopic instruments (in wavelength and/or direction).
Specifically, the run plan was:
1. Get a discharge with the right characteristics. Check outer strike
and adjust ZXL to get it on or below probe 7. Set up 25msec Ar puff.

2. Run 4 constant shots for spectroscopic scan to see H_2 lines

3. Switch back to D2, turn on RF at 0.9sec.
Spectroscopy scan for 14 shots.

4. Scan McP across x-point (10 shots).

5. If time permits, scan x-point in R.
We essentially completed through step 3. After much fiddling, the RF group
succeeded in getting the two transmitters to overlap, producing a maximum net
power around 2.5MW on the last several shots. These all had brief H-modes
around 1.0sec. All in all, not a bad result for the first full run after a
vacuum break.

The startup segment for this run was taken from 950424007. A 15A tweak to EF4
was applied at shot 4 to improve the startup and eliminate runaway problems.
The fill pressure was raised from 1.7e-5 to 2.3e-5 during the H2 shots, and
left at 2.3e-5 for the D2.

Segment 2 started from 950317024, with several modifications;EF2_by_EF4 was
added and the CLEARIN rampdown modified as on 950424007. The main features are
the high x-point and the NL ramp, as described above.

Hydrogen operation proved difficult, from the standpoint of railing power
supplies. The plasmas were quite cold and resistive, and several tweaks were
tried in a largely unsuccessful attempt to keep the supplies happy with loop
voltages above 1.7V. Three that were somewhat beneficial were lowering the
plasma (ZCUR) by 5mm (shot 6), getting rid of the pre-programmed V_OH2 points
at +20V and 1sec (shot 15), and reducing the ZXU gain from 9.5; this ended up
at 1 on shot 10, after some experiments that included turning it off entirely
late in the shot. The Ip flattop was reduced to 1.0sec from 1.05 during the H2
operation, and put back for D2. ZXU gain was brought back up to 3 during the D2
shots (shot 19). Among the things that didn't work was recalculating the Ip
controller with lower voltage weights on OH2 and EF1 (shots 5-6).

Beginning with shot 16, we changed over to D2. The D2 shots had noticeably
lower loop voltage and slightly higher temperatures according to the ECE. RF
was fired beginning at 0.9sec. The high density was raised from 1.3e20 to
1.4e20 on shot 17. The ZXU gain was raised to 3 on shot 19, and the RXU gain
to 2.4 on shot 20. After shot 20, the only changes were to the rampdown; these
were only marginally successful, delaying the disruption from 1.25sec to
1.32sec. The final disruption was typically a VDE, abetted by a shark fin, as
the density would not ramp down. Interestingly, I ended up with a fully
diverted rampdown, as long as it lasted. Both EF1L and OH2L were on their
positive voltage rails for some time before the disruption. Any of the last
six or so shots, except #33, would seem to be a reasonable place to start
tomorrow. Shot #33 was an attempt to ramp CLEARIN in faster during rampdown,
and seemed to be a step in the wrong direction. #34 went the opposite way, and
seemed better. For details of the various thrashings shot-to-shot, see the
Physics_Operator topic in the logbook.

The startup was fairly robust, with only two fizzles (#10 and #24). The first
of these followed a bad disruption, and had a CII signal of 0.008mW/cm2/ster,
over twice the normal maximum. The reason for the fizzle on #24 is unclear,
and no changes were made for 25, which ran ok. There were also two short ugly
shots, #3 and 12. Both followed disruptions, and both had serious runaway
problems. For #13, the fill was raised to 2.3e-5 and remained there the rest
of the day.

Scorecard:
---------
Tests 1
Duds 0
Fizzles 2
Plasmas 31 (2 < 0.5sec, 4 halo warnings, no strikes)
------- --
Total 34

Session Leader Comments
Apr 25 1995 09:17:12:990AMJim TerryWe discharge cleaned on Monday April 24 in H_2 and are beginning the run in H_2,
although we plan to switch to D_2 early in the run.

The goals of this X-pt run (scheduled for 950424 and 950425) are:

a) determine what impurities are responsible for the radiation coming
from the X-pt region
b) try to determine the reason for the location of the peak in emissivity
near the X-pt
c) obtain profiles of electron density from below the strike pts to above the
X-pt using stark-broadened Balmer lines and the views of the K and A
bottom arrays
d) document the presence or absence of H_2 lines in the visible and/or in the VUV.
This is the reason for beginning the run in H_2. The literature on H_2 spectra
is more extensive than on D_2.
e) measure the optical thickness of The n=3 to n=1 line (Lyman_beta) in H
for views through or below the X-pt

We will load shot 950317024 which has Ip=800 kA, Z_XL=-37.75 cm, R_XL=56.0 cm.
NL04 is initially 0.6e20 at 0.5 s, but at 0.58 s is ramped to 1.34e20.
For this shot STRIKEPSI is turned off and X-pt control is in use.
For this programming we will determine where the outer strike point
is. If it is not at or lower than Probe 7, then we will lower the X-pt
until it is. The gaps are about 2 cm.

Apr 25 1995 09:18:11:420AM950425001Jim Terryshot 001 - Usual Tues. morning test

Apr 25 1995 09:18:39:420AM950425002Jim Terryshot 002 - loaded shot 950317024 - Good shot for first attempt
Slide aways early - disrupted at 1.0 sec.

Apr 25 1995 09:19:12:890AM950425003Jim Terryshot 003 - raised fill to 2.0e-5. Short plasma lasting 0.14 s.

Apr 25 1995 09:40:23:590AM950425004Jim Terryshot 004 - reduced the early hard x-ray problem - good shot but disrupted at 1.02 s
X-pt at R=55.9 cm, Z=-37.6 cm. The outer strike pt just at Probe 7,
although it is slightly above Probe 7 for a short time.

Apr 25 1995 09:40:48:830AM950425005Jim Terryshot 005 - plasma, but disrupted at .91 - many Mo injections

Apr 25 1995 10:20:02:450AM950425006Jim Terryshot 006 - attempting to lower the X-pt a few mm and to drop the plasma center.
Plasma OK, disrupted at 1.34 during rampdown

Apr 25 1995 10:20:49:310AM950425007Jim Terryshot 007 Plasma OK, disrupted at same time (1.34 s) during rampdown.
Xpt moving in and up after .9 s.

Apr 25 1995 10:53:01:350AM950425008Jim Terryshot 008 Plasma OK, disrupted at 1.0 s. Xpt staying more const. after 0.8 s

Apr 25 1995 10:54:01:780AM950425009Jim Terryshot 009 Plasma OK, disrupted at 1.08 s. Watch out for upper Xpt moving in.

Apr 25 1995 11:30:56:740AM950425010Jim Terryshot 010 fizzle

Apr 25 1995 11:31:17:800AM950425011Jim Terryshot 011 Plasma OK, disrupted at 1.02 s.

Apr 25 1995 12:21:18:990PM950425012Jim Terryshot 012 Ugly plasma, disrupted at .418 s. After this shot,
we are letting the RF people into the cell.
So there will be a delay.

Apr 25 1995 12:22:23:990PM950425013Jim Terryshot 013 Plasma OK, disrupted at 1.02 s.
RF generating alot of edge stuff at .9 s. Chromex sees continuum
feature.

Apr 25 1995 12:53:30:270PM950425014Jim Terryshot 014 Plasma OK, disrupted at 1.02 s.

Apr 25 1995 12:54:50:040PM950425015Jim Terryshot 015 Plasma OK, disrupted at 1.20 s during rampdown. Best so far.

Apr 25 1995 01:39:37:340PM950425016Jim Terryshot 016 Switched to D_2 on this shot. Plasma OK, disrupted at 1.20 s
during rampdown. CX shows H/(H+D)~60%

Apr 25 1995 01:40:14:960PM950425017Jim Terryshot 017 Plasma OK, disrupted at 1.24 s. Starting spectral scan
with 1 MW of RF. CX shows H/(H+D)~35-40%

Apr 25 1995 04:39:17:200PM950425018Jim Terryshot 018 Plasma OK, disrupted at 1.24 s. RF tripped very quickly
CX shows H/(H+D)~30%

Apr 25 1995 02:18:44:630PM950425019Jim Terryshot 019 Plasma OK, disrupted at 1.26 s. RF power 1.5 and 1.0 MW
with trips.

Apr 25 1995 02:19:01:300PM950425020Jim Terryshot 020 Plasma OK, disrupted at 1.25 s. RF power 1.5 and 1.0 MW.

Apr 25 1995 02:19:24:370PM950425021Jim Terryshot 021 Plasma OK, disrupted at 1.29 s. RF power 1.0 MW.

Apr 25 1995 03:07:27:220PM950425022Jim Terryshot 022 Plasma OK, disrupted at 1.30 s. RF power 1.0 MW.
RF reattaches the divertor. CX shows H/(H+D)~12%.

Apr 25 1995 03:07:47:560PM950425023Jim Terryshot 023 Plasma OK, disrupted at 1.29 s. RF power 1.0 MW to 1.16 MW.

Apr 25 1995 04:39:37:900PM950425024Jim Terryshot 024 fizzle

Apr 25 1995 04:40:51:550PM950425025Jim Terryshot 025 Plasma OK, disrupted at 1.30 s. RF power 1.0 MW to 1.16 MW.
McP wavelength possibly screwed up.

Apr 25 1995 04:41:21:190PM950425027Jim Terryshot 027 Plasma OK, disrupted at 1.30 s. RF power at 1.17 MW.

Apr 25 1995 04:41:38:010PM950425028Jim Terryshot 028 Plasma OK, disrupted at 1.31 s. RF power at 1.35 MW.

Apr 25 1995 04:41:50:930PM950425029Jim Terryshot 029 Plasma OK, disrupted at 1.32 s. RF power from 1.35 to 1.0 MW.

Apr 25 1995 04:42:10:060PM950425030Jim Terryshot 030 Plasma OK, disrupted at 1.32 s. RF power from 1.38 to 1.0 MW.

Apr 25 1995 04:42:24:890PM950425031Jim Terryshot 031 Plasma OK, disrupted at 1.32 s. RF power 1.36, 2.3 and 1.0 MW.

Apr 25 1995 04:56:44:510PM950425031Jim Terryshot 031 Short H-mode from 1.00 to 1.025 s

Apr 25 1995 04:57:16:720PM950425032Jim Terryshot 032 Plasma OK, disrupted at 1.32 s. RF power 1.36, 2.3 and 1.0 MW.
Short H-mode from 1.00 to 1.05 s

Apr 25 1995 05:07:36:280PM950425033Jim Terryshot 033 Plasma OK, disrupted at 1.29 s. RF power 1.15, 2.5 and 1.35 MW.
Short H-mode from 1.00 to 1.015 s

Apr 25 1995 05:12:44:170PM950425034Jim Terryshot 034 Plasma OK, disrupted at 1.31 s. RF power 1.13, 2.46 and 1.35 MW.
Very short H-mode at 1.00 s

Physics Operator Comments
Apr 25 1995 07:31:09:890AMSteve WolfeTEXT: Setting up for 950425
Start from PCS$WOLFE:PCS_950425901, produced as folows:
Start from 950424007, Ian's last shot from Monday.
Copy (IMPORT SEGMENT) segment 2 to segment 3, for future reference
Import segment 2 from pcs$wolfe, #950424901; this shot was previously
produced by importing 950317024, and incorporating an ef2_by ef4 from
950331038.
Reduce ef2_by_ef4 gain to 2 (from 4)
Slow down CLEARIN ramp in ramp-down phase.
Load into model and save as pcs$wolfe:950425901

Load model at 25-Apr-1995 07:20:14.00
Coldstart successful

Apr 25 1995 07:38:11:200AMSteve WolfeRun plan for 950425
MP#109 - X-point studies
SL: Terry
PO: Wolfe

Start with segment 1 from 950424007. This startup is similar to
950331038, with some tweaks to OH1 voltage, which may want to be undone.

Segment 2 is based on 950317024, with an ef2_by_ef4 wire put in with
gain of 2, and the clearin rampdown modified as on 950424007. Note
that the parent shot was on the EF1 voltage rail; I may need to do
tweaking.

Apr 25 1995 07:42:38:840AMSteve WolfeRun plan for 950425 (cont)

Begin the run in H2. H2 ECDC has been run overnight.

1. Get a discharge with the right characteristics. Check outer strike and
adjust ZXL to get it on or below probe 7. Set up 25msec Ar puff.

2. Run 4 constatn shots for spectroscopic scan to see H_2 lines

3. Switch back to D2, turn on RF at 0.9sec.
Spectroscopy scan for 14 shots.

4. Scan McP across x-point (10 shots).

5. If time permits, scan x-point in R.

Apr 25 1995 08:32:42:600AM950425001Steve WolfeShot 950425001

Start with the traditional Tuesday morning test
OH1 and OH2's look ok.

Apr 25 1995 08:46:24:150AM950425002Steve WolfeShot 950425002

Fill at 1.7e-5Torr, H2
Plasma attempt.

Disrupted, right at end of flattop
Bad hesitation at 15msec, almost lost it.
ECE shows signal across whole chamber, saturates at 22msec
Looks like a lot of hards.

Apr 25 1995 09:06:22:860AM950425003Steve WolfeShot 950425003

Raise fill to 2.0e-5
Reduce ZXU to .035
Early disruption.
Runaways again.

Apr 25 1995 09:15:52:360AM950425004Steve WolfeShot 950425004

EF4 from -1085 to -1070a
Ran, still disrupted at EOF.
Still railing EF1's and OH2U
Breakdown later

Apr 25 1995 09:35:51:940AM950425005Steve WolfeShot 950425005

Get rid of IP ramp.
Change Ip controller beginning at .6 to use
TAUOPT=0.3,VWEIGHT=[0.2,0.2,0.5,0.5,3.65,1.05,0.9,0.1,0.1]*1.E3
delay old rampdown controller to 1.4

Still disrupting, this one died earlier, at .91
Looks like lots of injections
This may not be a fair test.

Apr 25 1995 09:57:00:970AM950425006Steve WolfeShot 950425006

Drop ZXL from .0125 to .0105
Drop ZCUR from -.01 to -.015
Drop ZXU gain from 9.5 to 4

Disrupted in rampdown 1.16sec.
ZXU still out of control.

Apr 25 1995 10:13:43:810AM950425007Steve WolfeShot 950425007

Ar puff to 25msec, and enable B-side lower.
Put Ip controller back the way it was, except manually changed OH2 slice
to 1.05sec
Drop zxu gain to 2.0

Still disrupting on rampdown.
Still losing EF1's at .8 sec

Apr 25 1995 10:30:27:280AM950425008Steve WolfeShot 950425008

Ar puff to 35msec
Slow down RCUR, ZCUR, CLEARIN on rampdown

Disrupted earlier, at 1.02.
Halo warning on the way
We are losing the lower x-point control when the EF1 rails.

Apr 25 1995 10:54:12:100AM950425009Steve WolfeShot 950425009

Drop ZXU gain to 0. at .76sec
Forgot to move the Ar pulse to .3 sec, as requested. Will get it for
next time.

Still disrupting at 1.07.
EF1U now stays well off the rail, current actually turns around at .75,
so that wasn't the problem.
EF2U goes to zero current at 1.03, and we lose it after
EFC goes to zero.

Apr 25 1995 11:09:47:350AM950425010Steve WolfeShot 950425010

Put ZXU gain at 1.0 at .76 sec
Move Ar pulse to .3 sec
Leave EF2_by_EF4 program high after rampdown.
Turn off integral gain on CLEARIN at 1.05sec

Fizzle. CII at .008mw/cm2/ster

Apr 25 1995 11:29:18:800AM950425011Steve WolfeShot 950425011

Try again>
Put ZXU gain at 1.0 at .76 sec
Move Ar pulse to .3 sec
Leave EF2_by_EF4 program high after rampdown.
Turn off integral gain on CLEARIN at 1.05sec

Still disrupting. This one went before EF2 went to zero.
OH2L still hard on voltage rail.

Apr 25 1995 11:46:04:750AM950425012Steve WolfeShot 950425012

Get rid of late gas pulse on A-side
Bring Ip rampdown back to 1.0sec

Short disruptive, lots of hards. lasts till .4 sec, but in trouble
from breakdown on.
TF crowbar
RF boys must go in cell to turn on a NIM crate; now seems a good time.

Apr 25 1995 12:22:18:850PM950425013Steve WolfeShot 950425013

Raise fill to 2.3e-5Torr
Disrupted at 1.02 sec again.
Another Halo warning, that makes 3

Apr 25 1995 12:29:44:730PM950425014Steve WolfeShot 950425014

Repeat, without RF firing at the end. I don't think that's it, but we'll
find out, maybe.

Same thing. It isn't the RF.

Apr 25 1995 12:45:57:320PM950425015Steve WolfeShot 950425015

Get rid of V_oh2U and V_oh2L points at 1sec, + 20V.

Lasted till 1.2sec!
This one survived the EF2U going to zero current at 1.04sec

Apr 25 1995 12:59:50:440PM950425016Steve WolfeShot 950425016

Go to D2- A-side plenum to 19psi of D2
Leave fill at 2.3e-5

Disrupted at 1.2, like the previous one.
Rf at 1.5MW beginning at .9sec

Apr 25 1995 01:22:20:190PM950425017Steve WolfeShot 950425017

Extend Ip flattop back to 1.05sec
Raise NL_04 to 1.4
Slow down ramp some more.

Still dying around 1.2sec

Apr 25 1995 01:27:36:910PM950425018Steve WolfeShot 950425018

Minor tweak to RCUR rampdown
Disrupts at 1.23sec

Apr 25 1995 01:48:26:920PM950425019Steve WolfeShot 950425019

Raise ZXU gain back up to 3. from 0.3 sec on.
Ramp ZXL up after 1.05sec

Still disrupting around 1.25sec, but this time th eEF2's didn't go
to zero.
EF1U is back on the rail.

Apr 25 1995 02:00:25:270PM950425020Steve WolfeShot 950425020

Raise RXU gain to 30/sec. (was 12.5/sec)

Still disrupting at the same time.
According to Rejean, H/(H+D) was .2 on shot 19, .15 on #20

Apr 25 1995 02:14:53:210PM950425021Steve WolfeShot 950425021

Slow down Ip ramp by removing intermediate points
Disrupts at 1.28 sec.

Apr 25 1995 02:26:38:490PM950425022Steve WolfeShot 950425022

Small tweak to CLEARIN rampdown (less negative)
No difference

Apr 25 1995 02:38:11:910PM950425023Steve WolfeShot 950425023

Increase RCUR rampin by about a factor of 2

No change. still disrupts at 1.25sec

Apr 25 1995 03:02:30:460PM950425024Steve WolfeShot 950425024

No change. See if it evolves at all on its own
Fizzle. So much for leaving things alone!
Late bd - 8.1msec. Previous one was fine.

Repeat and see if it comes back.

Apr 25 1995 03:13:09:200PM950425025Steve WolfeShot 950425025

Repeat and see if it comes back.
It did. BD at 6msec, pretty good current rise.
Still disrupting at 1.28

Apr 25 1995 03:35:07:970PM950425026Steve WolfeShot 950425026

No changes
Ran ok, still disrupts at 1.29
Barolo hung up on this one with no pagefile. Granetz has been evicted.

Apr 25 1995 03:39:18:040PM950425027Steve WolfeShot 950425027

No changes
Hangin' in there.

Apr 25 1995 03:59:37:370PM950425028Steve WolfeShot 950425028

Ramp CLEARIN in faster after 1.2sec
Breakdown was not so good on the last one, slow current rise and bounces
at 28msec. Nothing obviously wrong with the fields. Leave it alone and
see if it improves.

It looks pretty similar, maybe 10msec longer.
BD looks better. No bounce and a tad earlier.

Apr 25 1995 04:04:28:120PM950425029Steve WolfeShot 950425029

No changes.
Same. JT and BLIP are continuing the spectroscopy scan.

Apr 25 1995 04:17:40:120PM950425030Steve WolfeShot 950425030

Ramp CLEARIN in hard after 1.2sec.
Essentially the same. Ian thinks the disruption may be due to a vertical
instability that begins at a gain switch on the slow ZCUR.

Apr 25 1995 04:36:25:790PM950425031Steve WolfeShot 950425031

Get rid of the switches on slow ZCUR gains in rampdown
Disrupts at 1.318sec this time. Not much difference.
Still vertically unstable.

Apr 25 1995 04:48:44:190PM950425032Steve WolfeShot 950425032

Reduce rampin of RCUR during rampdown.
No change in disruption time.

Apr 25 1995 04:56:18:950PM950425033Steve WolfeShot 950425033

Ramp CLEARIN faster by removing point at 1.2 sec
Disrupted at 1.28, slightly earlier

Apr 25 1995 05:10:14:890PM950425034Steve WolfeShot 950425034

Ramp CLEARIN in slower and hold it out longer.
This will be the last shot today

Disruption is at 1.318, like the earlier ones.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:29:31:250AMTestOkoh coax test
208:38:07:740AMPlasmaOkno faults
308:54:24:690AMPlasmaOk
409:09:48:340AMPlasmaOk
509:27:33:660AMPlasmaOk
609:43:45:780AMPlasmaOkoh2l fault late in the shot
710:04:16:960AMPlasmaOk
810:20:25:480AMPlasmaOk
910:43:10:230AMPlasmaOk
1011:02:14:490AMPlasmaOk
1111:12:13:720AMPlasmaOk
1211:35:12:190AMPlasmaBadtf crobar
1312:12:29:190PMPlasmaOk
1412:24:06:110PMPlasmaOk
1512:38:45:220PMPlasmaOk
1612:55:22:900PMPlasmaOk
1701:07:46:750PMPlasmaOk
1801:24:51:230PMPlasmaOk
1901:39:42:210PMPlasmaOk
2001:52:26:390PMPlasmaOkNo Faults.
2102:03:14:360PMPlasmaOkNo faults.
2202:19:45:390PMPlasmaOkNo Faults.
2302:32:02:380PMPlasmaOkNo Faults.
2402:51:34:050PMPlasmaOkNo Faults.
2503:06:55:330PMPlasmaOkNo Faults.
2603:16:23:750PMPlasmaOkNo Faults.
2703:36:28:160PMPlasmaOkNo Faults.
2803:51:12:580PMPlasmaOkNo Faults.
2904:01:38:910PMPlasmaOkNo Faults.
3004:14:06:470PMPlasmaOkNo Faults
3104:26:30:960PMPlasmaOkNo Faults.
3204:41:48:220PMPlasmaOkNo Faults.
3304:52:55:780PMPlasmaOkNo Faults.
3405:04:50:960PMPlasmaOkNo Faults