Alcator C-Mod Run 1000623 Information

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Miniproposals
Miniproposal:272
Date Filed: 5/18/2000
Title:Investigation of ICRF Mode Conversion
First Author:E. Nelson Melby
Session Leader:E. Nelson Melby (shots 1-25)

Operators
Session leader(s):E. Nelson Melby
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Cochran,Gary Dekow

Engineering Operator Run Comment
MP272 - Mode Conversion Physics SL:Nelson-Melby, PO: Wolfe, EO:Dekow/Coc

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:24:523PM
Author: To Be Determined
#41 of 44 OPS
Date: 26-JUN-2000 07:25 Expires: 10-JUL-2000 00:00
From: CMOD2::MELBY
Subj: Run summary for 1000623

Session Leader summary for run 1000623
MP 272: Mode Conversion Physics

Most shots will be inner wall limited. Start with an RF pulse of D
port only, starting at 0.6 sec, steady 1.2 MW until 0.8 sec, then RF
power modulation (from 0.9 MW to 1.5 MW, about 20 ms modulation
period) until about 1.1 sec. Shot can end at 1.2 sec.

1. Try to locate mode-converted IBW within PCI window and from
break-in-slope by trying a few different B fields. Start with 5.8 T.
Aim for a target total density of 1.0 - 1.4 x10^20 ne0 (i.e. about .5
to .7 x10^20 nl01) and at least 30% He3 ions (try 200 msec He3 gas
puff first, based on 9802 experience) and at least 20% H ions in the
plasma (the rest D). This will probably take a few shots to get the
right mix and total density and get an estimate of He3 concentration
-- adjust B field as needed to allow for actual ion mix. (3 to 6
shots?)

There is a range of parameters for which strong mode conversion is
expected: B0 from 5.3 to 5.9 T, 15% to 35% He3, H/D from .75 to 10
(with the field being chosen to place the IBW in the PCI viewing range
depending on the species mix)

2. Once signal is located, take a shot at constant B field, determined
from step 1, with strong PCI signal to make sure it is reproducible,
then take an identical shot with 1/2 the PCI beam blocked, to verify
it is an RF PCI signal. (2 shots)

PLAN B: if no RF PCI signal is observed, yet GPC signal indicates mode
conversion is present in the radial window of PCI, try the other (E
port) transmitter, and try higher powers. If still no signal is
observable on PCI, study mode conversion further with rotation and
electron temperature data.

3. Change PCI window to get higher wave number resolution, get a
good shot to measure the perpendicular wave number. (1 shot)

4. If time, continue with parameter scans:

4a. Scan RF power, from highest available power down to about .5 MW
(3 shots)

4b. Scan density with constant B field and species mix (.5
to 1.1x10^20 nl01) (4 shots)

4c. Scan gas mixture, adjusting B field as needed to keep mode
conversion within PCI window. (4 shots)

4d. Scan current (1.0, .8, .6 MA) with additional power from E port
to see poloidal flow current dependence. (3 shots)

---------------------------------

Overall a very successful run day. Almost all the goals of the mini-proposal
were reached. RF PCI signal was seen from shot 1. The wave number for the
RF wave (in the range of 4 to 6 cm^-1) is in agreement with the dispersion
relation of an ion Bernstein wave shortly after mode conversion at the
ion-ion hybrid layer (in this case, the H-He3 hybrid layer). Signal was
seen for both D port and E port antennas (the PCI laser passes through
E port top and bottom), although stronger for D port. No poloidal flow
was seen, but there were difficulties with the HIREX signal today.

Shot 1: 5.74 T, saw signal from D port at 350.87 kHz (heterodyne
beat frequency with 80.5 MHz D port power)
Shot 2: repeat of shot 1, stronger signal (better PCI laser performance
on this shot).
Shot 3: blocked 1/2 the PCI laser beam to verify real plasma signal and
not RF pickup in the circuitry -- signal at 350.87 kHz dropped by a
factor of 5

Shots 4 and 5 also see good D port signal, with different densities
and plasma ion species mix.

Shots 6 and 7 were duds.

FOR SHOTS 8 - 13 NARROW LASER BEAM, HIGHER K RESOLUTION.

Shot 8: Good PCI signal seen, varying in strength and location
during shot (note: for shots 8,9,10 sound burst calibration was
weak, use shot 6 or 11 for PCI positions calibration)

Shots 9 and 10: B field ramps (from 5.9 T to 5.5 T) to see RF PCI
signal move across channels, signals 6 to 10 times higher than
background noise level.

Shots 11, 12, 13: D port power ramps to see scaling with power.
Density and varying species mix seems to be playing a role as well
in changing signal strength.

FOR SHOTS 14-END OF RUN: WIDER LASER BEAM, MORE SPATIAL COVERAGE,
LESS K RESOLUTION.

Shot 14: D port power ramp, signal strength more or less follows
power ramp.

FOR SHOTS 15-END OF RUN: CHANGE PCI RF SIGNAL GENERATOR TO 40.18
MHZ (FROM 40.075 MHZ) TO LOOK FOR E PORT POWER AT AROUND 360 KHZ.

Shot 15: RF PCI signal seen at 359.11 kHz, 4 times higher than
background noise level.
Shots 16,17: repeat of 15, with 1/2 the PCI laser blocked, to verify
real signal. (Shot 16 had an unstable PCI laser)

Shots 18, 19, 20: varying ratios of He3, H and D. Signal seen
for E port at 4 to 6 times background noise level, moving in
PCI window radially during the shots. Some signal seen for D port
around 150 kHz on shot 20 as well.

Shot 21: 1.0 MA shot (rest of day has been .8 MA) to see
if ion Bernstein wave damping changes. Strong signal seen for
both D and E port, initial comparison with shot 20 shows that
indeed the PCI signal is more localized.

Shot 22: attempt at 1.2 MA to see if damping changes even more,
but fizzle.

For many shots D and E port rf power was modulated to look
for prompt electron heating on GPC and GPC2 electron temperature
diagnostics. This analysis still needs to be done but initial
indications are strong off-axis heating for most shots.
In addition, analysis still needs to be done using Helium, Hydrogen
and Deuterium spectroscopic data and Z effective and density traces
to determine the actual ion species mix for each shot.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:11:473PM
Author: To Be Determined
Physics Operator Summary for 1000623

MP#272: Mode Conversion Physics
SL: Nelson-Melby
PO: wolfe
EO: Dekow

For this run, the requirement is for limited plasmas with
approximately equal H and He3, and as little D as possible.
Field range is 5.4 - 5.9T, density below 1e20 nl4.

Run began at 08:00 and ran to 17:00.

Engineering setup:
--------------------

ECDC overnight in **Hydrogen**, stopping 1-2 hours before run.
Note: HYDROGEN (H2), not deuterium (d2)

Power system setup: Same as for 1000622001, except tf limit at 175000 amp.

Set OH1, OH2U and OH2L fizzle delays at 300ms
Set TF fizzle delay at 400 ms

Gas setup: B-Top 6 psi D2 Hybrid Enabled
B-side lower 1 psi Argon Hybrid DISABLED
B-side Upper 16 psi He3 HYBRID Enabled
C-side 30 psi H2 Hybrid Enabled
J-bottom 30 psi D2 Hybrid DISABLED

*** Notice that C-side should be filled with HYDROGEN and
B-side Upper with Helium-3

The following Gate Valves should be ENABLED, assuming vacuum ok:
ECE, VUV, Hirex, PCI

--------------------------------------------------------------------

The plan was to take the last hour of the day to run deuterium
plasmas, so that we can reload the walls with D2 before boronization.
If the Marmar meter does not return to H/D<10%, then we would ecdc in
D first, otherwise boronize.

The machine was prepared with overnight ECDC in H, following
yesterday's H/D changeover experiment which ended with majority
hydrogen. The RGA showed a lot of H2 at the beginning of the day.

The initial shots were programmed for nl4=6e19, with a non-feedback He3 puff
of 200msec, and 35V maintenance level. This resulted in nl4 and nl1 over
1.2e20, mostly composed of He3. Zave showed values of 2.5; H/D was over 2, but
it wasn't clear the signal was meaningful. Later in the day, we put the
B-side upper valve on the NL04 feedback controller. This also seemed to work,
although we ran above the target density for almost all shots. The He3 program
signals varied from the initial settings and included main puffs of 100 and
50msec, and maintenance levels up to 50V.

Signals were seen on the PCI, the principal diagnostic for the MC to IBW,
right from the first shot. Modulated signals were also clear on the GPC,
indicating a strong interaction well off-axis. Attempts to measure poloidal
rotation, predicted to be driven by the MC waves, were unsuccessful. Aside
from this, the experiments produced good data at a variety of fields, in a
narrow density range, and with several He3 fractions (actual values hopefully
can be determined). We also got one good shot at 1MA, which indicated a change
in the damping, according to instant analysis. See the session leader summary
for details of what got measured on which shots.

The attempt to change back to D2 wall loading in the last hour was not
successful, with the minimum value of H/D only getting down to 0.5-0.6. We
therefore decided to go to overnight ECDC in D2, and postpone boronization to
Saturday morining.

The machine ran very well in H/He3, with fast current rises and no
hesitations. Late in the RF run, as we were trying to reduce the density, we
started getting runaways. Increasing the pre-puff to 26msec (over .07mTorr)
helped a little, and a small Bz tweak may have helped more. Even with this
high a pressure the current rises were fast (over 50kA at 15msec).

The only fizzle was shot 22, following a 1MA disruption; that could possibly
have been avoided if I had reduced the pre-puff, but I didn't. There were two
duds due to PLC/IGOR issues, an Ack failure (no power supplies fired) followed
by a shot on which only half the supplies fired, as sometimes happens after
backing out of a shot.

Shots 1-21 were H/He3 shots in the MC experiment. All ran successfully, except
#6 and 7.
Shot#22 was supposed to be 1.2MA, but fizzled.

Shots#23-25 were all D2 puffing, cleanup attempts. #23 disrupted. J-bot was
used to fuel #23, then C-side was pumped out and filled with D2 and that was
used for #24-25 (segment 3).

Scorecard:
---------
Tests 0
Duds 2 (PLC/IGOR)
Fizzles 1
Plasmas 22
------- --
Shots 25

Session Leader Comments
Jun 23 2000 08:35:02:967AM1000623001E. Nelson Melby200 msec He3 gas puff, 5.74 T -- RF PCI signal is seen on high field side
channels!
Repeat to get GPC and H/D data
Jun 23 2000 08:36:31:437AM1000623002E. Nelson Melby200 msec He3 gas puff, 5.74 T -- RF PCI signal is even stronger.
Next shot, repeat with 1/2 beam blocked to verify a real signal and not RF pickup
Jun 23 2000 09:15:41:373AM1000623003E. Nelson Melby200 msec He3 gas puff, 5.74 T -- identical to 002
with 1/2 the beam blocked, RF PCI signal dropped by about
a factor of 5, thus verifying real RF PCI signal.
Jun 23 2000 09:34:15:577AM1000623004E. Nelson MelbyShorter gas puff, 100 msec He3, try to get more H
density now 1.0 nl01
RF PCI sees strongest signal at around 63.4 cm

next shot: raise field, see if entire signal moves across PCI window.
Jun 23 2000 10:19:13:153AM1000623005E. Nelson MelbyShorter gas puff, 100 msec He3, try to get more H
density now 1.0 nl01
BTor now 5.88 T
RF PCI signal did move about 2 cm to the low field side
Jun 23 2000 10:19:29:373AM1000623006E. Nelson Melbyno plasma, CAMAC errors.
Jun 23 2000 10:19:41:293AM1000623007E. Nelson MelbyDud.
(Power supply problems)
Jun 23 2000 11:11:24:810AM1000623008E. Nelson MelbyNarrowed PCI laser beam to get higher k number resolution,
repeat shot. Saw PCI signal at k of +6 (no -6) cm^-1
Jun 23 2000 11:22:57:763AM1000623009E. Nelson MelbyRepeat shot 8 with narrow PCI beam, but with a B field
ramp to see signal move across window -- B field ramp was
not quite so low as we wanted, and PCI laser jumped in power,
repeat with bigger ramp (down to 5.5 T)
Jun 23 2000 11:50:34:340AM1000623010E. Nelson MelbyRepeat of shot 9 with bigger B field ramp, saw the RF PCI
signal move across all the channels.

Next shot: D port ramp, attempt to see signal from E port, constant 5.8 T
Jun 23 2000 12:41:19:873PM1000623011E. Nelson MelbyPower ramp, saw PCI signal vary in a different way than the power -- maybe
the species mix is changing? Density is lower as well.

Next shot: repeat ramp and see about species mix
Jun 23 2000 12:49:03:500PM1000623012E. Nelson MelbyRepeat of last shot, see if species mix still changes (i.e. He3 from McPherson spectrometer),
and H/D ratio from Earl's Balmer line spectrometer
Jun 23 2000 01:10:56:873PM1000623014E. Nelson MelbyRepeat shot 13 (power ramps) but with a different k range on PCI beam (larger beam, more coverage)

We still see the signal from higher k (aliased) and also perhaps a fast wave signal ? at lower k.
Jun 23 2000 01:25:28:043PM1000623015E. Nelson MelbyLook for E port RF PCI signal now, (RF signal generator for PCI now at 40.18 MHz)
move E port earlier, put back in modulation.

Saw something at 360 kHz -- just as expected for E port 80.0 MHz, next
shot: repeat, block 1/2 the beam to verify E port signal is not just pick -up.
Jun 23 2000 01:58:40:500PM1000623016E. Nelson MelbyBlock 1/2 the beam, but the laser became unstable, try again with a better laser mode.
Jun 23 2000 02:54:59:437PM1000623017E. Nelson MelbyBlocked 1/2 the beam to determine if E port is real signal,
signal was blocked.
Jun 23 2000 02:55:25:890PM1000623018E. Nelson Melbyfull beam again, different He3 and H mix, try to see how it affects the mode conversion efficiency.
Jun 23 2000 03:15:14:293PM1000623019E. Nelson MelbyDifferent He3 and H mix again. Good signal from E port, at the 1.7 mV level (5 times noise
level)
Jun 23 2000 03:31:34:950PM1000623020E. Nelson MelbyKeep the same mix, try for a lower total density.

Density didn't get too much lower, but still strong signal.
k numbers near 4 cm^-1 (unless it is being aliased from higher k)

Next shot: try higher current (1.0 MA)
Jun 23 2000 04:24:05:000PM1000623021E. Nelson Melby1.0 MA, PCI laser mode stable, disrupted at 1.5 sec.

Good PCI signal, more localized than before.
Jun 23 2000 04:24:18:153PM1000623022E. Nelson MelbyAttempt for 1.2 MA, fizzle.

Physics Operator Comments
Jun 22 2000 06:25:07:827PMSteve WolfeLoad/CLEAN into model for run 1000623:
Started from 1000622015, and modified extensively-
We will start with an 800kA, 6e19 limiter discharge
with a 200msec He3 puff, and 35V He3 maintenance level;
initial tf will be 5.8T (tf=161ka).


Tommy is putting He3 in the B-side upper plenum

Machine is ECDC'ing in Hydrogen; should run overnight.

Note: NINJA is disabled, and JT has turned Kaiser off in the tree,
so we won't be getting He4 pulses tomorrow.

Jun 23 2000 07:05:57:170AMSteve Wolfe B-side upper has 17.2 p.s.i. of Helium-3 and both P1in and PUR1
valves have been disabled to prevent accidental pumping and/or
mixing of the plenum.


P.S.

Also, GV1 has also beeen disabled for the bakeout.



Tom T.
vac shop
Jun 23 2000 07:08:16:810AMSteve Wolfecoldstart at 07:05
all matrices respond, no errors
Jun 23 2000 07:14:39:623AMSteve WolfeECDC in H2 ran overnight, shut down at 06:35 this morning

Jun 23 2000 07:23:07:670AMSteve Wolfengineering Setup and Run Plan for 1000623

MP 272: Mode Conversion physics
SL: Nelson-Melby
PO: wolfe

------------------------------------------------------------

Engineering Setup:

ECDC overnight in **Hydrogen**, stopping 1-2 hours before run.
Note: HYDROGEN (H2), not deuterium (d2)

Run begins at 8:00 and ends at 17:00.
The last hour will be used to change back to deuterium, so the walls will be
loaded with D2 for boronization.

If the H/D is satisfactory at the end of the day, we will begin boronization
immediately. Otherwise, we will begin ECDC in Deuterium overnight, and
boronize on Saturday.

Power system setup: Same as for 1000622001, except tf limit at 175000 amp.

Set OH1, OH2U and OH2L fizzle delays at 300ms
Set TF fizzle delay at 400 ms


Gas setup: B-Top 6 psi D2 Hybrid Enabled
B-side lower 1 psi Argon Hybrid DISABLED
B-side Upper 16 psi He3 HYBRID Enabled
C-side 30 psi H2 Hybrid Enabled
J-bottom 30 psi D2 Hybrid DISABLED

*** Notice that C-side should be filled with HYDROGEN and
B-side Upper with Helium-3

The following Gate Valves should be ENABLED, assuming vacuum ok:
ECE, VUV, Hirex, PCI

Run Plan:
----------
We will start with an 800kA, 6e19 limiter discharge
with a 200msec He3 puff, and 35V He3 maintenance level;
initial tf will be 5.8T (tf=161ka).

Most shots will be inner wall limited. Start with an RF pulse of D
port only, starting at 0.6 sec, steady 1.2 MW until 0.8 sec, then RF
power modulation (from 0.9 MW to 1.5 MW, about 20 ms modulation
period) until about 1.1 sec. Shot can end at 1.2 sec.

1. Try to locate mode-converted IBW within PCI window and from
break-in-slope by trying a few different B fields. Start with 5.8 T.
Aim fo a target total density of 1.0 - 1.4 x10^20 ne0 (i.e. about .5
to .7 x10^20 nl01) and at least 30% He3 ions (try 200 msec He3 gas
puff first, based on 9802 experience) and at least 20% H ions in the
plasma (the rest D). This will probably take a few shots to get the
right mix and total density and get an estimate of He3 concentration
-- adjust B field as needed to allow for actual ion mix. (3 to 6
shots?)

There is a range of parameters for which strong mode conversion is
expected: B0 from 5.3 to 5.9 T, 15% to 35% He3, H/D from .75 to 10
(with the field being chosen to place the IBW in the PCI viewing range
depending on the species mix)

2. Once signal is located, take a shot at constant B field, determined
from step 1, with strong PCI signal to make sure it is reproducible,
then take an identical shot with 1/2 the PCI beam blocked, to verify
it is an RF PCI signal. (2 shots)

PLAN B: if no RF PCI signal is observed, yet GPC signal indicates mode
conversion is present in the radial window of PCI, try the other (E
port) transmitter, and try higher powers. If still no signal is
observable on PCI, study mode conversion further with rotation and
electron temperature data.

3. Change PCI window to get higher wave number resolution, get a
good shot to measure the perpendicular wave number. (1 shot)

4. If time, continue with parameter scans:

4a. Scan RF power, from highest available power down to about .5 MW
(3 shots)

4b. Scan density with constant B field and species mix (.5
to 1.1x10^20 nl01) (4 shots)

4c. Scan gas mixture, adjusting B field as needed to keep mode
conversion within PCI window. (4 shots)

4d. Scan current (1.0, .8, .6 MA) with additional power from E port
to see poloidal flow current dependence. (3 shots)

The RF experiment will end at 16:00, followed by changeover shots to reload the
walls with D2 before boronization.
[EOB]
Jun 23 2000 07:40:04:000AMSteve WolfeStarting points in seg1 (from yesterday)
Pg4 = 24msec
BR0 offset=0.000
ic_ef4u = -1295
rcur offset=5500
Jun 23 2000 08:32:37:700AM1000623001Steve Wolfeshot#1: begin ramping tf down at 1.2sec, current and rf to stay on.
program is 0.8Ma, 6e19, 200msec He3 puff, clearin=-.015, tf=-161ka

plasma full length, vertical thrash in rampdown.
density peaks at 1.2e20, after He3 puff.
Big hash on halpha from .42 to .61, also during density rise.
plasma is only marginally limited early, 2cm outer gap.
need to move clearin further in.
very slow current rise.
Earl's Ha/Da signal is out to lunch.

next shot: clearin from -.015 t0 -.022
pg4 from 24msec to 22msec
enable Argon
Jun 23 2000 08:44:33:233AM1000623002Steve Wolfeshot#2: clearin from -.015 t0 -.022
pg4 from 24msec to 22msec

plasma, similar, less of a 2pi burst this time, but current
still has a dip at 450msec, density (nl01 over 1e20) faster startup current rise
loop voltage goes over 2V during He3 puff. I think it is a He3 discharge!
H/D is giving funny results, but seems to be high; I don't know if it means anything.
Zave is over 2.5
OUter gap is still around 2cm?

PCI is seeing signal, so next shot will be a repeat, with half
of PCI beam blocked, to verify that it is real.
Jun 23 2000 09:07:01:607AM1000623003Steve Wolfeshot#3:repeat, with half of PCI beam blocked, to verify that signal is real.
plasma, a few injections, disrupts in rampdown at 1.75sec
early current rise even a little faster this time.
nl01 up to 1.3e20, mostly from the he3 puff.

next shot: unblock pci, reduce He3 puff to 100msec.
move rcur out by 4mm to .663, to reduce outer gap.
Jun 23 2000 09:35:08:717AM1000623004Steve Wolfeshot#4:unblock pci, reduce He3 puff to 100msec.
move rcur out by 4mm to .663, to reduce outer gap.

plasma, full length. nl01=1e20 this time, outer gap is growing
from 1.1 to 1.7cm, but rf looks steady.
zave is down to 2.3; h/d drops fro 2->1 during shot, but I don't know if it's real.

next shot: put a ramp on rcur from .663 to .666
increase tf from 161 to 165.5ka
Jun 23 2000 09:52:03:280AM1000623005Steve Wolfeshot#5:put a ramp on rcur from .663 to .666
increase tf from 161 to 165.5ka

plasma, injections from vicinity of d-port?
mag_traq1 data corrupted on this shot; have to re-run EFIT from pcs signals.
bt=5.88T
PCI had a problem on this shot.

next shot: they're removing a lens in the PCI optics, to improve k-resolution.
otherwise, just a repeat. JR is still trying to get the HIREX camac working.
Jun 23 2000 10:11:55:793AM1000623006Steve Wolfeshot#6: they're removing a lens in the PCI optics, to improve k-resolution.
otherwise, just a repeat, except that Steve will start bringing on E-port late.
JR is still trying to get the HIREX camac working.

Ack failure during pulse. No shot.
Magnetics camac has errors, not surprisingly


Next shot: Add aditional 25msec Ar puff at 0.8sec, for HIREX


Jun 23 2000 10:21:01:140AM1000623007Steve Wolfeshot#7: they're removing a lens in the PCI optics, to improve k-resolution.
otherwise, just a repeat, except that Steve will start bringing on E-port late.
JR is still trying to get the HIREX camac working.
Add aditional 25msec Ar puff at 0.8sec, for HIREX

Missing oh1, ef1's, tf. Also missing the plasma of course.

Next shot: One more try!

Jun 23 2000 10:51:17:640AM1000623008Steve Wolfeshot#8: Try that again.
they've removed a lens in the PCI optics, to improve k-resolution.
otherwise, just a repeat of #5, except that Steve will start bringing on E-port late.
Add aditional 25msec Ar puff at 0.8sec, for HIREX

plasma, finally!
but the rf faulted after 1sec.
However, the PCI boys seem happy enough, they got a k measurement.
The marmar-meter is hardly registering at all now.
Jun 23 2000 11:19:26:280AM1000623009Steve Wolfeshot#9: ramp tf from -165.5 to -158.5(5.5T) between .65 and 1.0sec, then hold to 1.2
JR is complaining about lack of Argon; I'll put in a wider second puff next shot.

plasma, mag_traq1 errors again! Re-run EFIT on PCS data.
D-faults out when E turns on.
TF only went down to 5.65tesla? Should have been 155800 instead of 158500.

Next shot: Extend second Ar puff to 40msec.
Change tf ramp to bottom=154800
Jun 23 2000 11:35:14:890AM1000623010Steve Wolfeshot#10:Extend second Ar puff to 40msec.
Change tf ramp to bottom=154800 (should really be 5.5T)

plasma, some small injections
RF both stayed on. max rfpower is 2.5MW.

Next shot: eliminate the tf ramp, go to 5.84T (164.4ka)
Jun 23 2000 11:57:08:700AM1000623011Steve Wolfeshot#11: eliminate the tf ramp, go to 5.84T (164.4ka)
RF will ramp d-port power.
Increase second ar puff to 60msec

plasma, but e-port antenna faulted; d power ramp is ok.

next shot, lower density

Jun 23 2000 12:25:18:543PM1000623012Steve Wolfeshot#12: Try for lower density, with He3 in the feedback.
Put pulse gas2 in the nl04 controller, 4.5e-19, same as Pg3.
Shorten pg2 puff to 40msec, keep 35V maintenance.
NL04 is still programmed for 6e19.

plasma, rf: D ramps up and down.
some early runaways. density a liittle lower, nl01=.88
Zave varies from 2 to 2.5 and back down to 2; jt sees less he3 by factor of 2 or so.
breakdown a little late on this one, 7ms; was actually later last shot.
current rise is still fast, leave it till it fails.



next shot: repeat with different rf
Jun 23 2000 12:46:56:077PM1000623013Steve Wolfeshot#13: repeat with different rf waveform.
plasma, big runaway spike early.
Looks like 12.

next shot: Increase early pg3 puff, increase pg4 by 2msec
to try to kill the runaways. Otherwise, a repeat with
PCI looking at a different k
Jun 23 2000 01:07:57:920PM1000623014Steve Wolfeshot#14: Never loaded the startup changes.
a repeat with PCI looking at a different k

plasma, hards getting worse., fill is also down a bit.
this time load the changes.
E-port stayed on this time, up to 2.5MW, density increases some.

Next shot: raise He3 maintenance puff from 35 to 50V, big pulse to 50msec.
increase pre-puf to 24 and increase pg3 in seg1 (like I said before)
Jun 23 2000 01:24:25:467PM1000623015Steve Wolfeshot#15: raise He3 maintenance puff from 35 to 50V, big pulse to 50msec.
increase pre-puff to 24 and increase pg3 in seg1 (like I said before)

plasma, runaways better, still one big spike early
I/Bz is getting very big

nl01 at 0.9e20, This time they are using E-port early, adding D after 1.2sec
They see something, but now they need to block half the beam to check for
pickup again.
Jun 23 2000 01:51:30:467PM1000623016Steve Wolfeshot#16: repeat, with PCI blocked (half the beam)to check for
pickup again.

plasma, still hards early. another late breakdown
but current rise is fast.
d failed, e stays on. density down to 8e19.
PCI laser mode jumped, they'll have to redo it.

next shot: move early pg3 puff from 25 to 20msec
raise pre-puff to 26msec
Jun 23 2000 02:02:57:653PM1000623017Steve Wolfeshot#17: repeat, with PCI blocked (half the beam)to check for
pickup again.
move early pg3 puff from 25 to 20msec
raise pre-puff to 26msec

plasma, still hards. RF ran ok.

next shot: put feedback on 10:1 in He3.
Jun 23 2000 02:29:47:983PM1000623018Steve Wolfeshot#18: Try to do a He3 concentration scan:
drop pg3 in nl4 feedback from 4.5e-19 to 0.5e-19; leave pg2 at 4.5e-19.
raise pre-puff to 28msec.

plasma, had some flashes on the tv.
We're still getting hard x-rays. I may have to tweak the breakdown fields.
rf trips at 1.2sec, density is up to 1e20

PG3 is on all shot? Oh, since the density was high, it turns the maintenance off,
but it turns it off less on the smaller controller. I should have killed
the pg3 maintenance level. I expect that one is lower He3, instead of higher.
Jun 23 2000 02:31:37:030PM1000623018Steve Wolfeshot#18: Try to do a He3 concentration scan:
drop pg3 in nl4 feedback from 4.5e-19 to 0.5e-19; leave pg2 at 4.5e-19.
raise pre-puff to 28msec.

plasma, had some flashes on the tv.
We're still getting hard x-rays. I may have to tweak the breakdown fields.
rf trips at 1.2sec, density is up to 1e20

PG3 is on all shot? Oh, since the density was high, it turns the maintenance off,
but it turns it off less on the smaller controller. I should have killed
the pg3 maintenance level. I expect that one is lower He3, instead of higher.

Next shot: turn off Pg3 maintenance voltage after .2sec
Jun 23 2000 03:00:15:420PM1000623019Steve Wolfeshot#19: turn off Pg3 maintenance voltage after .2sec.
Feedback will be almost all He3 this time.
TF flattop to 1.3sec.
IC_ef4 from -1295 to -1300.

plasma, hards much better. D-port didn't go.
nl01=9e19.

Next shot: try to reduce density. All I can do is get rid of
the pre-programmed puffs.
Jun 23 2000 03:54:00:483PM1000623021Steve Wolfeshot#21: 1MA
disrupted at 1.5sec
It looks like EF1U and OH2L hit current rails.
OH2L should be at 26ka, but in fact stalled at 24ka

Next shot: try for 1.2MA, shorten shot to 1.1sec, increase OH2 current limits
Jun 23 2000 04:03:50:200PM1000623022Steve Wolfeshot#22: try for 1.2MA, shorten shot to 1.1sec, increase OH2 current limits

fizzle. Disruption did us in.
OK, that's all for the RF run. Now to try for changeover.
Jun 23 2000 04:27:54:623PM1000623023Steve Wolfeshot#23: Drop fill to 22msec, reload seg 2 from 1000622015, change
NL04 feedback to J-bot, copy pg3 waveforms to pg5.
disable b-side upper, c-side, and bside-lower; turn on jbottom.

disrupted early 400msec, pf breaker pulled.
Go back to 1MA shot for next shot.
H/d down to .66.

Jun 23 2000 04:41:54:827PM1000623024Steve Wolfeshot#24: import seg2 of 1000622010 into seg 3, and turn on.
Fill C-side with D2. Drop pre-puff to 20msec.
turn off Jbot, turn on C-side

plasma to 1.8sec. GOt some rf.
Injection at .45 or so, drops the density
H/D around 0.7 during the RF.

next shot: repeat
Jun 23 2000 05:05:17:340PM1000623025Steve Wolfeshot#25: repeat
plasma, still marfe's
H/D ~0.5

It's not going to get to 10% today.
We'll ECDC in D tonight, and boronize tomorrow.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:04:20:483AMPlasmaOk
208:28:05:060AMPlasmaOk
308:49:28:140AMPlasmaOk
409:16:15:513AMPlasmaOk
509:36:36:793AMPlasmaOk
610:07:44:780AMPlasmaOk
710:17:01:250AMPlasmaBadNo TF, OH1, or EF1 supplies
810:34:02:733AMPlasmaOk
911:02:38:873AMPlasmaOk
1011:22:01:437AMPlasmaOk
1111:48:19:217AMPlasmaOk
1212:07:36:200PMPlasmaOk
1312:31:50:780PMPlasmaOk
1412:52:14:890PMPlasmaOk
1501:12:25:483PMPlasmaOk
1601:32:54:763PMPlasmaOk
1701:56:00:187PMPlasmaOk
1802:21:51:013PMPlasmaOk
1902:50:49:000PMPlasmaOk
2003:12:53:750PMPlasmaOk
2103:34:54:763PMPlasmaOk
2203:55:45:187PMPlasmaOk
2304:14:20:357PMPlasmaOk
2404:33:42:043PMPlasmaOk
2504:54:46:077PMPlasmaOk