Alcator C-Mod Run 1050405 Information

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Miniproposals
Miniproposal:417
Date Filed: 2/24/2005
Title:Plasma performance, boronization and ICRF heating effectiveness with high-Z antenna guards and all-m
First Author:Yijun Lin
Session Leader:Martin Greenwald (shots 1-14)
Session Leader:Bruce Lipschultz (shots 15-32)

Operators
Session leader(s):Martin Greenwald,Bruce Lipschultz
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Cochran,Bill Byford,Bill Parkin

Engineering Operator Run Comment
MP#417and MP#416

Session Leader Plans
Entered: Apr 5 2005 09:05:23:117AM
Author: Martin Greenwald
Continuation of MP417 - "Plasma performance, boronization and ICRF heating effectiveness with high-Z antenna guards and all metal surface"

Aims:

1) Look at the confinement in L-mode at a range in densities.
2) Calibrate the bolos with 100% radiation in limited plasmas so that the divertor does not detach.
3) Same, but with LSN and Ne
4) Same but with USN and Kr.


Plan

1) 1-2 shots to tune up shot, get RF working
~8 shots, limited plasmas - L-Mode density scan at constant power, current
Ip = 1.0 MA, 3MW RF, nl04 = 0.8, 1.2, 1.6,2.0, 2.4e20m^-2
step down in RF at end of waveform to get Pabs
ECDC 5-10 minutes between shots (ECDC should scan between R=0.58 and R=0.92 m)

2) ~4 shots, limited plasmas, puff krypton slowly to disruption, pick from among previous plasmas for starting point. power constant, start Kr at 2psi, 60 ms out of each 160 msec, starting at 0.5seconds into discharge.
(see 1050330025)

3) ~ 2 shots, USN (start at DN and ramp up to +.5 SSEP over a second or so). Request is for a 1MA shot.
~ 5 shots, USN with Kr puffing as before.

4) ~ 5 LSN sshots (e.g. 1050401019), with Ne puff (40 ms puff to start, fill 3 Psi) after first shot


Physics Operators Plans
Entered: Apr 4 2005 05:56:57:787PM
Author: Steve Wolfe
MP#417 pre-boronization evaluation of all-metal ...
MP#416 (piggyback 3 shots) baseline offsets
SL: Greenwald, Lipschultz
PO: wolfe

Engineering setup:
Overnight ECDC in D2, bake at 60C

Run begins at 09:00 ends at 17:00 EDT

Power systems as on 1050401019 
A-coil in standard configuration (+Dtop -Dbot -Jtop +Jbot)
Transmitters 1,2,3,4 in RUN-ON by 08:30

Gas setup:
fill B-top with 6 psi D2 hybrid enabled (PG4)
fill B-side lower with 2 psi Kr Hybrid disabled (PG1) *
leave B-side upper with He3 Hybrid disabled (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)

*May change gas later in the day

Enable the following gate valves (assuming no vacuum problems):
ECE, VUV, Z-bolo shutter

We will be doing ECDC between shots (10 minutes to start, then shorter)
Initially we will not be closing GV1 and GV2 during pulse, but we may do so
later in the run. 


Plan
----

Start with limiter L-mode discharges and do a density scan (Martin's
part of the run). Import segment 4 from 1050309021 (into 
segment 3). Remove offsets. Increase Ip to 1MA. Raise nl04 to 8e19 for first 
shot. Go from there. 

Early on (shot#1?), sneak in the MP#416 program into seg1 and put the 
input_pros:switch_times to -2.1sec; if unsuccessful, don't take more than
3 shots before putting it back.

After finishing L-mode scan, puff Kr to destruction (100% Prad) in limiter 
case. 

Then run USN starting with SSEP control to +.005 (modify seg4) 
and puff Kr to 100%, using modulation on PG1 as on 1050330025. If SSEP 
isn't working, try a true USN as on 1050309019, seg 3 and raise Ip to 1MA.

If time available, go back to LSN (seg2) as on last Friday, put 3psi Ne in
B-side lower and puff to disruption, starting with 40ms long puff. 



Session Leader Summaries
Entered: Apr 5 2005 05:08:17:307PM
Author: Martin Greenwald
Plan:

Density scan in L-mode with strong ICRF heating for comparison with previous post-boron experiments

Nominal target was 1.0 MA, 5.4 T, 3.0MW, Limited, nebar from 1.2 to 4e20

Results:

We essentially completed these experiments, though there were problems at the low and high ends of the proposed density range. It was difficult to get nebar below 1.5e20. Rather than waste time cleaning off the walls, we pushed to higher densities, reaching 3.1e20. Above this density the plasma was too resistive to sustain the discharge. The RF had trouble with the neutral densities

The degradation of heating/confinement previously observed for L-mode plasmas in a boronized machine was recovered in this pre-boronized state.

Shots for further Analysis:

Shot          nebar      Prf     Wmhd     H89(assuming frf = 0.8)
1050405002    1.6        1.6     0.80     0.93
1050405003    1.7        3.3     0.10     0.96
1050405005    1.66       3.0     0.10     0.96
1050405006    1.55       3.0     0.096    0.94
1050405009    2.3        2.2     0.085    0.85 
1050405011    2.6        2.9     0.092    0.90
1050405012    2.8        1.4     0.074    0.80
1050405013    3.1        3.0     0.093    0.83
1050405014    3.1        3.0     0.95     0.85



Entered: Apr 5 2005 06:12:33:230PM
Author: Bruce Lipschultz
1050405 (2nd half of day) - mp 417

SL: Lipschultz
PO: Wolfe

Continuation of MP417 - "Plasma performance, boronization and ICRF heating effectiveness with high-Z antenna guards and all metal surface"

Aims:

1) Calibrate the bolos with 100% radiation in limited plasmas so that the divertor does not detach.
2) Same but with USN and Kr.


Accomplished most of our goals today with a number of fizzles along the way which limited the amount of data for USN. Greenwald will be posting as well about confinement measurements:

1) Got limited plasmas with radiated powers of up to 2.5 MW on the foil bolo array (shots 16, 18, 20 are good examples). Good data with the McPherson on shot 20. This shot was also interesting from the point of the AXUV bolos in that 2 emissivity peaks can be resolved (see entry under 'bolo') and the outer peak at R=0.85 increases with RF and with the Kr injection. The density (nebar) was ~ 2.7e20.

2) USN plasmas were obtained on 25, 27 and 31 (SSEP = +0.5). Kr was injected on 31. Good McPherson data. Unfortunately the gains were different so the comparison with shot 20 is not direct. Radiated power up to almost 2.5 MW (1 MW on shot 27 without Kr). This was lower density than the inner wall limited shots (nebar = 1.75).

Other thoughts:

We need some definitive analysis of the bolo profiles with Ar before closing this out. We would like to see if a different peak appears on the emissivity profiles with Ar. We also may get some data with Ne tomorrow.

The second peak in the AXUV emissivity profile is unexplained (R=0.78). This could be Mo in that it is higher mass than Kr. Matt thinks that the 0.78 peak was not there early in the run period.

The Kr was still quite significant after 4 fizzles following a Kr injection??

F was quite high on Chromex views of various surfaces around the torus, perhaps a bit higher on views of the inner wall and the LH antenna.

It seemed that the FIX CXRS line (479.468 nm, 9-10) was evident on the Chromex (see spectroscopy entry for shot 27). This may be useful for keeping track of the F density.


Physics Operator Summaries
Entered: Apr 6 2005 06:51:40:903AM
Author: Steve Wolfe
Physop summary for Tues. 1050405
MP#417 (day N of pre-boronization evaluation)
SL: Greenwald, Lipschultz
PO: wolfe
EO: the Bills (Cochran, Byford, Parkin)

A difficult run, but we actually got points 1, 2, and 4 of the 
SL plan done. The only item not done was Ne puff into LSN
plasmas. In addition, MP#416 was completed as we started out 
with baseline subtraction in segment 1. The consequent change
to the startup may have contributed to the low startup fraction,
but I don't think this was the case. However, it certainly 
can't be claimed that it made things better. Decent startups, with
no tweaks, were obtained for shots #11-16; I recommend starting
with seg1 from any of these tomorrow.

Note that the limiter discharges were all run out of segment 3, 
and the upper null shots out of segment 4. Segment 2 was loaded 
from 1050330025 for the purpose of copying the Kr puff, but
not actually run. 

Startup was problematic all day, especially the second half 
(sorry Bruce) and we ended up with 16 plasmas
plus one final horrendous runaway shot out of 31 attempts. 
Actually, the startup wasn't so bad until around shot 17, with
11 out of 15 good starts on shots 2-16 (shot 1 was a no-power
data cycle), and six in a row from 11-16. This sequence included
cases with and without between shot ecdc, several gas tweaks 
and some tweaks to Br0 and IC_EF4U. Also, on shots#6 and 7 the gate 
valves were closed in pulse (no ecdc). From 17-32 we only got
five successful startups and one saturating runaway shot on #32
that disrupted at 0.5sec. These shots were from after we started 
puffing Krypton, and also began when we started closing the 
gate valves again, but the trouble persisted after I had the
gate valves re-opened, so that's likely a red herring. RGA peaks 
at 49 and 50 were high and got worse during the day. For part
of the day the 69 peak was high, but that went away later. CIII
signal was above 0.01 for fizzles, but also for some ok startups.
We only tried ecdc once during the last half of the run, and then 
only for 5minutes, which may not have accomplished much. Given 
the same circumstances again, I would suggest a 20 minute ecdc
session. 

During the L-mode inner wall density scan we experienced difficulty
getting the density down below about nl04=1e20. The gas valve
basically turned off and the plasma fueled from the loaded inner
wall. We got the loading down somewhat by abandoning the ecdc, but
that did seem to lead to an increase in H/D. The combination of
higher density (which did require puffing) and ecdc for 5minutes
did seem to reduce H/D later in the sequence. Shots for the limiter
density scan were 2-14. 

Krypton puffing to destruction of the inner wall discharges 
began with shot#15 and continued through shot#20 (4 plasmas). 

We began trying upper null shots at shot#21 and actually got
the first plasma on #25. This shot was programmed with a slow
(1sec) ramp of SSEP from 0 to +5mm, and actually got to about
SSEP~8mm. On shot #27 we succeeded in getting a long upper null
with SSEP~6mm from .65sec on. This was basically the target used
for the upper null Kr puff shot, which we finally got on shot#31, 
except that we dropped the density from 1.5e20 to 1.0e20 for 
the later shot to help J-port stay on (which it did). Shot 31
is a nice example of a radiative collapse in upper null, which
should give good data for bolo calibration and radiation
evaluation. Shot #32 was an attempt at a lower density case, 
but was completely runaway dominated, and did not make it to
the Kr puff.  Matt reported that for #25 and 27 there was
still Kr around on shots where we did not puff any, which 
is somewhat surprising since I would have expected it to be 
pumped away, especially in view of the multiple fizzles. 
Maybe it's a clue?

On the positive side, upper null operation seemed to be ok,
with no repetition of the multiple injections, "rain of dust"
phenomena encountered during upper and near-double null 
experiments several weeks ago. As near as I can see, the
use of SSEP offset=0 instead of the old value -2500A-m gives
a pretty good result, now that DPCS baseline subtraction is
enabled. 

Scorecard:
----------
     Tests    1
     Duds     3
     Fizzles 11
     Plasmas 17 (including one 0.5sec disrupting runaway)
     ======= ==
     Shots   32




Session Leader Comments
Apr 5 2005 09:16:43:460AM1050405002Martin GreenwaldGood Shot
Limited
nebar ~ 1.6
Prf ~ 1.6 MW
Ip = 1.0
Apr 5 2005 09:37:58:033AM1050405003Martin GreenwaldGood Shot, Limited

nebar ~ 1.5-1.9
Prf ~ 3.3 MW with some faults
Ip = 1.0
Wmhd = 0.10 MJ
H89 = 0.96 using frf = 0.8
Apr 5 2005 09:47:16:397AM1050405004Martin GreenwaldDud
Apr 5 2005 10:03:43:570AM1050405005Martin GreenwaldGood Shot, Limited

nebar ~ 1.6-1.76
Prf ~ 3.0 MW with some faults
Ip = 1.0
Wmhd = 0.10 MJ
H89 = 0.96 using frf = 0.8
Apr 5 2005 10:26:36:470AM1050405006Martin GreenwaldGood Shot, Limited

nebar ~ 1.5-1.6
Prf ~ 3.0 MW with some faults
Ip = 1.0
Wmhd = 0.096 MJ
H89 = 0.94 using frf = 0.8
Apr 5 2005 10:36:12:870AM1050405007Martin GreenwaldDud
Apr 5 2005 10:52:48:850AM1050405008Martin GreenwaldFizzle
Apr 5 2005 11:12:49:920AM1050405009Martin GreenwaldGood Shot, Limited

nebar ~ 2.3
Prf ~ 2.2 MW with lots of faults
Ip = 1.0
Wmhd = 0.085 MJ
H89 = 0.85 using frf = 0.8
Apr 5 2005 11:34:25:520AM1050405010Martin GreenwaldFizzle
Apr 5 2005 11:52:03:697AM1050405011Martin GreenwaldGood Shot, Limited

nebar ~ 2.6
Prf ~ 2.9 MW
Ip = 1.0
Wmhd = 0.092 MJ
H89 = 0.90 using frf = 0.8
Apr 5 2005 12:06:43:863PM1050405012Martin GreenwaldGood Shot, Limited

nebar ~ 2.8
Prf ~ 1.4 MW
Ip = 1.0
Wmhd = 0.074 MJ
H89 = 0.80 using frf = 0.8
Apr 5 2005 12:19:40:050PM1050405013Martin GreenwaldGood Shot, Limited

nebar ~ 3.1
Prf ~ 3.0 MW
Ip = 1.0
Wmhd = 0.093 MJ
H89 = 0.83 using frf = 0.8
Apr 5 2005 12:33:03:527PM1050405014Martin GreenwaldGood Shot, Limited

nebar ~ 3.1
Prf ~ 3.0 MW
Ip = 1.0
Wmhd = 0.095 MJ
H89 = 0.85 using frf = 0.8
Apr 5 2005 12:51:46:517PM1050405015Bruce LipschultzLimited shot with Kr. Disrupted at 1.1 sec.

nebar ~ 2.7
Prf ~ 1.25 MW
Ip = 1.0
Wmhd = 0.08 MJ

The radiated power increases from 1.25 MW to 2.0 before going unstable and screaming up to 3 MW and the disruption. Need more RF power.

Will try again to get better RF matching and move the Kr pulses later in time
Apr 5 2005 01:04:45:490PM1050405016Bruce LipschultzLimited shot with Kr. Disrupted at 1.23 sec.

nebar ~ 2.7
Prf ~ 3.2 MW
Ip = 1.0
Wmhd = 0.08 MJ

Not clear what happened on this shot. The radiation did not go nonlinear. There was a notch in the RF around that time. Take out the notch and try again.
Apr 5 2005 01:32:57:490PM1050405017Bruce Lipschultzfizzle
Apr 5 2005 01:54:47:657PM1050405018Bruce Lipschultz
Limited shot with Kr. Disrupted at 1.31 sec.

nebar ~ 2.7
Prf ~ 3.2 MW
Ip = 1.0
Wmhd = 0.08 MJ

Radiation got to 2.7 MW (4MW on 2Pi) and then it disrupted. Still having issues with McPherson data. One more try.
Apr 5 2005 02:24:10:077PM1050405020Bruce LipschultzLimited shot with Kr. Disrupted at 1.29 sec.

nebar ~ 2.7
Prf ~ 3.2 MW
Ip = 1.0
Wmhd = 0.09 MJ

Radiation got to 2.5 MW (3.6MW on 2Pi) before taking off. McPherson data ok. On to USN plasmas.
Apr 5 2005 02:37:07:520PM1050405021Bruce Lipschultzfizzle
Apr 5 2005 03:37:10:200PM1050405025Bruce LipschultzDN diverted plasma changing to USN.

nebar ~ 2.7
Prf ~ 1.6 MW
Ip = 1.0
Wmhd = 0.07 MJ
PRAD ~ 1MW (foil array)

No Kr injected. McPherson data indicates that there is still Kr around. Next shot change the gaps and get into USN faster. No Kr.
Apr 5 2005 05:03:07:760PM1050405027Bruce LipschultzUSN diverted plasma (SSEP = +0.5)

nebar ~ 2.7
Prf ~ 1.8-3 MW
Ip = 1.0
Wmhd = 0.07-.09 MJ
PRAD ~ 0.8-1.0 MW (foil array)

No Kr injected. Go for the Kr
Apr 5 2005 04:59:23:083PM1050405031Bruce LipschultzUSN diverted plasma (SSEP = +0.5)

nebar ~ 1.7
Prf ~ 3.0 MW
Ip = 1.0
Wmhd = 0.1 MJ
PRAD ~ 2.3MW (foil array)

Kr injected. Good McPherson data
Apr 5 2005 05:06:37:993PM1050405032Bruce LipschultzBad shot. Problems with startup

Physics Operator Comments
Apr 5 2005 07:19:02:117AMSteve Wolfe
Setting up shot 1 for 1050405
Restore 1050405000 which I had saved in ~/pcs_trees yesterday:
has the 1MA limiter program in seg3. 
Import seg1 from 1050401019; this shot ran, but seemed to have
too positive Br0 and Bz, and next two failed.

I'm going to go ahead and try for baseline_sub on first
shot:
RCUR 2000 -> 2500
Br0 -.002-> -.001 (+.0015 for baseline -.0005 adjustment)
IC_OH1 -20000 -> -19600
IC_OH2U -27500 -> -27100
IC_EF1L -6000 -> -5900
IC_EF1U copy from IC_EF1L
IC_EF4U -1345 (unchanged = +10A for baseline -10A adjustment)
Change switch_times from [0.1] -> [-2.1]
Load at  5-Apr-2005 07:18:47.00
Open tree /home/wolfe/pcs_scratch      -1
Open tree done


Apr 5 2005 07:46:20:650AM1050405001Steve Wolfe
Shot#1: test cycle with gas
Went thru ok, after Andy unlocked the state machine. 
Hangs in store on amhd.
baseline jumps in at -2.1sec 
Looking more closely at the magnitudes, I'm seeing
jumps of
RCUR -600
ZCUR +3500
Br0 -.0013
IC_oh1 -420
IC_oh2 -130 **
IC_ef1U -100
IC_ef1L -70
IC_ef2U -10
IC_ef2L -20
IC_ef4u -12

Change waveform for IC_OH2 from -27100 to -27400 (was -27500)
Load at  5-Apr-2005 07:45:48.00
Open tree /home/wolfe/pcs_scratch      -1
Open tree done



Apr 5 2005 09:19:11:157AM1050405002Steve Wolfe
While I'm waiting, change the name on the 
IC_OH2U to IC_OH2 (it's actually the average)
and redo the predictor and controller (there were
two entries at 3.0sec in the old controller)

Still waiting. Import seg2 from 1050330025 to check on pg1 prog.
for SL's step #2.
Load at  5-Apr-2005 08:26:28.00
Open tree /home/wolfe/pcs_scratch      -1
Open tree done
Had to reboot pcdaq1 per instruction from twf;
if it hangs again, I'll turn off amhd in the tree.
Bruce requests 10psi D2 in NINJA

Shot#2: Try for a plasma shot
plasma full length. Baseline subtraction is working in 
startup. MP416 is done. 
Modify the \hybrid::top.config:config_id.
Had some runaways and Bz is a little negative
nl04 looks too high but gas is going off at 0.7sec

Next shot: move switch_time to -3.4sec
IC_ef4u from -1345 to -1335




Apr 5 2005 09:37:04:300AM1050405003Steve Wolfe
shot#3: plasma full length
nl04 is higher, gets to 1.1e20; may need to stop doing 
the ECDC. Give it 5minutes this time, but maybe not do
it next time.

Hards seem to be gone, Bz still looks a little negative,
but leave it for now. 

Apr 5 2005 09:52:45:950AM1050405004Steve Wolfe
shot#4: No changes. 
Dud? Got all the supplies and waited until p0=1.5e-6

next shot: PG4 from 21 to 24ms
IC_ef4 from -1335 to -1325 
No ecdc

Apr 5 2005 10:06:47:903AM1050405005Steve Wolfe
shot#5:PG4 from 21 to 24ms
IC_ef4 from -1335 to -1325 
ECDC off. 

plasma full length
Startup looks ok, but so did 3. 
nl04 down to about 1.0, asking for 0.8
Gas is completely off in seg2!
Next shot: no changes

Apr 5 2005 10:27:07:050AM1050405006Steve Wolfe
shot#6: no changes, except ask for Btop to be topped off to 6psi
and close gate valves in pulse and for 5 minutes after.

plasma to 1.66sec, nl04 at 0.8 before 1sec, then rising. 
Hesitation in startup, pressure went way up, from 
38 to 55 uTorr. Maybe some hards as well. 

next shot: back off on pg4 from 24->22ms


Apr 5 2005 10:37:05:213AM1050405007Steve Wolfe
shot#7:  back off on pg4 from 24->22ms
Dud, I guess I shouldn't have dropped the gas.
Pressure looks the same?

Next shot: go on to 1.5e20

Apr 5 2005 10:54:52:867AM1050405008Steve Wolfe
shot#8: go on to 1.5e20, leave pg4 puff at 22
ecdc back on for 5 minutes (H/D was going up, and so was
Z70_yag). P0 back to 1.5e-6 at ~15minutes.

fizzle. breakdown is early 4.8msec, CIII is high,
pressure=.045mTorr, almost made it, then went in I think.
Br looks a little negative. 

next shot: Br0 up by .0005

Apr 5 2005 11:17:30:510AM1050405009Steve Wolfe
shot#9: go on to 1.5e20, leave pg4 puff at 22
Br0 from -.001 to -.0005
No ecdc this time.
EF4u resistance temp looked high before shot,
but TC's look balanced. Balance ok (-30A) on shot 8.

plasma, marfing like crazy. full length. 
nl04 looks like 1.4e20, D&E aren't too happy.
Startup is fair, we'll ecdc again. 

next shot: slow down early density demand to try 
to reduce Marfe.

Apr 5 2005 11:36:42:973AM1050405010Steve Wolfe
shot#10: slow down early density demand to try 
to reduce Marfe. Practice benign neglect on the startup.

fizzle, needs more practice (or more benign). 
Fields look good to me. Early zcur is claiming to 
be very low, but Br is what I'm asking for.
pressure is .038 or so, which is where we started.
Loses it inside.

next shot: no changes



Apr 5 2005 11:46:09:660AM1050405011Steve Wolfe
shot#11: plasma 
nl04 is 1.5e20, as drawn; marfe went away pretty much.
startup looks ok, pressure is the same as last time.
RF stayed on. 

next shot: nl04 to 2.0e20



Apr 5 2005 12:09:54:720PM1050405012Steve Wolfe
shot#12: nl04 to 2.0e20, ecdc 5 minutes this time. 
wait until 1.3e-6 @17 min.

plasma to 1.45sec, got to 2e20. 
close to railing oh's, I think it did rail oh2l

Next shot: raise oh1, oh2 current limits from -27,-26,-26
to -30,-30,-30

Apr 5 2005 12:20:51:207PM1050405013Steve Wolfe
shot#13: No pcs changes.
raise oh1, oh2 current limits from -27,-26,-26 to -30,-30,-30

plasma to 1.3 sec, LH may have fired after that?
Is there a delay on their fizzle signal?

Next shot: raise nl04 to 2.2e20

Apr 5 2005 12:30:26:857PM1050405014Steve Wolfe
shot#14:  raise nl04 to 2.2e20, reduce pg4 from 22 to 20ms
(previous startup had hesitation)

plasma to 1.3sec again, almost got to 2.2e20.

Next shot: drop nl04 to 1.5e20 and add Kr 

Apr 5 2005 12:46:02:263PM1050405015Steve Wolfe
shot#15:  drop nl04 to 1.5e20 and add Kr 
copy PG1 trace from seg2, previously loaded from 
1050330025 (60ms on every 160ms). Plenum is 1.7psi Kr

plasma to 1.03sec, Prad main climbs to ~2MW, and then
goes non-linear.


Apr 5 2005 01:04:22:567PM1050405016Steve Wolfe
shot#16: Move the pulse train later by 160ms
plasma to 1.22sec, pf breaker pulled.
RF notch was at 1.2sec, so this is a different
case, the RF was on until then, plasma dies right
after RF off

next shot: repeat without notch.
 

Apr 5 2005 01:20:02:333PM1050405017Steve Wolfe
shot#17:  repeat without notch.
Fizzle. Note- we have now closed the gate valve in pulse
also, the oh limits have been changed to -26,-28,-28

pressure is up a little, around .045mTorr this time
probably the gate valve closure. 

next shot: drop pg4 by 1ms

Apr 5 2005 01:52:44:403PM1050405018Steve Wolfe
shot#18: drop pg4 20 to 19ms
plasma to 1.305sec
still a bit of hesitation in startup, 
and lots of hard xrays.
PradMain gets to ~2.5MW, 

next shot: no changes

Apr 5 2005 02:03:26:087PM1050405019Steve Wolfe
shot#19:  no changes
fizzle. breakdown is a little early again,
pressure is up again, around .04mTorr. 
Bz may be creeping up. 
take another ms off pg4, at risk of either dud or more hards


Apr 5 2005 02:24:17:500PM1050405020Steve Wolfe
shot#20:pg4 from 19->18ms  
plasma to 1.28sec

next shot: upper null

Apr 5 2005 02:29:10:660PM1050405021Steve Wolfe
Shot #21: Move on to upper null. 
In segment 4, change ssep offset to 0 from -2500
Program ssep to move from 0 to .005 from .5s to 1.5s
Also zcur to 0 after .5sec, copy nl04 and ip from seg3
zero out pg3 and pg1 puff, turn seg3 off, seg4 on.

fizzle. What happened to "more robust"
pressure is up again? 
next shot: 10A negative on ef4, 1ms off pg4


Apr 5 2005 02:46:27:077PM1050405022Steve Wolfe
Shot #22: ef4 from -1325 to -1335, pg4 from 18ms to 17ms
Another fizz. 
pressure came down to .035mTorr, but Bz is more positive
than before. 

I think I went the wrong way. Reload seg1 from shot 18


Apr 5 2005 02:56:39:690PM1050405023Steve Wolfe
Shot #23: reload seg1 from 18, open gate valves during pulse.
This one may have too positive a Bz, it's two changes old (-1325)
dud. Bz looks fine. Br looks like it has all day.
pressure is ~.030mTorr, too low. 

next shot: ecdc (getting desperate).



Apr 5 2005 03:18:04:583PM1050405024Steve Wolfe
Shot #24: ecdc 5minutes. Also,  somehow I hadn't copied in
 the current; it was still set at 800kA, so it wouldn't 
have been right anyway. Redo that and raise pg4 to 20ms.
wait for p0 to drop to 1.5e-6 (13min)

fizzle. Haven't a clue.
try rcur
 


Apr 5 2005 03:31:53:483PM1050405025Steve Wolfe
Shot #25: rcur from 2500 to 2000 (try to slow down Bz)
 if this doesn't work, go back to #16 

plasma to 1.58sec, SSEP (efit) goes from 0 to 
+.8cm, loses it in rampdown, both gaps get to 2.2cm.
current rise is slow.

next shot: ramp ssep faster. Try to reduce gaps.

Apr 5 2005 03:43:58:747PM1050405026Steve Wolfe
Shot #26: ramp ssep to .004 between .4 and .65sec. 
CLEARIN from -.002 to 0 early, +.002 at 1.5sec
fizzle. Not surprised; that's different though, this one 
bounced. Try reloading seg 1 from 16. 


Apr 5 2005 03:57:39:643PM1050405027Steve Wolfe
Shot #27:Seg 1 from 16 (instead of 18 this time); this
was part of a series of successful starts 11-16.
 
ramp ssep to .004 between .4 and .65sec. 
CLEARIN from -.002 to 0 early, +.002 at 1.5sec
plasma to 1.68sec, gaps are still around 2.2cm
but flatter this time.J-port RF still not happy. F-side pressure
is very high

Drop nl04 to 1.0, and copy in the same Kr puff as before. 


Apr 5 2005 04:14:08:773PM1050405028Steve Wolfe
Shot #28:Drop nl04 to 1.0, and copy in PG1 Kr puff 
from seg 3. I'm tempted to raise the fill on this one, 
since the hards are bad again, but leave it alone.

fizzle. CIII is up a little, current slow again. 
next shot: Try re-calculating the zcur predictors.

Apr 5 2005 04:29:37:903PM1050405029Steve Wolfe
Shot #29:Recalculate the zcur predictors in seg1; they
haven't been changed since before 2002, apparently, since
the version number changed. Of course, neither have the
ones in seg4.
Drop nl04 to 1.0, and copy in PG1 Kr puff from seg 3.

And another fizzle. CIII is up a little more. Doesn't look
like the zcur did much, Br0 is unchanged,
but this was a late breakdown, around 8msec!

reload seg1 from 16 and raise the puff to 23msec


Apr 5 2005 04:40:15:767PM1050405030Steve Wolfe
Shot#30: reload seg1 from 16 and raise the puff to 23msec
Still trying to get an upper null Kr puff shot.
fizzle. Still late breakdown, this one is at 10msec!




Apr 5 2005 04:57:47:113PM1050405031Steve Wolfe
Shot#31: ic_ef4 from -1325 to -1345 (so much for reloads)
Finally, a plasma to 1.34sec
Bolo ramping up to 2.2MW
breakdown back to 4.8ms, runaways are back. 
J stayed on, got nice steady 3MW
That's the shot we've been waiting for. 

next: nl04 down to 0.7


Apr 5 2005 05:14:21:963PM1050405032Steve Wolfe
Shot#32:  nl04 down to 0.7
plasma only to 0.5sec, very bright on wide 2
Bite out of the current at 0.22sec
Lots of runaways, saturated; startup is ratty with
lots of small injections or bounces.
Density seemed to run away, gets to 1.3e20 with no main
 gas puff after 0.33sec. Lots of injections on the zmeter 
signal too. 



Engineering Operator Comments
ShotTimeTypeStatusComment
107:25:42:170AMTestOkShot Cycle Test
209:05:25:430AMPlasmaOkPlasma
309:27:30:283AMPlasmaOk
409:45:36:350AMPlasmaOk
509:59:02:063AMPlasmaOk
610:19:55:430AMPlasmaOk
710:32:33:567AMPlasmaOk
810:50:30:540AMPlasmaOk
911:06:26:730AMPlasmaOk
1011:26:26:707AMPlasmaOk
1111:40:01:943AMPlasmaOk
1212:00:00:347PMPlasmaOk
1312:14:09:773PMPlasmaOk
1412:26:41:343PMPlasmaOk
1512:40:00:493PMPlasmaOk
1612:53:26:610PMPlasmaOk
1701:15:30:317PMPlasmaOk
1801:39:41:280PMPlasmaOk
1901:57:13:120PMPlasmaOk
2002:10:19:817PMPlasmaOk
2102:26:22:030PMPlasmaOk
2202:39:15:050PMPlasmaOk
2302:52:34:000PMPlasmaOk
2403:08:34:390PMPlasmaOk
2503:23:09:510PMPlasmaOk
2603:39:07:977PMPlasmaOk
2703:51:54:213PMPlasmaOk
2804:08:55:270PMPlasmaOk
2904:21:32:990PMPlasmaOk
3004:34:19:877PMPlasmaOk
3104:46:48:620PMPlasmaOk
3205:00:55:053PMPlasmaOk