Alcator C-Mod Run 1051129 Information

Miniproposals

Miniproposal: 419

Date Filed: 4/8/2005

Title: Fiducial wall pumping measurements for comparing operating conditions

First Author: Bruce Lipschultz

Session Leader: Bruce Lipschultz (shots 1-33)

Operators
Session leader(s):	Bruce Lipschultz
Physics operator(s):	Steve Wolfe,Ian Hutchinson
Engineering operator(s):	Bill Cochran,Bill Byford,Ed Fitzgerald

Engineering Operator Run Comment
MP#419 Wall pumping

Session Leader Plans

Entered: Nov 28 2005 05:56:37:517PM

Author: Bruce Lipschultz

SL plan for 1051129
Session Leader: B. Lipschultz

MP #419: 'Fiducial wall pumping measurements for comparing operating conditions'
Parts of this were attempted before. However, the results were muddled by the Ti in the machine and we decided they need to be repeated.

There are several goals for this run:

We are looking for 1 MA shots with densities just under nl04=1.e20. We need the shots not to disrupt through to current reaching close to zero. No RF. Gate valves closed after the first shot or two that go through.

1) We want to return to the standard shot of last run period and see if we can repeat the pumping. This will require several shots (The equilibrium used will be 1051118003). This will mean starting with nl04~0.5. When that is taken, move on to nl04=0.9. Finally, nl04=1.2. (6-8 shots including tuneup).

2) We will be seeing if the wall pumping saturates as well. So this will require at least 5 constant shots. Take this at nl04=1.0. (5 shots).

3) Vary the wetted area to see if that affects the pumping. We will start with LSN on the vertical target (step 1). Then move to slot (e.g. 1050620024), inner wall limited (no success previously). Finally to upper single null (shot 1051118022 for equilibrium). Three shots at each new magnetic equilibrium (12 shots).

4) We would also like to know if the pumping saturates with length of shots (fluence). This will require several shots at verious flattop periods varying from 0. (e.g. 1050805031), 0.5 (e.g. 1050805029), 1.0, 1.5, & 2.0 s (e.g. 1050805028) . The density should be down around 0.85 and the current 0.8 MA. Likely not time enough today.

Physics Operators Plans

Entered: Nov 28 2005 06:35:03:017PM

Author: Steve Wolfe

Physop plan and engineering setup for Tuesday, Nov 29, 2005 MP#419 Wall pumping SL: Blip PO: Wolfe,Hutch ECDC overnight (if no conflict with other activities) and 60C bake. Run begins at 09:00 (lockup at 08:30) and ends at 17:00 Power systems as on 1051118003 A-coil in standard configuration (+Dtop -Dbot -Jtop +Jbot) and enabled Fizzle delay on OH2's set to 300msec. Gas setup: fill B-top 6psi D2 Hybrid Enabled (PG4) fill B-side lower 1psi Argon+2psi Neon, Hybrid Disabled (PG1) leave B-side Upper alone Hybrid DISABLED (PG2) fill B-main 40psi D2 Hybrid Enabled (PG3) Enable: ECE, VUV, Z-bolo shutter. Do not enable DNB TMP#2 gate valve should be closed for the day After the first successful shot, we will want TMP#1 gate valve closed in pulse and for five minutes after the shot for the remainder of the run. NO ICRF for this run. If desired, RF group can test the fix on FMIT#3 HV interlock fault, but no RF into the machine. Plan- See SL_PLAN for goals and reasons. Begin with 1051118003 (1MA, LSN, 5.2T), NL04 reduced to 0.5e20. May raise TF to 5.4T if SL prefers. Proceed to higher densities 0.9 and 1.2e20 Take ~5 shots at constant NL04=1.0e20 Move strike point into slot (program similar to 1050620024). Change to inner wall limited discharge Change to upper null, e.g. 1051118022 (I think this is already in seg3 of 1051118003) If time permits (unlikely), vary Ip flattop duration with Ip=0.8MA, nl04=0.85e20

Session Leader Summaries

Entered: Nov 29 2005 05:58:34:140PM

Author: Bruce Lipschultz

SL summary for 1051129
Session Leader: B. Lipschultz

MP #419: 'Fiducial wall pumping measurements for comparing operating conditions'

The start of the day waqs difficult - primarily computer/CAMAC problems. Then things got going.

We covered a decent fraction of the MP today - primarily the pulselength and saturation question.

Saturation of pumping - shots 11-18 showed that the wall pumping decreasesd over 3-4 shots. This appears to be a combination of changes in amount puffed and gas remaining in the machine. When we did this previously, after the Ti problems last run preiod, the wall pumping seemed to hold more constant. But today we had more shots.

pulselength - The amount puffed certainly decreased with pulselength. However, the amount remaining did to such that the wall pumping did not vary very much. For example the gas injected varied from 30 to 20 tl as the pulselength was decreased. But the amount 'pumped' varied from ~ 8 to 5.5 tl in going from 1.5 to 0.5 current inversion time. It may be that current rise and rampdown are having a largeeer effect on pumping than anticipated.

Other thoughts
- We had a number of cases where we had poloidal detachment during rampdown. I am concerned that this may be affecting things. For example, shot 28 had a MARFE the entire shot. The density was higher than requested and the gas turned off. The wall pumping was 0 on that shot. So MARFEs and poloidal detachment tend to fuel the plasma from somewhere and it seems to be from the wall.

- Varying the equilibrium - particularly inner wall limited seems to have become more important to do.

- The amount pumped at low density is higher than what we have observed before. That is puzzling, particularly since the amount pumped at higher densities drops after repeated shots. This deserves further discussion.

shot gas inj gas remain diff Ip nl04 falttop inversion
2 12.5 5 7.5 1. .5 1.5
4 2.3 16.3 -14 1. .5 1.5 disrupted early
7 13.8 4.7 9 1. .5 1.5
8 12.4 5.3 7.1 1. .6 1.5
9 24.4 9.5 14.9 1. 0.82 1.5
11 29 15.5 4.5 1. 1.0 1.5
13 26.7 16 10.7 1. 1.0 1.5
15 27. 17.3 9.7 1. 1.0 1.5
16 25. 17.5 7.5 1. 1.0 1.5
17 25.3 18.0 7.3 1. 1.0 1.5
18 24.7 17.8 6.9 1. 1.0 1.5
19 31. 23.2 7.8 0.8 1.0 1.5
20 28. 20.3 7.7 0.8 1.0 1.5
21 30.9 22.5 8.4 0.8 1.0 1.5
23 22.6 17.1 5.5 0.8 0.8 0.5 disrupt @200 kA
24 19.6 14.4 5.1 0.8 0.8 0.5 disrupt @200 kA
25 19.1 14.0 5.1 0.8 0.8 0.5 disrupt @110 kA
26 25.5 19.2 6.3 0.8 1.0 1.0 disrupt @300 kA
27 26.4 19.8 6.6 0.8 1.0 1.0 disrupt @110 kA
28 17.3 17.3 0.0 0.8 1.25 1.0 MARFE the entire shot
29 26.9 19.0 7.9 0.8 1.0 1.0 disrupt @250 kA
30 26.7 18.8 7.9 1.0 1.0 1.5
31 24.3 25.5 -1.2 1.0 1.0 1.5 slot divertor 500 kA disruption
32 23.5 15.7 7.8 1.0 1.0 1.5 slot divertor
33 20.2 15.0 5.2 1.0 1.0 1.5 slot divertor

Physics Operator Summaries

Entered: Nov 29 2005 05:20:06:263PM

Author: Ian Hutchinson

Summary
_______

This run, with gate-valves closed after the shot, posed some interesting problems for initiation. The master initiation developed at the start of this campaign was reloaded 1051101023. This is known to be reliable at controlled fill pressure. However, because of the closed gate valves, the fill pressure rises of its own accord because of the outgassing. This is stronger at higher plasma density, of course.

It was found that this initiation cannot support more than about 0.06mtorr of fill without fizzling. We therefore had to pay attention to the outgassing and fill control. Fill puff was lowered in steps to 10ms. Then we were getting approximately half of the fill pressure from the base. The reason this was so high was that when the gate valve is closed at the start of init, the base pressure rises continuously to values on the e-5 scale. This problem was helped by delaying the gate valve closing by 30 into init. We still got one fizzle (22) at 0.048mtorr fill, but at lower pressure things seemed generally more satisfactory and down to .035mtorr was observed to work fine.

The aims of the MP were mostly addressed. There were (as expected by me) problems with ramp-down of short shots, in that they quite often had smallish disruptions before reaching zero current.

Scorecard _________ Shot,Duration(s),Ipmax(MA),Result Shot,Duration(s),Ipmax,Result | 01 0.000 0.024 Dud | 2 No Ip | | 03 0.000 0.002 Dud | 04 0.359 0.826 Plasma | | 05 0.000 0.025 Dud | 06 0.000 0.028 Fizzle | | 07 1.972 1.015 Plasma | 08 1.971 1.010 Plasma | | 09 1.964 1.005 Plasma | 10 0.000 0.024 Fizzle | | 11 1.944 1.002 Plasma | 12 0.000 0.024 Fizzle | | 13 1.927 1.001 Plasma | 14 0.000 0.023 Fizzle | | 15 1.928 1.002 Plasma | 16 1.923 1.001 Plasma | | 17 1.921 1.000 Plasma | 18 1.932 1.001 Plasma | | 19 1.888 0.811 Plasma | 20 1.911 0.815 Plasma | | 21 1.900 0.819 Plasma | 22 0.000 0.025 Fizzle | | 23 0.843 0.809 Plasma | 24 0.868 0.802 Plasma | | 25 0.996 0.797 Plasma | 26 1.345 0.807 Plasma | | 27 1.417 0.804 Plasma | 28 1.394 0.792 Plasma | | 29 1.419 0.806 Plasma | 30 1.934 1.001 Plasma | | 31 1.746 1.048 Plasma | 32 1.953 1.054 Plasma | | 33 1.955 1.057 Plasma Date 1051129: 33 shots. 24 plasmas. 5 fizzles. 3 duds. 1 System Error. (Plasma = Ip gt 50.0 kA Dud = H_alpha lt 0.40 V) Total plasma duration: 39.41 s (exceeding -100 kA)

Session Leader Comments

Nov 29 2005 09:09:06:210AM 1051129001 Bruce Lipschultz dud

Nov 29 2005 10:04:12:333AM 1051129002 Bruce Lipschultz Shot went - sort of. No magnetics (after a very long delay for computer problems). Steve says that we got 1 MA. The density appears wobbly just below nl04=5e20.

Gas injected - 12.5 tl
Gas remaining - ~ 5 tl
Wall pumping 7.5 tl

Nov 29 2005 10:05:20:303AM 1051129003 Bruce Lipschultz test shot for data system

Nov 29 2005 10:36:44:663AM 1051129004 Bruce Lipschultz disrupted early - not useful.

gas injected - 2.3 tl
gas remaining - 16.3 tl
outgassed 14 tl

Nov 29 2005 10:40:10:960AM 1051129005 Bruce Lipschultz dud :-(

Nov 29 2005 10:59:14:943AM 1051129006 Bruce Lipschultz fizzle :-(

Nov 29 2005 11:20:36:490AM 1051129007 Bruce Lipschultz Yes! a 1 MA plasma. nl04 = 0.5e20
gaps a bit small. Will increase.

gas injected - 13.8 tl
gas remaining - 4.6 - 4.9 tl
wall pumping - 9 tl

Nov 29 2005 11:33:44:287AM 1051129008 Bruce Lipschultz 1 MA plasma. nl04 = 0.6e20
gaps ~ 1.5 cm both sides.

gas injected - 12.4 tl
gas remaining - 5.3 tl
wall pumping - 7.1 tl

In the previous run period this density led to lower wall pumping. A bit of a mystery. Move on to higher densities.

Nov 29 2005 11:46:58:570AM 1051129009 Bruce Lipschultz 1 MA plasma. nl04 = 0.82e20

gas injected - 24.4 tl
gas remaining - 9.5 tl
wall pumping - 14.9 tl

Nov 29 2005 11:56:25:070AM 1051129010 Bruce Lipschultz fizzle

Nov 29 2005 12:12:50:320PM 1051129011 Bruce Lipschultz 1 MA plasma. nl04 = 1.e20
Some number of small H-modes

gas injected - 29. tl
gas remaining - 15.5 tl
wall pumping - 14.5 tl

repeat the shot to see if the wall pumping holds constant. We will allow the Ne/Ar mixture in for the next shot.

Nov 29 2005 12:15:41:380PM 1051129012 Bruce Lipschultz fizzle

Nov 29 2005 12:39:18:537PM 1051129013 Bruce Lipschultz 1 MA, nl04=1.e20 repeat to see if wall pumping changes.
More small H-modes

Gas injected - 26.7 tl
gas remaining - 16 tl
wall pumping - 10.7 tl

less than the previous shot!

Nov 29 2005 12:53:49:210PM 1051129014 Bruce Lipschultz fizzle

Nov 29 2005 01:08:42:680PM 1051129015 Bruce Lipschultz 1 MA, nl04=1.0 repeat.

gas injected - 27 tl
gas remaining - 17.3tl
wall pumping - 9.7 tl

slightly less pumping

Nov 29 2005 01:26:08:787PM 1051129016 Bruce Lipschultz 1 MA, nl04=1.0 repeat.
Dithering into H-modes....

gas injected - 25 tl
gas remaining - 17.5tl
wall pumping - 7.5 tl

slightly less pumping. Next shot we are going to reduce the time the gate valcve is closed before the shot in hopes of reducing the timebetween shots (waiting for the pressure in the machine to coem down to the level needed).

Nov 29 2005 04:23:39:890PM 1051129017 Bruce Lipschultz 1 MA, nl04=1.0 repeat.
Dithering into H-modes....

gas injected - 25.3 tl
gas remaining - 18.0 tl
wall pumping - 7.3 tl

Nov 29 2005 01:52:50:803PM 1051129018 Bruce Lipschultz 1 MA, nl04=1.0 repeat.
Dithering into H-modes....

gas injected - 24.7 tl
gas remaining - 17.8tl
wall pumping - 6.9 tl

slightly less pumping. Next shot lower current.

Nov 29 2005 02:07:54:600PM 1051129019 Bruce Lipschultz 0.8 MA, nl04=1.0 to set up for different length shots

gas injected - 31.0 tl
gas remaining - 23.2 tl
wall pumping - 7.8 tl

Nov 29 2005 02:31:22:100PM 1051129020 Bruce Lipschultz 0.8 MA, nl04=1.0 second shot.

gas injected - 28.0 tl
gas remaining - 20.3 tl
wall pumping - 7.7 tl

same as last shot.

Nov 29 2005 02:36:42:977PM 1051129021 Bruce Lipschultz 0.8 MA, nl04=1.0 second shot.

gas injected - 30.9 tl
gas remaining - 22.5 tl
wall pumping - 8.4 tl

similar to last shot.

Nov 29 2005 02:37:48:520PM 1051129022 Bruce Lipschultz fizzle.

Nov 29 2005 03:03:33:630PM 1051129023 Bruce Lipschultz short shot (0.5 s at rampdown. nl04=1.0, Ip=0.8 MA.
Disruption at 200 kA following a 'sharkfin'.

gas injected - 22.6 tl
gas remaining - 17.1 tl
wall pumping - 5.5 tl

try again to get rid of the disruption.

Nov 29 2005 03:17:57:710PM 1051129024 Bruce Lipschultz short shot (0.5 s at rampdown. nl04=1.0, Ip=0.8 MA.
Disruption at 200 kA following a 'sharkfin'.

gas injected - 19.6 tl
gas remaining - 14.4 tl
wall pumping - 5.1 tl

try again to get rid of the disruption.

Nov 29 2005 03:30:54:083PM 1051129025 Bruce Lipschultz short shot (0.5 s at rampdown. nl04=1.0, Ip=0.8 MA.
Disruption at 110 kA.

gas injected - 19.1 tl
gas remaining - 14.0 tl
wall pumping - 5.1 tl

move to longer shots next.

Nov 29 2005 03:43:22:867PM 1051129026 Bruce Lipschultz short shot (1.0 s at rampdown. nl04=1.0, Ip=0.8 MA.
Disruption at 325 kA.

gas injected - 25.5 tl
gas remaining - 19.2 tl
wall pumping - 6.3 tl

try to get rid of the disruption.

Nov 29 2005 04:03:06:877PM 1051129027 Bruce Lipschultz short shot (1.0 s at rampdown. nl04=1.0, Ip=0.8 MA.
dsirupted at 110 kA
gas injected - 26.4 tl
gas remaining - 19.8 tl
wall pumping - 6.6 tl

try to get rid of the disruption.

Nov 29 2005 04:08:59:153PM 1051129028 Bruce Lipschultz short shot (1.0 s at rampdown. nl04=1.25, Ip=0.8 MA.
This one had a problem with density early on. MARFE or something led to higher densities and the gas valve shut.

gas injected - 17.3 tl
gas remaining - 17.3 tl
wall pumping - 0. tl

try to get rid of the disruption and the MARFE.

Nov 29 2005 04:24:56:360PM 1051129029 Bruce Lipschultz 0.8 MA, nl04=1.0 repeat.
sharkfin as before, disrupt at 250 kA.

gas injected - 26.9 tl
gas remaining - 19.0 tl
wall pumping - 7.9 tl

Return to 1 MA

Nov 29 2005 04:37:56:983PM 1051129030 Bruce Lipschultz 1.0 MA, nl04 =1.0e20
rampdown to 90 kA, sharkfin.

start of changes in equilibrium

gas injected - 26.7 tl
gas remaining - 18.8 tl
wall pumping - 7.9 tl

Nov 29 2005 04:50:32:530PM 1051129031 Bruce Lipschultz 1.0 MA, nl04 =1.0e20
switch to slot divertor
disruption at 550 kA

gas injected - 24.3 tl
gas remaining - 25.5 tl
wall pumping - -1.2 tl

Nov 29 2005 05:03:35:047PM 1051129032 Bruce Lipschultz 1.0 MA, nl04 =1.0e20
slot divertor
H-modes (Ar and Ne on the last shot. turned off here)

gas injected - 23.5 tl
gas remaining - 15.7 tl
wall pumping - 7.8 tl

Nov 29 2005 05:19:13:530PM 1051129033 Bruce Lipschultz 1.0 MA, nl04 =1.0e20
slot divertor
H-modes

gas injected - 20.2 tl
gas remaining - 15.0 tl
wall pumping - 5.2 tl

Physics Operator Comments

Nov 29 2005 07:46:21:193AM Steve Wolfe
Setting up for today's blip run (MP419) Slightly weird behavior from PCS: edit wire screen is coming up iconized. X may have gotten confused because my scopes were popping up at the same time. Blow away PCS and restart it. Seems ok now. Notes on current state of startup segment (from 1051123): RCUR offset at 1500a-m Br0=-1e-4 IC_ef4u=-1350 pg4=29msec oh1_volt at 200V from 0.003sec

Nov 29 2005 10:01:36:333AM 1051129001 Steve Wolfe
Shot#1: Contrary to what it says in the run plan, go ahead and close gate valves during pulse for first shot. I'll leave pg4 at 29msec and see what we get. Probably need to reduce it. Dud. Somewhat of a surprise. Bz looks very negative, about -7mT before t=0, despite the fact that I raised it 10A from last week. Br maybe a little higher than normal, but not too bad. Pressure at .065mTorr, a bit higher than last week, as expected. I think the problem is probably the fields. OH2u coax looks ok, ends up below 2uOhm. I think I can afford a few failed startups before we start getting warnings. next shot: ef4 to -1325, br0 more negative

Nov 29 2005 10:01:06:100AM 1051129002 Steve Wolfe
Shot#2: ef4 from -1340 to -1325, br0 from 0 to -.0003 Leave gas and oh voltage where they were and try again Long delay while Tom clears a problem with an LH store action. I have set the .LH node /noinclude for shot 2 and following. Plasma full length. Breakdown a little late (9msec) No magnetics signals this time. Looks like we had a lot of runaways, but they seem to develop late. No density trace yet, because it waits for the current, but I think the density was very low. Rick ran it manually; it is between 4 and 5e19 and has some oscillations, also seen on the halpha Magnetics data is toast. I'll have to reboot pcdaqmhd1 in the cell next shot: no changes.

Nov 29 2005 10:06:29:320AM 1051129003 Steve Wolfe
Shot#3: Take a no power shot at twf's request/suggestion after rebooting pcdaqmhd1. Ian is back and I'm logging out.

Nov 29 2005 11:38:30:070AM 1051129004 Ian Hutchinson Disrupts at .35s. Not completely clear why, but density is low. Might be a
locked mode at about 3.2s, certainly there is a very resistive event.

Add some gas in segment 2 early.

Nov 29 2005 11:38:58:100AM 1051129005 Ian Hutchinson Dud.

Remove -.3mT Br offset.
Load OH1V from 1050525002.

Nov 29 2005 11:39:57:710AM 1051129006 Ian Hutchinson Fizzle.

Load segment 1 from 1051101023. There's a problem with the wire name changes.
Reload segment 1 from shot 6. OK. Reload segment 1 from 1051101023. It works
this time!!!

Nov 29 2005 11:40:30:210AM 1051129007 Ian Hutchinson Plasma to rampdown. Gaps are 1.25cm, and 1cm inner outer.

Add PG3 Voltage at .1s.
Set nl04 to .6 throughout.
Blip calls for 1.5,1.5cm gaps. This needs 2mm increase in clearin, and
1 mm reduction in rcur. Done. Load.

Nov 29 2005 11:41:05:007AM 1051129008 Ian Hutchinson Plasma to rampdown.

nl04 maybe to .85e20. Yes. Loaded.

Nov 29 2005 11:49:02:537AM 1051129009 Ian Hutchinson Plasma to rampdown.

nl04 to 1.e20 maybe. Yes. Load

Nov 29 2005 12:29:36:740PM 1051129010 Ian Hutchinson Fizzle. Actual breakdown pressure has risen from .05 to .07 because of the residual gas.

Lower fill puff to 18ms from 21ms. (Trouble is that this fizzle will cause the fill to be lower on its own.)

Nov 29 2005 12:15:37:507PM 1051129011 Ian Hutchinson Plasma.

Set Ar/Ne puff to 30ms (from 50) enable for next shot. Load.

Nov 29 2005 12:28:30:240PM 1051129012 Ian Hutchinson Fizzle. Actual fill .065. Started init at 2.5e6. Seems too early.

EF4 to -1320A from -1325. Tweak to hope that we could avoid the fizzles caused by high base pressure. Was about 1.4e6 at init start.

Nov 29 2005 12:55:18:820PM 1051129013 Ian Hutchinson Plasma to rampdown.

Reduce fill puff to 16ms. Enter init at 2.5e-6. 1.13-5 entering pulse.

Nov 29 2005 12:55:50:163PM 1051129014 Ian Hutchinson Fizzle. Enter init at 2.5e-6. 1.13-5 entering pulse. 0.06mtorr at breakdown.
Plainly it does not like having the base pressure so high. Apparently there
is only one pump running at the moment.

No pcs changes. Disable VUV gate valve.

Nov 29 2005 01:12:10:693PM 1051129015 Ian Hutchinson Plasma.
Was 1.2e-6 entering init. entering pulse: 5.8e-6.

Lower fill puff to 14ms.
Wait for base pressure to reach 2.0e6 before init (14 min)

Nov 29 2005 01:26:09:053PM 1051129016 Ian Hutchinson Plasma to rampdown.
Pressure at pulse. 9.5e6 at pulse. 0.053mtorr total fill. Looks as if it only just went.

Lower fill puff to 12ms. PLC change to make the gate valve close 30seconds later.
Since the total of init and check is roughly 120sec, we reduce the pressure increase by about 25%. We will allow ourselves a higher level at enter init correspondingly. 2.3e-6, time 12min20s.

Nov 29 2005 01:33:50:490PM 1051129016 Ian Hutchinson Plasma to rampdown.
Pressure at pulse. 9.5e6 at pulse. 0.053mtorr total fill. Looks as if it only just went.

Lower fill puff to 12ms. PLC change to make the gate valve close 30seconds later.
Since the total of init and check is roughly 120sec, we reduce the pressure increase by about 25%. We will allow ourselves a higher level at enter init correspondingly. 2.3e-6, time 12min20s.

Nov 29 2005 01:39:30:897PM 1051129017 Ian Hutchinson Plasma to rampdown.
Got Pressure at check: 6.2e-6. Pressure at pulse: 9.5e-6. Fill 0.048mtorr.

Fill puff to 10ms. Go to init at 2.6e-6, 11min.

Nov 29 2005 01:52:57:790PM 1051129018 Ian Hutchinson Plasma.
Got: Pulse at 1.e-5. 0.045mtorr.

Lower Ip to 1MA. Go to init at 2.8e-6, 10:15min.

Nov 29 2005 02:07:05:727PM 1051129019 Ian Hutchinson Plasma.
Got Pulse at 1.1e-5. Fill 0.049mtorr.

Move Rcur in 1mm. Adjust the rxl ramp to help keep the strikepoint lower.
Go to init at 2.7e-6, 11min.

Nov 29 2005 02:24:23:630PM 1051129020 Ian Hutchinson Plasma.
Got 1.1e-5 at pulse. Fill 0.047mtorr.

Tweak rxl in more at the end of the shot. Init at 2.3, 13m because of cooling delay.

Nov 29 2005 02:37:43:320PM 1051129021 Ian Hutchinson Plasma.
Got 9.3e-6 at pulse. Fill 0.043mtorr.

Shorten shot to rampdown at 0.5s, using all Ps but no V-changes in segment 3.
Forgot to switch segments.
Enter init at 2.7e-6. Pulse at 1.1e-5.

Nov 29 2005 02:58:22:490PM 1051129022 Ian Hutchinson Fizzle. Fill 0.048 can't be blamed on completely on fill pressure.

Switch segments to the short shot.

Nov 29 2005 03:02:54:193PM 1051129023 Ian Hutchinson Plasma flat-top only to 0.5s. Small terminating disruption. Fill 0.036mtorr.

Reduce the rcur swing inward. Raise nl04 earlier to make the gas puff earlier.
Ramp Bt down earlier.

Nov 29 2005 03:22:30:350PM 1051129024 Ian Hutchinson Plasma.
Got Pulse at 9.1e-6

Similar ramp-down disruption. Seems to be caused by OH1 going to zero and sticking at cross-over. This causes a wild increase in clearin.
Try ramping down slower.

Nov 29 2005 03:31:24:727PM 1051129025 Ian Hutchinson Plasma disrupts at 1s, 100kA. Bruce says good enough.

Program end of flattop at 1s. Enter init at 2.3e-6.

Nov 29 2005 03:53:08:350PM 1051129026 Ian Hutchinson Plasma. Disrupts at 300kA. I forgot to lengthen the Bt pulse so it began
to ramp down early.
Got pulse pressure: 9.5e-6. 0.043mtorr.

Delay Bt rampdown.

Nov 29 2005 03:59:46:770PM 1051129027 Ian Hutchinson Plasma disrupts at about 100kA.

Make nl04 rampdown earlier. Slow Ip ramp down. Adjust other aspects of ramp down.

Nov 29 2005 04:15:00:157PM 1051129028 Ian Hutchinson Plasma. Disrupts at 320kA. But also this shot had radiative events early which look like marfes or similar.

Delay the ramp up of nl04 to 1.e20 at .3s.

Nov 29 2005 04:32:21:030PM 1051129029 Ian Hutchinson Plasma. Disrupts at about 300kA.

Load from shot 18. Load.

Nov 29 2005 04:38:31:670PM 1051129030 Ian Hutchinson Plasma.

Load segment 2 from 1050620024.
Call all controllers.

Nov 29 2005 04:50:20:937PM 1051129031 Ian Hutchinson Plasma.

Slow EF4 inversion ramp. Disable Ar/Ne pulse which was large.

Nov 29 2005 05:01:00:937PM 1051129032 Ian Hutchinson Plasma. Ramped down. Got many ohmic H-modes.

Slow EF4 rampdown some more.

Nov 29 2005 05:18:40:470PM 1051129033 Ian Hutchinson Plasma. Very similar.

Engineering Operator Comments

Shot Time Type Status Comment

1 09:05:22:587AM Plasma Ok

2 09:40:11:537AM Plasma Ok

3 10:03:46:380AM Test Ok No power data system test shot

4 10:18:06:397AM Plasma Bad OH1 Type 1 Flt

5 10:36:49:897AM Plasma Ok

6 10:49:37:710AM Plasma Ok

7 11:07:13:553AM Plasma Ok

8 11:20:31:413AM Plasma Ok

9 11:34:10:693AM Plasma Ok

10 11:47:36:570AM Plasma Ok

11 12:00:17:303PM Plasma Ok

12 12:13:50:537PM Plasma Ok

13 12:26:20:413PM Plasma Ok

14 12:40:42:037PM Plasma Ok

15 12:55:25:473PM Plasma Ok

16 01:11:58:257PM Plasma Ok

17 01:26:42:820PM Plasma Ok

18 01:40:37:770PM Plasma Ok

19 01:53:19:617PM Plasma Ok

20 02:06:57:083PM Plasma Ok

21 02:22:36:147PM Plasma Ok

22 02:35:50:973PM Plasma Ok

23 02:48:19:240PM Plasma Ok

24 03:02:10:180PM Plasma Ok

25 03:17:20:880PM Plasma Ok

26 03:30:44:257PM Plasma Ok

27 03:43:24:083PM Plasma Ok

28 03:56:19:913PM Plasma Ok

29 04:11:29:043PM Test Ok

30 04:24:21:843PM Test Ok

31 04:37:01:483PM Test Ok

32 04:50:56:030PM Test Ok

33 05:03:30:123PM Test Ok

Session Leader Comments
Nov 29 2005 09:09:06:210AM	1051129001	Bruce Lipschultz	dud
Nov 29 2005 10:04:12:333AM	1051129002	Bruce Lipschultz	Shot went - sort of. No magnetics (after a very long delay for computer problems). Steve says that we got 1 MA. The density appears wobbly just below nl04=5e20. Gas injected - 12.5 tl Gas remaining - ~ 5 tl Wall pumping 7.5 tl
Nov 29 2005 10:05:20:303AM	1051129003	Bruce Lipschultz	test shot for data system
Nov 29 2005 10:36:44:663AM	1051129004	Bruce Lipschultz	disrupted early - not useful. gas injected - 2.3 tl gas remaining - 16.3 tl outgassed 14 tl
Nov 29 2005 10:40:10:960AM	1051129005	Bruce Lipschultz	dud :-(
Nov 29 2005 10:59:14:943AM	1051129006	Bruce Lipschultz	fizzle :-(
Nov 29 2005 11:20:36:490AM	1051129007	Bruce Lipschultz	Yes! a 1 MA plasma. nl04 = 0.5e20 gaps a bit small. Will increase. gas injected - 13.8 tl gas remaining - 4.6 - 4.9 tl wall pumping - 9 tl
Nov 29 2005 11:33:44:287AM	1051129008	Bruce Lipschultz	1 MA plasma. nl04 = 0.6e20 gaps ~ 1.5 cm both sides. gas injected - 12.4 tl gas remaining - 5.3 tl wall pumping - 7.1 tl In the previous run period this density led to lower wall pumping. A bit of a mystery. Move on to higher densities.
Nov 29 2005 11:46:58:570AM	1051129009	Bruce Lipschultz	1 MA plasma. nl04 = 0.82e20 gas injected - 24.4 tl gas remaining - 9.5 tl wall pumping - 14.9 tl
Nov 29 2005 11:56:25:070AM	1051129010	Bruce Lipschultz	fizzle
Nov 29 2005 12:12:50:320PM	1051129011	Bruce Lipschultz	1 MA plasma. nl04 = 1.e20 Some number of small H-modes gas injected - 29. tl gas remaining - 15.5 tl wall pumping - 14.5 tl repeat the shot to see if the wall pumping holds constant. We will allow the Ne/Ar mixture in for the next shot.
Nov 29 2005 12:15:41:380PM	1051129012	Bruce Lipschultz	fizzle
Nov 29 2005 12:39:18:537PM	1051129013	Bruce Lipschultz	1 MA, nl04=1.e20 repeat to see if wall pumping changes. More small H-modes Gas injected - 26.7 tl gas remaining - 16 tl wall pumping - 10.7 tl less than the previous shot!
Nov 29 2005 12:53:49:210PM	1051129014	Bruce Lipschultz	fizzle
Nov 29 2005 01:08:42:680PM	1051129015	Bruce Lipschultz	1 MA, nl04=1.0 repeat. gas injected - 27 tl gas remaining - 17.3tl wall pumping - 9.7 tl slightly less pumping
Nov 29 2005 01:26:08:787PM	1051129016	Bruce Lipschultz	1 MA, nl04=1.0 repeat. Dithering into H-modes.... gas injected - 25 tl gas remaining - 17.5tl wall pumping - 7.5 tl slightly less pumping. Next shot we are going to reduce the time the gate valcve is closed before the shot in hopes of reducing the timebetween shots (waiting for the pressure in the machine to coem down to the level needed).
Nov 29 2005 04:23:39:890PM	1051129017	Bruce Lipschultz	1 MA, nl04=1.0 repeat. Dithering into H-modes.... gas injected - 25.3 tl gas remaining - 18.0 tl wall pumping - 7.3 tl
Nov 29 2005 01:52:50:803PM	1051129018	Bruce Lipschultz	1 MA, nl04=1.0 repeat. Dithering into H-modes.... gas injected - 24.7 tl gas remaining - 17.8tl wall pumping - 6.9 tl slightly less pumping. Next shot lower current.
Nov 29 2005 02:07:54:600PM	1051129019	Bruce Lipschultz	0.8 MA, nl04=1.0 to set up for different length shots gas injected - 31.0 tl gas remaining - 23.2 tl wall pumping - 7.8 tl
Nov 29 2005 02:31:22:100PM	1051129020	Bruce Lipschultz	0.8 MA, nl04=1.0 second shot. gas injected - 28.0 tl gas remaining - 20.3 tl wall pumping - 7.7 tl same as last shot.
Nov 29 2005 02:36:42:977PM	1051129021	Bruce Lipschultz	0.8 MA, nl04=1.0 second shot. gas injected - 30.9 tl gas remaining - 22.5 tl wall pumping - 8.4 tl similar to last shot.
Nov 29 2005 02:37:48:520PM	1051129022	Bruce Lipschultz	fizzle.
Nov 29 2005 03:03:33:630PM	1051129023	Bruce Lipschultz	short shot (0.5 s at rampdown. nl04=1.0, Ip=0.8 MA. Disruption at 200 kA following a 'sharkfin'. gas injected - 22.6 tl gas remaining - 17.1 tl wall pumping - 5.5 tl try again to get rid of the disruption.
Nov 29 2005 03:17:57:710PM	1051129024	Bruce Lipschultz	short shot (0.5 s at rampdown. nl04=1.0, Ip=0.8 MA. Disruption at 200 kA following a 'sharkfin'. gas injected - 19.6 tl gas remaining - 14.4 tl wall pumping - 5.1 tl try again to get rid of the disruption.
Nov 29 2005 03:30:54:083PM	1051129025	Bruce Lipschultz	short shot (0.5 s at rampdown. nl04=1.0, Ip=0.8 MA. Disruption at 110 kA. gas injected - 19.1 tl gas remaining - 14.0 tl wall pumping - 5.1 tl move to longer shots next.
Nov 29 2005 03:43:22:867PM	1051129026	Bruce Lipschultz	short shot (1.0 s at rampdown. nl04=1.0, Ip=0.8 MA. Disruption at 325 kA. gas injected - 25.5 tl gas remaining - 19.2 tl wall pumping - 6.3 tl try to get rid of the disruption.
Nov 29 2005 04:03:06:877PM	1051129027	Bruce Lipschultz	short shot (1.0 s at rampdown. nl04=1.0, Ip=0.8 MA. dsirupted at 110 kA gas injected - 26.4 tl gas remaining - 19.8 tl wall pumping - 6.6 tl try to get rid of the disruption.
Nov 29 2005 04:08:59:153PM	1051129028	Bruce Lipschultz	short shot (1.0 s at rampdown. nl04=1.25, Ip=0.8 MA. This one had a problem with density early on. MARFE or something led to higher densities and the gas valve shut. gas injected - 17.3 tl gas remaining - 17.3 tl wall pumping - 0. tl try to get rid of the disruption and the MARFE.
Nov 29 2005 04:24:56:360PM	1051129029	Bruce Lipschultz	0.8 MA, nl04=1.0 repeat. sharkfin as before, disrupt at 250 kA. gas injected - 26.9 tl gas remaining - 19.0 tl wall pumping - 7.9 tl Return to 1 MA
Nov 29 2005 04:37:56:983PM	1051129030	Bruce Lipschultz	1.0 MA, nl04 =1.0e20 rampdown to 90 kA, sharkfin. start of changes in equilibrium gas injected - 26.7 tl gas remaining - 18.8 tl wall pumping - 7.9 tl
Nov 29 2005 04:50:32:530PM	1051129031	Bruce Lipschultz	1.0 MA, nl04 =1.0e20 switch to slot divertor disruption at 550 kA gas injected - 24.3 tl gas remaining - 25.5 tl wall pumping - -1.2 tl
Nov 29 2005 05:03:35:047PM	1051129032	Bruce Lipschultz	1.0 MA, nl04 =1.0e20 slot divertor H-modes (Ar and Ne on the last shot. turned off here) gas injected - 23.5 tl gas remaining - 15.7 tl wall pumping - 7.8 tl
Nov 29 2005 05:19:13:530PM	1051129033	Bruce Lipschultz	1.0 MA, nl04 =1.0e20 slot divertor H-modes gas injected - 20.2 tl gas remaining - 15.0 tl wall pumping - 5.2 tl

Physics Operator Comments
Nov 29 2005 07:46:21:193AM		Steve Wolfe	Setting up for today's blip run (MP419) Slightly weird behavior from PCS: edit wire screen is coming up iconized. X may have gotten confused because my scopes were popping up at the same time. Blow away PCS and restart it. Seems ok now. Notes on current state of startup segment (from 1051123): RCUR offset at 1500a-m Br0=-1e-4 IC_ef4u=-1350 pg4=29msec oh1_volt at 200V from 0.003sec
Nov 29 2005 10:01:36:333AM	1051129001	Steve Wolfe	Shot#1: Contrary to what it says in the run plan, go ahead and close gate valves during pulse for first shot. I'll leave pg4 at 29msec and see what we get. Probably need to reduce it. Dud. Somewhat of a surprise. Bz looks very negative, about -7mT before t=0, despite the fact that I raised it 10A from last week. Br maybe a little higher than normal, but not too bad. Pressure at .065mTorr, a bit higher than last week, as expected. I think the problem is probably the fields. OH2u coax looks ok, ends up below 2uOhm. I think I can afford a few failed startups before we start getting warnings. next shot: ef4 to -1325, br0 more negative
Nov 29 2005 10:01:06:100AM	1051129002	Steve Wolfe	Shot#2: ef4 from -1340 to -1325, br0 from 0 to -.0003 Leave gas and oh voltage where they were and try again Long delay while Tom clears a problem with an LH store action. I have set the .LH node /noinclude for shot 2 and following. Plasma full length. Breakdown a little late (9msec) No magnetics signals this time. Looks like we had a lot of runaways, but they seem to develop late. No density trace yet, because it waits for the current, but I think the density was very low. Rick ran it manually; it is between 4 and 5e19 and has some oscillations, also seen on the halpha Magnetics data is toast. I'll have to reboot pcdaqmhd1 in the cell next shot: no changes.
Nov 29 2005 10:06:29:320AM	1051129003	Steve Wolfe	Shot#3: Take a no power shot at twf's request/suggestion after rebooting pcdaqmhd1. Ian is back and I'm logging out.
Nov 29 2005 11:38:30:070AM	1051129004	Ian Hutchinson	Disrupts at .35s. Not completely clear why, but density is low. Might be a locked mode at about 3.2s, certainly there is a very resistive event. Add some gas in segment 2 early.
Nov 29 2005 11:38:58:100AM	1051129005	Ian Hutchinson	Dud. Remove -.3mT Br offset. Load OH1V from 1050525002.
Nov 29 2005 11:39:57:710AM	1051129006	Ian Hutchinson	Fizzle. Load segment 1 from 1051101023. There's a problem with the wire name changes. Reload segment 1 from shot 6. OK. Reload segment 1 from 1051101023. It works this time!!!
Nov 29 2005 11:40:30:210AM	1051129007	Ian Hutchinson	Plasma to rampdown. Gaps are 1.25cm, and 1cm inner outer. Add PG3 Voltage at .1s. Set nl04 to .6 throughout. Blip calls for 1.5,1.5cm gaps. This needs 2mm increase in clearin, and 1 mm reduction in rcur. Done. Load.
Nov 29 2005 11:41:05:007AM	1051129008	Ian Hutchinson	Plasma to rampdown. nl04 maybe to .85e20. Yes. Loaded.
Nov 29 2005 11:49:02:537AM	1051129009	Ian Hutchinson	Plasma to rampdown. nl04 to 1.e20 maybe. Yes. Load
Nov 29 2005 12:29:36:740PM	1051129010	Ian Hutchinson	Fizzle. Actual breakdown pressure has risen from .05 to .07 because of the residual gas. Lower fill puff to 18ms from 21ms. (Trouble is that this fizzle will cause the fill to be lower on its own.)
Nov 29 2005 12:15:37:507PM	1051129011	Ian Hutchinson	Plasma. Set Ar/Ne puff to 30ms (from 50) enable for next shot. Load.
Nov 29 2005 12:28:30:240PM	1051129012	Ian Hutchinson	Fizzle. Actual fill .065. Started init at 2.5e6. Seems too early. EF4 to -1320A from -1325. Tweak to hope that we could avoid the fizzles caused by high base pressure. Was about 1.4e6 at init start.
Nov 29 2005 12:55:18:820PM	1051129013	Ian Hutchinson	Plasma to rampdown. Reduce fill puff to 16ms. Enter init at 2.5e-6. 1.13-5 entering pulse.
Nov 29 2005 12:55:50:163PM	1051129014	Ian Hutchinson	Fizzle. Enter init at 2.5e-6. 1.13-5 entering pulse. 0.06mtorr at breakdown. Plainly it does not like having the base pressure so high. Apparently there is only one pump running at the moment. No pcs changes. Disable VUV gate valve.
Nov 29 2005 01:12:10:693PM	1051129015	Ian Hutchinson	Plasma. Was 1.2e-6 entering init. entering pulse: 5.8e-6. Lower fill puff to 14ms. Wait for base pressure to reach 2.0e6 before init (14 min)
Nov 29 2005 01:26:09:053PM	1051129016	Ian Hutchinson	Plasma to rampdown. Pressure at pulse. 9.5e6 at pulse. 0.053mtorr total fill. Looks as if it only just went. Lower fill puff to 12ms. PLC change to make the gate valve close 30seconds later. Since the total of init and check is roughly 120sec, we reduce the pressure increase by about 25%. We will allow ourselves a higher level at enter init correspondingly. 2.3e-6, time 12min20s.
Nov 29 2005 01:33:50:490PM	1051129016	Ian Hutchinson	Plasma to rampdown. Pressure at pulse. 9.5e6 at pulse. 0.053mtorr total fill. Looks as if it only just went. Lower fill puff to 12ms. PLC change to make the gate valve close 30seconds later. Since the total of init and check is roughly 120sec, we reduce the pressure increase by about 25%. We will allow ourselves a higher level at enter init correspondingly. 2.3e-6, time 12min20s.
Nov 29 2005 01:39:30:897PM	1051129017	Ian Hutchinson	Plasma to rampdown. Got Pressure at check: 6.2e-6. Pressure at pulse: 9.5e-6. Fill 0.048mtorr. Fill puff to 10ms. Go to init at 2.6e-6, 11min.
Nov 29 2005 01:52:57:790PM	1051129018	Ian Hutchinson	Plasma. Got: Pulse at 1.e-5. 0.045mtorr. Lower Ip to 1MA. Go to init at 2.8e-6, 10:15min.
Nov 29 2005 02:07:05:727PM	1051129019	Ian Hutchinson	Plasma. Got Pulse at 1.1e-5. Fill 0.049mtorr. Move Rcur in 1mm. Adjust the rxl ramp to help keep the strikepoint lower. Go to init at 2.7e-6, 11min.
Nov 29 2005 02:24:23:630PM	1051129020	Ian Hutchinson	Plasma. Got 1.1e-5 at pulse. Fill 0.047mtorr. Tweak rxl in more at the end of the shot. Init at 2.3, 13m because of cooling delay.
Nov 29 2005 02:37:43:320PM	1051129021	Ian Hutchinson	Plasma. Got 9.3e-6 at pulse. Fill 0.043mtorr. Shorten shot to rampdown at 0.5s, using all Ps but no V-changes in segment 3. Forgot to switch segments. Enter init at 2.7e-6. Pulse at 1.1e-5.
Nov 29 2005 02:58:22:490PM	1051129022	Ian Hutchinson	Fizzle. Fill 0.048 can't be blamed on completely on fill pressure. Switch segments to the short shot.
Nov 29 2005 03:02:54:193PM	1051129023	Ian Hutchinson	Plasma flat-top only to 0.5s. Small terminating disruption. Fill 0.036mtorr. Reduce the rcur swing inward. Raise nl04 earlier to make the gas puff earlier. Ramp Bt down earlier.
Nov 29 2005 03:22:30:350PM	1051129024	Ian Hutchinson	Plasma. Got Pulse at 9.1e-6 Similar ramp-down disruption. Seems to be caused by OH1 going to zero and sticking at cross-over. This causes a wild increase in clearin. Try ramping down slower.
Nov 29 2005 03:31:24:727PM	1051129025	Ian Hutchinson	Plasma disrupts at 1s, 100kA. Bruce says good enough. Program end of flattop at 1s. Enter init at 2.3e-6.
Nov 29 2005 03:53:08:350PM	1051129026	Ian Hutchinson	Plasma. Disrupts at 300kA. I forgot to lengthen the Bt pulse so it began to ramp down early. Got pulse pressure: 9.5e-6. 0.043mtorr. Delay Bt rampdown.
Nov 29 2005 03:59:46:770PM	1051129027	Ian Hutchinson	Plasma disrupts at about 100kA. Make nl04 rampdown earlier. Slow Ip ramp down. Adjust other aspects of ramp down.
Nov 29 2005 04:15:00:157PM	1051129028	Ian Hutchinson	Plasma. Disrupts at 320kA. But also this shot had radiative events early which look like marfes or similar. Delay the ramp up of nl04 to 1.e20 at .3s.
Nov 29 2005 04:32:21:030PM	1051129029	Ian Hutchinson	Plasma. Disrupts at about 300kA. Load from shot 18. Load.
Nov 29 2005 04:38:31:670PM	1051129030	Ian Hutchinson	Plasma. Load segment 2 from 1050620024. Call all controllers.
Nov 29 2005 04:50:20:937PM	1051129031	Ian Hutchinson	Plasma. Slow EF4 inversion ramp. Disable Ar/Ne pulse which was large.
Nov 29 2005 05:01:00:937PM	1051129032	Ian Hutchinson	Plasma. Ramped down. Got many ohmic H-modes. Slow EF4 rampdown some more.
Nov 29 2005 05:18:40:470PM	1051129033	Ian Hutchinson	Plasma. Very similar.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:05:22:587AM	Plasma	Ok
2	09:40:11:537AM	Plasma	Ok
3	10:03:46:380AM	Test	Ok	No power data system test shot
4	10:18:06:397AM	Plasma	Bad	OH1 Type 1 Flt
5	10:36:49:897AM	Plasma	Ok
6	10:49:37:710AM	Plasma	Ok
7	11:07:13:553AM	Plasma	Ok
8	11:20:31:413AM	Plasma	Ok
9	11:34:10:693AM	Plasma	Ok
10	11:47:36:570AM	Plasma	Ok
11	12:00:17:303PM	Plasma	Ok
12	12:13:50:537PM	Plasma	Ok
13	12:26:20:413PM	Plasma	Ok
14	12:40:42:037PM	Plasma	Ok
15	12:55:25:473PM	Plasma	Ok
16	01:11:58:257PM	Plasma	Ok
17	01:26:42:820PM	Plasma	Ok
18	01:40:37:770PM	Plasma	Ok
19	01:53:19:617PM	Plasma	Ok
20	02:06:57:083PM	Plasma	Ok
21	02:22:36:147PM	Plasma	Ok
22	02:35:50:973PM	Plasma	Ok
23	02:48:19:240PM	Plasma	Ok
24	03:02:10:180PM	Plasma	Ok
25	03:17:20:880PM	Plasma	Ok
26	03:30:44:257PM	Plasma	Ok
27	03:43:24:083PM	Plasma	Ok
28	03:56:19:913PM	Plasma	Ok
29	04:11:29:043PM	Test	Ok
30	04:24:21:843PM	Test	Ok
31	04:37:01:483PM	Test	Ok
32	04:50:56:030PM	Test	Ok
33	05:03:30:123PM	Test	Ok