Alcator C-Mod Run 1050621 Information

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Miniproposals
Miniproposal:415
Date Filed: 2/24/2005
Title:Rotation and H-mode Power Threshold for LSN and USN at Different IP and ne
First Author:John Rice
Session Leader:John Rice (shots 1-33)

Operators
Session leader(s):John Rice
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Cochran,Bill Parkin

Engineering Operator Run Comment
MP #415

Session Leader Plans
Entered: Jun 20 2005 01:33:51:640PM
Author: John Rice
MP 415

First touch base with earlier results at 0.8 MA. Load 1050614026 with 470 kW ICRF power. If this
goes into H-mode, repeat with 400 kW ICRF to confirm the H-mode threshold from 1050614. If this
first shot is L-mode, repeat with 550 kW to get H-mode threshold. Once the threshold is determined,
go to USN and determine the threshold, initially with a power ramp (probably up to 3 MW) to get the
rough value, then two shots with flat RF waveforms, above and below the threshold (within 200 kW).
Repeat this procedure at 0.6 MA, nl04 of 1.0, with both LSN and USN, and then at 1.0 MA. Next
repeat at these three currents, LSN and USN, at nl04 of 0.8.

Inner wall probe, HIREX and any other velocity diagnostics would be nice, including edge Thomson.
1.5 psi argon.

for USN, try 1050427021, unless there is a better recent favorite.

Physics Operators Plans
Entered: Jun 20 2005 03:02:35:043PM
Author: Steve Wolfe
Physics Operator Plan for Tuesday, 21-Jun-2005

MP#415 Rotation and H-mode threshold
SL: Rice
PO: wolfe

NO ECDC
Overnight bake at 60C
Run begins at 09:00 and ends at 17:00

Power systems as on 1050614026
Acoil configuration: standard  [+Dtop -Dbot -Jtop +Jbot] and enabled,
C-coil Start=0.3sec, Invert=2.0 sec

Gas Setup:
-----------
fill B-top with 6psi D2 HYBRID Enabled (PG4)
fill B-side lower with 1.5 psi Argon HYBRID Enabled (PG1)
fill B-Main with 30psi D2 HYBRID Enabled (PG3)
Leave B-side upper as is, HYBRID DISABLED (PG2)
NINJA not used 

Enable ECE, VUV and Z-bolo shutter (assuming no vacuum problems).
Torus Pumping Gate Valves NOT CLOSED during pulse

ICRF Setup: all transmitters in RUN ON at 08:30
-------------------------------------------------------
Run Plan: 
---------
1) Start with a re-run of 1050614026, nl04=1.0, 0.8MA and check threshold
2) Repeat with Upper Null ,e.g. 1050427021 and ICRF ramp, then refine threshold
3) Change current to 0.6MA, nl04=1.0, LSN
4) At 0.6MA change to USN 
5) Change current to 1MA, Lower then upper null
6) Reduce density and repeat 3 current values. 

Session Leader Summaries
Entered: Jun 21 2005 05:28:37:737PM
Author: John Rice
Session Leader Run Summary for 1050621 MP415 Rotation and H-mode Power Threshold

This run was successful in determining the core rotation velocity and H-mode power threshold
for both LSN and USN discharges at three currents, 0.6, 0.8 and 1.0 MA, at a single value for
the target electron density, nl04 of 1.0. The results are summarized here:

Ip config ICRF H-mode power threshold

0.6 LSN 1080 kW
0.6 USN 3000 kW
0.8 LSN 350 kW
0.8 USN 1770 kW
1.0 LSN 360 kW
1.0 USN 2220 kW

The core rotation velocities in L-mode for both LSN and USN at 1.0 MA were the
same, yet the ICRF power was very different, in contrast to findings at 0.8 MA.

Physics Operator Summaries
Entered: Jun 21 2005 05:38:01:653PM
Author: Steve Wolfe
This was a reasonably successful run. We got through steps
1-5 of the 6 steps in the plan, missing only the reduced
density points. The machine ran pretty well, except for 
some early (.12sec) disruptions at 600kA (#11-12), and some duds
and fizzles (#17-18, 24-26) which seemed to be due to too
high a pre-puff. Shot#19 was a power supply fault dud. 

Lower null shots were run from segment 2, upper from segment
3. Startup was robust for the first 16 shots, with only small
tweaks to gas and ef4 to deal with bounces and runaways.
Raising pg4 above 25msec, which pushed the ratiomatic reading
over .05mTorr, was apparently too much, and we had some duds 
and one fizzle (breakdown at 18msec!) until I finally dropped
it back down to 23ms at shot 27, and left it there. 

Scorecard:
-----------
Date 1050621:  33 shots.  27 plasmas.   1 fizzles.   5 duds.   0 System Error.
        (Plasma = Ip gt 50.0 kA   Dud = H_alpha lt  0.40 V)
Total plasma duration: 45.02 s (exceeding  -81 kA)


Session Leader Comments
Jun 21 2005 09:13:40:027AM1050621001Matt ReinkeFilling in for Rice as session_leader for the first few shots

LSN H-mode at 470 kW RF

NEXT: Reduce to 400 kW
Jun 21 2005 10:20:22:407AM1050621001John Rice0.8 MA, 480 kW H-mode
Jun 21 2005 09:24:54:130AM1050621002Matt ReinkeStill got a small H-Mode at 1.1 seconds as the RF started to transiently increase beyond about 425 kW.

NEXT: Reduce RF to 350 kW, just to be sure.
Jun 21 2005 10:20:34:550AM1050621002John Rice0.8 MA, 400 kW H-mode
Jun 21 2005 09:38:23:910AM1050621003Matt ReinkeGot a tiny H-mode near the end of the RF pulse. At the programmed Ip/nl_04 I think we've found the threshhold, but near the end of the shot these values drift.

NEXT: USN w/ 0-3 MW RF ramp to find a rough RF limit.
Jun 21 2005 10:21:05:407AM1050621003John Rice0.8 MA, LSN, 340 kW marginal H-mode
Jun 21 2005 10:21:30:533AM1050621004John Rice0.8 MA, USN, 1820 kW ramp H-mode
Jun 21 2005 10:21:48:390AM1050621005John Rice0.8 MA, USN, 1830 kW H-mode
Jun 21 2005 10:21:59:127AM1050621006John Rice0.8 MA, USN, 1960 kW H-mode
Jun 21 2005 10:27:40:513AM1050621007John Rice0.8 MA, USN, 1720 kW L-mode
Jun 21 2005 10:38:42:167AM1050621008John Rice0.8 MA, USN, 1760 kW barely H-mode
Jun 21 2005 10:52:14:630AM1050621009John Rice0.6 MA, LSN, 980 kW with trips L-mode
Jun 21 2005 11:04:27:860AM1050621010John Rice0.6 MA, LSN, 1020 kW L-mode
Jun 21 2005 11:14:29:090AM1050621011John Ricedisrupted early
Jun 21 2005 11:30:20:177AM1050621012John Ricedisrupted early
Jun 21 2005 11:50:38:770AM1050621013John Rice0.6 MA, LSN 1150 kW H-mode
Jun 21 2005 12:07:56:140PM1050621014John Rice0.6 MA, LSN 750 kW L-mode
Jun 21 2005 12:49:35:830PM1050621015John Rice0.6 MA, LSN 1200 kW H-mode
Jun 21 2005 01:07:07:587PM1050621016John Rice0.6 MA, USN 1850 kW L-mode
Jun 21 2005 01:14:37:240PM1050621017John Ricedud
Jun 21 2005 01:34:55:030PM1050621018John Ricefiz
Jun 21 2005 01:40:29:870PM1050621019John Ricedud
Jun 21 2005 02:10:57:547PM1050621020John Rice0.6 MA, USN 2970 kW with trips, L-mode
Jun 21 2005 02:26:35:823PM1050621021John Rice0.6 MA, USN 3050 kW with trips, sort of H-mode
Jun 21 2005 02:39:27:943PM1050621022John Rice0.6 MA, USN 3220 kW with trips, sort of H-mode
Jun 21 2005 02:47:47:110PM1050621023John Rice1.0 MA, LSN disrupted
Jun 21 2005 02:58:34:793PM1050621024John Ricedud
Jun 21 2005 03:11:09:163PM1050621025John Ricedud
Jun 21 2005 03:24:06:393PM1050621026John Ricedud
Jun 21 2005 03:54:15:540PM1050621027John Riceearly disruption
Jun 21 2005 04:00:13:583PM1050621028John Rice1.0 MA, LSN 220 kW, L-mode
Jun 21 2005 04:12:06:187PM1050621029John Rice1.0 MA, LSN 560 kW, H-mode
Jun 21 2005 04:28:26:353PM1050621030John Rice1.0 MA, USN 0 kW, L-mode
Jun 21 2005 04:38:37:677PM1050621031John Rice1.0 MA, USN 540 kW, L-mode
Jun 21 2005 04:52:46:720PM1050621032John Rice1.0 MA, USN 1090 kW, L-mode
Jun 21 2005 05:06:15:357PM1050621033John Rice1.0 MA, USN 2220 kW, H-mode

Physics Operator Comments
Jun 21 2005 07:27:06:757AMSteve Wolfe
Setting up for MP#415 run
Load from 1050614026
  Seg 2 is active, change title to 0.8MA SNL
Import seg 4 from 1050427021 into seg3 (upper null)
Note that seg1 has ef4 at -1280 and funny seg1 pg3
  Kill pg3 points before 25ms
  pg4 from 21ms to 18ms
  ic_ef4 from -1280 to -1300
Load at 21-Jun-2005 07:24:37.00
Open tree /home/wolfe/pcs_scratch      -1
Open tree done


Jun 21 2005 09:07:05:500AM1050621001Steve Wolfe
Shot#1: Attempt to reproduce 1050614026 (SNL, 0.8MA, 0.9e20)
plasma full length, H-mode at 1.0sec
bouncy startup, pressure is only .035mTorr

next shot: raise pg4 from 18ms to 21msec, RF will reduce power

Jun 21 2005 09:36:19:940AM1050621002Steve Wolfe
Shot#2:raise pg4 from 18ms to 21msec, RF will reduce power
plasma full length, hmode at 1.1sec
startup better, no hards. P0~.045mTorr
Note that on shot 1 gate valve was closed (despite
instruction to the contrary). 

Next shot: at request of kmarr, try to eliminate ssep 
variation after 1.3sec. RF will lower again. 

Jun 21 2005 09:35:53:190AM1050621003Steve Wolfe
Shot#3: at request of kmarr, try to eliminate ssep 
variation after 1.3sec: Flatten ZXU at 0.047,
 leave RXU alone this time.
RF to lower power again (hardly worth turning it on!)
plasma full length, weak h-mode at 1.23sec
Still have a rise in SSEP, probably because I forgot to 
load the change. 

Next shot: go to upper null case. 




Jun 21 2005 09:47:57:763AM1050621004Steve Wolfe
Shot#4: go to upper null case. Seg2 off, seg3 on. 
Increase pg1 puff from 30 to 60msec
plasma full length, upper null. 
H-mode at 1.13sec, at ~1.9MW

next shot: repeat, Rf will try to bracket threshold


Jun 21 2005 10:02:22:913AM1050621005Steve Wolfe
Shot#5: repeat, Rf will try to bracket threshold
NINJA puffing around 1.2sec
plasma full length, no H-mode. Injection around 0.5sec
Bouncy startup, some runaways. 

next: ic_ef4 from -1300 to -1290

Jun 21 2005 10:12:22:537AM1050621006Steve Wolfe
Shot#6: ic_ef4 from -1300 to -1290
plasma full length, brief H-modes starting at 0.85sec
bounce is gone, but bd is a little later, 6ms. No runaways

next: repeat with lower and delayed RF

Jun 21 2005 10:27:36:937AM1050621007Steve Wolfe
Shot#7:repeat with lower and delayed RF
plasma disrupted at 1.1sec; injection?
No H-mode, but RF is only on for 200ms before the first
injection.

next: repeat

Jun 21 2005 10:36:47:120AM1050621008Steve Wolfe
Shot#8: repeat
plasma full length; short H-mode at 1.2sec

next: 0.6MA, lower null

Jun 21 2005 10:49:50:053AM1050621009Steve Wolfe
Shot#9: 0.6MA, lower null (seg3 off, seg2 on)
plasma full length. No h-mode. 
breakdown getting a little later, current rise getting faster

next shot: increase pg4 by 2ms

Jun 21 2005 11:05:39:843AM1050621010Steve Wolfe
Shot#10: increase pg4 from 21 to 23msec
Try again to get zxu flat after 1.3sec
plasma to 1,.85sec, looked like an early marfe and/or 
injection. SSEP looks flatter. No H-mode
breakdown is later again, 7.5msec; p0~.055mTorr

next: ic_ef4 back to -1300

Jun 21 2005 11:19:36:087AM1050621011Steve Wolfe
Shot#11:ic_ef4 back to -1300 from -1290
drop ip point at .1sec from 600 to 550kA
Brock is going to shoot a pellet at 1.35sec
Early disruption. Looks like the same injection?
Breakdown was earlier though.

next: drop seg1 pg3 puff, slow density rise in early seg2

Jun 21 2005 11:36:27:300AM1050621012Steve Wolfe
Shot#12: drop seg1 pg3 puff, slow density rise in early seg2
Another early disruption. 
Looks exactly the same. Something is hitting at .117sec


Jun 21 2005 11:48:33:907AM1050621013Steve Wolfe
Shot#13: put early ip point back to 600 (shouldn't matter)
If this one does the same thing, reload shot 9
plasma full length; whatever it was went away.
Nl04 trace is flakey early. feedback went bad on this one;
density is wrong. got an h-mode, but at lower density. 

next: try again

Jun 21 2005 12:06:29:533PM1050621014Steve Wolfe
shot#14: try again.
Long hang in INIT for a video init that wouldn't clear
plasma full length, No h-mode, we did get the pellet that
time.
No rf cell data.
next: try higher rf power

Jun 21 2005 12:22:14:683PM1050621014Steve Wolfe
delay for data system; have a cell access for
beam and for JT while we wait for jas.



Jun 21 2005 12:48:19:017PM1050621015Steve Wolfe
shot#15: try for higher rf power
beam will fire into machine. I should raise pg4 but will wait.
Noah and JT think they fixed the ISP.

plasma full length, but looked like some runaways. Need
to raise the puff. p0 down to .042 from .055mTorr
denity is down some, but John thinks it's good enough

next shot: upper null, 600kA

Jun 21 2005 01:06:32:337PM1050621016Steve Wolfe
shot#16: pg4 from 23 to 25ms
 upper null, 600kA; seg2 off, seg3 on
plasma full length. No h-mode
Not getting jport cell data.

next shot: raise the power (from whatever it was)

Jun 21 2005 01:17:19:410PM1050621017Steve Wolfe
shot#17: raise the power
increase inner gap by 5mm (clearin by 5mm, rcur by 2.5mm)
dud! gas looks ok, fields look ok. No obvious reason

next: raise pg4 by 2ms

Jun 21 2005 01:31:32:703PM1050621018Steve Wolfe
shot#18: raise pg4 from 25 to 27msec
increase inner gap by 5mm (clearin by 5mm, rcur by 2.5mm)
fizzle, very late breakdown 18msec!
Fields look fine, but drop ef4 by 10A anyway

Jun 21 2005 01:57:14:317PM1050621019Steve Wolfe
shot#19: ic_ef4 from -1300 to -1310
dud. PF breaker pulled out early. 
OH2L seems to have gone first.
 
Next shot: try again

Jun 21 2005 02:11:22:610PM1050621020Steve Wolfe
shot#20: ic_ef4 at -1310
See if it will go this time
plasma to 1.7sec, no h-mode
runaways, early breakdown(5ms) and bouncy
Close to 3MW. 
Outer gap is very small, looks like it's touching late.
Also want 3mm more on inner gap

Jun 21 2005 02:28:03:120PM1050621021Steve Wolfe
shot#21: change clearin to -.002 from .6sec on, rcur to .660
(from .663)
plasma but it looks like it marfes. TCI has a problem.
Also got a big injection at .13sec again


Jun 21 2005 02:36:04:803PM1050621022Steve Wolfe
shot#22: No PCS changes
plasma, still marfing and injecting
and this one had a bouncy startup and runaways. 

Give up. Go to lower null 1MA

Jun 21 2005 02:57:37:233PM1050621023Steve Wolfe
shot#23:  Go to lower null 1MA (seg3 off, seg2 on)
disrupts at .78sec. Another bouncy startup, but the runaways
aren't bad. TCI feedback goes berserk (valve off)

next: try again

Jun 21 2005 03:02:05:433PM1050621024Steve Wolfe
shot#24:  Try again for lower null 1MA 
dud. pressure reads about .06mTorr
drop br0 by .25mT

Jun 21 2005 03:12:45:633PM1050621025Steve Wolfe
shot#25: br0 to -.00025mT from 0
another dud. put the br back, raise the pre-puff, drop ef4

Jun 21 2005 03:27:08:910PM1050621026Steve Wolfe
shot#26: br0 to 0, ioc_ef4 from -1310 to -1320, 
pg4 from 27 to 29ms. Hard to believe the pressure is too low
at .06, but try anyway
And that didn't work either. Another dud. 

OK, drop the pre-puff back down to 23msec. 
If that doesn't help, ecdc

Jun 21 2005 03:59:22:910PM1050621027Steve Wolfe
shot#27: pg4 from 29 to 23msec. 
If that doesn't help, ecdc
plasma, runaways, disrupts at .6sec
tci lost fringes, density is very low, runaways develop late. 
nl04 appears to be around 3e19, possible locked mode.
Startup looks fine. I guess I did have the pre-puff too high!

next: irby has an access to fix tci. Then we'll try again.

Jun 21 2005 03:59:33:630PM1050621028Steve Wolfe
shot#28:  try again.
plasma full length, bouncy startup, had some runaways
No h-mode, maybe dithering

next: ic_ef4 back to -1310

Jun 21 2005 04:11:36:407PM1050621029Steve Wolfe
shot#29:ic_ef4 back to -1310 from -1320
plasma, with h-modes.  no runaways, although it swings
pretty far out in startup 

Good enough, go to upper null 1MA case

Jun 21 2005 04:28:56:323PM1050621030Steve Wolfe
shot#30:go to upper null 1MA case seg2 off, seg3 on
plasma full length, no H-mode. Looks like E faulted.
breakdown slightly late, no runaways
Injection at 0.5sec, not serious.

next:once more, with power?

Jun 21 2005 04:37:48:710PM1050621031Steve Wolfe
shot#31: repeat
plasma full length no h-mode, got some rf this time (.55MW)
breakdown back to 5msec

next: more RF, I guess

Jun 21 2005 04:52:55:470PM1050621032Steve Wolfe
shot#32: repeat, at 1MW
plasma full length, no h-mode, prf=1.1MW
bouncy startup, some runaways.

next: more power

Jun 21 2005 05:07:32:450PM1050621033Steve Wolfe
shot#33: repeat, with more power
plasma full length, some hards, some h-modes
prf~2MW

That's all for today. 

Engineering Operator Comments
ShotTimeTypeStatusComment
109:02:49:703AMPlasmaOk
209:16:57:947AMPlasmaOk
309:29:28:910AMPlasmaOk
409:42:44:640AMPlasmaOk
509:55:09:777AMPlasmaOk
610:07:34:007AMPlasmaOk
710:20:12:627AMPlasmaOk
810:32:52:653AMPlasmaOk
910:46:31:913AMPlasmaOk
1010:58:58:753AMPlasmaOk
1111:12:01:920AMPlasmaOk
1211:24:29:367AMPlasmaOk
1311:41:31:923AMPlasmaOk
1411:54:07:827AMPlasmaOk
1512:43:05:940PMPlasmaOk
1612:56:22:640PMPlasmaOk
1701:12:42:570PMPlasmaOk
1801:25:17:360PMPlasmaOk
1901:38:36:717PMPlasmaOk
2002:03:40:067PMPlasmaOk
2102:17:34:123PMPlasmaOk
2202:31:21:837PMPlasmaOk
2302:43:59:440PMPlasmaOk
2402:56:42:983PMPlasmaOk
2503:09:30:853PMPlasmaOk
2603:22:15:207PMPlasmaOk
2703:35:11:827PMPlasmaOk
2803:53:44:710PMPlasmaOk
2904:07:34:923PMPlasmaOk
3004:20:52:683PMPlasmaOk
3104:33:25:260PMPlasmaOk
3204:47:04:410PMPlasmaOk
3305:01:08:437PMPlasmaOk