Alcator C-Mod Run 1050422 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:Yijun Lin (shots 1-27)

Operators
Session leader(s):Yijun Lin
Physics operator(s):Earl Marmar,Joseph Snipes,Earl Marmar
Engineering operator(s):Sam Pierson,Bill Byford

Engineering Operator Run Comment
MP 417 EO: Pierson PO: Marmar SL: YIN

Session Leader Plans
Entered: Apr 22 2005 08:19:19:060AM
Author: Yijun Lin
SL_plan for 1040422 (MP 417, day 3 post-boronization)

1) Repeat fiducial shot at the start of the day. (1050421030)
2) Repeat fiducial shot at 3 MW level (fine tune the strike point)
3) 1 MA, a lot higher target density at 1.4e20. Puffing as hard as possible (like in 960227034)
4) Puff N2 and see whether the performance is better.
5) L-mode high power shots (limited or USN) to understand how much of the radiation is due to H-mode (confinement) and how much due to increased influxes (RF heating).

This run plan is subject to changes depending on what we find along the way.



Physics Operators Plans
Entered: Apr 21 2005 05:04:43:777PM
Author: Earl Marmar
MP#417 post-boronization evaluation of all-metal ...

SL: Y. Lin
PO: E. Marmar

ECDC overnight D2, P=2e-4 guage, bake at 60C

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

Power systems as on 1050421029

A-coil in standard configuration and enabled (+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 1 psi argon, hybrid enabled (PG1)
leave B-side upper with He3 Hybrid disabled (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)

***we need nitrogen for this run; take neon off and add nitrogen*****

fill Ninja to 8 PSI nitrogen



Enable the following: ECE and VUV gate valves, Z-bolo shutter

Session Leader Summaries
Entered: Apr 22 2005 05:15:47:650PM
Author: Yijun Lin
SL_summary:

The idea was to cool the divertor and any other places that produce impurities during H-mode, without degrading the H-mode pedestal.

The H-modes were short and ELM-like for the fiducial plasma shape and density (shot 3, 21). Attempt to get a fiducial in the end failed (shot 27 was a fizzle).

Puff D2, we have steadier H-mode. Slightly higher Wmhd. Less Mo. Slightly lower Prad. (shot 4, 5, 6)

Puff N2, we have steadier H-mode and significantly lower Prad_main (similar 2pi foil). Higher Wmhd. Lower Mo. (compare 13 and 14) Too much N2 --> Prad came down, but Wmhd also came down (shot 19) (Pedestal degraded?). Too much N2 can also cause disruption (shot 16, 18).

Puff both D2 and N2 in H-mode gave the best stored energy (shot 8, 10, 11, 12, 13) But, not in shot 26 (too much N2 in already?)

Puff He from main chamber didn't seemt to help (shot 22, 23).

The performance did not get worse earlier in the day (compare shot 3 and 21).

We have definitely learned something to get better performance, and lower Prad_main. Because the boronization enhancement has already faded, we were not able to have good performance however we tried. It will be interesting to see what happens if we run similar tricks after fresh boronization.

Physics Operator Summaries

Session Leader Comments
Apr 22 2005 10:08:35:640AM1050422001Yijun Linshot 1: fiducial shot. repeat 1050421030.
Request: 1. MA, 5.4 T, nl = 1.e20 m^-2.

Result: Plasma.
W = 130 kJ at 3 MW. L-H threshold ~ 1.8 MW.

it is very similar to the last shot yesterday 1050421030.
Same Prad, same Wmhd, some L-H threshold


Apr 22 2005 10:12:03:357AM1050422002Yijun Linshot 2: fiducial shot.
Request: 1. MA, 5.4 T, nl = 1.e20 m^-2. 3 MW Prf
Result: Plasma. disrupted 0.44 sec

Apr 22 2005 10:28:43:497AM1050422003Yijun Linshot 3
Request: 1. MA, 5.4 T, nl = 1.e20 m^-2. 3 MW Prf
result: 7 H-modes.
Wmax 130 kJ. Strike point is fine.

next: Puff D2 in H-mode.

Apr 22 2005 10:43:01:623AM1050422004Yijun Lin
shot 4
Request: 1. MA, 5.4 T, nl = 1.e20 m^-2. 3 MW Prf, Puff D2 in H-mode.
result: Long EDAish H-mode.
Wmax at 143 kJ, 3 MW RF. D port dropped out after 1.1 sec and Wmhd dropped out.

Next: more D2 puff and see if there any more enhancement.

Apr 22 2005 10:58:17:123AM1050422005Yijun Linshot 5
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf, Puff D2 (more) in H-mode.
result: Long EDAish H-mode.
Wmax at 146 kJ, 3 MW RF.

Next: start puff N2 from NINJA. reduce D2 puff in H-mode back to level in shot 4.

Apr 22 2005 11:11:26:153AM1050422006Yijun Linshot 6
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (40 Volt), and N2 (0.6 sec)
result: Many H-L back transitions. D2 puff too small.
Wmax at 137 kJ, 3 MW RF.

next: Raise D2 puff to the level in shot 4 (60 Volt) at 0.7 sec. Same N2 at 0.6 sec

Apr 22 2005 11:25:38:307AM1050422007Yijun Linshot 7
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt), and N2 (starting at 0.6 sec)
result:
Wmax at 137 kJ, 3 MW RF. Still had back transitions.
Blip thought the N2 may be puffed to the places we did not want.
Zeff was getting higher.

Next: change NINJA capillaries and also start puff earlier


Apr 22 2005 11:47:06:590AM1050422008Yijun Linshot 8
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt), and N2 (starting at 0.6 sec)
result:
Wmax at 140 kJ, 3 MW RF. Still had back transitions earlier.
Interestingly, the H-mode got better vs. time.
Prad is getting smaller in time (improvement over shot 7)

Next: more N2.
Apr 22 2005 12:07:16:737PM1050422009Yijun Linshot 9. disrupted at 0.43 sec.

Apr 22 2005 12:35:02:337PM1050422010Yijun Linshot 10.
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt), and N2
Result:
Wmax at 135 kJ, 3 MW RF. Back transitions earlier.
(No improvement over shot 8).
Next more N2.

Apr 22 2005 12:52:38:470PM1050422011Yijun Linshot 11.
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt) from 0.7 sec.
and N2 (8 PSI, from 0.5 sec, last 0.4 sec. need 0.15 sec to get in)
Result:
Wmax at 148 kJ, 3 MW RF. (Some improvement. The RF has some faults).
Lower Prad than shot 10

next: More N2 (starting 0.5 sec, last 0.4 sec. 8 psi)

Apr 22 2005 01:08:53:120PM1050422012Yijun Linshot 12.
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt) from 0.7 sec.
and N2 (8 PSI, from 0.5 sec, last 0.4 sec. need 0.15 sec to get in)
Result:
Wmax at 145 kJ, 3 MW RF. similar to shot 11.

next: starting N2 0.4 sec, last 0.4 sec. 8 psi

Apr 22 2005 01:20:48:757PM1050422013Yijun Linshot 13
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt) from 0.7 sec.
and N2 (8 PSI, from .4 sec, last 0.4 sec. need 0.15 sec to get in)
Result:
Wmax at 150 kJ, 3 MW RF. marginally better than shot 12. (Seen in Te. and Neutron rate in
the 2nd and third H-modes.

next: No N2 puff and see whether the plasma gets worse

Apr 22 2005 01:36:59:953PM1050422014Yijun Linshot 14
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt) from 0.7 sec.
No N2 puff.
Result:
Wmax at 137 kJ, 3 MW RF. More Prad earlier on. Less Wmax.

Note Wmhd drooped while previous shots with N2 puff Wmhd increased in H-mode.

Next: raise N2 pressure to 13 psi (previously, it was 10 psi)
puff from 0.4 sec, last for 0.4 sec.
Apr 22 2005 02:31:48:870PM1050422015Yijun Linshot 15
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (60 Volt) from 0.7 sec.
and N2 (13 PSI, from .4 sec, last 0.4 sec. need 0.15 sec to get in)
Result: 16 Torr-liter N2 in. (shot 13 got 9 torr-liter in)
Prad way down. But Wmhd also down to 130 kJ. Dalpha signal indicates the H-mode was
marginal. (Is it that the confinement quality down?)

next: same N2. No D2 puff. See what happens

Apr 22 2005 02:32:57:573PM1050422016Yijun Linshot 16
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
No D2 puff in H-mode
N2 (13 PSI, from .4 sec, last 0.4 sec. need 0.15 sec to get in)
Result: Disrupted 0.68 sec

(N2 may have been the culprit of this disruption. Next reduce N2 to 11 psi)

Apr 22 2005 02:30:44:590PM1050422017Yijun Lindud.
Apr 22 2005 02:44:41:867PM1050422018Yijun Linshot 18.
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
No D2 puff in H-mode
N2 (11 PSI, from .4 sec, last 0.4 sec. need 0.15 sec to get in)

Result: Disrupted 0.68 sec
(N2 may have been the culprit of this disruption.)
Next: puff N2 later, start at 0.55 sec.

Apr 22 2005 03:07:42:200PM1050422019Yijun Linshot 19.
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
No D2 puff in H-mode
N2 (11 PSI, from .55 sec, last 0.4 sec. need 0.15 sec to get in)

Result: 16 Torr-liter N2 in.
Wmhd at 132 kJ, but not drooping. Long H-mode. Core Prad is way down in comparison to shot without N2. Zeff is 2. (probably too much N2 in).

Next: no N2, no D2. see how bad the performance is now.

Apr 22 2005 03:17:05:557PM1050422020Yijun Linshot 20:
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
No D2 puff in H-mode
No N2
result: short H-modes.
No power from D port. Wmax at 117 kJ. Prad is about the same as shot 19 at 3 MW level. (Still had about half of N level in the previous shot).

next repeat.
Apr 22 2005 03:27:02:740PM1050422021Yijun Linshot 21:
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
No D2 puff in H-mode
No N2
Result:
Similar to shot 3. 130 kJ, Prad 2 MW. Short ELM free H-modes.
At least we know that the machine condition is roughly the same as earlier today.

Next: Helium puff, and see whether we can get better plasma.

Apr 22 2005 04:04:24:850PM1050422022Yijun Linshot 22:
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Helium puff from B-side lower during H-mode.

Result: very similar to shot 21. Not much helium in?

Apr 22 2005 04:15:10:970PM1050422023Yijun Linshot 23:
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Helium puff from B-side lower during H-mode.

Result: A short H-mode. All antennas triped and the plasma stayed in L-mode
Wmax ~ 130 kJ

Next: Puff D2 in H-mode (75 V, between shot 4 and 5). Reduced He puff

Apr 22 2005 04:16:16:657PM1050422024Yijun Linshot 24:
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
he puff from B-side lower during H-mode.
Puff D2 in H-mode (75 V)

Result: H-modes.
Wmax 140 kJ. Prad in the 2nd H-mode is way low. the first one
is similar to shot with only D2 puff.

Next: No He puff. N2 + D2 puff.
Apr 22 2005 04:31:26:107PM1050422025Yijun Linshot 25:
Request: 1. MA, 5.4 T, nl = 1.1e20 m^-2. 3 MW Prf
Puff D2 in H-mode (80 V)
Puff N2 (0.65 sec, lasts for 0.4 sec, 11 PSI)
Result: H-modes.
Wmax 140 kJ. Prad is about the same as shot 24.
N2 started to come in at 0.8 sec (too late)
Too much D2?

next: N2 starts at 0.55 sec. D2 at 60 V.


Apr 22 2005 05:14:01:683PM1050422027Yijun Linfizzle

Physics Operator Comments
Apr 22 2005 10:16:03:873AM1050422001Earl Marmarload from 1050421030 (yesterday's fiducial)

delay at start of run, camac highway driver problem

plasma
very similar to 1050421030

EF3 crowbar after the shot; many magnetics offset errors as a result
Apr 22 2005 10:15:36:077AM1050422002Earl Marmartweak RXL to try to get the strike point off the outer nose
plasma
early disruption (0.44 seconds)
Apr 22 2005 10:32:27:497AM1050422003Earl Marmaradditional small change to RXL before 0.5 seconds

plasma
Outer strike looks better
Apr 22 2005 10:38:14:327AM1050422004Earl Marmarnl_04 target to 1.2e20
nl_04 prop gain to 0 at .7 s
add 60 volt PG3 puff starting at .7 s

plasma
much steadier H-mode (EDAish)



Apr 22 2005 10:45:15:060AM1050422005Earl Marmargo to 90 volt PG3 puff starting at .7 s




Apr 22 2005 11:09:01:730AM1050422006Earl Marmarreduce prefill puff by 1 msec to 18 msec

go to 40 volt PG3 puff starting at .7 s
Ninja puffing N2 starting at 0.6 s

plasma
some back-transitions early; probably want a little more D2 during the RF

Apr 22 2005 11:26:32:087AM1050422007Earl Marmargo to 60 volt PG3 puff starting at .7 s
Ninja puffing N2 starting at 0.6 s

plasma

Apr 22 2005 11:39:07:280AM1050422008Earl Marmarno pcs changes
Ninja puffing N2 from different capillaries

plasma; very similar to shot 7

Apr 22 2005 11:40:26:950AM1050422009Earl Marmarcell access before shot 9
no pcs changes
Increase N2 puff from Ninja




Apr 22 2005 12:21:29:827PM1050422009Joseph SnipesI took over as physics operator for shot 1050422009 and it disrupted at 0.416 s. The plasma touches both the
inner wall and outboard limiter at OH1 crossover. Try increasing CLEARIN early to 0.01 m then bring it back
to 0.001 m by 0.56 s for shot 10.
Apr 22 2005 12:27:03:853PM1050422010Joseph SnipesShot 10: Increasing CLEARIN early to 0.01 m then back to 0.001 m by 0.56 s. Reduced the rate of rise of the
density. Good shot.
Apr 22 2005 12:45:19:143PM1050422011Joseph SnipesShot 11: Repeat. Good shot.
Apr 22 2005 01:00:25:437PM1050422012Joseph SnipesShot 12: Increased RCUR and CLEARIN during the rampdown to attempt to avoid the disruption in rampdown.
Good shot. Rampdown did not improve much. Disrupted at 1.76 s.
Apr 22 2005 01:13:09:980PM1050422013Joseph SnipesShot 13: Decreased ZXL and increased ZXU in the rampdown to attempt to avoid the disruption in rampdown.
Good shot. Rampdown is a bit worse. Disrupted earlier at 1.72 s.
Apr 22 2005 01:25:42:020PM1050422014Joseph SnipesShot 14: Reloaded shot 12. Good shot. Rampdown improved with no N2!
Apr 22 2005 02:06:48:253PM1050422015Earl Marmarno pcs changes
Ninja N2 back on
Increase Ninja N2 plenum pressure from 9.9 to 13 psi

plasma


Apr 22 2005 02:30:08:027PM1050422016Earl Marmarno pcs changes
Early disruption (~.7 s); sawteeth got very small before that, around the time the nitrogen hits the plasma.
Apr 22 2005 02:31:32:573PM1050422017Earl Marmarturn off D2 puff during H-mode
reduce Ninja N2 plenum pressure to 11 psi (from 13)
Ninja still enabled

dud; no pulsed gas - plc problem

Apr 22 2005 02:52:33:800PM1050422018Earl Marmarno pcs changes
reduce Ninja N2 plenum pressure to 11 psi (from 13).
plasma
Early disruption (~.7 s); appears to still be too much nitrogen.
Apr 22 2005 03:03:24:607PM1050422019Earl Marmarno pcs changes
delay Ninja trun-on by 150 ms (now opening at 550 ms).

plasma
semi-steady h-mode; not as good as nitrogen plus deuterium
Apr 22 2005 03:26:42:723PM1050422020Earl Marmarno pcs changes
disable Ninja nitrogen puff
still no D2 puff during H-mode

plasma
only 2 MW ICRF
Apr 22 2005 03:28:12:520PM1050422021Earl Marmarno pcs changes

plasma
repetitive ELM-free H-modes
Apr 22 2005 03:45:46:717PM1050422022Earl Marmarpuff helium-4 during the H-mode
B-side lower filled to 20 psi He-4
PG1 puff at .72 s, 60 volt preprogram
nl_04 feedback prop gain to 0 after .72 seconds

plasma
looks much like 21
got the valve programming; no obvious gas
Apr 22 2005 04:04:56:600PM1050422023Earl Marmarpuff helium-4 during the H-mode
B-side lower filled to 20 psi He-4
PG1 puff at .70 s for about .4 sec, 100 volt preprogram

plasma
one ELM-free H-mode; lasted a bit longer than the first H-mode with no puffing during RF




Apr 22 2005 04:11:45:520PM1050422024Earl Marmarpuff helium-4 during the H-mode
B-side lower filled to 20 psi He-4
PG1 puff at .72 s for about .1 sec, 100 volt preprogram
PG3 (D2) puff, 75 volt during RF

plasma
2 H-modes, perhaps a little more EDA-ish



Apr 22 2005 04:43:43:320PM1050422025Earl Marmarturn off He puff
PG3 (D2) puff, 80 volt during RF
Ninja puffing N2, starting at .65s

plasma
missing data, camac highway 3 is malfunctioning
(neutrons, H/D, ...)

Apr 22 2005 05:05:28:000PM1050422026Earl MarmarPG3 (D2) puff, 60 volt during RF
Ninja puffing N2, starting at .55s

plasma
Apr 22 2005 05:12:28:353PM1050422027Earl Marmarfiducial-like
gate valves closed
no D2 puff during expected H-mode time

fizzle

Engineering Operator Comments
ShotTimeTypeStatusComment
109:53:49:217AMPlasmaOk
210:07:04:263AMPlasmaOk
310:19:25:170AMPlasmaOk
410:33:06:357AMPlasmaOk
510:45:39:450AMPlasmaOk
610:58:39:683AMPlasmaOk
711:11:33:700AMPlasmaOk
811:26:12:023AMPlasmaOk
912:03:10:460PMPlasmaOk
1012:25:08:027PMPlasmaOk
1112:39:13:147PMPlasmaOk
1212:57:33:467PMPlasmaOk
1301:10:39:837PMPlasmaOk
1401:23:23:270PMPlasmaOk
1501:36:43:203PMPlasmaOk
1602:02:27:007PMPlasmaOk
1702:26:40:277PMPlasmaBadNo HV enable for the pulsed Gas
1802:40:28:290PMPlasmaOk
1902:53:01:160PMPlasmaOk
2003:06:01:217PMPlasmaOk
2103:20:13:960PMPlasmaOk
2203:36:13:063PMPlasmaOk
2303:49:06:150PMPlasmaOk
2404:03:32:380PMPlasmaOk
2504:18:15:127PMPlasmaOk
2604:50:02:427PMPlasmaOk
2705:08:23:937PMPlasmaOk