Alcator C-Mod Run 1050421 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:Bruce Lipschultz (shots 1-30)

Operators
Session leader(s):Bruce Lipschultz
Physics operator(s):Ron Parker,Steve Wolfe,Ron Parker
Engineering operator(s):Bill Cochran,Gary Dekow,Ed Fitzgerald

Engineering Operator Run Comment
MP#417

Session Leader Plans
Entered: Apr 21 2005 08:54:25:167AM
Author: Bruce Lipschultz
Continuation of post-boronization MP #417 - Plasma performance, boronization and
ICRF heat effectiveness with high-Z antenna guards and all-metal surfaces.

SL - B. Lipschultz (standin for Y. Lin)

1) Start off with a fiducial shot. This should include the gate valvews closed.
The equilibrium should be loaded from 1050420025. The RF power should ramped to
2MW starting at 0.75 seconds. This gives us an Ohmic phase, some information on
the H-mode threshold. The ramp in RF power should be followed by a step up to 3
MW. It would probably be useful to have a dropout in the ICRF for heating
efficiency as well. Following the fiducial at least one shot is needed at 3 MW
to compare to 1050420 shots.


2) Proceed with the current scan: After optimizing the RF and gaps at 3MW and 1
MA, go back to 1.2 MA (1050420032) and the same density (nl04=1) and 2 MW RF for
the RF to tune up.Then increase the power to 3 MW. Once the power is increased
go through the density scan.

3) H-mode threshold: If the 1 MA shots are not worth pursuing for stored energy
levels, then do the H-mode threshold at this current at various densities. This
would be followed by the same threshold study at 1 MA.


4) Repeat fiducial shot at end of day.



Physics Operators Plans
Entered: Apr 20 2005 04:56:10:720PM
Author: Ron Parker
MP#417 post-boronization evaluation of all-metal ...

SL: Lipschultz
PO: Parker

Engineering setup as on shot 1050420032

ECDC overnight in D2, bake at 60 C.

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

Power systems as on 1050420032

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 as it was at the end of the run 1050405 disabled (PG1)
leave B-side upper with He3 Hybrid disabled (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)

NINJA puff setup (fill to 10 PSI D2, but disable)

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

Run Plan: This will be a continuation of MP417, detailed run plan TBD
pending results of 1050420 run.

Session Leader Summaries
Entered: Apr 21 2005 05:37:30:220PM
Author: Bruce Lipschultz
Continuation of post-boronization MP #417 - Plasma performance, boronization and
ICRF heat effectiveness with high-Z antenna guards and all-metal surfaces.

SL - B. Lipschultz (standin for Y. Lin)
PO: R. Parker (and S. Wolfe)

The day started out with poorer confinement performace plasmas than yesterday. We scrapped the
plan to go to higher current to boost stored energies and concentrated on understanding
the level of impurities and the changes in confinement.

After some initial problems getting the McPherson going we were able to verify that the
Mo levels were higher than yesterday. They appear to be factors of 2 higher. The radiated
was also higher.

We then concentrated on optimizing the strike point position. We had noticed that the strike point
had been wandering up to the outer divertor nose. Some camera pictures hinted that there
was some melting there. In any case a bad idea as those tiles are not optimized for heat loads.

Since the radiated power and Mo in the core were screaming up at the beginning of the H-mode
we wanted to see if we could reduce this and perhaps get something more steady state. This
seemed to work - e.g. shot 16, 17 & 19.

We noticed that the above shots, with low power on J, seemed better in terms of impurities.
For comparison we increased J antenna from 0.4 to 1.2 MW and dropped E to 400 kW. This
was not quite as good. But we are not sure whether to blame J for that difference.

We dropped the puff (shots 24, 25) during the H-mode and things got worse again. This
was true for the E antenna low power (J high) and the opposite. We increased the puff
again on shot 27 and the H-mode was more steady state. However, the radiated power
was higher than earlier shots (e.g. 17) indicating that the level of Mo had gone steadily up.

We repeated the fiducial from earlier in the day (keeping the equilibrium changes). The plasma
performance was definitely degraded. The observations through the day seemed to indicate that
this was a steady decrease.

Other summary comments:

H/D was pretty steady at 5% through most the day.

Zeff during the RF was 1.5 and higher (for no puff during H-mode).

J antenna may lead to more Mo influx than D/E for the same delivered power. However,
it is difficult to make the case strongly. Certainly it fared no better than D/E even at lower
power per unit area.

Puffing during the initial rise of the H-mode, and perhaps at a low level during the H-mode, appeared to keep the radiation from running away. I suppose this could be due to cooling locally around the antenna if that were the source of Mo. It would also help the divertor because we can see the pressure rise there as well. I note that the Chromex measurements never indicated that D/E were the source of Mo during these experiments. That could mean that the D/E source was out of the field of view or that it was elsewhere.



Physics Operator Summaries
Entered: Apr 21 2005 05:24:43:047PM
Author: Ron Parker
The machine ran generally well for this run, with only one fizzle
and two disruptions. No tuning of the startup was necessary and breakdown
was consistently at ~ 5 ms. There were a few problems with data system
hangups that caused short delays, but 30 shots were run.

Regarding the disruptions, S. Wolfe moved X-point (see PO log, shots 9-16) and
changed the density rise. These changes may have cured the disruption problem that
we had in shots 6 & 7.

Scorecard: 30 shots, 1 fizzle, 2 early disruptions, 1 data problem,
1 operator error and 25 shots with useful data.

Session Leader Comments
Apr 21 2005 09:48:59:527AM1050421001Bruce LipschultzAttempt at fiducial. VUV spectrometer off because of pump issues. RF had problems. Try again.

H-mode threshold ~ 1.2 MW. 140 kJ & 2.2 MW.

H/(H+D) ~ 3.5%. Radiated power kills off each H-mode.
Apr 21 2005 09:46:29:713AM1050421002Bruce LipschultzSecond attempt at fiducial. VUV spectrometer off because of pump issues. RF had problems.

H-mode threshold ~ 1.55 MW.

Try again to get D-port going, raise the density a little to perhaps help with radiation.

H/(H+D) ~ 3.5%. Radiated power kills off each H-mode
Apr 21 2005 09:46:06:570AM1050421003Bruce LipschultzD a little better but still tripping

H-mode threshold ppaears high - 2 MW. H factor poor. Things have definitely degraded since yesterday. 165 kJ & 3 MW RF.

Try again to get D-port settled then on to

H/(H+D) ~ 4%.
Apr 21 2005 10:09:07:993AM1050421004Bruce LipschultzH-mode threshold a~ 1.66 MW. H factor poor.
W~ 155 kJ & 3 MW RF.

H/(H+D) ~ 4%.
Apr 21 2005 10:09:18:243AM1050421005Bruce Lipschultzfizzle
Apr 21 2005 10:27:33:057AM1050421006Bruce Lipschultzearly disruption of unknown origin
Apr 21 2005 11:12:18:040AM1050421008Bruce Lipschultz160 kJ and 3 MW.

Radiated power ~ 2 MW

Apr 21 2005 11:13:29:790AM1050421009Bruce Lipschultz150 kJ and 3 MW.

Radiated power ~ 2 MW

H/(H+D) creeping up to 6%

Apr 21 2005 11:58:19:010AM1050421011Bruce Lipschultz150 kJ and 3 MW.

Radiated power ~ 2 MW, in and out H-mode

VUV spectrometer on. Hope to get some data on the radiation.

H/(H+D) ~ 5%

Apr 21 2005 12:28:16:540PM1050421012Bruce Lipschultz150 kJ and 3 MW.

Radiated power ~ 2 MW, in and out H-mode

VUV spectrometer on. Hope to get some data on the radiation.

Jim indicates dominance of Mo and increase over yesterday.

H/(H+D) ~ 5%

Apr 21 2005 12:30:08:350PM1050421013Bruce Lipschultz150 kJ and 3 MW.

Radiated power ~ 2 MW, in and out H-mode

VUV spectrometer on. Hope to get some data on the radiation.

Jim indicates dominance of Mo and increase over yesterday.

Zeff hit 1.7.

H/(H+D) ~ 5.5%

Apr 21 2005 12:38:47:723PM1050421014Bruce LipschultzDropped current to 800 kA to see if we get better EDAish plasmas. Not any better.
115 kJ and 3 MW.

Radiated power ~ 2 MW, in and out H-mode

VUV spectrometer on. Hope to get some data on the radiation.

Jim indicates dominance of Mo and increase over yesterday.

Zeff hit 1.8.

H/(H+D) ~ 5.5%

Apr 21 2005 12:58:19:910PM1050421015Bruce Lipschultz800 kA
120 kJ and 3 MW.

Radiated power ~ 2 MW, in and out H-mode

Zeff hit 1.9.

H/(H+D) ~ 5.%



Apr 21 2005 01:13:13:410PM1050421016Bruce Lipschultz800 kA
120 kJ and 2 MW we think. J was on and off.

Radiated power ~ 1.3 MW, and dropping

Zeff hit 1.5.

H/(H+D) ~ 4.5%



Apr 21 2005 01:24:42:783PM1050421017Bruce Lipschultzno power shot cycle - CAMAC problems

Apr 21 2005 01:54:19:487PM1050421017Bruce LipschultzChanged the puff during the H-mode to just in the density rise to reduce the Mo. Seems to have helped. Next shot increase the power primarily with D/E.

PRF ~ 2.5 MW W~ 100kJ J~400 kW

Zeff ~ 1.5

H/(H+D) ~ 1.5


Apr 21 2005 01:54:56:753PM1050421018Bruce LipschultzNo power shot
Apr 21 2005 02:26:25:470PM1050421019Bruce LipschultzAlso a pretty steady state plasma once the Mo is coughed out at 0.89 s. We have reduced the gas puff at 0.85 seconds for the next shot so as to not cool the plasma too much.

P_RF ~ 3 MW, W ~ 110 kJ

No H/D data. Also held up for CPCI data again.


Apr 21 2005 03:04:21:423PM1050421020Bruce LipschultzSimilar to 19 - Also a pretty steady state plasma once the Mo is coughed out at 0.89 s. We have reduced the gas puff at 0.85 seconds for the next shot so as to not cool the plasma too much.

P_RF ~ 3 MW, W ~ 117 kJ

H/D ~ 4,5 %, Zeff ~ 1.5


Apr 21 2005 03:16:26:033PM1050421021Bruce LipschultzSwitched J for E port antenna to see if there is any difference in the effect on the plasma. J tripped out many times. The plasma was ELM-free, meaing rising density, from the very beginning.

P_RF ~ 3 MW, W ~ 117 kJ P_rad going intitially above 1.5 MW and then dropping and rising.

H/D ~ 4,5 %, Zeff ~ 1.5

Unfortunately J was too high. Scale back the next shot to level of D on shot 20.


Apr 21 2005 03:49:26:580PM1050421022Bruce LipschultzSomewhat steady state with J having more power.

P_RF ~ 3 MW, W ~ below 100 kJ after initial rise. P_rad going intitially to 2 MW and then dropping to 1.6.

H/D ~ 5 %, Zeff ~ 1.5

UJ about th right level

Apr 21 2005 03:50:40:813PM1050421023Bruce Lipschultz3 small drops out of H-mode

P_RF ~ 3 MW, W ~ below 100 kJ after initial rise. P_rad going intitially to 2 MW and then dropping to 1.6.

H/D ~ 5 %, Zeff ~ 1.5

J antenna about the right level

Apr 21 2005 03:52:26:753PM1050421024Bruce LipschultzNo puffs durng H-mode that time. Things are worse.

P_RF ~ 3 MW, W ~ below 100 kJ after initial rise. P_rad going intitially to 2 MW and then constantly oscillating up to 1.8 MW.

H/D ~ 5 %, Zeff ~ 1.5

J antenna about the right level. Next shot switch J back to a low level and bring E back up to higher power.

Apr 21 2005 04:26:11:660PM1050421025Bruce LipschultzThis case is with D & E antennas dominant. No puffs durng H-mode that time. Things are worse than before.

P_RF ~ 3 MW, W ~ below 100 kJ after initial rise. P_rad going intitially to 2 MW and then constantly oscillating up to 1.8 MW.

H/D ~ 5 %, Zeff ~ 1.5

Next shot put the gas on during the initial H-mode
Apr 21 2005 04:50:24:097PM1050421026Bruce LipschultzThis case is with D & E antennas dominant. Puffs during the H-mode rise. No better - so we have not reproduced the earlier shots (e.g. 17).

P_RF ~ 3 MW, W ~ below 100 kJ after initial rise. P_rad going up to 2 MW.

H/D ~ 5 %, Zeff ~ 1.5

Next try for more gas puffing.
Apr 21 2005 05:11:30:253PM1050421027Bruce LipschultzThis case is with D & E antennas dominant. Higher puffs during the H-mode rise. Pretty steady state.

P_RF ~ 3 MW, W ~ 100 kJ after initial rise. P_rad going up to 2 MW.

H/D ~ 5 %, Zeff ~ 1.5

Apr 21 2005 05:11:51:020PM1050421028Bruce LipschultzNo power shot
Apr 21 2005 05:28:54:440PM1050421029Bruce LipschultzTurned the gas feedback on in the period after the start of the H-mode shooting for higher density than the H-mode gives. Things were pretty steady state.

Radiated power 1.7 MW, stored ednergy dropping.


Apr 21 2005 05:36:25:063PM1050421030Bruce LipschultzFiducial repeat of shot 4.

Much worse in terms of radiation a

Physics Operator Comments
Apr 21 2005 09:08:14:900AM1050421001Ron ParkerShot 1050421025 was loaded and ran as programmed.

The shot will be repeated on shot 2.
Apr 21 2005 09:27:24:573AM1050421002Ron ParkerShot 2 ran as programmed. Interrupted H-modes.

Next shot: n_eL(4) increased from 9.5 to 10.5e13 cm-2
Apr 21 2005 09:46:04:087AM1050421003Ron ParkerShot 3 ran as programmed. H-Mode sustained.

Cell axis to turn off NPA electronics.

Next: Moved plasma 3 mm further from inside wall. (Clearin -3 mm, Rcur -1.5 mm)
Apr 21 2005 10:02:16:213AM1050421004Ron ParkerShot 4 ran, intermitent H-mode.

For next shot, density will be increased during H-mode

Density programme: 2.7e20 on n_eL(4) from 1.25 to 1.4 s
Apr 21 2005 10:09:50:993AM1050421005Ron ParkerShot fizzled. Rcur readjusted by +3 mm to restore outer gap to
same value as in shots 1-3.

Apr 21 2005 10:25:33:777AM1050421006Ron ParkerShot 6 disrupted at ~0.64 s.

Try again.
Apr 21 2005 10:31:49:400AM1050421007Ron ParkerShot disrupted again, no apparent reason.

Next: reload shot 3
Apr 21 2005 10:47:38:353AM1050421008Ron ParkerShot ran, was it due to reloaded shot or coincidence?

Steve Wolfe taking over as PO for next shots, until ~ 12:45.
Apr 21 2005 11:07:59:917AM1050421009Steve Wolfe
Shot#9: Make clearin flat at +.002
rcur out by 2mm after .7sec
RXL in to -.01
Probably should have raised the fill too. 
Plasma full length
Still lots of radiation. Had an early marfe that takes a bite out 
of the current.

Next shot: move rxl in earlier, to avoid the nose at .4sec
move zxl up to get it off the floor

Apr 21 2005 11:23:09:823AM1050421010Steve Wolfe
Shot#10:  move rxl in earlier, to avoid the nose at .4sec
move zxl up to get it off the floor (from -.01 to -.005)
raise nl04 from 1.05 to 1.15, slow down early rise
Turn on argon, 30 ms puff at 0.3sec

Plasma full length, but had some problems with tci and other things.
Actually, B-side lower was filled with 2.1psi of Krypton! 
Was based on  1050405? Why?
Pump it out and put in 1psi argon. 



Apr 21 2005 11:57:46:197AM1050421011Steve Wolfe
Shot#11: Strike was still on the floor on shot 10.
Move rxl back out to -.005 before at .5sec, ramp to -.01 at .9 sec
Argon in bside lower this time.
Plasma full length. 
Radiation is still high, rises are slower than with Krypton though
Wmhd~155kJ in multiple H-modes; Outer strike is just at the bottom of
the plate.
Prefill pressure still looks very low, but don't mess for now.

Next shot: no changes, JT will survey

Apr 21 2005 12:06:21:010PM1050421012Steve Wolfe
Shot#12: No pcs changes
Plasma full length. JT is scanning VUV

Next shot: drop nl04 to 0.8e20

Apr 21 2005 12:15:07:277PM1050421013Steve Wolfe
Shot#13: drop nl04 to 0.8e20; Argon off.
Plasma full length, flickering h-modes
First hmode 147kJ, later ones worse.
Radiated power PradMain~2MW at each collapse

Next shot: Drop Ip to 800kA

Apr 21 2005 12:31:18:737PM1050421014Steve Wolfe
Shot#14:  Drop Ip to 800kA, try again to get strike on the tile.
Move rxl out to -.006 from -.01 at 0.9sec, let it ramp on in to -.01

Plasma full length. Strike is still on the floor! 
Wmhd is down to 110kJ. 

Next shot: add puff in H-mode, move rxl over some more

Apr 21 2005 12:44:17:830PM1050421015Steve Wolfe
Shot#15:   add puff in H-mode (nl04 to 2.4e20 betwen 1.2 and 1.4sec),
 move rxl over some more to -.003 to -.007

plasma full length. Seems to have more density during the puff, didn't
get to 2.4e20

next shot: program nl04 1.5@.85 to 2@1.4

Apr 21 2005 12:55:19:160PM1050421016Steve Wolfe
Shot#16:   program nl04 1.5e20@.85 to 2e20@1.4
Raise zxl by 1cm, still trying to get the early strike off the floor.


Apr 21 2005 01:44:39:080PM1050421017Ron ParkerShot 17a was a no-power shot, due to data system hangup.

The density pulse was modified for this shot to ramp from 1.5e20 to
1.7e20 over the time period .85 to 1.0 s. Since the shot didn't go,
We'll shoot it again on shot 18.

Apr 21 2005 01:45:20:033PM1050421017Ron ParkerShot 17 ran well.
Apr 21 2005 01:53:52:673PM1050421018Ron ParkerShot 18a was a no-power shot.
Apr 21 2005 02:17:42:550PM1050421019Ron ParkerShot 19 ran well.

Next shot: density puff lowered to 1.35e20 at t=0.85 s,
1.7e20 @ t=1.0 s.

Apr 21 2005 02:39:32:110PM1050421019Ron ParkerBreak in the action while data system problems get fixed.
Apr 21 2005 03:19:01:160PM1050421020Ron ParkerShot 20 ran well. No machine change for next shot.
Apr 21 2005 03:19:21:610PM1050421021Ron ParkerShot 21 ran well. No Change in machine parameters for next shot.
Apr 21 2005 03:30:49:487PM1050421022Ron ParkerShaot 22 ran well. Next: gas puff into H-mode.
Apr 21 2005 03:33:33:300PM1050421023Ron ParkerShot 23 ran well.
Apr 21 2005 03:41:08:313PM1050421023Ron ParkerShot 23 ran well. Programmed pulse of gas injected during H-mode.
Next: repeat, but with no gas injected into H-mode.
Apr 21 2005 03:47:42:393PM1050421024Ron ParkerShot ran well. Intermittent H-mode.
Apr 21 2005 04:03:04:847PM1050421025Ron ParkerShot ran well. Intermittent H-mode.
Next: return to shot 23 with gas puff into H-mode.
Apr 21 2005 04:22:13:643PM1050421026Ron ParkerShot ran well, as programmed.

Next shot: Reprogrammed gas puff into H-mode.
Apr 21 2005 04:34:12:097PM1050421027Ron ParkerShot 27 ran well, with fairly steady H-mode.

next:Back to feedback of density, specifically shot 17
Apr 21 2005 04:42:55:660PM1050421028Ron ParkerShot was a no power shot- operator error.
Apr 21 2005 04:59:09:847PM1050421029Ron ParkerShot 29 ran well.

Next (and last shot): Reload shot 004 as fidicial
Apr 21 2005 05:04:25:073PM1050421030Ron ParkerShot 30 ran well.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:02:30:993AMPlasmaOk
209:15:54:760AMPlasmaOk
309:28:44:260AMPlasmaOk
409:48:10:557AMPlasmaOk
510:02:28:433AMPlasmaOk
610:15:00:120AMPlasmaOk
710:27:36:823AMPlasmaOk
810:40:37:980AMPlasmaOk
911:00:30:337AMPlasmaOk
1011:16:51:730AMPlasmaOk
1111:43:26:337AMPlasmaOk
1211:58:15:010AMPlasmaOk
1312:10:54:837PMPlasmaOk
1412:23:27:713PMPlasmaOk
1512:36:47:650PMPlasmaOk
1612:54:51:970PMPlasmaOk
1701:16:16:957PMPlasmaOk
1801:51:15:673PMPlasmaBadDatasystem problem
1902:06:02:050PMPlasmaOk
2002:49:43:707PMPlasmaOk
2103:03:26:817PMPlasmaOk
2203:16:25:550PMPlasmaOk
2303:29:44:520PMPlasmaOk
2403:42:14:970PMPlasmaOk
2503:55:55:253PMPlasmaOk
2604:14:27:643PMPlasmaOk
2704:27:21:750PMPlasmaOk
2804:39:46:987PMTestOkThis was a no power shot
2904:50:02:267PMPlasmaOk
3005:02:24:783PMPlasmaOk