Alcator C-Mod Run 1021108 Information

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Miniproposals
Miniproposal:328a
Date Filed:11/1/2003
Title:2 MA Operation on Alcator C-Mod
First Author:Jim Irby
Session Leader:Robert Granetz (shots 1-23)

Operators
Session leader(s):Robert Granetz
Physics operator(s):Jim Irby
Engineering operator(s):Bill Parkin,Bill Cochran

Engineering Operator Run Comment
MP 328A 2MA Operation on Alcator C-Mod. Granetz/Irby/Cochran/Parkin

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:31:883PM
Author: To Be Determined
Session leader's summary for run 1021108 (Friday):

MP xxx: 2 MA operation

Session leader: R. Granetz
Physics operator: J. Irby
Engineer: W. Cochran/W. Parkin

Summary: We got to 1.7 MA at 7.8 T for about a half-second, but the final
ascent to 2.0 MA couldn't be attempted because a small vacuum leak
opened up. Throughout the day we had troubles with disruptions,
which may have been due to locked modes. We were able to finally
get a 1.2 MA discharge to ramp all the way down, but all higher
current shots disrupted.

Scorecard: 20 plasmas
0 fizzles
1 duds (no EF4)
2 tests
0 aborted and/or screwed up by computer problems
----------
23 total

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Run Plan: Start with 1 MA, 5.4 T. Increase Ip in steps of 0.2 MA. Use some
ICRF during the current ramp to help the flux consumption.

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Shot 01 -- Test. (Computer networks were taken down last night.)

Shot 02 -- Plasma. Full length. 1 MA, 5.33 T. Nearly double null. Rampdown
starts at t=1.3 s.

Next shot: increase SSEP; increase flattop duration.

Shot 03 -- Plasma. Disrupted during rampdown. SSEP programming was not
extended with the flattop extension. Upper gussets light up at
end.

Next shot: extend -10 mm SSEP to t=2.0 s.

Shot 04 -- Plasma. Still disrupted during rampdown at about the same time.
Peak Ihalo=90 kA.

Next shot: Give up on this SSEP-controlled shot (which was chosen
because it appeared to have full 1 MA rampdowns) and start from
a more standard shot, such as 1021105007 (0.8 MA, 5.4 T)

Shot 05 -- Plasma. 0.8 MA, 5.4 T. Full rampdown. Prf=0.5 MW from t=0.1 to
t=0.6 s.

Next shot: increase Ip to 1 MA; smooth the early Ip programming;
extend low-power RF to t=1.0 s.

Shot 06 -- Plasma. 1.0 MA, 5.4 T. Disrupted about halfway through rampdown.
Peak Ihalo=100 kA. Kappa is going down and q95 is going up during
the rampdown, as desired. n/ncrit is remaining low. These have
all been thermal quench disruptions. Ian is suggesting the
possibility of a locked mode.

Next shot: raise Ip to 1.2 MA, startup rampdown earlier. Turn off
gas puffing late in shot.

Shot 07 -- Plasma. 1.2 MA, 5.4 T. Disrupted during flattop. Big injection.
There's a change in core parameters around t=0.8 s, which may
hint of some MHD such as a locked mode. q95=3.1 at that time.

Next shot: raise Bt a little to avoid being near q95=3.

MHDQ batch queue is all clogged up. Stewart is looking into it.

Shot 08 -- Plasma. Full rampdown. 1.2 MA, 5.7 T. Still looks like there's
something affecting the core plasma starting at t=0.8 s. There
were lots of spiky things from t=1.3-1.5 s. q95=3.28. n/ncrit
is getting close to 1.2.

Next shot: try turning off the low-power RF

Shot 09 -- Plasma. Disrupted early in rampdown. 1.2 MA, 5.7 T, no RF.
Drop in confinement is now delayed until t=1.08 s. Still don't
know what it is. No rotating MHD seen...still could be a locked
mode.

Next shot: try keeping the density at the flattop level for
long into the rampdown.

Shot 10 -- Plasma. Disrupted in rampdown. 1.2 MA, 5.7 T. Injection at
t=0.63 s, which is the same time that the core plasma parameters
degrade.

Next shot: try putting in 2 MW of RF from t=0.5 to 1.2 s.

Shot 11 -- Plasma. Disrupts late in rampdown. 1.2 MA, 5.7 T. Multiple
H-modes. Got about 1.7 MW.

Next shot: try reducing RXU and RXL by 1 cm to change shape and
strike points. Keep RF power at 2 MW.

Shot 12 -- Plasma. Disrupted early in rampdown. Short H-mode. Prf=2.0 MW.

Next shot: increase inner gap from 12 to 15 mm, keeping outer
gap the same. Keep RF at 2 MW.

Shot 13 -- Plasma. Disrupted early in rampdown. 1.2 MA, 5.7 T. Very similar
to previous shot. Prf=2.0 MW, very constant.

Next shot: what's left to vary? Let's increase nl_04 from 0.8 to
1.1e20 m-2.

Shot 14 -- Plasma. Good shot. Full rampdown, finally! 1.2 MA, 5.7 T.
Multiple H-modes. Prf=2.0 MW, pretty clean.

Next shot: raise Ip to 1.4 MA, Bt to 5.9 T, and have the RF add
a power rampdown from 2.0 to 0.0 MW over t=1.2 to 1.4 s.

Shot 15 -- Dud. No EF4

Next shot: try again.

Shot 16 -- Plasma. 1.4 MA, 5.9 T. Disrupted during flattop. Ihalo_L=80 kA,
Ihalo_U=70 kA, did not drop down all the way. Signs of a locked
mode at 0.74 s. Prf=2.0 MW.

Next shot: raise nl_04 to 1.3e20 m-2.

Shot 17 -- Plasma. 1.4 MA, 5.9 T. Disrupted later in flattop. Halo currents
and rangefinder amplitudes continue to remain low because the
plasma remains near the midplane. Prf=2.0 MW. q95=3.0, which
is definitely a bad thing.

Next shot: increase Btor to 6.3 T in order to raise q95 above 3.

Shot 18 -- Test. No power shot. Jim realized in time that he didn't actually
load the change in Btor, and we'd rather avoid the disruption.

Next shot: try again; 6.3 T

Shot 19 -- Plasma. 1.4 MA, 6.25 T. Disrupted during rampdown. Prf=2.0 MW.
Short H-mode. q95=3.22. n/ncrit gets up to 1.17, but EFC looks
quiet. Halo currents remain below 100 kA and rangefinder remains
below 50 um, since plasma only drops to -20 cm.

Next shot: raise Ip to 1.6 MA, Bt to 6.5 T. Turn off RF. (EF3
and TF PLC current limits are being raised.)

Shot 20 -- Plasma. 1.4 MA, 6.45 T. Jim loaded the increase in Btor, but
not Ip. Disrupted at t=1.4 s, which is similar to the previous
shot, although we've turned off the RF. q95=3.3.

Next shot: Jim and I have agreed to go to 1.7 kA and 6.8 T.
No RF (no He3).

Shot 21 -- Plasma. 1.67 MA, 6.8 T. Disrupted during flattop at t=0.82 s.
q95=2.86. Vertical stability is still okay. EF3's are reaching
12 kA.

Next shot: increase upper triangularity, and shift lower strike
points outward a bit. Ian, Earl, Steve W, and everyone else are
pushing for 8 T (225 kA), so we'll do it.

Shot 22 -- Plasma. Very short shot. Ip only got to 0.87 MA. Btor got
to 7.6 T, but not until nearly t=1 s.

Next shot: start Btor rampup earlier.

Shot 23 -- Plasma. Ip=1.7 MA, Btor=7.9 T (after t=1.0 s). Disrupted
at t=1.1 s. Plasma became limited on inboard wall because
OH1 railed at 25 kA. q95=3.3. Nothing too bad on the videos.
Halo current has completely opposite polarity from normal, which
is consistent with the limiter configuration.

Next shot: raise OH1 and OH2 PLC limits. Decrease nl_04 to 1.0e20.
Raise Ip to 2.0 MA.

Problem: There's a small leak which has cropped up...probably a gate valve
which has gotten too cold.
End of run.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:16:990PM
Author: To Be Determined
Engineering setup for Friday, November 8th, Run 1021108

MP 328A 2 MA Operation on Alcator C-Mod

Session leader: Granetz Physics Operator: Irby Engineering Ops :
Byford, Cochran, Parkin

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Results
-------------------------------------------------------------------------------

The primary purpose of this mini-proposal was to obtain 2 MA operation
for 0.5 s and fulfill milestone 62. A new Alcator C-Mod record plasma
current of 1.67 MA was obtained on shot 23, but a vacuum leak stopped
us from taking the 2.0 MA shot. After losing some time in the morning
bringing up the data system following the es-net upgrade, we spend
much of the day tuning up density and shape parameters in an attempt
to extend the rampdown. We made adjustments to RXL, RXU, RCUR, and
were able to achieve a good ramp down at 1.2 MA, but not above this
value. The primary problem seems to be the development of a locked
mode, possibly combined with impurity injections. The ICRF ran very
reliably at between 500 kW and 2 MW at the lower TF fields to help
reduce the volt-second requirements, though it was not clear that it
really helped.

There were no duds or fizzles today.

Shot 1 was a test shot to make sure the data system was back in
operation. On shot 15 we did not enable the ef4 supply.


Plasmas 02,03,04,05,06,07,08,09,10,11,12,13,14,16,17,19,20,21,22,23 20
Tests 01,18 02
Faults 15 --- no EF4 supply 01
---
23



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1021108xxx irby PHYSICS_OPERATOR Nov 8 2002 9:55:57:336AM
. . . . . . . . . . . . . . . . . . . .
Engineering setup for Friday, November 8th, Run 1021108

MP 328A 2 MA Operation on Alcator C-Mod

Session leader: Granetz
Physics Operator: Irby

ECDC overnight in D2 stopping by 07:00.
Overnight bake at 60C

Engineering setup as on 1021002031

Power systems the same as shot 1020822010 Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

J-Bottom should be disabled and pumped out

Enable the following gate valves: ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: FMIT1, 2, and 3 in Run On by 07:00
-------------------------------------------------------------------------------

We will start with a 1 MA shot and then work our way up in 0.2 MA
steps to the 2 MA/0.5 s level.
----------------------------------------------------------------------------
1021108001 irby PHYSICS_OPERATOR Nov 8 2002 10:25:23:470AM
. . . . . . . . . . . . . . . . . . . .
Reloaded last shot from 1021107 into seg 1
Loaded shot 10210002031 into seg 2 ---- 1 MA shot

Yijun is preparing to deliver 250 kW from D&E at 100 ms for 0.5 s

This shot will be a cycle test since we just recovered from es-net network troubles



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1021108002 irby PHYSICS_OPERATOR Nov 8 2002 10:33:48:073AM
. . . . . . . . . . . . . . . . . . . .
Good shot --- 1 MA and good rampdown

Almost double null --- will adjust SSEP for next shot

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1021108003 irby PHYSICS_OPERATOR Nov 8 2002 10:59:05:773AM
. . . . . . . . . . . . . . . . . . . .
SSEP from -.003 to -.01 m

Dropped nl04 request from 1.1e20 to 0.8e20 /m^2

Plasma to 1.64 s ---- didn't extend SSEP programming into rampdown

OH coax resistance okay
TF tap resist okay
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1021108004 irby PHYSICS_OPERATOR Nov 8 2002 11:16:39:166AM
. . . . . . . . . . . . . . . . . . . .
SSEP programming extended to 2.0 s

Plasma for 1.62 s --- not any better


SL suggests reloading shot 007 from Tuesday to get a good rampdown
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1021108005 irby PHYSICS_OPERATOR Nov 8 2002 11:23:21:770AM
. . . . . . . . . . . . . . . . . . . .
Loaded shot 1021105007 --- only 800 kA, but it did make rampdown

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1021108006 irby PHYSICS_OPERATOR Nov 8 2002 11:37:53:430AM
. . . . . . . . . . . . . . . . . . . .
Ip from 800 kA to 1000 kA --- reach peak current at 0.4 s
Extended rf pulse width to 1 s

Plasma to 1.7 s


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1021108007 irby PHYSICS_OPERATOR Nov 8 2002 11:53:53:403AM
. . . . . . . . . . . . . . . . . . . .
Ip to 1.2 MA at 0.4 s, then rampdown to 0.8 MA starting at 1.2 s

Dropped prepuff by 2 ms

Ramped nl_04 programming down starting at 1.0 s ---- help keep gas valve off

Plasma for 1.04 s ---- not too good

Ian reports locked modes --- will try raising Bt next shot


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1021108008 irby PHYSICS_OPERATOR Nov 8 2002 12:19:41:946PM
. . . . . . . . . . . . . . . . . . . .
TF current to 158 kA --- 5.7 T

Increased prefill gate to 26 ms

Plasma into rampdown at 1.2 MA

Still have locked mode
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1021108009 irby PHYSICS_OPERATOR Nov 8 2002 12:37:47:883PM
. . . . . . . . . . . . . . . . . . . .
Asked Yijun to turn off rf for one shot

Plasma for 1.29 s ----

Density and temperature look cleaner w/o rf --- but we still lost it because
of locked modes

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1021108010 irby PHYSICS_OPERATOR Nov 8 2002 1:00:04:650PM
. . . . . . . . . . . . . . . . . . . .
Removed density ramp that started at 1.0 s ---- repeat otherwise

Plasma to 1.358 s

Injection at 0.62 s ---- Chris notes sparkles on j-port antenna
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1021108011 irby PHYSICS_OPERATOR Nov 8 2002 1:13:02:670PM
. . . . . . . . . . . . . . . . . . . .
Will try 2 MW of rf from .5 to 1.2 s

Plasma into rampdown --- 1.62 s --- several elm-free h-modes

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1021108012 irby PHYSICS_OPERATOR Nov 8 2002 1:31:14:826PM
. . . . . . . . . . . . . . . . . . . .
RXU from -.02 to -.03

RXL from +.02 to 0.00

Plasma for 1.33 s



----------------------------------------------------------------------------
1021108013 irby PHYSICS_OPERATOR Nov 8 2002 1:46:03:473PM
. . . . . . . . . . . . . . . . . . . .
Increased CLEARIN by .003 m

Increased RCUR by .0015 m

Plasma for 1.31 s

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1021108014 irby PHYSICS_OPERATOR Nov 8 2002 2:01:27:580PM
. . . . . . . . . . . . . . . . . . . .
NL04 from 0.8 to 1.1 e20 /m^2

Plasma into rampdown

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1021108015 irby PHYSICS_OPERATOR Nov 8 2002 2:27:12:773PM
. . . . . . . . . . . . . . . . . . . .
TF and Oh resistances were fine for last shot ---

Ip to 1.4 MA

Tf to 164 kA, 5.9 T

No EF4 supply --- Operator did not enable supply

Tf field okay
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1021108016 irby PHYSICS_OPERATOR Nov 8 2002 2:44:32:536PM
. . . . . . . . . . . . . . . . . . . .
Try again with EF4 supply
TF ramp up started at 0.0 s

Plasma for .92 s ---



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1021108017 irby PHYSICS_OPERATOR Nov 8 2002 3:01:57:880PM
. . . . . . . . . . . . . . . . . . . .
Nl04 request to 1.3e20 /m^2
Started TF ramp a little earlier

Plasma for 1.09 s --- Steve Wolfe notes q95 is 3.0 --- not a good thing

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1021108018 irby PHYSICS_OPERATOR Nov 8 2002 3:15:11:916PM
. . . . . . . . . . . . . . . . . . . .
TF/OH look good

TF current from 164 to 175 kA --- PLC limits to 178 kA

Forgot to load changes ---- no power test
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1021108019 irby PHYSICS_OPERATOR Nov 8 2002 3:31:27:483PM
. . . . . . . . . . . . . . . . . . . .
Take shot 18 with power

Plasma for 1.35 s --- a little h-mode
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1021108020 irby PHYSICS_OPERATOR Nov 8 2002 3:47:02:620PM
. . . . . . . . . . . . . . . . . . . .
TF to 181 kA, 6.5 T ---- PLC limit to 184
Ip to 1.6 MA
EF3 supply limit to 15 kA

Plasma to 1.39 s ---

Only 1.4 MA again ---- did not load it!!
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1021108021 irby PHYSICS_OPERATOR Nov 8 2002 4:25:48:256PM
. . . . . . . . . . . . . . . . . . . .
Ip to 1.7 MA

TF to 6.85 T, 190 kA, PLC limit to 195 kA

Plasma for .810 s

Ip to 1.676 MA *********** NEW Alcator C-Mod Record *****************

Large injections at 0.5 s --- locked modes seen near this time


Alternator crew happy --- no new noises
TF and OH look very good
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1021108022 irby PHYSICS_OPERATOR Nov 8 2002 4:32:28:540PM
. . . . . . . . . . . . . . . . . . . .
TF to 222 kA ---- 8T
Ip still at 1.7 MA
RXU decreased by 0.015 m
RXL increased by 0.005 m

Plasma to 0.291 s

TF/OH resistances look very good
----------------------------------------------------------------------------
1021108023 irby PHYSICS_OPERATOR Nov 8 2002 4:51:07:746PM
. . . . . . . . . . . . . . . . . . . .
Extended RXU flat-top to 1.22 s
PLC start time for TF moved back to -1.5 s
Prefill puff 28 ms

Plasma for 1.13 s ---- OH1 hit limits --- plasma moved inside

Ip flat-topped at 1.67 MA

Density and radiation start ramping up at 1.02 s or so

LN2 induced leak ends run.

Session Leader Comments
Nov 8 2002 10:45:32:987AM1021108002Robert GranetzShot 02 -- Plasma. Full length. 1 MA, 5.33 T. Nearly double null. Rampdown
starts at t=1.3 s.

Next shot: increase SSEP; increase flattop duration.
Nov 8 2002 11:02:12:020AM1021108003Robert GranetzShot 03 -- Plasma. Disrupted during rampdown. SSEP programming was not
extended with the flattop extension. Upper gussets light up at
end.

Next shot: extend -10 mm SSEP to t=2.0 s.
Nov 8 2002 11:14:34:340AM1021108004Robert GranetzShot 04 -- Plasma. Still disrupted during rampdown at about the same time.
Peak Ihalo=90 kA.

Next shot: Give up on this SSEP-controlled shot (which was chosen
because it appeared to have full 1 MA rampdowns) and start from
a more standard shot, such as 1021105007 (0.8 MA, 5.4 T)
Nov 8 2002 11:30:03:860AM1021108005Robert GranetzShot 05 -- Plasma. 0.8 MA, 5.4 T. Full rampdown. Prf=0.5 MW from t=0.1 to
t=0.6 s.

Next shot: increase Ip to 1 MA; smooth the early Ip programming;
extend low-power RF to t=1.0 s.
Nov 8 2002 11:40:49:820AM1021108006Robert GranetzShot 06 -- Plasma. 1.0 MA, 5.4 T. Disrupted about halfway through rampdown.
Peak Ihalo=100 kA. Kappa is going down and q95 is going up during
the rampdown, as desired. n/ncrit is remaining low. These have
all been thermal quench disruptions. Ian is suggesting the
possibility of a locked mode.

Next shot: raise Ip to 1.2 MA, startup rampdown earlier. Turn off
gas puffing late in shot.
Nov 8 2002 11:58:43:807AM1021108007Robert GranetzShot 07 -- Plasma. 1.2 MA, 5.4 T. Disrupted during flattop. Big injection.
There's a change in core parameters around t=0.8 s, which may
hint of some MHD such as a locked mode. q95=3.1 at that time.

Next shot: raise Bt a little to avoid being near q95=3.
Nov 8 2002 12:06:09:457PM1021108007Robert GranetzMHDQ batch queue is all clogged up. Stewart is looking into it.
Nov 8 2002 01:39:24:130PM1021108008Robert GranetzShot 08 -- Plasma. Full rampdown. 1.2 MA, 5.7 T. Still looks like there's
something affecting the core plasma starting at t=0.8 s. There
were lots of spiky things from t=1.3-1.5 s. q95=3.28. n/ncrit
is getting close to 1.2.

Next shot: try turning off the low-power RF
Nov 8 2002 01:39:36:910PM1021108009Robert GranetzShot 09 -- Plasma. Disrupted early in rampdown. 1.2 MA, 5.7 T, no RF.
Drop in confinement is now delayed until t=1.08 s. Still don't
know what it is. No rotating MHD seen...still could be a locked
mode.

Next shot: try keeping the density at the flattop level for
long into the rampdown.
Nov 8 2002 01:39:50:583PM1021108010Robert GranetzShot 10 -- Plasma. Disrupted in rampdown. 1.2 MA, 5.7 T. Injection at
t=0.63 s, which is the same time that the core plasma parameters
degrade.

Next shot: try putting in 2 MW of RF from t=0.5 to 1.2 s.
Nov 8 2002 01:38:09:970PM1021108011Robert GranetzShot 11 -- Plasma. Disrupts late in rampdown. 1.2 MA, 5.7 T. Multiple
H-modes. Got about 1.7 MW.

Next shot: try reducing RXU and RXL by 1 cm to change shape and
strike points. Keep RF power at 2 MW.
Nov 8 2002 01:37:01:403PM1021108012Robert GranetzShot 12 -- Plasma. Disrupted early in rampdown. Short H-mode. Prf=2.0 MW.

Next shot: increase inner gap from 12 to 15 mm, keeping outer
gap the same. Keep RF at 2 MW.
Nov 8 2002 01:53:43:527PM1021108013Robert GranetzShot 13 -- Plasma. Disrupted early in rampdown. 1.2 MA, 5.7 T. Very similar
to previous shot. Prf=2.0 MW, very constant.

Next shot: what's left to vary? Let's increase nl_04 from 0.8 to
1.1e20 m-2.
Nov 8 2002 02:09:16:427PM1021108014Robert GranetzShot 14 -- Plasma. Good shot. Full rampdown, finally! 1.2 MA, 5.7 T.
Multiple H-modes. Prf=2.0 MW, pretty clean.

Next shot: raise Ip to 1.4 MA, Bt to 5.9 T, and have the RF add
a power rampdown from 2.0 to 0.0 MW over t=1.2 to 1.4 s.
Nov 8 2002 02:26:24:817PM1021108015Robert GranetzShot 15 -- Dud. No EF4

Next shot: try again.
Nov 8 2002 02:47:06:577PM1021108016Robert GranetzShot 16 -- Plasma. 1.4 MA, 5.9 T. Disrupted during flattop. Ihalo_L=80 kA,
Ihalo_U=70 kA, did not drop down all the way. Signs of a locked
mode at 0.74 s. Prf=2.0 MW.

Next shot: raise nl_04 to 1.3e20 m-2.
Nov 8 2002 03:07:21:147PM1021108017Robert GranetzShot 17 -- Plasma. 1.4 MA, 5.9 T. Disrupted later in flattop. Halo currents
and rangefinder amplitudes continue to remain low because the
plasma remains near the midplane. Prf=2.0 MW. q95=3.0, which
is definitely a bad thing.

Next shot: increase Btor to 6.3 T in order to raise q95 above 3.
Nov 8 2002 03:13:45:443PM1021108018Robert GranetzShot 18 -- Test. No power shot. Jim realized in time that he didn't actually
load the change in Btor, and we'd rather avoid the disruption.

Next shot: try again; 6.3 T
Nov 8 2002 03:37:12:860PM1021108019Robert GranetzShot 19 -- Plasma. 1.4 MA, 6.25 T. Disrupted during rampdown. Prf=2.0 MW.
Short H-mode. q95=3.22. n/ncrit gets up to 1.17, but EFC looks
quiet. Halo currents remain below 100 kA and rangefinder remains
below 50 um, since plasma only drops to -20 cm.

Next shot: raise Ip to 1.6 MA, Bt to 6.5 T. Turn off RF. (EF3
and TF PLC current limits are being raised.)
Nov 8 2002 04:19:19:580PM1021108021Robert GranetzShot 21 -- Plasma. 1.67 MA, 6.8 T. Disrupted during flattop at t=0.82 s.
q95=2.86. Vertical stability is still okay. EF3's are reaching
12 kA.

Next shot: increase upper triangularity, and shift lower strike
points outward a bit. Ian, Earl, Steve W, and everyone else are
pushing for 8 T (225 kA), so we'll do it.
Nov 8 2002 04:34:38:030PM1021108022Robert GranetzShot 22 -- Plasma. Very short shot. Ip only got to 0.87 MA. Btor got
to 7.6 T, but not until nearly t=1 s.

Next shot: start Btor rampup earlier.
Nov 8 2002 05:13:12:587PM1021108023Robert GranetzShot 23 -- Plasma. Ip=1.7 MA, Btor=7.9 T (after t=1.0 s). Disrupted
at t=1.1 s. Plasma became limited on inboard wall because
OH1 railed at 25 kA. q95=3.3. Nothing too bad on the videos.
Halo current has completely opposite polarity from normal, which
is consistent with the limiter configuration.

Next shot: raise OH1 and OH2 PLC limits. Decrease nl_04 to 1.0e20.
Raise Ip to 2.0 MA.
Nov 8 2002 05:14:47:683PM1021108023Robert GranetzProblem: There's a small leak which has cropped up...probably a gate valve
which has gotten too cold.
End of run.

Physics Operator Comments
Nov 8 2002 09:55:57:337AMJim IrbyEngineering setup for Friday, November 8th, Run 1021108

MP 328A 2 MA Operation on Alcator C-Mod

Session leader: Granetz
Physics Operator: Irby

ECDC overnight in D2 stopping by 07:00.
Overnight bake at 60C

Engineering setup as on 1021002031

Power systems the same as shot 1020822010 Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)

J-Bottom should be disabled and pumped out

Enable the following gate valves: ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: FMIT1, 2, and 3 in Run On by 07:00
-------------------------------------------------------------------------------

We will start with a 1 MA shot and then work our way up in 0.2 MA
steps to the 2 MA/0.5 s level.
Nov 8 2002 10:25:23:470AM1021108001Jim IrbyReloaded last shot from 1021107 into seg 1
Loaded shot 10210002031 into seg 2 ---- 1 MA shot

Yijun is preparing to deliver 250 kW from D&E at 100 ms for 0.5 s

This shot will be a cycle test since we just recovered from es-net network troubles



Nov 8 2002 10:33:48:073AM1021108002Jim IrbyGood shot --- 1 MA and good rampdown

Almost double null --- will adjust SSEP for next shot

Nov 8 2002 10:59:05:773AM1021108003Jim IrbySSEP from -.003 to -.01 m

Dropped nl04 request from 1.1e20 to 0.8e20 /m^2

Plasma to 1.64 s ---- didn't extend SSEP programming into rampdown

OH coax resistance okay
TF tap resist okay
Nov 8 2002 11:16:39:167AM1021108004Jim IrbySSEP programming extended to 2.0 s

Plasma for 1.62 s --- not any better


SL suggests reloading shot 007 from Tuesday to get a good rampdown
Nov 8 2002 11:23:21:770AM1021108005Jim IrbyLoaded shot 1021105007 --- only 800 kA, but it did make rampdown

Nov 8 2002 11:37:53:430AM1021108006Jim IrbyIp from 800 kA to 1000 kA --- reach peak current at 0.4 s
Extended rf pulse width to 1 s

Plasma to 1.7 s


Nov 8 2002 11:53:53:403AM1021108007Jim IrbyIp to 1.2 MA at 0.4 s, then rampdown to 0.8 MA starting at 1.2 s

Dropped prepuff by 2 ms

Ramped nl_04 programming down starting at 1.0 s ---- help keep gas valve off

Plasma for 1.04 s ---- not too good

Ian reports locked modes --- will try raising Bt next shot


Nov 8 2002 12:19:41:947PM1021108008Jim IrbyTF current to 158 kA --- 5.7 T

Increased prefill gate to 26 ms

Plasma into rampdown at 1.2 MA

Still have locked mode
Nov 8 2002 12:37:47:883PM1021108009Jim IrbyAsked Yijun to turn off rf for one shot

Plasma for 1.29 s ----

Density and temperature look cleaner w/o rf --- but we still lost it because of locked modes

Nov 8 2002 01:00:04:650PM1021108010Jim IrbyRemoved density ramp that started at 1.0 s ---- repeat otherwise

Plasma to 1.358 s

Injection at 0.62 s ---- Chris notes sparkles on j-port antenna
Nov 8 2002 01:13:02:670PM1021108011Jim IrbyWill try 2 MW of rf from .5 to 1.2 s

Plasma into rampdown --- 1.62 s --- several elm-free h-modes

Nov 8 2002 01:31:14:827PM1021108012Jim IrbyRXU from -.02 to -.03

RXL from +.02 to 0.00

Plasma for 1.33 s



Nov 8 2002 01:46:03:473PM1021108013Jim IrbyIncreased CLEARIN by .003 m

Increased RCUR by .0015 m

Plasma for 1.31 s

Nov 8 2002 02:01:27:580PM1021108014Jim IrbyNL04 from 0.8 to 1.1 e20 /m^2

Plasma into rampdown

Nov 8 2002 02:27:12:773PM1021108015Jim IrbyTF and Oh resistances were fine for last shot ---

Ip to 1.4 MA

Tf to 164 kA, 5.9 T

No EF4 supply --- Operator did not enable supply

Tf field okay
Nov 8 2002 02:44:32:537PM1021108016Jim IrbyTry again with EF4 supply
TF ramp up started at 0.0 s

Plasma for .92 s ---



Nov 8 2002 03:01:57:880PM1021108017Jim IrbyNl04 request to 1.3e20 /m^2
Started TF ramp a little earlier

Plasma for 1.09 s --- Steve Wolfe notest q95 is 3.0 --- not a good thing

Nov 8 2002 03:15:11:917PM1021108018Jim IrbyTF/OH look good

TF current from 164 to 175 kA --- PLC limits to 178 kA

Forgot to load changes ---- no power test
Nov 8 2002 03:31:27:483PM1021108019Jim IrbyTake shot 18 with power

Plasma for 1.35 s --- a little h-mode
Nov 8 2002 03:47:02:620PM1021108020Jim IrbyTF to 181 kA, 6.5 T ---- PLC limit to 184
Ip to 1.6 MA
EF3 supply limit to 15 kA

Plasma to 1.39 s ---

Only 1.4 MA again ---- did not load it!!
Nov 8 2002 04:25:48:257PM1021108021Jim IrbyIp to 1.7 MA

TF to 6.85 T, 190 kA, PLC limit to 195 kA

Plasma for .810 s

Ip to 1.676 MA *********** NEW Alcator C-Mod Record *****************

Large injections at 0.5 s --- locked modes seen near this time


Alternator crew happy --- no new noises
TF and OH look very good
Nov 8 2002 04:32:28:540PM1021108022Jim IrbyTF to 222 kA ---- 8T
Ip still at 1.7 MA
RXU decreased by 0.015 m
RXL increased by 0.005 m

Plasma to 0.291 s

TF/OH resistances look very good
Nov 8 2002 04:51:07:747PM1021108023Jim IrbyExtended RXU flat-top to 1.22 s
PLC start time for TF moved back to -1.5 s
Prefill puff 28 ms

Plasma for 1.13 s ---- OH1 hit limits --- plasma moved inside

Ip flat-topped at 1.67 MA

Density and radiation start ramping up at 1.02 s or so

Engineering Operator Comments
ShotTimeTypeStatusComment
110:09:36:357AMTestOk
210:22:44:190AMPlasmaOk
310:47:07:080AMPlasmaOk
411:00:04:693AMPlasmaOk
511:17:23:210AMPlasmaOk
611:30:13:937AMPlasmaOk
711:44:59:253AMPlasmaOk
812:06:42:127PMPlasmaOk
912:24:49:643PMPlasmaOk
1012:50:35:203PMPlasmaOk
1101:05:05:190PMPlasmaOk
1201:18:49:400PMPlasmaOk
1301:39:27:347PMPlasmaOk
1401:52:48:290PMPlasmaOk
1502:21:56:227PMPlasmaBadNO EF4, operator error
1602:34:44:510PMPlasmaOk
1702:50:56:210PMPlasmaOk
1803:09:56:980PMTestOkNo power shot
1903:21:35:543PMPlasmaOk
2003:40:06:507PMPlasmaOk
2103:57:56:320PMPlasmaOk
2204:22:55:543PMPlasmaOk
2304:41:56:360PMPlasmaOk