Alcator C-Mod Run 990521 Information

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Miniproposals
Miniproposal:249
Date Filed: 5/13/1999
Title:Impurity Transport Coefficients during Ohmic H-modes
First Author:John Rice
Session Leader:Ian Hutchinson (shots 1-32)
Session Leader:John Rice (shots 1-32)

Operators
Session leader(s):Ian Hutchinson,John Rice
Physics operator(s):Jim Irby
Engineering operator(s):Gary Dekow,Bill Cochran,Frank Silva

Engineering Operator Run Comment
Irby/Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:20:540PM
Author: To Be Determined
Run summary for 990521, MP249, Impurity Transport during Ohmic H-mode

There were many extended periods of Ohmic ELM-free and EDA H-mode in
several of the discharges. These H-modes however were not the most
robust, as moderate levels of argon and/or small CaF2 injections often
terminated the H-mode. In spite of this the objectives of MP249 were
achieved. There was good correlation between the rotation velocities
determined by Doppler shifts and from the fast magnetics. Many of
the plasmas had large stored energy increases; shot 28 had a stored energy
of 160 kJ. Plasma currents as high as 1.44 MA were obtained. Edge Te and
x-ray pedestals were measured. The impurity confinement
during ELM-free H-modes were much longer than the discharge length,
which led to the termination of the H-mode. For EDA Ohmic discharges,
the confinement was shorter, but the injection often caused the plasma
to return to ELM-free. The main result is that the impurity confinement
in Ohmic H-mode plasmas is very similar to ICRF H-mode discharges.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:01:363PM
Author: To Be Determined
PHYSOP Summary for 990521

MP#249 Impurity Xport in Ohmic H-mode

EO Silva/Cochran/Dekow
PO Irby
SL Rice/Hutch


Engineering Setup for 990521:

Load from 990305013

ECDC in D2 for two hours before the run

Note that the TF will be ramped down from 5.4 to 4 T during the shot

Gas setup:

B-top - 6 psi of D2
B-side lower - 1 psi of Ar
C-side - 30 psi D2

General:

Machine ran well with record ohmic H-mode parameters. The
cause of a couple of full current disruptions should be
investigated.

Disruptions were found to affect both br0 and bz0
for the next shot(s) with deltas of over 2 mT. Now that
the machine is pretty clean, these variations may be more
the cause of post disruption fizzles than gas/wall
conditions.

We obtained record stored energy for an ohmic H-mode
on shot 28. Neutron rate was approaching 10^13/s today, peak
density 5e20.

Current rise was a little fast and probably should have been
tweeked at some point, but since it was running....

SL claims success for MP249.


Problems:

03 EF4 crossover com fault. May have been caused by
seg1 to seg2 discontinuity in TF programming. Found
voltage regulator offset that may have been around for
some time --- Bill and Gary will investigate.

16 Com fault in OH2L --- supply okay. EF1 breaker pulled out.

32 Runaway process caused us to abort shot 32

Score:

3 test shots
3 fizzles
25 plasmas
-------------
31 shots


----------------------------------------------------------------------------
990521001 IRBY PHYSICS_OPERATOR May 21 1999 7:56:22:530AM
. . . . . . . . . . . . . . . . . . . .
OH2 Commutation test

hybrid gas disabled

----------------------------------------------------------------------------
990521002 IRBY PHYSICS_OPERATOR May 21 1999 8:11:08:826AM
. . . . . . . . . . . . . . . . . . . .
Plasma attempt
ECE, VUV, Laser blowoff, argon puff enabled
no plasma

----------------------------------------------------------------------------
990521003 IRBY PHYSICS_OPERATOR May 21 1999 8:34:19:420AM
. . . . . . . . . . . . . . . . . . . .
BR0 too small, added .0015 to offset
pre-puff pressure was okay for last shot --- no change

plasma for 0.5 seconds -- EF4 shoot through --- oh1 crowbar


----------------------------------------------------------------------------
990521004 IRBY PHYSICS_OPERATOR May 21 1999 9:10:09:263AM
. . . . . . . . . . . . . . . . . . . .
need to do EF4 crossover test: loaded 990121008 --- ef4 PLC limites set for +-2kA

moved fizzle from .08 to 1.3 seconds

results: ef4 looks okay, but may have offset in ef4 regulator --- we have had
it at least since 1/21/99
----------------------------------------------------------------------------
990521005 IRBY PHYSICS_OPERATOR May 21 1999 9:14:33:950AM
. . . . . . . . . . . . . . . . . . . .
PLC limits to -8 to +4 on EF4 to see if supply follows programming

EF4 looks great ---- assume TF jump caused problem at crossover
----------------------------------------------------------------------------
990521006 IRBY PHYSICS_OPERATOR May 21 1999 9:25:57:250AM
. . . . . . . . . . . . . . . . . . . .
loading in 990521003 ---- copied TF seg2 to TF seg1 to keep from having TF current glitch

good plasma ---
----------------------------------------------------------------------------
990521007 IRBY PHYSICS_OPERATOR May 21 1999 9:51:22:890AM
. . . . . . . . . . . . . . . . . . . .
repeat of previous shot

John reduced spot size of beam --- to much CaF2

Brian pokes plasma with probe

plasma --- several H-modes --- 82 kJ peak
----------------------------------------------------------------------------
990521008 IRBY PHYSICS_OPERATOR May 21 1999 10:05:40:716AM
. . . . . . . . . . . . . . . . . . . .
Ar puff extended by 10 ms to 0.412

Bringing up density programming a little earlier --- get H-mode earlier?

plasma --- H-modes a little earlier --- 83 kj
----------------------------------------------------------------------------
990521009 IRBY PHYSICS_OPERATOR May 21 1999 10:25:06:546AM
. . . . . . . . . . . . . . . . . . . .
Argon disabled

good longer lasting H-Modes
----------------------------------------------------------------------------
990521010 IRBY PHYSICS_OPERATOR May 21 1999 10:40:27:920AM
. . . . . . . . . . . . . . . . . . . .
Argon enabled but 10 ms shorter pulse: .402 seconds again

Ip raised to 800,000 at 0.2704

good H-modes --- next shot w/o argon --- 84 kj
----------------------------------------------------------------------------
990521011 IRBY PHYSICS_OPERATOR May 21 1999 11:13:18:500AM
. . . . . . . . . . . . . . . . . . . .
Argon disabled

Raised early density from .97 to 1.1 e 20 at 0.291 seconds

111 kj
----------------------------------------------------------------------------
990521012 IRBY PHYSICS_OPERATOR May 21 1999 11:20:06:280AM
. . . . . . . . . . . . . . . . . . . .
Raised current from 1.05 to 1.15 MA

Raised TF to match

Great H-mode --- 127 kj
----------------------------------------------------------------------------
990521013 IRBY PHYSICS_OPERATOR May 21 1999 11:37:59:250AM
. . . . . . . . . . . . . . . . . . . .
RXU from .02 to .05

Laser blowoff at 0.75 stopped H-mode, 103 kj
----------------------------------------------------------------------------
990521014 IRBY PHYSICS_OPERATOR May 21 1999 12:08:20:013PM
. . . . . . . . . . . . . . . . . . . .
Argon enabled --- width to 25 ms from 30 ms

plasma --- 103 kj
----------------------------------------------------------------------------
990521015 IRBY PHYSICS_OPERATOR May 21 1999 12:17:43:733PM
. . . . . . . . . . . . . . . . . . . .
Repeat

plasma --- not much of an H-mode --- injection near L to H transition
----------------------------------------------------------------------------
990521016 IRBY PHYSICS_OPERATOR May 21 1999 12:47:24:140PM
. . . . . . . . . . . . . . . . . . . .
Argon off

IC_EF4 raised to 3400 amps at 0.612 seconds ---- Goetz fix for disruptions at higher current

Disruption --- com fault on OH2L

Plasma for abt 0.46 seconds
----------------------------------------------------------------------------
990521017 IRBY PHYSICS_OPERATOR May 21 1999 12:59:21:636PM
. . . . . . . . . . . . . . . . . . . .
repeat - nothing found on power supplies

good shot --- not a great H-mode --- looks like CaF2 did it in again
----------------------------------------------------------------------------
990521018 IRBY PHYSICS_OPERATOR May 21 1999 1:15:58:093PM
. . . . . . . . . . . . . . . . . . . .
Current up to 1.25 MA
TF current to match (127 kA)

plasma --- H-mode killed early again
----------------------------------------------------------------------------
990521019 IRBY PHYSICS_OPERATOR May 21 1999 1:35:27:186PM
. . . . . . . . . . . . . . . . . . . .
Laser blowoff disabled --- H-mode length?

dropped rcur from 0.668 to 0.667 --- give Brian a little better target

better plasma, but H-mode still late --- solid EDA --- 132 kj
----------------------------------------------------------------------------
990521020 IRBY PHYSICS_OPERATOR May 21 1999 1:55:35:123PM
. . . . . . . . . . . . . . . . . . . .
Argon enabled

Fizzle --- startup up bad
----------------------------------------------------------------------------
990521021 IRBY PHYSICS_OPERATOR May 21 1999 2:07:34:250PM
. . . . . . . . . . . . . . . . . . . .
bro offset back to 0.000

IC_EF4U to -1300 from -1275

Plasma --- H-mode --- 131 kj
----------------------------------------------------------------------------
990521022 IRBY PHYSICS_OPERATOR May 21 1999 2:26:39:060PM
. . . . . . . . . . . . . . . . . . . .
Argon disabled

RCUR from 0.667 to 0.665 to give probe a better target

Early density to 1.2e20 (t = 0.29 s)

Put BR0 offset to 0.0005 T

plasma okay
----------------------------------------------------------------------------
990521023 IRBY PHYSICS_OPERATOR May 21 1999 2:41:50:700PM
. . . . . . . . . . . . . . . . . . . .
Ip to 1.35 MA

Bt to 137 kA to match

plasma --- no H-mode until ramp down
----------------------------------------------------------------------------
990521024 IRBY PHYSICS_OPERATOR May 21 1999 3:01:21:950PM
. . . . . . . . . . . . . . . . . . . .
Dropped TF current to 132 kA from 137

Dropped early density to 1.1 from 1.2 e 20

Dropped EF4 current beyond 1.13 seconds by about 500 amps to reduce EF2 swing toward zero

Strong fizzle
----------------------------------------------------------------------------
990521025 IRBY PHYSICS_OPERATOR May 21 1999 3:17:47:920PM
. . . . . . . . . . . . . . . . . . . .
EF4 changed from -1300 to -1310

BR0 dropped by 1 mT --- offset now -.0005

Ian noted that these br/bz tweeks seem to have been required after the disruptions on shot 16

Plasma --- H-modes start a little earlier
----------------------------------------------------------------------------
990521026 IRBY PHYSICS_OPERATOR May 21 1999 3:42:40:216PM
. . . . . . . . . . . . . . . . . . . .
We asked Brian to remove his first fsp scan

repeat last shot

great plasma --- long elm free --- 146 kj
----------------------------------------------------------------------------
990521027 IRBY PHYSICS_OPERATOR May 21 1999 3:55:39:623PM
. . . . . . . . . . . . . . . . . . . .
Tweeked Bt current to 132 kA at 0.65 seconds, to 155 kA at 0.75

H-mode started a little later
----------------------------------------------------------------------------
990521028 IRBY PHYSICS_OPERATOR May 21 1999 4:15:12:450PM
. . . . . . . . . . . . . . . . . . . .
Ip to 1.45 MA

Bt current to 165 kA to match Ip

Dropped EF4 by 500 amps beyond 1.34 seconds to help EF2

Good H-mode, start at 0.62 , 158 kj
----------------------------------------------------------------------------
990521029 IRBY PHYSICS_OPERATOR May 21 1999 4:45:08:390PM
. . . . . . . . . . . . . . . . . . . .
Changed RCUR by 1mm to .664 from .665

Probe running again

Nice disruption ---
----------------------------------------------------------------------------
990521030 IRBY PHYSICS_OPERATOR May 21 1999 4:56:39:090PM
. . . . . . . . . . . . . . . . . . . .
Bt "ramp up" delayed by 50 ms to 0.7 seconds

Bt current to 170 kA

Fizzle
----------------------------------------------------------------------------
990521031 IRBY PHYSICS_OPERATOR May 21 1999 5:11:53:216PM
. . . . . . . . . . . . . . . . . . . .
BR0 up 2 mT from -.0005 to .0015

EF4 current to -1275 from -1310 to raise Bz0

disruption at full current

Session Leader Comments
May 21 1999 11:28:15:967AM990521006John RiceCaF2 injection at 0.7 s temporarily killed the ELM-free Ohmic H-mode, but it recovered, with an
EDA at the edge of the shot. impurity tau from 50 to 117 ms.
decent rotation from argon and fast magnetics
May 21 1999 11:29:06:153AM990521007John RiceCaF2 injection at 0.7 s temporarily killed the ELM-free Ohmic H-mode, but it recovered, with an
EDA at the edge of the shot. impurity tau from 50 to 117 ms.
decent rotation from argon and fast magnetics
May 21 1999 11:30:00:200AM990521008John RiceCaF2 injection at 0.8 s , tau of 70 ms. in and out of Ohmic H-mode
May 21 1999 11:31:05:263AM990521009John RiceCaF2 injection at 0.7 s , tau of 40 ms, increasing to 300 ms during ELM-free Ohmic H-mode.
argon disabled, allowing sustained H-mode period
May 21 1999 11:31:49:797AM990521010John RiceCaF2 injection at 1.05 s
argon enabled
May 21 1999 11:32:03:123AM990521011John RiceCaF2 injection at 1.05 s
argon disabled
May 21 1999 11:32:49:827AM990521012John Riceno CaF2 injection
argon disabled
higher current, long EDA
May 21 1999 11:45:34:250AM990521013John RiceCaF2 injection .75s, infinite confinement until plasma goes out of H-mode
argon disabled
May 21 1999 12:01:56:983PM990521014John RiceCaF2 injection .75s, before EDA, L-mode tau
argon enabled, 25 ms pulse
May 21 1999 12:18:40:280PM990521015John RiceCaF2 injection .8s,
argon enabled, 25 ms pulse
this combination was too much for the H-mode
May 21 1999 12:53:43:233PM990521016John RiceCaF2 injection .8s,
argon disabled
early disruption
May 21 1999 12:59:10:920PM990521017John RiceCaF2 injection .8s, knocked it out of H-mode
argon disabled
He beam on
May 21 1999 01:16:33:920PM990521018John RiceCaF2 injection .8s, 1/4 spot size, still killed it
argon disabled
May 21 1999 01:50:14:297PM990521019John Riceno CaF2 injection
argon disabled
He beam on
good EDA
May 21 1999 02:14:19:793PM990521021John Riceno CaF2 injection
argon enabled, short ELM-free
He beam on
May 21 1999 02:23:51:717PM990521021John RiceCaF2 injection .8s, 1/8 spot, infinite confinement
argon disabled
May 21 1999 02:41:24:450PM990521022John RiceCaF2 injection .8s, 1/8 spot, infinite confinement
argon disabled
May 21 1999 02:45:43:997PM990521023John RiceCaF2 injection .85s, 1/20 spot, 40 ms tau, late H-mode
argon disabled
May 21 1999 03:42:36:937PM990521026John RiceCaF2 injection 1.1s, 1/20 spot, missed H-mode
argon disabled
May 21 1999 03:58:54:640PM990521027John RiceCaF2 injection .9s, 1/20 spot, killed H-mode
argon enabled
May 21 1999 04:25:16:967PM990521028John Riceno CaF2 injection
argon enabled

Physics Operator Comments
May 21 1999 07:56:22:530AM990521001Jim IrbyOH2 Commutation test
May 21 1999 07:57:25:857AM990521001Jim Irbyhybrid gas disabled
May 21 1999 08:11:08:827AM990521002Jim IrbyPlasma attempt
ECE, VUV, Laser blowoff, argon puff enabled
no plasma
May 21 1999 08:34:19:420AM990521003Jim IrbyBR0 too small, added .0015 to offset
pre-puff pressure was okay for last shot --- no change

plasma for 0.5 seconds -- EF4 shoot through --- oh1 crowbar


May 21 1999 09:10:09:263AM990521004Jim Irbyneed to do EF4 crossover test: loaded 990121008 --- ef4 PLC limites set for +-2kA

moved fizzle from .08 to 1.3 seconds

results: ef4 looks okay, but may have offset in ef4 regulator --- we have had it at least since 1/21/99
May 21 1999 09:14:33:950AM990521005Jim IrbyPLC limits to -8 to +4 on EF4 to see if supply follows programming

EF4 looks great ---- assume TF jump caused program at crossover
May 21 1999 09:25:57:250AM990521006Jim Irbyloading in 990521003 ---- copied TF seg2 to TF seg1 to keep from having TF current glitch

good plasma ---
May 21 1999 09:51:22:890AM990521007Jim Irbyrepeat of previous shot

John reduced spot size of beam --- to much CaF2

Brian pokes plasma with probe

plasma --- several H-modes --- 82 kJ peak
May 21 1999 10:05:40:717AM990521008Jim IrbyAr puff extended by 10 ms to 0.412

Bringing up density programming a little earlier --- get H-mode earlier?

plasma --- H-modes a little earlier --- 83 kj

May 21 1999 10:25:06:547AM990521009Jim IrbyArgon disabled

good longer lasting H-Modes



May 21 1999 10:40:27:920AM990521010Jim IrbyArgon enabled but 10 ms shorter pulse: .402 seconds again

Ip raised to 800,000 at 0.2704

good H-modes --- next shot w/o argon --- 84 kj


May 21 1999 11:13:18:500AM990521011Jim IrbyArgon disabled

Raised early density from .97 to 1.1 e 20 at 0.291 seconds

111 kj

May 21 1999 11:20:06:280AM990521012Jim IrbyRaised current from 1.05 to 1.15 MA

Raised TF to match

Great H-mode --- 127 kj
May 21 1999 11:37:59:250AM990521013Jim IrbyRXU from .02 to .05

Laser blowoff at 0.75 stopped H-mode, 103 kj
May 21 1999 12:08:20:013PM990521014Jim IrbyArgon enabled --- width to 25 ms from 30 ms

plasma --- 103 kj
May 21 1999 12:17:43:733PM990521015Jim IrbyRepeat

plasma --- not much of an H-mode --- injection near L to H transition
May 21 1999 12:47:24:140PM990521016Jim IrbyArgon off

IC_EF4 raised to 3400 amps at 0.612 seconds ---- Goetz fix for disruptions at higher current

Disruption --- com fault on OH2L

Plasma for abt 0.46 seconds
May 21 1999 12:59:21:637PM990521017Jim Irbyrepeat - nothing found on power supplies

good shot --- not a great H-mode --- looks like CaF2 did it in again
May 21 1999 01:15:58:093PM990521018Jim IrbyCurrent up to 1.25 MA
TF current to match (127 kA)

plasma --- H-mode killed early again

May 21 1999 01:35:27:187PM990521019Jim IrbyLaser blowoff disabled --- H-mode length?

dropped rcur from 0.668 to 0.667 --- give Brian a little better target

better plasma, but H-mode still late --- solid EDA --- 132 kj

May 21 1999 01:55:35:123PM990521020Jim IrbyArgon enabled

Fizzle --- startup up bad


May 21 1999 02:07:34:250PM990521021Jim Irbybro offset back to 0.000

IC_EF4U to -1300 from -1275

Plasma --- H-mode --- 131 kj

May 21 1999 02:26:39:060PM990521022Jim IrbyArgon disabled

RCUR from 0.667 to 0.665 to give probe a better target

Early density to 1.2e20 (t = 0.29 s)

Put BR0 offset to 0.0005 T

plasma okay

May 21 1999 02:41:50:700PM990521023Jim IrbyIp to 1.35 MA

Bt to 137 kA to match

plasma --- no H-mode until ramp down

May 21 1999 03:01:21:950PM990521024Jim IrbyDropped TF current to 132 kA from 137

Dropped early density to 1.1 from 1.2 e 20

Dropped EF4 current beyond 1.13 seconds by about 500 amps to reduce EF2 swing toward zero

Strong fizzle

May 21 1999 03:17:47:920PM990521025Jim IrbyEF4 changed from -1300 to -1310

BR0 dropped by 1 mT --- offset now -.0005

Ian noted that these br/bz tweeks seem to have been required after the distruption on shot 16

Plasma --- H-modes start a little earlier
May 21 1999 03:42:40:217PM990521026Jim IrbyWe asked Brian to remove his first fsp scan

repeat last shot

great plasma --- long elm free --- 146 kj

May 21 1999 03:55:39:623PM990521027Jim IrbyTweeked Bt current to 132 kA at 0.65 seconds, to 155 kA at 0.75

H-mode started a little later
May 21 1999 04:15:12:450PM990521028Jim IrbyIp to 1.45 MA

Bt current to 165 kA to match Ip

Dropped EF4 by 500 amps beyond 1.34 seconds to help EF2

Good H-mode, start at 0.62 , 158 kj


May 21 1999 04:45:08:390PM990521029Jim IrbyChanged RCUR by 1mm to .664 from .665

Probe running again

Nice disruption ---
May 21 1999 04:56:39:090PM990521030Jim IrbyBt "ramp up" delayed by 50 ms to 0.7 seconds

Bt current to 170 kA

Fizzle
May 21 1999 05:11:53:217PM990521031Jim IrbyBR0 up 2 mT from -.0005 to .0015

EF4 current to -1275 from -1310 to raise Bz0

disruption at full current


Engineering Operator Comments
ShotTimeTypeStatusComment
107:57:55:577AMTestOkOH2 comm. test 10KA/1395commvolts OK
208:08:19:513AMPlasmaOkno faults/fizzel
308:21:10:920AMPlasmaBadPower supply problems, caused disruption
408:54:07:967AMTestOkEF4 test ?????
509:11:58:217AMTestOkEF4 pulse test hybrid control OK
609:22:25:513AMTestOkno faults/plasma
709:37:42:200AMPlasmaOkno faults/plasma
809:58:07:373AMPlasmaOkno faults/plasma
910:16:14:250AMPlasmaOkno faults/plasma
1010:36:08:060AMPlasmaOkno faults/plasma
1110:53:17:623AMPlasmaOkno faults/plasma
1211:12:36:140AMPlasmaOkno faults/plasma
1311:32:57:920AMPlasmaOkno faults/plasma
1411:55:38:500AMPlasmaOkno faults/plasma
1512:12:07:420PMPlasmaOkno faults/plasma
1612:33:40:670PMPlasmaBadOH2l comm fault after plasma disruption
1712:54:45:717PMPlasmaOkno faults/plasma
1801:10:11:683PMPlasmaOkNo Faults / Plasma
1901:30:13:810PMPlasmaOkNo Faults / Plasma
2001:48:16:403PMPlasmaOkNo Faults
2102:03:47:513PMPlasmaOkNo Faults
2202:19:37:547PMPlasmaOkNo Faults
2302:39:43:420PMPlasmaOkNo Faults
2402:58:43:467PMPlasmaOkNo Faults
2503:14:46:047PMPlasmaOkNo Faults
2603:33:01:780PMPlasmaOkNo Faults / plasma
2703:52:14:857PMPlasmaOkNo Faults
2804:11:18:403PMPlasmaOkNo Faults
2904:32:39:890PMPlasmaOkNo Faults / Plasma
3004:53:36:030PMPlasmaOkNo Faults
3105:07:53:653PMPlasmaOkNo Faults
3205:38:57:480PMTestBad