Alcator C-Mod Run 991022 Information

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Miniproposals
Miniproposal:214
Date Filed: 1/5/1999
Title:D and E-port RF System Commissioning
First Author:Steve Wukitch
Session Leader:Earl Marmar (shots 1-25)
Miniproposal:252
Date Filed: 9/24/1999
Title:Effects of hydrogen minority fraction on ICRF heating
First Author:Earl Marmar
Session Leader:Earl Marmar (shots 1-25)

Operators
Session leader(s):Earl Marmar,Earl Marmar
Physics operator(s):Earl Marmar,Robert Granetz
Engineering operator(s):Bill Cochran,Gary Dekow

Engineering Operator Run Comment
Run Plan for Friday, 991022 MP 214 and MP 252 Marmar/Granetz/Cochran/D

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:21:507PM
Author: To Be Determined
Session Leader Run Summary -- 991022

The purpose of the run was MP252, Optimization of Hydrogen Fraction for
Minority Heating
Piggyback -- MP214 D&E commissioning

Session leader: E. Marmar
Physics operator: E. Marmar/R. Granetz

The run was preceded by overnight ECDC in deuterium.

The run was quite successful, with H/D ratio scanned from 0.025 (natural at the
beginning of the run) all the way up to >.23 on shot 25.

General observations:

The best heating and confinement, and lowest radiated powers, were obtained
with no extra hydrogen puffing. The plasmas clearly degraded as the hydrogen
fraction was brought above 0.05. Based on H-factor confinement enhancement, the
optimum H level is at or below 0.025, the lowest we have seen during this run
campaign. The sawtooth reheat rate (not adjusted for density differences) was
also maximized for hydrogen fraction between 0.025 and 0.06. The shots with
0.04 degraded toward type III Elms or Elmfree, with increased radiation and
decreased confinement. Once the fraction
reached 0.08, even quasi-steady H-modes were impossible; the radiated power increased
continuously, and the plasmas returned to L-mode. For fractions greater than
0.08, only the very briefest of H-Modes were obtained, with basically
steady-state L-mode the result.

Shots for further analysis:

shot H/D Mode H-ITER89 (assuming 80% RF absorption)

03 .023 EDA 1.43
04 .032 EDA 1.30 (only 1.3 MW RF on this one)
05 .024 EDA 1.39
06 .031 EDA 1.36
07 .036 EDA 1.32
09 .056 EDA 1.32 --> 1.16
11 .070 EDA 1.06 & dropping
13 .083 Elmfree 0.86
14 .062 EDA 1.16
15 .050 EDA 1.33
16 .049 EDA 1.22
17 .046 EDA 1.23
18 .044 EDA 1.30
19 .042 EDA 1.33
20 .043 EDA 1.32
21 .040 EDA 1.30
23 .083 L 0.74
24 .143 L 0.58
25 .230 L 0.57

There were reports of significant Mo radiation on all shots. We may be overdue
for a boronization.

Based on this run, puffing low levels of hydrogen had no benefit, and once the
level exceeded about 0.05, things rapidly got worse with increasing H levels.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:09:770PM
Author: To Be Determined
Physics operator summary for run 991022:

MP 214 -- ICRF commissioning (D & E)
MP 252 -- H-fraction optimization

SL: E. Marmar
PO: E. Marmar/R. Granetz
EO: B. Cochran/G. Dekow

Summary: H/D ratio was scanned from 2.5% (at beginning of day) to 30% at the
end of the day. It was pretty conclusive that H-mode quality
decreased monotonically as H/D increased. Impurity generation during
H-mode also increased as H/D increased. See session leader's summary
for further details.

There were no unusual problems with machine operation today.

Scorecard: 22 plasmas
2 fizzles
0 duds (0 due to lack of one or more power supplies)
1 test
0 aborted
----------
25 total

-------------------------------------------------------------------------------

Engineering Setup for Friday, 991022:

Run will BEGIN at 08:00 and END at 16:00

Setup power supplies from shot 991020014 (0.8 MA, 5.4 T, flattop to 1.5 s,
extended Bt flattop at 50 kA), EXCEPT MOVE FIZZLE DETECTOR OFF TIME TO 1.7 s

OVERNIGHT ECDC in D2 prior to the run, stopping 1-2 hours before the run.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
fill B-side upper with 10 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:
ECE, VUV

-------------------------------------------------------------------------------

Run Plan for Friday, 991022:

MP 214 -- ICRF commissioning (D & E)
MP 252 -- H-fraction optimization

Session leader: E. Marmar
Physics operator: E. Marmar/R. Granetz

Load shot 991020014

Make sure the engineer changes fizzle detector "off" time to t=1.7 s.

Increase Btor to 5.4 tesla (from 5.2 tesla) in BOTH segments 1 and 2 !!!
(I_tf --> 150 kA).

Disable B-side-upper valve initially. As the run progresses, we will try to
increase the H/D ratio gradually on a shot-to-shot basis, and then, if time
permits, decrease it gradually.

Program RF power as per agreed upon plan, in order to provide a break-in-slope
analysis of the RF absorption fraction.

After each suitable shot, Granetz will run EFIT on a faster timescale (to a
private tree), and Melby will use the resulting WPLASM signal to calculate
the RF absorption fraction.

-------------------------------------------------------------------------------

Note: There was overnight ECDC in D2, stopping 1 hour prior to this run.

Hybrid coldstart done; no errors found
($set default cmod$models:[hybrid.tcl]
$@hybinit_dispatch
$@show_bitbus_log
Use editor search to verify no occurrences of "error" nor
"not respond")

Load 991020014. Increase Btor to 5.4 T in both segments 1 and 2, and
move fizzle detector "off" time to t=1.7 s.

Earl is presently the Physics Operator

Shot 01 -- Test. No power data cycle test.

Shot 02 -- Fizzle. Fill looks high; B_R a tad also.

Shot 03 -- Plasma.
Reduce prepuff to 22 msec
B_R offset to -.00175 from -.00075
plasma
fairly steady EDA, a few RF trips
H/D ~ .023

Granetz takes over as physics operator.

Fast EFIT done at t=1.250 +/- 0.050 s.

Next shot: no PCS changes.

Shot 04 -- Plasma. D-port: 1.2 MW, E-port: faulted early, but we still had
an EDA H-mode. Fast EFIT done at t=1.000 +/- 0.050 s.
Eric finds absorption = 87%, with H/D=3%.
Next shot: no PCS changes.

Shot 05 -- Plasma. EDA H-mode. Total Prf = 2.6 MW. Fast EFIT done at
t=1.000 +/- 0.050 s. H/D=2.5%

Next shot: no PCS changes.

Shot 06 -- Plasma. EDA H-mode. Good RF.
Fast EFIT done for t=1.000 +/- 0.050 s.

Next shot: add Btor blip from t=0.8-1.0 for ECE, and turn on H2
puff, with 100 volts from t=0.3 to 0.4 s, and 40 volts from t=0.4 to
1.4 s. Plenum pressure = 10 psi. Also move first RF cutout to
t=1.1 s to avoid Btor blip.

Shot 07 -- Plasma. Good EDA. Good RF. Btor blip worked. May be observing
a correlation between neutron rate and H/D.
Fast EFIT done around t=1.100 s.

Next shot: increase H2 maintenance level to 50 volts (from 40 V).

Shot 08 -- Plasma. Outer gap increased by 2 mm for no apparent reason.
H-mode is not very good. H/D=5%.

Next shot: extend Btor blip by 10 ms, in order to allow ECE channels
to overlap. Increase RCUR by 1 mm, in order to reduce outer gap
by 2 mm.

Short delay to check out an apparent high temperature reading on part of
the vessel. Willy Burke unplugged the relevant heater, but it had no power
going to it anyway, so he doesn't think the high temp reading was real.

Shot 09 -- Plasma. Lots of radiated power. H/D=5-6%.
Fast EFIT done around t=1.100 s.

Next shot: increase H2 some more, by raising maintenance level
to 60 volts.

Shot 10 -- Plasma. E-port faulted early. H/D=7-7.5%.
Fast EFIT done around t=1.260 s.

Next shot: change H2 valve programming. It will now turn on fully
from t=0.25 to 0.50 s, and then turn off completely.

Shot 11 -- Plasma. EDA and type-III ELMy H-modes. H/D=7%. Ugly looking shot.
Things seem to be getting worse as we puff more H2.

Next shot: increase H2 pulse to 350 ms (from 250 ms).

Shot 12 -- Plasma. Only had 1 MW of RF (D-port didn't fire). H/D=7-8%.

Next shot: try again for more RF; no PCS changes.

Shot 13 -- Plasma. Ugly H-modes. H/D=8%.

Next shot: disable H2 valve.

Shot 14 -- Plasma. H/D=6% (down a bit). EDA H-modes look somewhat better.

Next shot: no PCS changes. Let the H2 come down some more.

Shot 15 -- Plasma. H/D=5-6% (down a bit more). EDA H-mode during first 200 ms
was pretty good.

Short delay to check out a UPS breaker.

Next shot: repeat with no changes. Still no H2 being puffed.

Shot 16 -- Plasma. H/D=5% Initial H-mode lasted until t=1.0 s, but changed
from EDA to ELMy part way through (at the same time as the start of
the Btor blip).

Next shot: move Btor blip earlier by 100 ms.

Shot 17 -- Plasma. H/D=5%. Again, the change from EDA to ELMy was at
the (changed) time of the Btor blip.

Next shot: remove Btor blip altogether, and decrease Btor from 5.46
to 5.3 T (I_tf from 152 kA to 147.55 kA)

Shot 18 -- Plasma. Neutrons still turn over, even without a Btor blip.
Fast EFIT done around t=1.260 s.

Next shot: add Btor blip back in, starting at t=0.7 s (as for
shot 17), and raise nl_04 from 1.0 to 1.1e20 m-2.

Shot 19 -- Plasma. Target density didn't go up. Btor blip was okay. H/D=5%.

Next shot: try raising nl_04 to 1.25e20 m-2.

Shot 20 -- Plasma. Got nl_04=1.13e20 m-2. H/D=4.5-5%.
Fast EFIT done around t=0.870 s.

Next shot: increase outer gap by 2 mm (decrease RCUR by 1 mm).

Shot 21 -- Plasma. Long EDA H-mode. Outer gap did indeed increase by 2 mm.
H/D is down to 4%.

Next shot: increase outer gap by another 2 mm (decrease RCUR by
another 1 mm).

Shot 22 -- Fizzle. Bz jumped up by 3 mT and Br0 jumped up by 1 mT on this
shot.

Next shot: Bz and Br0 tweaks. Also, increase H2 pressure to 20 psi
and enable the H2 valve. Puff duration = 350 ms. Decrease outer
gap by 2 mm (in anticipation of H2 effect observed earlier today).

Shot 23 -- Plasma. One very short H-mode. One transmitter faulted early.
Outer gap=10-11 mm. Breakdown fields are back to normal.
Target density increased slightly to 1.25e20 m-2. H/D=8-15%.
Fast EFIT done around t=1.100 s.

Next shot: Keep H2 valve on at a maintenance level of 60 volts after
the main pulse. Decrease nl_04 from 1.25 to 1.15e20 m-2.

Shot 24 -- Plasma. One very short H-mode; similar to previous shot. RF stayed
on; Prf=2.1 MW. nl_04=1.2e20 m-2. H/D=15-16%.
Faster EFIT done around t=1.100 s.

Next shot: remove Btor blip, increase H2 puff, reduce target
density.

Shot 25 -- Plasma. No H-modes. H/D=23-33%

End of run.

Session Leader Comments
Oct 22 1999 07:54:24:827AMEarl MarmarRun Plan for Friday, 991022:

MP 214 -- ICRF commissioning (D & E)
MP 252 -- H-fraction optimization

Session leader: E. Marmar
Physics operator: E. Marmar/R. Granetz
Engineering operator: Bill Cochrane

Load shot 990924005
Modify TF to add post-plasma 50 kA flat top, as on 991021

Make sure the engineer changes fizzle detector "off" time to t=1.7 s.

Disable B-side-upper valve initially. As the run progresses, we will try to
increase the H/D ratio gradually on a shot-to-shot basis, and then, if time
permits, decrease it gradually.

Program RF power as per agreed upon plan, in order to provide a break-in-slope
analysis of the RF absorption fraction.

After each suitable shot, Granetz will run EFIT on a faster timescale (to a
private tree), and Melby will use the resulting WPLASM signal to calculate
the RF absorption fraction.
Oct 22 1999 07:54:42:670AM991022001Earl MarmarNo power data cycle test
Oct 22 1999 09:03:51:907AM991022004Earl Marmarplasma

Several RF trips; E-port never came back

H/D = 0.03

Oct 22 1999 10:00:57:543AM991022005Earl Marmarplasma

steadier, with a few trips

H/D = 0.026


Oct 22 1999 10:01:24:217AM991022006Earl Marmarplasma

one RF Trip

H/D = .032
Oct 22 1999 10:14:16:967AM991022007Earl Marmarplasma

TF sweep added for ECE

puffed H, starting at 0.3 seconds

Nice steady EDA; neutron rate drooping slightly through RF pulse

H/D 0.043 at start of RF, drooping to ~.032
Oct 22 1999 10:59:18:623AM991022008Earl Marmarplasma

add more H

H/D ~ .048

RF tripped (D-port)
Oct 22 1999 11:00:08:717AM991022009Earl Marmarplasma

H/D ~ .055

RF ok

2 MW radiated power
Oct 22 1999 11:21:13:717AM991022010Earl Marmarplasma

some RF trips

E port never comes back

H/D ~ .075


Oct 22 1999 11:37:02:153AM991022011Earl Marmarplasma

puffing H from 0.25 to 0.5, then off

H/D ~ .07

in and out of H-mode

lots of radiated power
Oct 22 1999 12:13:10:967PM991022012Earl Marmarplasma

mostly L-Mode; 2 short H-modes

no power from D port

H/D ~ .08 at 0.8 seconds
Oct 22 1999 12:14:53:687PM991022013Earl Marmarplasma

RF stayed on to first modulation

repetitive H-modes --> ramping P_rad --> back to L

H/D ~ 0.082
Oct 22 1999 12:34:12:357PM991022014Earl Marmarplasma

H puff turned off

RF on through first modulation

Better EDA early

H/D = 0.06
Oct 22 1999 02:16:31:373PM991022015Earl Marmarplasma

Better first H-Mode

H/D = 0.050 during early H-Mode
Oct 22 1999 02:17:00:903PM991022016Earl Marmarplasma

H/D ~ 0.05

RF ok
Oct 22 1999 02:17:24:187PM991022017Earl Marmarplasma

H/D ~ 0.05

RF ok
Oct 22 1999 02:17:49:340PM991022018Earl Marmarplasma

H/D ~ 0.045

RF good
Oct 22 1999 02:21:55:700PM991022019Earl Marmarplasma

raise nl_04 prog to 1.1e20
(got 1.0)

H/D ~ 0.045

RF Good

Physics Operator Comments
Oct 22 1999 08:16:02:030AM991022002Earl MarmarFizzle

Fill looks high; B_R a tad also
Oct 22 1999 08:44:48:873AM991022003Earl MarmarReduce prepuff to 22 msec

B_R offset to -.00175 from -.00075

plasma

fairly steady EDA, a few RF trips

H/D ~ .023
Oct 22 1999 09:10:12:420AM991022003Robert GranetzGranetz takes over as physics operator.

Fast EFIT done at t=1.250 +/- 0.050 s.

Next shot: no PCS changes.
Oct 22 1999 09:09:39:717AM991022004Robert GranetzShot 04 -- Plasma. D-port: 1.2 MW, E-port: faulted early, but we still had
an EDA H-mode. Fast EFIT done at t=1.000 +/- 0.050 s.

Next shot: no PCS changes.
Oct 22 1999 09:25:30:670AM991022004Robert GranetzEric finds absorption = 87%, with H/D=3%.
Oct 22 1999 09:29:05:123AM991022005Robert GranetzShot 05 -- Plasma. EDA H-mode. Total Prf = 2.6 MW. Fast EFIT done at
t=1.000 +/- 0.050 s. H/D=2.5%

Next shot: no PCS changes.
Oct 22 1999 09:55:43:297AM991022006Robert GranetzShot 06 -- Plasma. EDA H-mode. Good RF.

Next shot: add Btor blip from t=0.8-1.0 for ECE, and turn on H2
puff, with 100 volts from t=0.3 to 0.4 s, and 40 volts from t=0.4 to
1.4 s. Plenum pressure = 10 psi. Also move first RF cutout to
t=1.1 s to avoid Btor blip.
Oct 22 1999 10:19:42:013AM991022006Robert GranetzFast EFIT done for t=1.000 +/- 0.050 s.
Oct 22 1999 10:10:02:437AM991022007Robert GranetzShot 07 -- Plasma. Good EDA. Good RF. Btor blip worked. May be observing
a correlation between neutron rate and H/D.
Fast EFIT done around t=1.100 s.

Next shot: increase H2 maintenance level to 50 volts (from 40 V).
Oct 22 1999 10:30:28:717AM991022008Robert GranetzShot 08 -- Plasma. Outer gap increased by 2 mm for no apparent reason.
H-mode is not very good. H/D=5%.

Next shot: extend Btor blip by 10 ms, in order to allow ECE channels
to overlap. Increase RCUR by 1 mm, in order to reduce outer gap
by 2 mm.
Oct 22 1999 10:37:47:733AM991022008Robert GranetzShort delay to check out an apparent high temperature reading on part of
the vessel. Willy Burke unplugged the relevant heater, but it had no power
going to it anyway, so he doesn't think the high temp reading was real.
Oct 22 1999 10:52:58:717AM991022009Robert GranetzShot 09 -- Plasma. Lots of radiated power. H/D=5-6%.
Fast EFIT done around t=1.100 s.

Next shot: increase H2 some more, by raising maintenance level
to 60 volts.
Oct 22 1999 11:14:02:153AM991022010Robert GranetzShot 10 -- Plasma. E-port faulted early. H/D=7-7.5%.
Fast EFIT done around t=1.260 s.

Next shot: change H2 valve programming. It will now turn on fully
from t=0.25 to 0.50 s, and then turn off completely.
Oct 22 1999 11:51:26:640AM991022012Robert GranetzShot 12 -- Plasma. Only had 1 MW of RF (D-port didn't fire). H/D=7-8%.

Next shot: try again for more RF; no PCS changes.
Oct 22 1999 12:14:52:077PM991022013Robert GranetzShot 13 -- Plasma. Ugly H-modes. H/D=8%.

Next shot: disable H2 valve.
Oct 22 1999 12:34:58:187PM991022014Robert GranetzShot 14 -- Plasma. H/D=6% (down a bit). EDA H-modes look somewhat better.

Next shot: no PCS changes. Let the H2 come down some more.
Oct 22 1999 01:06:07:733PM991022015Robert GranetzShot 15 -- Plasma. H/D=5-6% (down a bit more). EDA H-mode during first 200 ms
was pretty good.

Short delay to check out a UPS breaker.

Next shot: repeat with no changes. Still no H2 being puffed.
Oct 22 1999 01:23:03:060PM991022016Robert GranetzShot 16 -- Plasma. H/D=5% Initial H-mode lasted until t=1.0 s, but changed
from EDA to ELMy part way through (at the same time as the start of
the Btor blip).

Next shot: move Btor blip earlier by 100 ms.
Oct 22 1999 01:37:45:170PM991022017Robert GranetzShot 17 -- Plasma. H/D=5%. Again, the change from EDA to ELMy was at
the (changed) time of the Btor blip.

Next shot: remove Btor blip altogether, and decrease Btor from 5.46
to 5.3 T (I_tf from 152 kA to 147.55 kA)
Oct 22 1999 02:05:25:560PM991022018Robert GranetzShot 18 -- Plasma. Neutrons still turn over, even without a Btor blip.
Fast EFIT done around t=1.260 s.

Next shot: add Btor blip back in, starting at t=0.7 s (as for
shot 17), and raise nl_04 from 1.0 to 1.1e20 m-2.
Oct 22 1999 02:16:33:763PM991022019Robert GranetzShot 19 -- Plasma. Target density didn't go up. Btor blip was okay. H/D=5%.

Next shot: try raising nl_04 to 1.25e20 m-2.
Oct 22 1999 02:34:43:903PM991022020Robert GranetzShot 20 -- Plasma. Got nl_04=1.13e20 m-2. H/D=4.5-5%.

Next shot: increase outer gap by 2 mm (decrease RCUR by 1 mm).
Oct 22 1999 03:32:49:793PM991022020Robert GranetzFast EFIT done around t=0.870 s.
Oct 22 1999 02:52:51:860PM991022021Robert GranetzShot 21 -- Plasma. Long EDA H-mode. Outer gap did indeed increase by 2 mm.
H/D is down to 4%.

Next shot: increase outer gap by another 2 mm (decrease RCUR by
another 1 mm).
Oct 22 1999 03:14:21:390PM991022022Robert GranetzShot 22 -- Fizzle. Bz jumped up by 3 mT and Br0 jumped up by 1 mT on this
shot.

Next shot: Bz and Br0 tweaks. Also, increase H2 pressure to 20 psi
and enable the H2 valve. Puff duration = 350 ms. Decrease outer
gap by 2 mm (in anticipation of H2 effect observed earlier today).
Oct 22 1999 03:32:06:700PM991022023Robert GranetzShot 23 -- Plasma. One very short H-mode. One transmitter faulted early.
Outer gap=10-11 mm. Breakdown fields are back to normal.
Target density increased slightly to 1.25e20 m-2. H/D=8-15%.

Next shot: Keep H2 valve on at a maintenance level of 60 volts after
the main pulse. Decrease nl_04 from 1.25 to 1.15e20 m-2.
Oct 22 1999 03:53:42:140PM991022023Robert GranetzFast EFIT done around t=1.100 s.
Oct 22 1999 03:55:02:217PM991022024Robert GranetzShot 24 -- Plasma. One very short H-mode; similar to previous shot. RF stayed
on; Prf=2.1 MW. nl_04=1.2e20 m-2. H/D=15-16%.

Next shot: remove Btor blip, increase H2 puff, reduce target
density.
Oct 22 1999 04:05:41:827PM991022024Robert GranetzFaster EFIT done around t=1.100 s.
Oct 22 1999 04:07:04:840PM991022025Robert GranetzShot 25 -- Plasma. No H-modes. H/D=23-33%

End of run.

Engineering Operator Comments
ShotTimeTypeStatusComment
107:54:47:200AMTestOkData system test shot, All Power Systems off
208:06:21:780AMPlasmaOkFizzle
308:26:09:810AMPlasmaOk(null)
408:52:33:717AMPlasmaOk(null)
509:12:26:890AMPlasmaOk(null)
609:34:08:750AMPlasmaOk(null)
709:54:53:983AMPlasmaOk(null)
810:14:39:840AMPlasmaOk(null)
910:39:02:857AMPlasmaOk(null)
1011:00:49:403AMPlasmaOk(null)
1111:21:06:857AMPlasmaOk(null)
1211:42:11:390AMPlasmaOk(null)
1312:04:41:030PMPlasmaOk(null)
1412:24:40:797PMPlasmaOk(null)
1512:45:03:047PMPlasmaOk(null)
1601:09:31:983PMPlasmaOk(null)
1701:26:29:357PMPlasmaOk(null)
1801:45:52:043PMPlasmaOk(null)
1902:06:06:733PMPlasmaOk(null)
2002:22:53:840PMPlasmaOk(null)
2102:40:28:373PMPlasmaOk(null)
2202:59:46:763PMPlasmaOk(null)
2303:17:06:263PMPlasmaOk(null)
2403:39:09:013PMPlasmaOk(null)
2503:57:10:467PMPlasmaOk(null)