Alcator C-Mod Run 960820 Information

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Miniproposals
Miniproposal:133
Date Filed:12/8/1995
Title:Boronization of Alcator C-Mod
First Author:Jim Terry
Session Leader:Yuichi Takase (shots 1-21)
Miniproposal:148
Date Filed: 7/16/1996
Title:RF Conditioning and Testing
First Author:Yuichi Takase
Session Leader:Yuichi Takase (shots 1-21)

Operators
Session leader(s):Yuichi Takase,Yuichi Takase
Physics operator(s):John Goetz
Engineering operator(s):Joe Daigle,Vinny Bertolino

Engineering Operator Run Comment
post boron fiducials/takase/goetz/silva/bertolino

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:15:913PM
Author: To Be Determined
Run summary 960820

MP133 - PostBoron Fiducials
MP148 - RF Conditioning

Run plan:
The objective is to get as high RF power as possible into the plasma.
The target is 1.5MW per antenna.
Run shots with high precharge and the EF4's in parallel, with current
flattop to 1.2sec.
Start with breakdown at 6T toroidal field and rampdown to 5.3T
with hybrid control.
Diagnostic alignment and tune-up to be done in parallel.
Also try to break down at 5.3T.

11 hrs. of ECDC boronization overnight + 2hrs. He ECDC this morning.
Report from J. Irby:
During last night's boronization we deposited about
60A of boron assuming a uniform coating (approximately
1/3 the thickness we obtained during our most ambitious
boronizations during the last run period). We are
prepared to do another boronization tonight if required.

Lots of problems still (fizzles and PS problems).
4 good shots (indicated by **) that were useful for RF conditioning.
We have gotten 1.5MW from each antenna, but more conditioning is still
required. The antenna loading is still anomalously high.

What is needed much more than RF conditioning is tokamak conditioning.
The neutral pressure is still very high, as is the H-mode threshold,
and the quality of H-mode is still poor.

Shot 001
OH test.

Shot 002
TF test.

Shot 003 Fizzle
Loaded 960816007

**Shot 004 Plasma
D: 0.6MW 15 Ohm
E: 1.1MW 20 Ohm
BT=5.4T (6T breakdown), Ip=0.8MA, nel=1.0, Rgap=0.8cm
W_EFIT=50kJ, very little heating

Shot 005 Fizzle

*Shot 006 Plasma
Rgap adjusted to 1.0cm (but didn't really get it)
Lost plasma to the inner wall after 0.7s (lost EF4).

Shot 007 EF4 test

Shot 008 Another EF4 test

Shot 009 Fizzle

Shot 010 Fizzle

Shot 011 Fizzle

Shot 012 Fizzle

Shot 013 Fizzle

Shot 014 Fizzle

**Shot 015 Plasma
loaded shot 004
D: 1.0MW 17 Ohm
E: 1.5MW 20 Ohm
nel=1.0 + small H-mode, Rgap=0.7cm
W_EFIT=50->65kJ

**Shot 016 Plasma
D: 1.5MW 15 Ohm
E: 1.5MW 20 Ohm
nel=1.0 + H-mode, Rgap=1.0cm
W_EFIT=50->65kJ

**Shot 017 Plasma
D: 1.5MW 15 Ohm
E: 0MW (pump tripped)
nel=1.0, W_EFIT=50->60kJ

Shot 018 dud (no TF)

Shot 019 Fizzle

Shot 020 Dud (early RF off)

*Shot 021 Plasma (early RF off)
Disrupt @ 0.8s (EF4 fault)

Physics Operator Summaries
Entered: Jul 7 2004 04:36:56:503PM
Author: To Be Determined
Physics operator summary for 960820

EO: Bertolino / Daigle
PO: Goetz
SL: Takase

Run 960820 was in support of Mini-Proposal #133 - Boronization of Alcator
C-Mod and Mini-Proposal #148 - RF Conditioning. The goals for today are to
try and get C-Mod operational once again. If indeed acceptable plasmas are
produced, check-out of diagnostics and RF conditioning will be done.

Plan:
TF tests
OH test
run with higher precharge on the ohmic stack and
with the EF4's in parallel
start with toroidal field > 6T and ramp down
twiddle gas and fields until reproducible
if ambitious, try to breakdown at 5.3T

The plan was not carried out completely. Some plasmas were obtained with
RF power of up to 1.5MW and even brief H-modes. There was not sufficient
time available to try and breakdown at 5.3T. See the session leader's
summary for details.

Some things discovered today:
1) The plasmas seemed to like Br ~ 1mT and Bz ~ 5mT at t=0. A prefill
puff width of 10 or 11msec seemed to work best. Plasmas with all
supplies operational ramped all the way down. Extending the RXL
drawn waveform may have solved the disruptions from last week.
Running with boronized walls seemed to be easier than the initial
attempts of 960112.
2) It was difficult to recover from the long waits after engineering
pitfalls. The fields seemed to change and the gas required was
also changing.
3) All legitimate attempts at plasma had breakdown except with 9msec
of prefill puff.
4) Shot 021 is a very good shot (before the EF4 problem). It had a
breakdown at about 7msec, no hesitation, and a very fast current rise.

Engineering, computing, and diagnostics today: EF4 power supply blew up twice
today. The supply detects a Type 1 fault and fires a crowbar. This
leads to blowing multiple fuses (total of 28 today). The TF did not
enable itself on one shot. A 24V power supply died in the CRYO PLC
causing a long wait to diagnose, fix, and recool.

Scorecard: 21 shots = 6 plasmas + 9 fizzles + 4 tests + 2 duds

Shot summary for Run 960820:

Load 960816007
extend RXL programming to 1.2sec in segment 2
draw TF waveform: [-1.5,.2,.4,1.3,2.3],[-175,-175,-151,-151,0]
in all 4 segments
coldstart hybrid - all matrices respond

Shot change result
____ _____ ______
1 OH coax test o.k.

2 TF test under PLC control clamping circuit appears to work

3 see above fizzle - b.d. @ .006; hit something
@ .014; Br = 2mT

4 BR_0 = .004 plasma - all the way down; o.gap=8mm
current rise a little slow

5 RCUR=.668; prefill puff=14msec fizzle - strong one - b.d. @ .0045
hit something @ .019; no GPC with
which to analyze

6 prefill puff = 12msec plasma - EF4 crowbar fired during the
shot - 20 fuses need to be replaced

1hr wait to replace the fuses and hi-pot

7 EF4 test shot o.k.

8 EF4 test shot (other direction) o.k.

9 40msec Ar puff; IC_EF4=-1470A fizzle - strong - moves up and in

10 IC_EF4 = -1480A fizzle - .06MA - hits something @ .02

lost 24V power supply on the CRYO - 1-1/2hr wait

11 IC_EF4=-1490A; lower PG3 @ .01 fizzle - weak - Bz too small

12 V_OH1 = 150V from .005 to .010s fizzle - no current rise; coil currents
IC_EF4=-1480A; prefill = 13msec just like 960816007

13 IC_EF4=-1470A, BR_0=.0045; fizzle - very weak; breakdown @ .006
prefill puff = 15msec vertical field in late

14 IC_EF4=-1480A; prefill=11msec fizzle - .04MA - breakdown @ .005
null looks o.k.

15 reload 960820004; prefill puff plasma - all the way down; Prf=1.5MW
= 10msec slight startup hesitation

16 V_OH1=125V; CLEARIN=-.001; plasma - all the way down; Prf=1.5MW
RCUR=.668; PG1=.045sec

17 V_OH1=100V & V_OH2's=-12V plasma - all the way down; very slow
current rise; one transmitter

18 V_OH1=175V from .005 to .015 dud - TF did not turn on
& V_OH2's=-2V at .01

19 try again fizzle - multiple bounces - long wait
for IOGR

20 prefill puff = 9msec; V_OH1 dud - fields o.k.; fill too low? no RF?
=150V and V_OH2's=-4V

21 prefill = 11msec plasma - good current rise - b.d. at
7.5msec - no hesitation - EF4 blewup
just like on 006 - 28 fuses blown

Session Leader Comments
Aug 20 1996 09:13:25:700AMYuichi TakaseMP133 - PostBoron Fiducials
MP148 - RF Conditioning

The objective is to get as high RF power as possible into the plasma.
The target is 1.5MW per antenna.
Run shots with high precharge and the EF4's in parallel, with current
flattop to 1.2sec.
Start with breakdown at 6T toroidal field and rampdown to 5.3T
with hybrid control.
Diagnostic alignment and tune-up to be done in parallel.
Also try to break down at 5.3T.

Aug 20 1996 09:13:57:040AM960820001Yuichi TakaseShot 001
OH test.

Aug 20 1996 09:14:48:010AM960820002Yuichi TakaseShot 002
TF test.

Aug 20 1996 09:37:21:980AM960820003Yuichi TakaseShot 003 Fizzle
Loaded 960816007

Aug 20 1996 10:07:35:210AM960820004Yuichi TakaseShot 004 Plasma
D: 0.6MW 15Ohm
E: 1.1MW 20Ohm (Transmitter gain changed since Friday)
BT=5.4T (6T breakdown), Ip=0.8MA, nel=1.0, Rgap=0.8cm
W_EFIT=50kJ, very little heating

Aug 20 1996 10:08:21:970AM960820005Yuichi TakaseShot 005 Fizzle

Aug 20 1996 10:51:23:700AM960820006Yuichi TakaseShot 006 Plasma
Rgap adjusted to 1.0cm (but didn't really get it)
Lost plasma to the inner wall after 0.7s (lost EF4).

Aug 20 1996 11:55:11:690AM960820007Yuichi TakaseShot 007 EF4 test

Aug 20 1996 12:11:20:740PM960820008Yuichi TakaseShot 008 Another EF4 test

Aug 20 1996 12:38:45:440PM960820009Yuichi TakaseShot 009 Fizzle

Aug 20 1996 12:39:01:560PM960820010Yuichi TakaseShot 010 Fizzle

Aug 20 1996 02:33:23:160PM960820011Yuichi TakaseShot 011 Fizzle

Aug 20 1996 02:33:55:370PM960820012Yuichi TakaseShot 012 Fizzle

Aug 20 1996 02:52:41:230PM960820013Yuichi TakaseShot 013 Fizzle

Aug 20 1996 03:12:48:790PM960820014Yuichi TakaseShot 014 Fizzle

Aug 20 1996 03:32:53:900PM960820015Yuichi TakaseShot 015 Plasma
loaded shot 004
D: 1.0MW 17 Ohm
E: 1.5MW 20 Ohm
nel=1.0 + small H-mode, Rgap=0.7cm
W_EFIT=50->65kJ

Aug 20 1996 03:51:59:410PM960820016Yuichi TakaseShot 016 Plasma
D: 1.5MW 15 Ohm
E: 1.5MW 20 Ohm
nel=1.0 + H-mode, Rgap=1.0cm
W_EFIT=50->65kJ

Aug 20 1996 04:02:37:600PM960820017Yuichi TakaseShot 017 Plasma
D: 1.5MW 15 Ohm
E: 0MW (pump tripped)
nel=1.0, W_EFIT=50->60kJ

Aug 20 1996 04:11:39:550PM960820018Yuichi TakaseShot 018 dud (no TF)

Aug 20 1996 04:36:00:410PM960820019Yuichi TakaseShot 019 Fizzle

Aug 20 1996 04:46:53:630PM960820020Yuichi TakaseShot 020 Dud (early RF off)

Aug 20 1996 06:59:02:330PM960820021Yuichi TakaseShot 021 Plasma (early RF off)
Disrupt @ 0.8s (EF4 fault)

Physics Operator Comments
Aug 20 1996 07:59:39:090AMJohn GoetzRun plan for 960820

MP133 - PostBoron Fiducials
MP148 - RF Conditioning

Run shots with high precharge and the EF4's in parallel. Start with
>6T toroidal field and rampdown to 5.3T with hybrid control (if approved
by IHH). Run shots for RF conditioning and diagnostic alignment and
tune-up. If time, try and break down at 5.3T.

Engineering setup:
start from 9608160007 - power supply and commutation resistors for
high precharge and EF4's in parallel
(make change to hybrid programming to satisfy
15kA / 100msec rampdown)

gas setup - hybrid enable B-top and A-side
fill A-side with 20 PSI of D2
fill B-top with 5 PSI of D2
fill B-side-lower with 4 PSI of Ar

Aug 20 1996 09:02:47:700AM960820001John GoetzShot 960820001:
OH coax test shot

Results:
o.k.

Aug 20 1996 09:21:10:530AM960820002John GoetzShot 960820002:
TF test shot (PLC control)

Results:
new clamping circuit appears to work

Aug 20 1996 09:42:08:210AM960820003John GoetzShot 960820003:
load 960816007
extend RXL programming to 1.2sec in segment 2
draw TF waveform: [-1.5,.2,.4,1.3,2.3],[-175,-175,-151,-151,0]
in all 4 segments

Results:
fizzle - no current channel
hit something at .014sec
breakdown at .006sec - radial field about 2mT

Aug 20 1996 10:02:10:680AM960820004John GoetzShot 960820004:
BR_0 offset = .004

Results:
plasma - all the way down
current rise a little slower than on 960816007
flat-top at 5.4T
outer gap ~ 8mm

Aug 20 1996 10:15:29:320AM960820005John GoetzShot 960820005:
RCUR = 0.668 (was 0.669)
prefill puff to 14msec

Results:
fizzle - strong one - breakdown at .0045
hits something at .019, but no GPC with which to analyze the
situation

Aug 20 1996 10:39:40:920AM960820006John GoetzShot 960820006:
prefill puff = 12msec

Results:
plasma - slower current rise than 004 - a slight bounce
a boom from the power room - EF4 crowbar fired
10 fuses in the forward cabinet and 10 fuses in the reverse
outer gap ~ 1cm

Aug 20 1996 12:08:18:660PM960820007John GoetzShot 960820007:
EF4 test shot

Results:
looks o.k.

Aug 20 1996 12:11:27:490PM960820008John GoetzShot 960820008:
EF4 test shot in other direction

Results:
looks o.k.

Aug 20 1996 12:27:08:960PM960820009John GoetzShot 960820009:
IC_EF4 = -1470A

Results:
fizzle - strong one - .05MA
moves up and in

Aug 20 1996 12:43:57:970PM960820010John GoetzShot 960820010:
IC_EF4 = -1480A

Results:
fizzle - up to .06MA - breakdown @ .005
hits something @ .02sec

Aug 20 1996 02:32:08:920PM960820011John GoetzShot 960820011:
IC_EF4 = -1490A
lower PG3 at .01sec
lost 24V power supply on CRYO - 1-1/2hr wait to repair

Results:
fizzle - vertical field too small (almost negative)

Aug 20 1996 02:43:34:700PM960820012John GoetzShot 960820012:
IC_EF4 = -1480A
prefill puff = 13msec
V_OH1 = 150V from .005 to .010sec

Results:
fizzle - breakdown at .005sec
fairly weak - no current rise

Aug 20 1996 02:56:42:700PM960820013John GoetzShot 960820013:
IC_EF4 = -1470A
prefill puff = 15msec
BR_0 = .0045

Results:
fizzle - breakdown @ .006sec
null looks o.k. but vertical field in too late

Aug 20 1996 03:07:41:670PM960820014John GoetzShot 960820014:
IC_EF4 = -1480A
prefill puff = 11msec
BR_0 = .004

Results:
fizzle - .04MA - breakdown at .005

Aug 20 1996 03:27:49:000PM960820015John GoetzShot 960820015:
reload shot 960820004
prefill puff = 10msec

Results:
plasma - all the way down
a slight hesitation at the startup
1.5MW of RF and an H-mode spotted at t=1.sec

Aug 20 1996 03:49:21:600PM960820016John GoetzShot 960820016:
V_OH1 = 125V from .005 to .010
CLEARIN = -.001
RCUR = .668
PG1 = 45msec

Results:
plasma - all the way down (by 1.6sec)
current rise a little slower, but the hesitation is better
better gaps; o.gap=1cm and i.gap=1.2cm

Aug 20 1996 03:56:54:130PM960820017John GoetzShot 960820017:
V_OH1 = 100V and V_OH2's = -12V from .005 to .010

Results:
plasma - all the way down
very slow current rise
some hards
only one RF transmitter

Aug 20 1996 04:11:39:680PM960820018John GoetzShot 960820018:
V_OH1 = 175V from .005 to .015 and V_OH2's = -2V at .01

Results:
dud - TF did not turn on

Aug 20 1996 04:35:13:940PM960820019John GoetzShot 960820019:
V_OH1 = 175V from .005 to .015 and V_OH2's = -2V at .01

Results:
fizzle - multiple bounces off of something - no current rise

Aug 20 1996 04:43:37:070PM960820020John GoetzShot 960820020:
V_OH1 = 150V from .005 to .010 and V_OH2's = -4V at .01
prefill puff = 9msec

Results:
dud
fields o.k.; puff too low?, no RF assist?

Aug 20 1996 05:39:31:360PM960820021John GoetzShot 960820021:
prefill puff = 11msec

Results:
plasma - breakdown at .007 - very good current rise - no
hesitation
highly recommended shot
the EF4 experienced the same problem as shot 006 - a Type 1
fault fired the crowbar and took out 28 fuses

Engineering Operator Comments
ShotTimeTypeStatusComment
108:58:32:740AMTestOkoh test
209:13:08:090AMTestOktf only
309:29:25:030AMPlasmaOk
409:47:40:760AMPlasmaOk
510:06:21:730AMPlasmaOk
610:23:38:610AMPlasmaBadef4 fault
711:53:09:020AMTestOk
812:08:39:040PMTestOk
912:19:11:750PMPlasmaOk
1012:34:08:790PMPlasmaOk
1102:19:39:720PMPlasmaOk
1202:30:49:550PMPlasmaOkComm Fault OH2U Bypass
1302:49:05:430PMPlasmaOkcomm fault OH2U bypass.
1403:00:52:360PMPlasmaOkOH2U comm. fault Bypass.
1503:15:36:310PMPlasmaOk
1603:31:14:530PMPlasmaOk
1703:49:33:800PMPlasmaOk
1804:05:00:670PMPlasmaBadTF did not turn on.
1904:22:15:440PMPlasmaOkComm Fault OH2U Bypass.
2004:36:24:510PMPlasmaOkOH2 Comm Fault Bypass.
2104:47:22:680PMPlasmaBadcccc