Alcator C-Mod Run 971212 Information

Miniproposals

Miniproposal: 163

Date Filed: 7/18/1996

Title: Detached Divertor High q

First Author: John Goetz

Session Leader: John Goetz (shots 1-36)

Operators
Session leader(s):	John Goetz
Physics operator(s):	Earl Marmar
Engineering operator(s):	Bill Cochran,Vinny Bertolino,Frank Silva

Engineering Operator Run Comment
mp 163

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:17:477PM

Author: To Be Determined

MP #163 High q_parallel Dissipative Divertor

This proposal is an attempt to achieve simultaneously a good confinement
H-mode with low Zeff and a detached divertor. The goal is to determine the
threshold amount of impurity gas necessary to detach the divertor. Also,
operation just above and just below the detachment threshold will be
investigated.

The plan is to start with a good shot from 971211 (1MA current, 1e20 line
density, good equilibrium, ...).

1. Try to get acceptable H-mode (preferably enhanced D-alpha).
2. Begin puffing N2 into the H-mode phase to try to detach.
Start with 100msec puff of nitrogen from J-bottom, beginning
100msec after the RF.
3. If successful in detaching with high q||, then try setting up
feedback on the J-Bottom valve using the divertor bolo signals.
4. Operate just above and just below the detachment threshold and
compare the confinement and cleanliness at these ese levels.
5. Try neon, argon, and krypton

Physiscs Summary:
Nothing was accomplished today toward completion of MiniProposal #163. Step
1 was not realized as no 'steady state' H-modes were achieved that had good
confinement. The 'steady state' H-modes achieved today only had H factors of
about 1.1. These types of H-mode were more easily achieved with 0.8MA of plasma
current as comopared to 1.0MA. Nitrogen was puffed through the J-Bottom
piezoelectric valve. Determination of the level of detachment in the divertor
awaits the analysis of scanning probe data. The scanning probe appears to be
rid of its pickup problems due to RF. Spectroscopy has noted that there is
silicon present in the machine, although the amount has not been determined.
A detailed shot log follows.

Shot Result
---- ------
001 Plasma - 2MW into SOL - low density - Zeff~3 - L-mode
002 Plasma - 1.5MW into SOL - low density - Zeff~3 - 5 H-modes
003 Plasma - ?? into SOL - better density - Zeff~3 - more EDAlike H-modes
004 Plasma - 1MW into SOL - Zeff~2.8 - last H-mode EDAlike
005 Plasma - 1.5MW into SOL - Zeff~2.5 - last H-mode EDAlike
006 Plasma - 1.5MW into SOL - Zeff~2.7->2.4 - ELMy H-modes
007 Plasma - 1.5MW into SOL - Zeff?? - 4 ELMy H-modes
008 Fizzle
009 Fizzle
010 Plasma - 1.5MW into SOL - Zeff ~ 2.2 - H-mode from .8 to 1. steady state
011 Fizzle
012 Eng. dud
013 Plasma - 1.5MW into SOL - Zeff?? - 3 H-modes; 2 are 0.2sec long
014 Fizzle
015 Plasma - <1.5MW into SOL - z_ave=1.1 - 3 H-modes; 1 from 0.72 to 1.0sec
016 Fizzle
017 Plasma - 1.2MW into SOL - z_ave=1.05 - 3 H-modes; 1st from 0.55 to .83
018 Plasma - disrupts @ .48sec
019 Plasma - 1.4MW into SOL - z_ave=1.2; H-mode from .56 to .96sec
020 Plasma - 1.3MW into SOL - z_ave=1.1; H-mode from .56 to 1.03sec; H=1.1
0.13Torr-l of nitrogen delivered; no sign of detachment
021 Fizzle
022 Plasma - 1.4MW into SOL - z_ave=1.1; H-mode from .56 to .75 & .78 to 1.2
0.2 Torr-l of nitrogen delivered; no sign of detachment
023 Plasma - 1.3MW into SOL - z_ave=1.0; H-mode from .85 to 1.15sec;
0.22Torr-l of nitrogen delivered; no sign of detachment
024 Plasma - 1.3MW into SOL - z_ave=1.2; H-mode from .56 to 1.15sec;
0.45Torr-l of nitrogen into divertor; no detachment
025 Eng. dud
026 Plasma - ??MW into SOL - z_ave=??; H-mode from .56 to 0.7
0.7 Torr-l N2 delivered
027 Eng. dud
028 Plasma - 1.3MW into SOL - z_ave=1.2; 8 H-modes (all short)
029 Plasma - 1.3MW (on average) into SOL; z_ave=1.3; multiple H-modes
030 Plasma - 2 H-modes; 1.6MW into SOL for 1st one; z_ave=1.2
031 Plasma - multiple H-modes; 1.2MW into SOL; 1.3Torr-l N2
032 Plasma - multiple H-modes (all short); 1.5MW into SOL; 1.6Torr-l N2
033 Plasma - ELMy H-mode; 1.5MW into SOL; 1.4Torr-l N2
034 Plasma - H-mode with somewhat steady-state; 1.5MW into S SOL; z_ SOL; z_ ave=1.1; z_ave=1.1
035 Plasma - Fiducial - disrupts @ 0.22sec
036 Plasma - Fiducial

Physics Operator Summaries

Entered: Jul 7 2004 04:36:58:177PM

Author: To Be Determined

Plan for 971212

ECDC overnight in Helium

Power supply setup as on shot 971211025, TF under hybrid control.

plenum setup:
20psi deuterium in K-side and 5psi in B-top
3psi argon in B-side-lower
5psi nitrogen in J-bottom

Enable the ECE gate valve for the first shot.

MP #163 High q_parallel Dissipative Divertor

This MP comprises a proposal to explore simultaneous achievement of a good
confinement H-mode with low Zeff and a detached divertor. The goal is to
determine the threshold amount of impurity gas necessary to detach the
divertor. Also, operation just above and just below the detachment threshold
will be investigated.

The plan is to start from shot 971211025.

1) Get acceptable H-mode (preferably enhanced D-alpha).

2) Puff N_2 into the H-mode phase to induce detachment; start with 100msec
puff from J-bottom, beginning 100msec after the RF.

3) If successful in detaching with high q||, then set up feedback on the
J-Bottom valve using the divertor bolo signals.

_____________________________________________________________________________
EO: Bertolino, Silva, Cochrane
SL: Goetz
PO: Marmar

We had reliable plasma operation, but never got good steady-state high
confinement H-Modes. The behavior was close to what we normally see without
boronization (high core radiated power fraction, significant moly, H-factors
barely above 1). There were also reports of silicon appearing on some shots.
Playing with density, current, gas puffing, and to a lesser extent, outer gap,
did not lead to any significant improvements. Nitrogen was puffed during
most of the run. The last shot of the day (#36) was a fiducial-like discharge.
An attempt to use segment 4 to accomplish this, on shot 35, led to blown fuses
on OH2L shortly after the segment switch. Operators are cautioned not to use
this segment, labeled lower single-null fiducial, until Steve Wolfe blesses it.

We had several cases of problems during INIT, followed by backing out to
RECOOL, running a no-power cycle and then a shot.

25 plasmas into ramp-down
6 fizzles

Shot-by-shot account

1. Load 971211025. Remove B_T wiggle; prepuff to 18 msec; nl_04 to 1e20 at .6 s; RF feedback on,
gain = -1500; plasma; disrupt in rampdown; some hards; lowish density; Z_eff ~
3

2. Add more puff volts in segment 1; hesitation during current rise; plasma;
more hards; in and out of H-mod; density still low.

3. increase B_R offset by 0.5 mT; increase early gas puff some more; plasma;
higher density; no hards.

4. move ZXL up 1 cm; RXU in 1 cm; plasma.

5. move ZXL up 2 mm; RXU in 1 cm; plasma

6. move ZXL up 1 mm; RCUR decrease 1 mm; plasma

7. more gas during RF; RCUR decrease 1 mm; plasma

8. more gas; fizzle

9. reduce prepuff to 16 ms; fizzle

10. prepuff to 17 ms; B_R offset reduced by .5 mT; plasma; hesitation during
current rise; some hards.

11. prepuff to 14 ms; raise early gas; raise gas during RF; reduce gain on
nl_04 during RF; fizzle

12. TF Fault during init; cycle test with no power;

13. prepuff to 18 ms; B_R offset to .0075; plasma; no hards.

14. more gas after 0.4 s; fizzle; breakdown is slightly late; possible sparker
problem?

15. retry; plasma

16. ask for 800 kA plasma current; fizzle

17. prefill to 17 msec; b_r offset to .007; plasma

18. add 2 mm to RCUR; disrupt at .5s; niobium.

19. repeat; plasma

20. turn on nitrogen puff; 70 msec starting at .65 s; plasma

21. nitrogen puff increased to 100 msec; fizzle

22. prefill to 16 msec; RXL out by 4 mm; plasma

23. RCUR out by 1 mm; plasma

24. increase nitrogen plenum to 10 psi from 5; plasma

25. TF fault during init; cycle test with no power.

26. increase nitrogen puff to 150 ms; increased gas puff from .1 to .3 sec,
reduced it after .5s; plasma

27. initialization problem; no power cycle

28. 1 MA; plasma; early marfe-like H-alpha and spikes on density; higher
density

29. lower early segment 2 gas; plasma

30. lower early segment 2 gas; more gas during RF; plasma; lost 1 antenna for
last part of RF pulse

31. repeat; plasma

32. nitrogen plenum to 17 psi; plasma

33. 800 kA; RCUR out by 1 mm; plasma;

34. puff hard between .6 and 1.1 s; plasma

35. switch to fiducial from segment 4 after 0.1 s; disrupt at .217 s; blown fuses on OH2L

36. back to old segment 2, nl_04 to 1e20; plasma; h-mode at 2 MW, not at 1 MW

Session Leader Comments

Dec 12 1997 08:29:15:080AM John Goetz MP #163 High q_parallel Dissipative Divertor

This proposal is an attempt to achieve simultaneously a good confinement
H-mode with low Zeff and a detached divertor. The goal is to determine the
threshold amount of impurity gas necessary to detach the divertor. Also,
operation just above and just below the detachment threshold will be
investigated.

The plan is to start with a good shot from 971211 (1MA current, 1e20 line density,
good equilibrium, ...).

1. Try to get acceptable H-mode (preferably enhanced D-alpha).
2. Begin puffing N2 into the H-mode phase to try to detach.
Start with 100msec puff of nitrogen from J-bottom, beginning 100msec after the RF.
3. If successful in detaching with high q||, then try setting up feedback on the
J-Bottom valve using the divertor bolo signals.
4. Operate just above and just below the detachment threshold and compare
the confinement and cleanliness at these operational levels.
5. Try neon, argon, and krypton

Dec 12 1997 09:07:24:340AM 971212001 John Goetz Shot 971212001
Plasma - disrupts @ 1.3sec - hard x-rays - low density
2MW into SOL; L-mode; Zeff ~ 3

Dec 12 1997 09:21:12:070AM 971212002 John Goetz Shot 971212002
Plasma - hard x-rays - low density
1.5MW into SOL; Zeff ~ 3; 5 ELM-free H-modes and 1 ELMy

Dec 12 1997 09:40:30:370AM 971212003 John Goetz Shot 971212003
Plasma - better on the density
??MW into SOL; Zeff ~ 3; 5 H-modes (progressively more EDA-like)

Dec 12 1997 09:57:50:210AM 971212004 John Goetz Shot 971212004
Plasma - getting closer
~1MW into SOL; Zeff ~ 2.8; 5 H-modes (more and more EDA-like)
last transition has less radiated power

Dec 12 1997 10:11:23:670AM 971212005 John Goetz Shot 971212005
Plasma -
~1.5MW into SOL; Zeff ~ 2.5; last H-mode pretty EDA-like

Dec 12 1997 10:20:19:220AM 971212006 John Goetz Shot 971212006
Plasma -
~1.5MW into SOL; Zeff ~ 2.7->2.4 ; 6 ELMy H-modes

Dec 12 1997 10:40:56:610AM 971212007 John Goetz Shot 971212007
Plasma -
~1.5MW into SOL; Zeff ~ ?? ; 4 ELMy H-modes

Dec 12 1997 10:41:11:190AM 971212008 John Goetz Shot 971212008
FIzzle

Dec 12 1997 10:54:45:700AM 971212009 John Goetz Shot 971212009
FIzzle

Dec 12 1997 11:11:04:290AM 971212010 John Goetz Shot 971212010
Plasma - some hard x-rays - higher density -
H-mode from 0.8 to 1. sec is somewhat steady state
Power into SOL ~ 1.5MW and Zeff ~ 2.2

Dec 12 1997 11:33:50:030AM 971212011 John Goetz Shot 971212011
Fizzle

Dec 12 1997 11:34:02:560AM 971212012 John Goetz Shot 971212012
Dud

Dec 12 1997 11:48:36:290AM 971212013 John Goetz Shot 971212013
Plasma - 3 H-modes (2 of them ~0.2sec long)
1.5MW into SOL; Zeff???

Dec 12 1997 11:48:52:020AM 971212014 John Goetz Shot 971212014
Fizzle

Dec 12 1997 12:05:36:420PM 971212015 John Goetz Shot 971212015
Plasma - long H-mode from 0.72 to 1.0sec
<1.5MW into SOL; z_ave=1.1

Dec 12 1997 12:14:32:530PM 971212016 John Goetz Shot 971212016
Fizzle

Dec 12 1997 12:28:16:990PM 971212017 John Goetz Shot 971212017
Plasma - 0.8MA - 3 H-modes (1st one from .55 to .83sec)
1.2MW into the SOL - z_ave = 1.05

Dec 12 1997 12:41:00:770PM 971212018 John Goetz Shot 971212018
Plasma - 0.8MA - disruption @ .48sec

Dec 12 1997 12:49:47:670PM 971212019 John Goetz Shot 971212019
Plasma - 0.8MA - H-mode from 0.56 to 0.96sec
1.4MW into SOL; z_ave=1.2

Dec 12 1997 01:09:48:870PM 971212020 John Goetz Shot 971212020
Plasma - 0.8MA - H-mode from 0.56 to 1.03sec
1.3MW into SOL; z_ave=1.1; no sign of detachment

Dec 12 1997 01:10:54:720PM 971212021 John Goetz Shot 971212021
Fizzle

Dec 12 1997 01:33:51:720PM 971212022 John Goetz Shot 971212022
Plasma - H-mode from .56 to .75 and from .78 to 1.2sec
1.4MW (and then 1.2MW) into SOL; Zeff = 1.1
0.2Torr-l of nitrogen delivered; no signs of detachment

Dec 12 1997 01:50:07:630PM 971212023 John Goetz Shot 971212023
Plasma - steady H-mode from .85 to 1.15sec
1.3MW (and then 1.2MW) into SOL; Zeff = 1.
0.2Torr-l of nitrogen delivered; no signs of detachment

Dec 12 1997 02:00:50:420PM 971212024 John Goetz Shot 971212024
Plasma - steady H-mode from .56 to 1.15sec
1.3 MW into SOL; z_ave=1.2;
0.45 Torr-l of nitrogen delivered;

Dec 12 1997 02:13:48:310PM 971212025 John Goetz Shot 971212025
Dud

Dec 12 1997 02:41:59:460PM 971212026 John Goetz Shot 971212026
Plasma - H-mode from 0.56 to 0.7 and then ELMy until 1.15
??MW into SOL; z_ave=??
0.7Torr-l of N2 delivered

Dec 12 1997 02:54:55:450PM 971212027 John Goetz Shot 971212027
Dud

Dec 12 1997 03:08:17:610PM 971212028 John Goetz Shot 971212028
Plasma - 8 H-modes (all short)
1.3MW into SOL; z_ave=1.2
0.73 Torr-l N2 delivered - no detachment

Dec 12 1997 03:38:59:370PM 971212030 John Goetz Shot 971212030
Plasma - 2 H-modes (then one transmitter tripped)
1.6MW into SOL; z_ave=1.3
1.2 Torr-l N2 delivered - no detachment

Dec 12 1997 03:52:00:150PM 971212031 John Goetz Shot 971212031
Plasma - multiple H-modes (ELMy from .95 to 1.15)
1.2MW into SOL; z_ave=1.1
1.3 Torr-l N2 delivered - no detachment

Dec 12 1997 04:08:10:250PM 971212032 John Goetz Shot 971212032
Plasma - multiple H-modes (all short)
1.5MW into SOL; z_ave=1.25
1.6 Torr-l N2 delivered

Dec 12 1997 04:21:39:640PM 971212033 John Goetz Shot 971212033
Plasma - ELMy H-modes
1.5MW into SOL; z_ave=1.25
1.4 Torr-l N2 delivered

Dec 12 1997 04:30:27:030PM 971212034 John Goetz Shot 971212034
Plasma - ELMy H-modes
1.5MW into SOL; z_ave=1.25
1.5 Torr-l N2 delivered

Dec 12 1997 04:43:19:200PM 971212035 John Goetz Shot 971212035
Fiducial plasma - disrupts @ 0.22sec

Dec 12 1997 05:13:04:750PM 971212036 John Goetz Shot 971212036
Fiducial plasma

Physics Operator Comments

Dec 12 1997 08:16:48:130AM Earl Marmar Plan for 971212

ECDC overnight in Helium

Power supply setup as on shot 971211025, TF under hybrid control.

plenum setup:
20psi deuterium in K-side and 5psi in B-top
3psi argon in B-side-lower
5psi nitrogen in J-bottom

Enable the ECE gate valve for the first shot.

MP #163 High q_parallel Dissipative Divertor

This MP comprises a proposal to explore simultaneous achievement of a good
confinement H-mode with low Zeff and a detached divertor. The goal is to
determine the threshold amount of impurity gas necessary to detach the
divertor. Also, operation just above and just below the detachment threshold
will be investigated.

The plan is to start from shot 971211025.

1) Get acceptable H-mode (preferably enhanced D-alpha).

2) Puff N_2 into the H-mode phase to induce detachment; start with 100msec
puff from J-bottom, beginning 100msec after the RF.

3) If successful in detaching with high q||, then set up feedback on the
J-Bottom valve using the divertor bolo signals.

Dec 12 1997 09:08:02:010AM 971212001 Earl Marmar 1. Remove B_T wiggle; prepuff to 18 msec; nl_04 to 1e20 at .6 s; RF feedback on,
gain = -1500; plasma; disrupt in rampdown; some hards; lowish density; Z_eff ~ 3

Dec 12 1997 09:25:43:340AM 971212003 Earl Marmar
2. Add more puff volts in segment 1; hesitation during current rise; plasma;
more hards; in and out of H-mod; density still low.

Dec 12 1997 09:42:38:550AM 971212003 Earl Marmar
3. increase B_R offset by 0.5 mT; increase early gas puff some more; plasma;
higher density; no hards.

Dec 12 1997 10:00:24:410AM 971212004 Earl Marmar 4. move ZXL up 1 cm; RXU in 1 cm; plasma.

Dec 12 1997 10:11:15:250AM 971212005 Earl Marmar 5. move ZXL up 2 mm; RXU in 1 cm; plasma

Dec 12 1997 10:19:44:370AM 971212006 Earl Marmar 6. move ZXL up 1 mm; RCUR decrease 1 mm; plasma

Dec 12 1997 10:43:46:890AM 971212007 Earl Marmar 7. more gas during RF; RCUR decrease 1 mm; plasma

Dec 12 1997 10:44:02:510AM 971212008 Earl Marmar 8. more gas; fizzle

Dec 12 1997 11:24:46:330AM 971212009 Earl Marmar 9. reduce prepuff to 16 ms; fizzle

Dec 12 1997 11:25:01:710AM 971212010 Earl Marmar 10. prepuff to 17 ms; B_R offset reduced by .5 mT; plasma; hesitation during
current rise; some hards.

Dec 12 1997 11:25:16:630AM 971212011 Earl Marmar 11. prepuff to 14 ms; raise early gas; raise gas during RF; fizzle

Dec 12 1997 11:30:30:320AM 971212012 Earl Marmar TF Fault during init; cycle test with no power;

Dec 12 1997 11:55:25:040AM 971212013 Earl Marmar 13. prepuff to 18 ms; B_R offset to .075; plasma; no hards.

Dec 12 1997 11:55:39:500AM 971212014 Earl Marmar 14. more gas after 0.4 s; fizzle; breakdown is slightly late; possible sparker
problem?

Dec 12 1997 01:18:09:980PM 971212015 Earl Marmar
15. retry; plasma

Dec 12 1997 01:18:23:740PM 971212016 Earl Marmar 16. ask for 800 kA plasma current; fizzle

Dec 12 1997 01:18:46:780PM 971212017 Earl Marmar 17. prefill to 17 msec; b_r offset to .007; plasma

Dec 12 1997 01:19:01:200PM 971212018 Earl Marmar 18. add 2 mm to RCUR; disrupt at .5s; niobium.

Dec 12 1997 01:19:15:520PM 971212019 Earl Marmar 19. repeat; plasma

Dec 12 1997 01:19:32:380PM 971212020 Earl Marmar 20. turn on nitrogen puff; 70 msec starting at .65 s; plasma

Dec 12 1997 01:19:49:090PM 971212021 Earl Marmar 21. nitrogen puff increased to 100 msec; fizzle

Dec 12 1997 01:42:52:020PM 971212023 Earl Marmar Wolfe says the hash on TF1 cabinet reappeared on this shot.

Dec 12 1997 05:18:07:290PM 971212023 Earl Marmar 23. RCUR out by 1 mm; plasma

Dec 12 1997 05:18:23:760PM 971212024 Earl Marmar 24. increase nitrogen plenum to 10 psi from 5; plasma

Dec 12 1997 05:18:37:780PM 971212025 Earl Marmar 25. TF fault during init; cycle test with no power.

Dec 12 1997 05:18:55:990PM 971212026 Earl Marmar 26. increase nitrogen puff to 150 ms; increased gas puff from .1 to .3 sec,
reduced it after .5s; plasma

Dec 12 1997 05:19:13:300PM 971212027 Earl Marmar 27. initialization problem; no power cycle

Dec 12 1997 05:19:29:600PM 971212028 Earl Marmar 28. 1 MA; plasma; early marfe-like H-alpha and spikes on density; higher
density

Dec 12 1997 05:19:46:840PM 971212029 Earl Marmar 29. lower early segment 2 gas; plasma

Dec 12 1997 05:19:58:590PM 971212030 Earl Marmar 30. lower early segment 2 gas; more gas during RF; plasma; lost 1 antenna for
last part of RF pulse

Dec 12 1997 05:20:14:950PM 971212031 Earl Marmar 31. repeat; plasma

Dec 12 1997 05:20:27:330PM 971212032 Earl Marmar 32. nitrogen plenum to 17 psi; plasma

Dec 12 1997 05:20:41:050PM 971212033 Earl Marmar 33. 800 kA; RCUR out by 1 mm; plasma

Dec 12 1997 05:20:51:860PM 971212034 Earl Marmar 34. puff hard between .6 and 1.1 s; plasma

Dec 12 1997 05:21:02:920PM 971212035 Earl Marmar 35. switch to fiducial from segment 4 after 0.1 s; disrupt at .217 s; blown fuses on OH2L

Dec 12 1997 05:21:33:140PM 971212036 Earl Marmar 36. back to old segment 2, nl_04 to 1e20; plasma; h-mode at 2 MW, not at 1 MW

Engineering Operator Comments

Shot Time Type Status Comment

1 08:55:01:480AM Plasma Ok

2 09:11:13:370AM Plasma Ok

3 09:24:59:880AM Plasma Ok

4 09:43:10:790AM Plasma Ok

5 09:57:54:930AM Plasma Ok

6 10:10:14:680AM Plasma Ok

7 10:21:53:150AM Plasma Ok

8 10:35:47:790AM Plasma Ok

9 10:44:39:230AM Plasma Ok

10 10:55:48:210AM Plasma Ok

11 11:12:02:400AM Plasma Ok

12 11:22:51:930AM Test Ok

13 11:35:12:070AM Plasma Ok

14 11:46:08:440AM Plasma Ok

15 11:54:55:460AM Plasma Ok

16 12:05:59:870PM Plasma Ok

17 12:15:11:860PM Plasma Ok

18 12:28:52:650PM Plasma Ok

19 12:39:02:400PM Plasma Ok

20 12:56:36:130PM Plasma Ok

21 01:09:20:880PM Plasma Ok NO FAULTS

22 01:21:01:420PM Plasma Ok NO FAULTS

23 01:35:38:940PM Plasma Ok HASH ON TF CONVERTOR #2

24 01:47:27:990PM Plasma Ok NO FAULTS

25 02:05:06:120PM Test Ok

26 02:15:51:690PM Plasma Ok

27 02:42:48:650PM Test Ok

28 02:55:47:710PM Plasma Ok

29 03:12:53:930PM Plasma Ok

30 03:25:08:850PM Plasma Ok

31 03:38:00:020PM Plasma Ok

32 03:55:41:250PM Plasma Ok

33 04:07:44:150PM Plasma Ok

34 04:19:57:370PM Plasma Ok

35 04:37:34:320PM Plasma Ok

36 05:08:03:440PM Plasma Ok

Session Leader Comments
Dec 12 1997 08:29:15:080AM		John Goetz	MP #163 High q_parallel Dissipative Divertor This proposal is an attempt to achieve simultaneously a good confinement H-mode with low Zeff and a detached divertor. The goal is to determine the threshold amount of impurity gas necessary to detach the divertor. Also, operation just above and just below the detachment threshold will be investigated. The plan is to start with a good shot from 971211 (1MA current, 1e20 line density, good equilibrium, ...). 1. Try to get acceptable H-mode (preferably enhanced D-alpha). 2. Begin puffing N2 into the H-mode phase to try to detach. Start with 100msec puff of nitrogen from J-bottom, beginning 100msec after the RF. 3. If successful in detaching with high q\|\|, then try setting up feedback on the J-Bottom valve using the divertor bolo signals. 4. Operate just above and just below the detachment threshold and compare the confinement and cleanliness at these operational levels. 5. Try neon, argon, and krypton
Dec 12 1997 09:07:24:340AM	971212001	John Goetz	Shot 971212001 Plasma - disrupts @ 1.3sec - hard x-rays - low density 2MW into SOL; L-mode; Zeff ~ 3
Dec 12 1997 09:21:12:070AM	971212002	John Goetz	Shot 971212002 Plasma - hard x-rays - low density 1.5MW into SOL; Zeff ~ 3; 5 ELM-free H-modes and 1 ELMy
Dec 12 1997 09:40:30:370AM	971212003	John Goetz	Shot 971212003 Plasma - better on the density ??MW into SOL; Zeff ~ 3; 5 H-modes (progressively more EDA-like)
Dec 12 1997 09:57:50:210AM	971212004	John Goetz	Shot 971212004 Plasma - getting closer ~1MW into SOL; Zeff ~ 2.8; 5 H-modes (more and more EDA-like) last transition has less radiated power
Dec 12 1997 10:11:23:670AM	971212005	John Goetz	Shot 971212005 Plasma - ~1.5MW into SOL; Zeff ~ 2.5; last H-mode pretty EDA-like
Dec 12 1997 10:20:19:220AM	971212006	John Goetz	Shot 971212006 Plasma - ~1.5MW into SOL; Zeff ~ 2.7->2.4 ; 6 ELMy H-modes
Dec 12 1997 10:40:56:610AM	971212007	John Goetz	Shot 971212007 Plasma - ~1.5MW into SOL; Zeff ~ ?? ; 4 ELMy H-modes
Dec 12 1997 10:41:11:190AM	971212008	John Goetz	Shot 971212008 FIzzle
Dec 12 1997 10:54:45:700AM	971212009	John Goetz	Shot 971212009 FIzzle
Dec 12 1997 11:11:04:290AM	971212010	John Goetz	Shot 971212010 Plasma - some hard x-rays - higher density - H-mode from 0.8 to 1. sec is somewhat steady state Power into SOL ~ 1.5MW and Zeff ~ 2.2
Dec 12 1997 11:33:50:030AM	971212011	John Goetz	Shot 971212011 Fizzle
Dec 12 1997 11:34:02:560AM	971212012	John Goetz	Shot 971212012 Dud
Dec 12 1997 11:48:36:290AM	971212013	John Goetz	Shot 971212013 Plasma - 3 H-modes (2 of them ~0.2sec long) 1.5MW into SOL; Zeff???
Dec 12 1997 11:48:52:020AM	971212014	John Goetz	Shot 971212014 Fizzle
Dec 12 1997 12:05:36:420PM	971212015	John Goetz	Shot 971212015 Plasma - long H-mode from 0.72 to 1.0sec <1.5MW into SOL; z_ave=1.1
Dec 12 1997 12:14:32:530PM	971212016	John Goetz	Shot 971212016 Fizzle
Dec 12 1997 12:28:16:990PM	971212017	John Goetz	Shot 971212017 Plasma - 0.8MA - 3 H-modes (1st one from .55 to .83sec) 1.2MW into the SOL - z_ave = 1.05
Dec 12 1997 12:41:00:770PM	971212018	John Goetz	Shot 971212018 Plasma - 0.8MA - disruption @ .48sec
Dec 12 1997 12:49:47:670PM	971212019	John Goetz	Shot 971212019 Plasma - 0.8MA - H-mode from 0.56 to 0.96sec 1.4MW into SOL; z_ave=1.2
Dec 12 1997 01:09:48:870PM	971212020	John Goetz	Shot 971212020 Plasma - 0.8MA - H-mode from 0.56 to 1.03sec 1.3MW into SOL; z_ave=1.1; no sign of detachment
Dec 12 1997 01:10:54:720PM	971212021	John Goetz	Shot 971212021 Fizzle
Dec 12 1997 01:33:51:720PM	971212022	John Goetz	Shot 971212022 Plasma - H-mode from .56 to .75 and from .78 to 1.2sec 1.4MW (and then 1.2MW) into SOL; Zeff = 1.1 0.2Torr-l of nitrogen delivered; no signs of detachment
Dec 12 1997 01:50:07:630PM	971212023	John Goetz	Shot 971212023 Plasma - steady H-mode from .85 to 1.15sec 1.3MW (and then 1.2MW) into SOL; Zeff = 1. 0.2Torr-l of nitrogen delivered; no signs of detachment
Dec 12 1997 02:00:50:420PM	971212024	John Goetz	Shot 971212024 Plasma - steady H-mode from .56 to 1.15sec 1.3 MW into SOL; z_ave=1.2; 0.45 Torr-l of nitrogen delivered;
Dec 12 1997 02:13:48:310PM	971212025	John Goetz	Shot 971212025 Dud
Dec 12 1997 02:41:59:460PM	971212026	John Goetz	Shot 971212026 Plasma - H-mode from 0.56 to 0.7 and then ELMy until 1.15 ??MW into SOL; z_ave=?? 0.7Torr-l of N2 delivered
Dec 12 1997 02:54:55:450PM	971212027	John Goetz	Shot 971212027 Dud
Dec 12 1997 03:08:17:610PM	971212028	John Goetz	Shot 971212028 Plasma - 8 H-modes (all short) 1.3MW into SOL; z_ave=1.2 0.73 Torr-l N2 delivered - no detachment
Dec 12 1997 03:38:59:370PM	971212030	John Goetz	Shot 971212030 Plasma - 2 H-modes (then one transmitter tripped) 1.6MW into SOL; z_ave=1.3 1.2 Torr-l N2 delivered - no detachment
Dec 12 1997 03:52:00:150PM	971212031	John Goetz	Shot 971212031 Plasma - multiple H-modes (ELMy from .95 to 1.15) 1.2MW into SOL; z_ave=1.1 1.3 Torr-l N2 delivered - no detachment
Dec 12 1997 04:08:10:250PM	971212032	John Goetz	Shot 971212032 Plasma - multiple H-modes (all short) 1.5MW into SOL; z_ave=1.25 1.6 Torr-l N2 delivered
Dec 12 1997 04:21:39:640PM	971212033	John Goetz	Shot 971212033 Plasma - ELMy H-modes 1.5MW into SOL; z_ave=1.25 1.4 Torr-l N2 delivered
Dec 12 1997 04:30:27:030PM	971212034	John Goetz	Shot 971212034 Plasma - ELMy H-modes 1.5MW into SOL; z_ave=1.25 1.5 Torr-l N2 delivered
Dec 12 1997 04:43:19:200PM	971212035	John Goetz	Shot 971212035 Fiducial plasma - disrupts @ 0.22sec
Dec 12 1997 05:13:04:750PM	971212036	John Goetz	Shot 971212036 Fiducial plasma

Physics Operator Comments
Dec 12 1997 08:16:48:130AM		Earl Marmar	Plan for 971212 ECDC overnight in Helium Power supply setup as on shot 971211025, TF under hybrid control. plenum setup: 20psi deuterium in K-side and 5psi in B-top 3psi argon in B-side-lower 5psi nitrogen in J-bottom Enable the ECE gate valve for the first shot. MP #163 High q_parallel Dissipative Divertor This MP comprises a proposal to explore simultaneous achievement of a good confinement H-mode with low Zeff and a detached divertor. The goal is to determine the threshold amount of impurity gas necessary to detach the divertor. Also, operation just above and just below the detachment threshold will be investigated. The plan is to start from shot 971211025. 1) Get acceptable H-mode (preferably enhanced D-alpha). 2) Puff N_2 into the H-mode phase to induce detachment; start with 100msec puff from J-bottom, beginning 100msec after the RF. 3) If successful in detaching with high q\|\|, then set up feedback on the J-Bottom valve using the divertor bolo signals.
Dec 12 1997 09:08:02:010AM	971212001	Earl Marmar	1. Remove B_T wiggle; prepuff to 18 msec; nl_04 to 1e20 at .6 s; RF feedback on, gain = -1500; plasma; disrupt in rampdown; some hards; lowish density; Z_eff ~ 3
Dec 12 1997 09:25:43:340AM	971212003	Earl Marmar	2. Add more puff volts in segment 1; hesitation during current rise; plasma; more hards; in and out of H-mod; density still low.
Dec 12 1997 09:42:38:550AM	971212003	Earl Marmar	3. increase B_R offset by 0.5 mT; increase early gas puff some more; plasma; higher density; no hards.
Dec 12 1997 10:00:24:410AM	971212004	Earl Marmar	4. move ZXL up 1 cm; RXU in 1 cm; plasma.
Dec 12 1997 10:11:15:250AM	971212005	Earl Marmar	5. move ZXL up 2 mm; RXU in 1 cm; plasma
Dec 12 1997 10:19:44:370AM	971212006	Earl Marmar	6. move ZXL up 1 mm; RCUR decrease 1 mm; plasma
Dec 12 1997 10:43:46:890AM	971212007	Earl Marmar	7. more gas during RF; RCUR decrease 1 mm; plasma
Dec 12 1997 10:44:02:510AM	971212008	Earl Marmar	8. more gas; fizzle
Dec 12 1997 11:24:46:330AM	971212009	Earl Marmar	9. reduce prepuff to 16 ms; fizzle
Dec 12 1997 11:25:01:710AM	971212010	Earl Marmar	10. prepuff to 17 ms; B_R offset reduced by .5 mT; plasma; hesitation during current rise; some hards.
Dec 12 1997 11:25:16:630AM	971212011	Earl Marmar	11. prepuff to 14 ms; raise early gas; raise gas during RF; fizzle
Dec 12 1997 11:30:30:320AM	971212012	Earl Marmar	TF Fault during init; cycle test with no power;
Dec 12 1997 11:55:25:040AM	971212013	Earl Marmar	13. prepuff to 18 ms; B_R offset to .075; plasma; no hards.
Dec 12 1997 11:55:39:500AM	971212014	Earl Marmar	14. more gas after 0.4 s; fizzle; breakdown is slightly late; possible sparker problem?
Dec 12 1997 01:18:09:980PM	971212015	Earl Marmar	15. retry; plasma
Dec 12 1997 01:18:23:740PM	971212016	Earl Marmar	16. ask for 800 kA plasma current; fizzle
Dec 12 1997 01:18:46:780PM	971212017	Earl Marmar	17. prefill to 17 msec; b_r offset to .007; plasma
Dec 12 1997 01:19:01:200PM	971212018	Earl Marmar	18. add 2 mm to RCUR; disrupt at .5s; niobium.
Dec 12 1997 01:19:15:520PM	971212019	Earl Marmar	19. repeat; plasma
Dec 12 1997 01:19:32:380PM	971212020	Earl Marmar	20. turn on nitrogen puff; 70 msec starting at .65 s; plasma
Dec 12 1997 01:19:49:090PM	971212021	Earl Marmar	21. nitrogen puff increased to 100 msec; fizzle
Dec 12 1997 01:42:52:020PM	971212023	Earl Marmar	Wolfe says the hash on TF1 cabinet reappeared on this shot.
Dec 12 1997 05:18:07:290PM	971212023	Earl Marmar	23. RCUR out by 1 mm; plasma
Dec 12 1997 05:18:23:760PM	971212024	Earl Marmar	24. increase nitrogen plenum to 10 psi from 5; plasma
Dec 12 1997 05:18:37:780PM	971212025	Earl Marmar	25. TF fault during init; cycle test with no power.
Dec 12 1997 05:18:55:990PM	971212026	Earl Marmar	26. increase nitrogen puff to 150 ms; increased gas puff from .1 to .3 sec, reduced it after .5s; plasma
Dec 12 1997 05:19:13:300PM	971212027	Earl Marmar	27. initialization problem; no power cycle
Dec 12 1997 05:19:29:600PM	971212028	Earl Marmar	28. 1 MA; plasma; early marfe-like H-alpha and spikes on density; higher density
Dec 12 1997 05:19:46:840PM	971212029	Earl Marmar	29. lower early segment 2 gas; plasma
Dec 12 1997 05:19:58:590PM	971212030	Earl Marmar	30. lower early segment 2 gas; more gas during RF; plasma; lost 1 antenna for last part of RF pulse
Dec 12 1997 05:20:14:950PM	971212031	Earl Marmar	31. repeat; plasma
Dec 12 1997 05:20:27:330PM	971212032	Earl Marmar	32. nitrogen plenum to 17 psi; plasma
Dec 12 1997 05:20:41:050PM	971212033	Earl Marmar	33. 800 kA; RCUR out by 1 mm; plasma
Dec 12 1997 05:20:51:860PM	971212034	Earl Marmar	34. puff hard between .6 and 1.1 s; plasma
Dec 12 1997 05:21:02:920PM	971212035	Earl Marmar	35. switch to fiducial from segment 4 after 0.1 s; disrupt at .217 s; blown fuses on OH2L
Dec 12 1997 05:21:33:140PM	971212036	Earl Marmar	36. back to old segment 2, nl_04 to 1e20; plasma; h-mode at 2 MW, not at 1 MW

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:55:01:480AM	Plasma	Ok
2	09:11:13:370AM	Plasma	Ok
3	09:24:59:880AM	Plasma	Ok
4	09:43:10:790AM	Plasma	Ok
5	09:57:54:930AM	Plasma	Ok
6	10:10:14:680AM	Plasma	Ok
7	10:21:53:150AM	Plasma	Ok
8	10:35:47:790AM	Plasma	Ok
9	10:44:39:230AM	Plasma	Ok
10	10:55:48:210AM	Plasma	Ok
11	11:12:02:400AM	Plasma	Ok
12	11:22:51:930AM	Test	Ok
13	11:35:12:070AM	Plasma	Ok
14	11:46:08:440AM	Plasma	Ok
15	11:54:55:460AM	Plasma	Ok
16	12:05:59:870PM	Plasma	Ok
17	12:15:11:860PM	Plasma	Ok
18	12:28:52:650PM	Plasma	Ok
19	12:39:02:400PM	Plasma	Ok
20	12:56:36:130PM	Plasma	Ok
21	01:09:20:880PM	Plasma	Ok	NO FAULTS
22	01:21:01:420PM	Plasma	Ok	NO FAULTS
23	01:35:38:940PM	Plasma	Ok	HASH ON TF CONVERTOR #2
24	01:47:27:990PM	Plasma	Ok	NO FAULTS
25	02:05:06:120PM	Test	Ok
26	02:15:51:690PM	Plasma	Ok
27	02:42:48:650PM	Test	Ok
28	02:55:47:710PM	Plasma	Ok
29	03:12:53:930PM	Plasma	Ok
30	03:25:08:850PM	Plasma	Ok
31	03:38:00:020PM	Plasma	Ok
32	03:55:41:250PM	Plasma	Ok
33	04:07:44:150PM	Plasma	Ok
34	04:19:57:370PM	Plasma	Ok
35	04:37:34:320PM	Plasma	Ok
36	05:08:03:440PM	Plasma	Ok