Alcator C-Mod Run 980123 Information

Miniproposals

Miniproposal: 163

Date Filed: 7/18/1996

Title: Detached Divertor High q

First Author: John Goetz

Session Leader: John Goetz (shots 1-34)

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

Engineering Operator Run Comment
mp 163

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:17:913PM

Author: To Be Determined

Run 980123 -- 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:
1. Start with a good shot from 980106, e.g. 980106025, and
try to get acceptable H-mode (preferably enhanced D-alpha).
Then get the max out of the RF with Ip=1MA, nl04=1.2e20, steady
strike points, ...
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 levels.
5. Try neon, argon, and krypton

Physics Summary:
The run was successful in producing enhanced Dalpha (EDA) H-modes
with 'steady-state' H-factors of about 1.6. The RF boys were able to couple
up to 3MW of power (with some voltage headroom). With the core radiation
levels being low, these plasmas had high power levels in the scrape-off layer.
The highest SOL power for the day was 2.5MW. Assuming the standard H-mode
power scale length, this corresponds to greater than 0.5GW per square meter;
high q-parallel indeed.
Divertor detachment was also achieved today. This was achieved with a
combination of deuterium, helium, and nitrogen gas puffing. The first half of
the run consisted of attempts to achieve a good EDA H-mode and to increase the
divertor radiation. The deuterium gas puff during the H-mode was determined to
be important in keeping the molybdenum levels low and the neutron rate high,
and seemed to eliminate the H->L transitions (thanks to ESM suggestion). The
puffing of helium and nitrogen in the divertor led to "death-ray" formation (by
shot 016), high divertor radiated power (by shot 025), and eventually divertor
detachment (shot 026). It was later determined that the helium puffing was not
necessary for detachment (shots 033 and 034) as nitrogen puffing alone was
sufficient, although the amount of nitrogen needed was increased. Shot 034
exhibits the deepest detachment of the day. The outer divertor plate is
detached up to probe 6. However the strike point is still 10-15eV. This is
very reminiscent of the previous trophy shot 960227019. The impurity gas was
turned off at 1.1sec and the RF power pulse at 1.2sec. This oversight allowed
the divertor to reattach. It is possible that if the length of the shot had
been extended, the strike point could have been detached also. This awaits
the final approved run in this series.
Impurity gas feedback was accomplished today. Kudos to Marmar-Wolfe.
Feedback was done on an edge bolometer channel (core). This channel was
identified earlier as a likely candidate to indicate when detachment was
ocurring. The waveforms drawn were trapezoidal in shape (in detachment the
waveform is triangular). Essentially this means we were trying to clip the
bolometer signal off by using feedback on the impurity gas, in this case,
nitrogen. The duty cycle driver board for J-Bottom was not successful in tests
last evening. In the testing, a high voltage op amp with gain of 25 was
installed instead of the nominal 10. The valve was run under straight voltage
control. Beware of feedback gains and pre-programmed voltages when the op amp
board is returned to its nominal state. The day started with hand drawn
waveforms for the gas voltage. When detachment was observed, the feedback was
switched on (shot 031) with a drawn waveform close to that of the previous
shot. The feedback worked well, trying to keep the bolometer waveform close
to that requested. With the helium puff turned off, the feedback requested
extra nitrogen to match the drawn waveform and reached detachment.
The goal of simultaneously achieving good confinement, low Zeff, and
a detached divertor was not quite reached. On the best shot, H-factors of 1.6
decreased to 1.4 after the divertor detached, but did not decrease any further
as detachment progressed. Zeff was high all day, never much less than 1.7
after the EDA H-mode was fully established. With impurity puffing, the
typical change in Zeff was about 0.5. There is now a starting point for
H-mode detachment studies. Comparison of plasma and divertor performance above
and below the detachment threshold can now proceed (and other experiments
requiring a detached H-mode).
Other interesting observations today:
Reconstructions (Boswell-Terry) of the high resolution divertor view in D-gamma
light show the regions where recombination is occuring. There is a region above
the outer strike point that moves up the plate as the detachment proceeds. When
the impurity gas flow is stopped, the region jumps back to just above the strike
point. More of the delta(stored energy) vs. delta(toroidal rotation) space was
filled in by Rice with today's plasmas.

Shot Result
---- ------
001 fizzle
002 plasma - EDA, but a moly injection kills it
003 plasma - barely EDA - only one transmitter
004 plasma - steady state EDA - H=1.6; PSOL=2MW; Prad,div=1MW; Prad=1.5MW
005 plasma - disrupts @ 0.35
006 plasma - lower target density - lots of H->L transitions
007 plasma - fewer H->L transitions
008 plasma - EDA - going away from 0.8 to 1.0 - too much Mo buildup
009 plasma - not very EDAlike - more Mo than 008
010 plasma - good EDA - Psol=2.0->1.6; Zeff=1.5->1.9; H=?
011 plasma - EDA - Psol=2.0->1.7MW - H=1.6->1.35 - Zeff=1.5->1.9;
0.85Torr-l of N2; Pdiv=0.7MW
012 plasma - EDA - Psol=2.0->1.6; Zeff=1.7->2.0; H=1.5->1.3; Pdiv=0.7MW;
0.89Torr-l of N2
013 no power
014 plasma - EDA - no detachment - H=1.6 - Zeff=1.85 - Psol>2MW -
0.78Torr-l of N2
015 plasma - EDA - no detachment - H=1.6->1.5 - Psol=2.4->2.0MW -
0.96Torr-l of N2; Pdiv=0.7MW
016 plasma - EDA - death ray forming - H=1.65->1.35 - 0.97Torr-l of N2 -
Psol=2.3MW - Pdiv=0.75 (flat)
017 plasma - EDA - death ray on probe 3 - EFIT "lock-up"
018 plasma - EDA - H=1.45->1.47Torr-l of N2 - Zeff=1.65->1.8; Pdiv=0.65MW
019 plasma - EDA - H=?; Zeff=1.6->1.9; Pdiv=0.65->0.75MW; Psol=2.4MW;
1.43torr-l of N2 plus 11Torr-l of He
020 plasma - disrupts @ 0.54
021 plasma - EDA - 1.8Torr-l of N2; Zeff=1.8->2.1; H=1.55->1.45;
Psol=2.3->2.0MW; Pdiv=0.65->0.70MW
022 plasma - EDA - 1.8Torr-l of N2; 11Torr-l of He; Zeff=1.55->1.9;
H=1.6->1.5; Pdiv=0.66->0.80MW; Psol=2.6MW
023 plasma - EDA - Mo injection @ 0.85 - 3.1Torr-l of N2 & 11Torr-l of He
024 plasma - EDA - 3.4Torr-l of N2; 19Torr-l of He; H=1.6->1.5;
Zeff=1.6->2.0; definite signs of detachment @ 0.98
025 plasma - EDA - H=1.6->1.5->1.4; Zeff=1.6->1.9; Pdiv=1.0MW; Psol=2.4MW
beginning of detachment @ 0.96
026 plasma - EDA - Zeff=1.7->2.2; Pdiv=1MW; Psol=2.6MW; H=1.5->1.3;
beginning of detachment @ 0.85
027 plasma - EDA - H=1.5->1.35->1.1 (after detach); Pdiv=1.0MW; Psol=2.0MW;
Prad=2.0MW; Zeff=1.7->2.4; 4Torr-l of N2 and 19Torr-l of He
028 plasma - EDA - 4.0Torr-l of N2; detachment @ 0.81; Pdiv=0.9MW;
Psol=2.0MW; Prad=2.0MW
029 plasma - EDA - ugly shot - detachment @ 0.81
030 plasma - EDA - Zeff=1.8->2.2; H=1.7->1.5; Pdiv=0.9->1.1; Psol=2.4MW;
detachment @ 0.95
031 plasma - EDA - first attempt at bolo feedback; 4.0Torr-l of N2;
detachment@0.87; Zeff=1.9->2.3; H=1.5->1.3; Pdiv=1.1MW
032 plasma - EDA - detachment earlier - Pdiv=1.15MW - Psol=2.4MW;
Prad=1.7MW; detachment not very deep
033 plasma - no He puff - EDA - 4.35Torr-l of N2 - detachment @ 0.85;
H=1.6->1.5; Zeff=1.7->2.3; Pdiv=0.95->1.05; Psol=2.5->2.0;
Prad=2.0MW
034 plasma - no He puff - EDA - detachment up to probe 6 - still >10eV
at strike point, but low pressure - Pdiv=0.9->1.1;
Zeff=1.7->2.2; H=1.6->1.4 after detachment

Physics Operator Summaries

Entered: Jul 7 2004 04:36:58:910PM

Author: To Be Determined

980123

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.

EO: Bertolino, Cochrane
PO: Marmar
SL: Goetz

This run went well.

From the physop point of view:

Startup was very reliable today; after a fizzle on the first shot, we got 32
plasmas in a row (97%).

Bolometer feedback to control the nitrogen puffing was added (with Steve
Wolfe's help) and successfully used at the end of the run.

Adding a D_2 puff (along with the He and nitrogen) seemed to decrease the droop
in H-Mode performance, and may have helped with moly radiation during the RF
pulse.

RF was very reliable today, with close to 3 MW coupled on many shots.

We had a couple of computer hangs which caused short delays, and one no-power
shot after an alternator slowdown forced us back from init to recool before shot
13.

Two shots disrupted early, apparently because of large impurity injection.

PHYSOPS NOTE: IF YOU LOAD FROM ANY OF THE SHOTS (27 through 34) WHICH HAVE
bolo_fdbk on wire 9 in segment 2,
BE AWARE THAT WIRES 9-12 ARE REFERENCED TO 10 VOLTS, NOT TO I_P. THE OTHER
WIRES IN THAT GROUP (10-12) WERE TURNED OFF FOR TODAY'S SHOTS, BUT TURNING THEM
ON WITHOUT CHANGING BACK TO I_P REFERENCE WOULD CAUSE PROBLEMS.

Summary of shots: 34 shot cycles = 32 plasmas + 1 fizzle + 1 no power cycle

John Goetz loaded the first shot, from 980107025.

1. strong fizzle; B_r looks 2 mT too positive

2. B_r offset from .006 to .0045 T; plasma

3. Rcur decrease by .002 m to increase outer gap slightly; plasma

4. no changes; plasma; hesitation during current rise

5. add N_2 puff from 0.7 to 1.1 s; disrupt at .35 s; brick

6. lower early gas (seg 1); nl_04 to 1.0e20 from 1.4e20; plasma; J bottom valve
not following demand properly.

7. disable N_2; plasma

8. raise nl_04 to 1.1e20 from 1e20; plasma

9. enable N_2 from .7 to 1.1 s; nl_04 to 1.25e20 from 1.1e20; B_r offset to
.004 from .0045 T; plasma; some data system problems

10. reduce argon puff by 4 msec; plasma; two early injections

11. reduce argon puff by 2 msec; add 2 volt to N_2 maintenance level; plasma

12. reduce N_2 maintenance level by 1 volt; plasma

13. alternator problem; no power shot to clear systems

14. nl_04 to 1.4e20 from 1.25e20; tweak N_2 puff; turn off argon; plasma;
stayed more EDA'ish; neutron rate rising slowly through RF pulse.

15. increase N_2 puff; plasma;

16. He puff from divertor capillary; plasma

17. more N_2; plasma;

pause for data system hang

18. repeat; plasma

19. more helium from NINJA; increase RF by ~200kW; plasma

20. more N_2; plasma; early disruption (.55 s); big injection

21. retry; plasma; interesting evolution after 1 second: P_Rad goes down, Moly
goes down, neutron rate goes up.

22. add D_2 puff between .75 and 1.2 s; plasma

23. J bottom (N_2) pressure from 10 psi to 20 psi; plasma

24. add 4 psi to lower divertor caps (He); increase N_2 puff; increase D_2
puff; plasma

25. reduced N_2; plasma

26. move He puff earlier in time; plasma

27. increase N_2; decrease D_2 puff during RF; plasma; big Mo injection early,
barely got passed it.

28. eliminate D_2 puff during RF; plasma; lower neutron rate

29. decrease early N_2; plasma; rf coupling ratty

30. add back D_2 puff ala shot 27; TF up to 5.6 T from 5.3; plasma

31. bolo_fdbk on, gain = 2, close your eyes; plasma; looks like the feedback
was doing the right thing; hards early in the shot.

32. gain=6 on bolo_fdbk; plasma; feedback looks good; hards gone.

33. He off; plasma; neutrons stay up.

34. Increase bolo_fdbk demand a touch; plasma

Session Leader Comments

Jan 23 1998 08:12:26:260AM 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.

Jan 23 1998 08:13:03:010AM John Goetz MP #163 High q_parallel Dissipative Divertor

The physics plan is to:
1. Start with a good shot from 980107, e.g. 980107025, and
try to get acceptable H-mode (preferably enhanced D-alpha).
Then get the max out of the RF with Ip=1MA, nl04=1.2e20, steady
strike points, ...
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.
3a. If successful in detaching with high q||, then try setting up
feedback on the J-Bottom valve using the divertor bolo signals.
3b. If not successful in detachment, determine why the divertor
radiation is not increasing (try helium, neon, and argon).
4. Operate just above and just below the detachment threshold and
compare the confinement and cleanliness at these levels.
5. Try helium, neon, and argon.

Jan 23 1998 08:48:20:390AM 980123001 John Goetz Shot 980123001
Fizzle

Jan 23 1998 08:50:52:290AM 980123002 John Goetz Shot 980123002
Plasma
EDA - moly injection @ 0.85 kills it and almost detaches the divertor
approximately 1MW radiated in the divertor before the injection

Jan 23 1998 09:01:10:780AM 980123003 John Goetz Shot 980123003
Plasma
barely EDA; only one transmitter

Jan 23 1998 09:13:35:380AM 980123004 John Goetz Shot 980123004
Plasma
Steady state EDA
H = 1.6; PSOL=2MW; Prad,div=1MW; Prad,core=1.5MW

Jan 23 1998 09:17:05:830AM 980123005 John Goetz Shot 980123005
Plasma - disrupts @ 0.35

Jan 23 1998 10:04:32:590AM 980123006 John Goetz Shot 980123006
Plasma
lower taraget density
lots of H->L transitions ; lots of RF trips
J-Bottom valve driver not working correctly - the pulse was wide open for the
whole command time

Jan 23 1998 10:05:21:090AM 980123007 John Goetz Shot 980123007
Plasma
some H->L transitions ; RF trips reduced
J-Bottom valve driver seems to have a gain of 30 (instead of the designed 10)

Jan 23 1998 10:25:57:020AM 980123008 John Goetz Shot 980123008
Plasma
EDA - but going away from 0.8 to 1.0
lots of molybdenum buildup; causing the H->L transition

Jan 23 1998 10:51:02:490AM 980123009 John Goetz Shot 980123009
Plasma
not very EDAlike - 2 H->L transitions
data troubles - servers didn't go - EFIT o.k. though
more moly on this shot than on 008

Jan 23 1998 11:06:56:760AM 980123010 John Goetz Shot 980123010
Plasma
good EDA
PSOL = 2.0 -> 1.6MW; Zeff = 1.5 -> 1.9; ~0.7MW Pdiv;

Jan 23 1998 11:24:12:740AM 980123011 John Goetz Shot 980123011
Plasma
good EDA
PSOL = 2.0 -> 1.7MW; Zeff = 1.5 -> 1.9; ~0.7MW Pdiv; H=1.6->1.35
[0.85Torr-l of N2 delivered]

Jan 23 1998 11:40:10:420AM 980123012 John Goetz Shot 980123012
Plasma
good EDA
PSOL = 2.0 -> 1.6MW; Zeff = 1.7 -> 2.0; ~0.7MW Pdiv; H=1.5->1.3
[0.89Torr-l of N2 delivered]
some signs of detachment moving up the plate - but the temperature near
the strike point is still high

Jan 23 1998 11:48:17:920AM 980123013 John Goetz Shot 980123013
no power shot

Jan 23 1998 12:16:44:240PM 980123014 John Goetz Shot 980123014
Plasma
nice EDA - Wp=0.16MJ - H=1.6 - Zeff=1.8 - all steady state
However, no signs of detachment - divertor is warmer than 012
higher target density and no argon puffed

Jan 23 1998 12:31:12:740PM 980123015 John Goetz Shot 980123015
Plasma
nice EDA - Wp=0.16->0.15MJ - H=1.6->1.5 - Zeff=1.6->1.7
0.96Torr-l of N2 - no argon
Psol = 2.4->2.0MW; Pdiv=0.7MW

Jan 23 1998 12:43:33:460PM 980123016 John Goetz Shot 980123016
Plasma
nice EDA - Wp=0.16->0.14MJ - H=1.65->1.35 - Zeff=1.6->1.9
0.97Torr-l of N2 - no argon - 1 valve of helium through divertor
Psol = 2.3MW; Pdiv=0.75MW and flat
'death-ray' is forming on the divertor plate

Jan 23 1998 01:18:16:010PM 980123017 John Goetz Shot 980123017
Plasma
nice EDA - no processed data because of EFIT "lock-up"
'death-ray' is forming on the divertor plate

Jan 23 1998 01:21:14:250PM 980123017 John Goetz Shot 980123017
Plasma
nice EDA - no processed data because of EFIT "lock-up"
'death-ray' is forming on the divertor plate

Jan 23 1998 01:35:01:060PM 980123018 John Goetz Shot 980123018
Plasma
Mo injection @ 0.96 sorta ruins the experiment
H=1.45->1.4
Zeff=1.65->1.8
Pdiv=0.65MW; Psol=2.4->1.7MW

Jan 23 1998 01:44:02:010PM 980123019 John Goetz Shot 980123019
Plasma
Mo injection @ 0.95 sorta ruins the experiment
H=?; Wp=0.17->0.16MJ
Zeff=1.6->1.9
Pdiv=0.65->0.75MW (finally an increase); Psol=2.4MW; Prf=2.9MW
1.43Torr-l of N2 plus 11Torr-l of helium

Jan 23 1998 01:51:04:850PM 980123020 John Goetz Shot 980123020
Plasma
disrupts @ 0.54; in trouble at 0.515

Jan 23 1998 02:11:10:570PM 980123021 John Goetz Shot 980123021
Plasma
EDA - change in Dalpha @ 1.0sec for a 100msec - drop in radiation, but no
change in density, neutrons, H, etc.
1.8Torr-l of N2
Zeff=1.8->2.1; H=1.55->1.45; Psol=2.3->2.0MW; Pdiv=0.65->0.75MW

Jan 23 1998 02:25:54:630PM 980123022 John Goetz Shot 980123022
Plasma
EDA - Mo injection @ 0.95
1.83Torr-l of N2 and 11Torr-l
Zeff=1.55->1.9; H=1.6->1.5; Psol=2.6MW; Pdiv=0.65->0.8MW

Jan 23 1998 02:37:07:570PM 980123023 John Goetz Shot 980123023
Plasma
EDA - Mo injection @ 0.85 & 0.86sec
3.1Torr-l of N2 and 11Torr-l
Zeff=1.65->1.85
no EFIT due to TRAQ2 corruption

Jan 23 1998 03:01:04:080PM 980123024 John Goetz Shot 980123024
Plasma - EDA
3.4Torr-l of N2 and 19Torr-l of He
Zeff=1.6->2.0; Zeff=1.6->2.0
definite signs of detachment - density goes up after 0.98
Isat footprint show drop @ 1.0
processed probe data show pressure drop below the
strike point, but no change above

Jan 23 1998 03:13:01:110PM 980123025 John Goetz Shot 980123025
Plasma - EDA
3.2Torr-l of N2 and 19Torr-l of He
Zeff=1.6->1.9; H=1.6->1.5->1.4 (after detachment begins)
definite signs of detachment - density goes up after 0.96
Isat footprint show drop @ 1.0
not as deep a detachment as shot 024

Jan 23 1998 03:26:45:680PM 980123026 John Goetz Shot 980123026
Plasma - EDA
3.25Torr-l of N2 and 19Torr-l of He
Zeff=1.7->2.2; H=1.5->1.3
processed probe data show a detachment beginning @ ~0.85-0.90

Jan 23 1998 03:40:58:890PM 980123027 John Goetz Shot 980123027
Plasma - EDA
4.6Torr-l of N2 and 19Torr-l of He
Zeff=1.7->2.4; H=1.55->1.35
processed probe data show a detachment beginning @ ~0.85
Pdiv=1MW; Psol=2.4MW; Prad=1.5MW

Jan 23 1998 03:55:05:970PM 980123028 John Goetz Shot 980123028
Plasma - EDA
4.0Torr-l of N2 and 19Torr-l of He
Zeff=1.7->2.4; H=1.5->1.35->1.1 (after detachment)
processed probe data show a detachment beginning @ ~0.9
Pdiv=0.9MW; Psol=2.0MW; Prad=2.0MW

Jan 23 1998 04:08:13:460PM 980123029 John Goetz Shot 980123029
Plasma - EDA
3.2Torr-l of N2 and 19Torr-l of He
ugly shot - detaches early - RF trips

Jan 23 1998 04:23:33:750PM 980123030 John Goetz Shot 980123030
Plasma - EDA
detachment beginning @ 0.95
Zeff=1.8->2.2; H=1.7->1.5
Pdiv=0.9->1.1MW; Psol=2.4MW; Prad=1.4->1.7MW

Jan 23 1998 04:34:04:980PM 980123031 John Goetz Shot 980123031
Plasma - EDA
first attempt at bolometer feedback on detachment
detachment beginning @ 0.87
Zeff=1.9->2.3; H=1.5->1.3
Pdiv=1.0->1.1MW; Psol=2.8->2.2MW; Prad=2.0->1.7MW

Jan 23 1998 04:46:13:460PM 980123032 John Goetz Shot 980123032
Plasma - EDA
higher feedback gain
detachment beginning @ 0.77
no Zeff; H=1.65->1.3
Pdiv=1.0->1.15MW; Psol=2.4MW; Prad=1.7MW

Jan 23 1998 05:00:41:760PM 980123033 John Goetz Shot 980123033
Plasma - EDA
no He puff
detachment beginning @ 0.85
Zeff=1.7->2.3; H=1.6->1.5
Pdiv=0.95->1.05MW; Psol=2.5->2.0MW; Prad=2.0MW
4.35 Torr-l of N2 delivered - feedback is doing a good job of controlling the
nitrogen flow

Jan 23 1998 05:29:07:030PM 980123034 John Goetz Shot 980123034
Plasma - EDA
no He puff
Zeff=1.7->2.2; H=1.6->1.4 after detachment
Pdiv=0.9->1.1MW; Psol=2.6->1.8MW; Prad=1.5->2.2MW
4.6 Torr-l of N2 delivered - feedback is doing a good job of controlling the
nitrogen flow
detachment begins @ 0.92; this is a deep detachment - all the way up to probe 6
although it is still >10eV at the strike point but with low electron pressure
definitely the best shot of the day

Physics Operator Comments

Jan 23 1998 09:18:50:520AM 980123005 Earl Marmar add N_2 puff (PG5) from .7 to 1.1 seconds

early disruption (.34 s), something fell in.

Jan 23 1998 09:42:40:100AM 980123006 Earl Marmar lower early gas (seg 1); nl_04 to 1.0e20 from 1.4e20; plasma; J bottom valve
not following demand properly.

Jan 23 1998 10:26:51:110AM 980123007 Earl Marmar disable N_2; plasma

Jan 23 1998 10:27:04:370AM 980123008 Earl Marmar raise nl_04 to 1.1e20 from 1e20; plasma

Jan 23 1998 10:50:32:490AM 980123009 Earl Marmar enable N_2 from .7 to 1.1 s; nl_04 to 1.25e20 from 1.1e20; B_r offset to
.004 from .0045 T; plasma; some data system problems

Jan 23 1998 11:01:07:650AM 980123010 Earl Marmar reduce argon puff by 4 msec; plasma

Jan 23 1998 11:48:24:210AM 980123011 Earl Marmar reduce argon puff by 2 msec; add 2 volt to N_2 maintenance level; plasma

Jan 23 1998 11:48:34:180AM 980123012 Earl Marmar reduce N_2 maintenance level by 1 volt; plasma

Jan 23 1998 11:48:45:680AM 980123013 Earl Marmar alternator problem; no power shot to clear systems

Jan 23 1998 01:19:14:500PM 980123014 Earl Marmar nl_04 to 1.4e20 from 1.25e20; tweak N_2 puff; turn off argon; plasma;
stayed more EDA'ish; neutron rate rising slowly through RF pulse.

Jan 23 1998 01:19:26:350PM 980123015 Earl Marmar increase N_2 puff; plasma

Jan 23 1998 01:19:37:010PM 980123016 Earl Marmar He puff from divertor capillary; plasma

Jan 23 1998 01:32:04:670PM 980123016 Earl Marmar He puff from divertor capillary; plasma

Jan 23 1998 01:32:26:550PM 980123017 Earl Marmar more N_2; plasma

pause for data system hang

Jan 23 1998 01:32:36:350PM 980123018 Earl Marmar repeat; plasma

Jan 23 1998 01:55:10:490PM 980123019 Earl Marmar more helium from NINJA; increase RF by ~200kW; plasma

Jan 23 1998 01:55:19:960PM 980123020 Earl Marmar more N_2; plasma; early disruption (.55 s); big injection

Jan 23 1998 02:12:33:250PM 980123021 Earl Marmar retry; plasma; interesting evolution after 1 second: P_Rad goes down, Moly
goes down, neutron rate goes up.

Jan 23 1998 03:40:14:240PM 980123023 Earl Marmar J bottom (N_2) pressure from 10 psi to 20 psi; plasma

Jan 23 1998 03:40:55:790PM 980123024 Earl Marmar add 4 psi to lower divertor caps (He); increase N_2 puff; increase D_2
puff; plasma

Jan 23 1998 03:41:06:810PM 980123025 Earl Marmar reduced N_2; plasma

Jan 23 1998 03:41:17:020PM 980123026 Earl Marmar move He puff earlier in time; plasma

Jan 23 1998 03:23:19:750PM 980123027 Earl Marmar For this shot, added a wire for bolo feedback. It's called

bolo_fdbk.

Also, wires 9-12 are switched to 0-10 reference.

Jan 23 1998 03:41:29:710PM 980123027 Earl Marmar increase N_2; decrease D_2 puff during RF; plasma; big Mo injection early,
barely got passed it.

Jan 23 1998 03:50:37:330PM 980123028 Earl Marmar eliminate D_2 puff during RF; plasma; lower neutron rate

Engineering Operator Comments

Shot Time Type Status Comment

1 08:29:17:160AM Plasma Ok

2 08:37:38:700AM Plasma Ok

3 08:46:55:280AM Plasma Ok

4 08:59:11:190AM Plasma Ok

5 09:13:07:730AM Plasma Ok

6 09:33:21:290AM Plasma Ok

7 09:52:53:670AM Plasma Ok

8 10:10:44:040AM Plasma Ok

9 10:25:26:070AM Plasma Ok

10 10:52:30:130AM Plasma Ok

11 11:07:25:510AM Plasma Ok

12 11:24:21:500AM Plasma Ok

13 11:39:13:830AM Plasma Ok

14 11:59:39:220AM Plasma Ok

15 12:15:06:640PM Plasma Ok

16 12:29:36:830PM Plasma Ok

17 12:43:54:120PM Plasma Ok

18 01:19:00:860PM Plasma Ok

19 01:32:19:460PM Plasma Ok

20 01:46:46:790PM Plasma Ok

21 01:54:38:010PM Plasma Ok

22 02:10:37:510PM Plasma Ok

23 02:27:43:800PM Plasma Ok

24 02:41:37:870PM Plasma Ok

25 02:57:25:490PM Plasma Ok

26 03:10:06:880PM Plasma Ok

27 03:23:54:920PM Plasma Ok

28 03:39:17:160PM Plasma Ok

29 03:53:58:360PM Plasma Ok

30 04:07:07:020PM Plasma Ok

31 04:20:50:770PM Plasma Ok

32 04:33:12:280PM Plasma Ok

33 04:45:45:270PM Plasma Ok

34 05:00:15:590PM Plasma Ok

Session Leader Comments
Jan 23 1998 08:12:26:260AM		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.
Jan 23 1998 08:13:03:010AM		John Goetz	MP #163 High q_parallel Dissipative Divertor The physics plan is to: 1. Start with a good shot from 980107, e.g. 980107025, and try to get acceptable H-mode (preferably enhanced D-alpha). Then get the max out of the RF with Ip=1MA, nl04=1.2e20, steady strike points, ... 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. 3a. If successful in detaching with high q\|\|, then try setting up feedback on the J-Bottom valve using the divertor bolo signals. 3b. If not successful in detachment, determine why the divertor radiation is not increasing (try helium, neon, and argon). 4. Operate just above and just below the detachment threshold and compare the confinement and cleanliness at these levels. 5. Try helium, neon, and argon.
Jan 23 1998 08:48:20:390AM	980123001	John Goetz	Shot 980123001 Fizzle
Jan 23 1998 08:50:52:290AM	980123002	John Goetz	Shot 980123002 Plasma EDA - moly injection @ 0.85 kills it and almost detaches the divertor approximately 1MW radiated in the divertor before the injection
Jan 23 1998 09:01:10:780AM	980123003	John Goetz	Shot 980123003 Plasma barely EDA; only one transmitter
Jan 23 1998 09:13:35:380AM	980123004	John Goetz	Shot 980123004 Plasma Steady state EDA H = 1.6; PSOL=2MW; Prad,div=1MW; Prad,core=1.5MW
Jan 23 1998 09:17:05:830AM	980123005	John Goetz	Shot 980123005 Plasma - disrupts @ 0.35
Jan 23 1998 10:04:32:590AM	980123006	John Goetz	Shot 980123006 Plasma lower taraget density lots of H->L transitions ; lots of RF trips J-Bottom valve driver not working correctly - the pulse was wide open for the whole command time
Jan 23 1998 10:05:21:090AM	980123007	John Goetz	Shot 980123007 Plasma some H->L transitions ; RF trips reduced J-Bottom valve driver seems to have a gain of 30 (instead of the designed 10)
Jan 23 1998 10:25:57:020AM	980123008	John Goetz	Shot 980123008 Plasma EDA - but going away from 0.8 to 1.0 lots of molybdenum buildup; causing the H->L transition
Jan 23 1998 10:51:02:490AM	980123009	John Goetz	Shot 980123009 Plasma not very EDAlike - 2 H->L transitions data troubles - servers didn't go - EFIT o.k. though more moly on this shot than on 008
Jan 23 1998 11:06:56:760AM	980123010	John Goetz	Shot 980123010 Plasma good EDA PSOL = 2.0 -> 1.6MW; Zeff = 1.5 -> 1.9; ~0.7MW Pdiv;
Jan 23 1998 11:24:12:740AM	980123011	John Goetz	Shot 980123011 Plasma good EDA PSOL = 2.0 -> 1.7MW; Zeff = 1.5 -> 1.9; ~0.7MW Pdiv; H=1.6->1.35 [0.85Torr-l of N2 delivered]
Jan 23 1998 11:40:10:420AM	980123012	John Goetz	Shot 980123012 Plasma good EDA PSOL = 2.0 -> 1.6MW; Zeff = 1.7 -> 2.0; ~0.7MW Pdiv; H=1.5->1.3 [0.89Torr-l of N2 delivered] some signs of detachment moving up the plate - but the temperature near the strike point is still high
Jan 23 1998 11:48:17:920AM	980123013	John Goetz	Shot 980123013 no power shot
Jan 23 1998 12:16:44:240PM	980123014	John Goetz	Shot 980123014 Plasma nice EDA - Wp=0.16MJ - H=1.6 - Zeff=1.8 - all steady state However, no signs of detachment - divertor is warmer than 012 higher target density and no argon puffed
Jan 23 1998 12:31:12:740PM	980123015	John Goetz	Shot 980123015 Plasma nice EDA - Wp=0.16->0.15MJ - H=1.6->1.5 - Zeff=1.6->1.7 0.96Torr-l of N2 - no argon Psol = 2.4->2.0MW; Pdiv=0.7MW
Jan 23 1998 12:43:33:460PM	980123016	John Goetz	Shot 980123016 Plasma nice EDA - Wp=0.16->0.14MJ - H=1.65->1.35 - Zeff=1.6->1.9 0.97Torr-l of N2 - no argon - 1 valve of helium through divertor Psol = 2.3MW; Pdiv=0.75MW and flat 'death-ray' is forming on the divertor plate
Jan 23 1998 01:18:16:010PM	980123017	John Goetz	Shot 980123017 Plasma nice EDA - no processed data because of EFIT "lock-up" 'death-ray' is forming on the divertor plate
Jan 23 1998 01:21:14:250PM	980123017	John Goetz	Shot 980123017 Plasma nice EDA - no processed data because of EFIT "lock-up" 'death-ray' is forming on the divertor plate
Jan 23 1998 01:35:01:060PM	980123018	John Goetz	Shot 980123018 Plasma Mo injection @ 0.96 sorta ruins the experiment H=1.45->1.4 Zeff=1.65->1.8 Pdiv=0.65MW; Psol=2.4->1.7MW
Jan 23 1998 01:44:02:010PM	980123019	John Goetz	Shot 980123019 Plasma Mo injection @ 0.95 sorta ruins the experiment H=?; Wp=0.17->0.16MJ Zeff=1.6->1.9 Pdiv=0.65->0.75MW (finally an increase); Psol=2.4MW; Prf=2.9MW 1.43Torr-l of N2 plus 11Torr-l of helium
Jan 23 1998 01:51:04:850PM	980123020	John Goetz	Shot 980123020 Plasma disrupts @ 0.54; in trouble at 0.515
Jan 23 1998 02:11:10:570PM	980123021	John Goetz	Shot 980123021 Plasma EDA - change in Dalpha @ 1.0sec for a 100msec - drop in radiation, but no change in density, neutrons, H, etc. 1.8Torr-l of N2 Zeff=1.8->2.1; H=1.55->1.45; Psol=2.3->2.0MW; Pdiv=0.65->0.75MW
Jan 23 1998 02:25:54:630PM	980123022	John Goetz	Shot 980123022 Plasma EDA - Mo injection @ 0.95 1.83Torr-l of N2 and 11Torr-l Zeff=1.55->1.9; H=1.6->1.5; Psol=2.6MW; Pdiv=0.65->0.8MW
Jan 23 1998 02:37:07:570PM	980123023	John Goetz	Shot 980123023 Plasma EDA - Mo injection @ 0.85 & 0.86sec 3.1Torr-l of N2 and 11Torr-l Zeff=1.65->1.85 no EFIT due to TRAQ2 corruption
Jan 23 1998 03:01:04:080PM	980123024	John Goetz	Shot 980123024 Plasma - EDA 3.4Torr-l of N2 and 19Torr-l of He Zeff=1.6->2.0; Zeff=1.6->2.0 definite signs of detachment - density goes up after 0.98 Isat footprint show drop @ 1.0 processed probe data show pressure drop below the strike point, but no change above
Jan 23 1998 03:13:01:110PM	980123025	John Goetz	Shot 980123025 Plasma - EDA 3.2Torr-l of N2 and 19Torr-l of He Zeff=1.6->1.9; H=1.6->1.5->1.4 (after detachment begins) definite signs of detachment - density goes up after 0.96 Isat footprint show drop @ 1.0 not as deep a detachment as shot 024
Jan 23 1998 03:26:45:680PM	980123026	John Goetz	Shot 980123026 Plasma - EDA 3.25Torr-l of N2 and 19Torr-l of He Zeff=1.7->2.2; H=1.5->1.3 processed probe data show a detachment beginning @ ~0.85-0.90
Jan 23 1998 03:40:58:890PM	980123027	John Goetz	Shot 980123027 Plasma - EDA 4.6Torr-l of N2 and 19Torr-l of He Zeff=1.7->2.4; H=1.55->1.35 processed probe data show a detachment beginning @ ~0.85 Pdiv=1MW; Psol=2.4MW; Prad=1.5MW
Jan 23 1998 03:55:05:970PM	980123028	John Goetz	Shot 980123028 Plasma - EDA 4.0Torr-l of N2 and 19Torr-l of He Zeff=1.7->2.4; H=1.5->1.35->1.1 (after detachment) processed probe data show a detachment beginning @ ~0.9 Pdiv=0.9MW; Psol=2.0MW; Prad=2.0MW
Jan 23 1998 04:08:13:460PM	980123029	John Goetz	Shot 980123029 Plasma - EDA 3.2Torr-l of N2 and 19Torr-l of He ugly shot - detaches early - RF trips
Jan 23 1998 04:23:33:750PM	980123030	John Goetz	Shot 980123030 Plasma - EDA detachment beginning @ 0.95 Zeff=1.8->2.2; H=1.7->1.5 Pdiv=0.9->1.1MW; Psol=2.4MW; Prad=1.4->1.7MW
Jan 23 1998 04:34:04:980PM	980123031	John Goetz	Shot 980123031 Plasma - EDA first attempt at bolometer feedback on detachment detachment beginning @ 0.87 Zeff=1.9->2.3; H=1.5->1.3 Pdiv=1.0->1.1MW; Psol=2.8->2.2MW; Prad=2.0->1.7MW
Jan 23 1998 04:46:13:460PM	980123032	John Goetz	Shot 980123032 Plasma - EDA higher feedback gain detachment beginning @ 0.77 no Zeff; H=1.65->1.3 Pdiv=1.0->1.15MW; Psol=2.4MW; Prad=1.7MW
Jan 23 1998 05:00:41:760PM	980123033	John Goetz	Shot 980123033 Plasma - EDA no He puff detachment beginning @ 0.85 Zeff=1.7->2.3; H=1.6->1.5 Pdiv=0.95->1.05MW; Psol=2.5->2.0MW; Prad=2.0MW 4.35 Torr-l of N2 delivered - feedback is doing a good job of controlling the nitrogen flow
Jan 23 1998 05:29:07:030PM	980123034	John Goetz	Shot 980123034 Plasma - EDA no He puff Zeff=1.7->2.2; H=1.6->1.4 after detachment Pdiv=0.9->1.1MW; Psol=2.6->1.8MW; Prad=1.5->2.2MW 4.6 Torr-l of N2 delivered - feedback is doing a good job of controlling the nitrogen flow detachment begins @ 0.92; this is a deep detachment - all the way up to probe 6 although it is still >10eV at the strike point but with low electron pressure definitely the best shot of the day

Physics Operator Comments
Jan 23 1998 09:18:50:520AM	980123005	Earl Marmar	add N_2 puff (PG5) from .7 to 1.1 seconds early disruption (.34 s), something fell in.
Jan 23 1998 09:42:40:100AM	980123006	Earl Marmar	lower early gas (seg 1); nl_04 to 1.0e20 from 1.4e20; plasma; J bottom valve not following demand properly.
Jan 23 1998 10:26:51:110AM	980123007	Earl Marmar	disable N_2; plasma
Jan 23 1998 10:27:04:370AM	980123008	Earl Marmar	raise nl_04 to 1.1e20 from 1e20; plasma
Jan 23 1998 10:50:32:490AM	980123009	Earl Marmar	enable N_2 from .7 to 1.1 s; nl_04 to 1.25e20 from 1.1e20; B_r offset to .004 from .0045 T; plasma; some data system problems
Jan 23 1998 11:01:07:650AM	980123010	Earl Marmar	reduce argon puff by 4 msec; plasma
Jan 23 1998 11:48:24:210AM	980123011	Earl Marmar	reduce argon puff by 2 msec; add 2 volt to N_2 maintenance level; plasma
Jan 23 1998 11:48:34:180AM	980123012	Earl Marmar	reduce N_2 maintenance level by 1 volt; plasma
Jan 23 1998 11:48:45:680AM	980123013	Earl Marmar	alternator problem; no power shot to clear systems
Jan 23 1998 01:19:14:500PM	980123014	Earl Marmar	nl_04 to 1.4e20 from 1.25e20; tweak N_2 puff; turn off argon; plasma; stayed more EDA'ish; neutron rate rising slowly through RF pulse.
Jan 23 1998 01:19:26:350PM	980123015	Earl Marmar	increase N_2 puff; plasma
Jan 23 1998 01:19:37:010PM	980123016	Earl Marmar	He puff from divertor capillary; plasma
Jan 23 1998 01:32:04:670PM	980123016	Earl Marmar	He puff from divertor capillary; plasma
Jan 23 1998 01:32:26:550PM	980123017	Earl Marmar	more N_2; plasma pause for data system hang
Jan 23 1998 01:32:36:350PM	980123018	Earl Marmar	repeat; plasma
Jan 23 1998 01:55:10:490PM	980123019	Earl Marmar	more helium from NINJA; increase RF by ~200kW; plasma
Jan 23 1998 01:55:19:960PM	980123020	Earl Marmar	more N_2; plasma; early disruption (.55 s); big injection
Jan 23 1998 02:12:33:250PM	980123021	Earl Marmar	retry; plasma; interesting evolution after 1 second: P_Rad goes down, Moly goes down, neutron rate goes up.
Jan 23 1998 03:40:14:240PM	980123023	Earl Marmar	J bottom (N_2) pressure from 10 psi to 20 psi; plasma
Jan 23 1998 03:40:55:790PM	980123024	Earl Marmar	add 4 psi to lower divertor caps (He); increase N_2 puff; increase D_2 puff; plasma
Jan 23 1998 03:41:06:810PM	980123025	Earl Marmar	reduced N_2; plasma
Jan 23 1998 03:41:17:020PM	980123026	Earl Marmar	move He puff earlier in time; plasma
Jan 23 1998 03:23:19:750PM	980123027	Earl Marmar	For this shot, added a wire for bolo feedback. It's called bolo_fdbk. Also, wires 9-12 are switched to 0-10 reference.
Jan 23 1998 03:41:29:710PM	980123027	Earl Marmar	increase N_2; decrease D_2 puff during RF; plasma; big Mo injection early, barely got passed it.
Jan 23 1998 03:50:37:330PM	980123028	Earl Marmar	eliminate D_2 puff during RF; plasma; lower neutron rate

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:29:17:160AM	Plasma	Ok
2	08:37:38:700AM	Plasma	Ok
3	08:46:55:280AM	Plasma	Ok
4	08:59:11:190AM	Plasma	Ok
5	09:13:07:730AM	Plasma	Ok
6	09:33:21:290AM	Plasma	Ok
7	09:52:53:670AM	Plasma	Ok
8	10:10:44:040AM	Plasma	Ok
9	10:25:26:070AM	Plasma	Ok
10	10:52:30:130AM	Plasma	Ok
11	11:07:25:510AM	Plasma	Ok
12	11:24:21:500AM	Plasma	Ok
13	11:39:13:830AM	Plasma	Ok
14	11:59:39:220AM	Plasma	Ok
15	12:15:06:640PM	Plasma	Ok
16	12:29:36:830PM	Plasma	Ok
17	12:43:54:120PM	Plasma	Ok
18	01:19:00:860PM	Plasma	Ok
19	01:32:19:460PM	Plasma	Ok
20	01:46:46:790PM	Plasma	Ok
21	01:54:38:010PM	Plasma	Ok
22	02:10:37:510PM	Plasma	Ok
23	02:27:43:800PM	Plasma	Ok
24	02:41:37:870PM	Plasma	Ok
25	02:57:25:490PM	Plasma	Ok
26	03:10:06:880PM	Plasma	Ok
27	03:23:54:920PM	Plasma	Ok
28	03:39:17:160PM	Plasma	Ok
29	03:53:58:360PM	Plasma	Ok
30	04:07:07:020PM	Plasma	Ok
31	04:20:50:770PM	Plasma	Ok
32	04:33:12:280PM	Plasma	Ok
33	04:45:45:270PM	Plasma	Ok
34	05:00:15:590PM	Plasma	Ok