Alcator C-Mod Run 1050805 Information

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Miniproposals
Miniproposal:398
Date Filed: 1/10/2005
Title:Complete identity experiments with JET on error field locked mode thresholds
First Author:T.C. Hender
Session Leader:T.C. Hender (shots 1-16)
Miniproposal:419
Date Filed: 4/8/2005
Title:Fiducial wall pumping measurements for comparing operating conditions
First Author:Bruce Lipschultz
Session Leader:Bruce Lipschultz (shots 17-31)

Operators
Session leader(s):T.C. Hender,Bruce Lipschultz
Physics operator(s):Joseph Snipes
Engineering operator(s):Andy Pfeiffer,Bill Byford,Bill Byford,Andy Pfeiffer,Ed Fitzgerald

Engineering Operator Run Comment
MP#398 Complete identity experiments with JET on error field locked mode

Session Leader Plans
Entered: Aug 4 2005 10:50:36:743AM
Author: T.C. Hender
MP#398 Complete identity experiments with JET on error field locked mode
thresholds
SL: Hender/Wolfe

PO: Snipes


Run begins at 9:00 and ends at 13:00


Note: Acoil configuration (+Bbot +Dtop -Gbot -Jtop)


RF Setup: NONE - no RF for this run.
---------------------------------------------------------------
Run Plan for MP#398:

q95=3.2 (I=0.81MA, B=4.1T, "JET shape") 1050415011 is a good reference
With (+Bbot +Dtop -Gbot -Jtop) trying to get LM data at low field (4T):

1. Repeat 1050415011 with density of n114=1.1e20. With full current square
wave in A-coil from 0.8s to 1.28s. And then vary A-coil current down to
find LM threshold. (This will give us 3 different quadrature phases of
locked mode and allow a direct determination of the intrinsic error).

2. Depending on the result of 1. repeat with density of n114=1.4e20 or
0.8e20. With 3kA square wave in A-coil from 0.8s to 1.28s. And then vary
A-coil current up and down to refine LM threshold.

3. Repeat with no A-coil and turn off gas at 0.8s to let the density drift
down to find intrinsic threshold


q95=3.2 (I=1.27MA, B=6.3T, "JET shape") 1050415014 is a good reference
With (+Bbot +Dtop -Gbot -Jtop) trying to get LM data at higher field (6.3
T):

4. Repeat 1050415014 but at nl14=1.8e20. With 2kA square wave in A-coil
from 0.8s to 1.28s. And then vary A-coil current up and down to refine LM
threshold.

5. Repeat 4. but at nl14=2.2e20

If time allows (possible but not too likely) repeat a 2004 pulse at 6.3T
data with -(Btop -Dbot -Gtop +Jbot) to check result is reproducible

6. Repeat 1040413029 exactly. With 1kA square wave in A-coil from 0.8s to
1.28s. And then vary A-coil current up and down to refine LM threshold.

Entered: Aug 4 2005 10:09:54:277PM
Author: Bruce Lipschultz
MP #419 D retention experiments

PO Snipes
SL Lipschultz

Special gas - He3 enabled. RF operator decision whether to use E or J for long pulses. Will need 1. - 1.5 MW.

All power supply, PLC, fizzle, and waveform limits set to allow 2 seconds flattop. A-coils need to be changed back from that needed forlocked mode studies. Magnetic field at 5.1T is needed if we use J port.

If possible monitor the divertor surface temperatures with IR

gate valves closed for 5 minutes to allow for pumping studies

No NINJA, Ar, Ne.....

1) Start shot 1050804001 and density of nl_04=1.0
2) Lower the current to 0.8MA & nl_04 to 0.4.
3-8) nl_04 =0.6,0.8,1.0,1.4
9-10) Decide whether to go to long pulse with 0.8 or 1.0 MA. Extend flattop to 1.8-2 sec depending on the current selected. Density will be nl_04=0.9 for 1.0 MA, lower value determined in shots 2-8 for 0.8 MA.
11 - 14) flattop ends at 1.5, 1.0, 0.5 seconds and then back to 1.5 seconds.
14) Back to shot 1
15) Sweep the strike point over the divertor plate

Physics Operators Plans
Entered: Aug 4 2005 04:51:36:637PM
Author: Joseph Snipes
Engineering Setup and Run Plan for 1050805

MP#398 Complete identity experiments with JET on error field locked mode thresholds

SL: Hender/Wolfe
PO: Snipes

Run begins at 9:00 and ends at 13:00

No ECDC required.

Power systems as on 1050415011

A-coil configuration: *** NOT normal (+Bbot +Dtop -Gbot -Jtop) and enabled.*** Needs to be changed before run.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1)
fill B-side upper with 15 psi He3 Hybrid disabled (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
No NINJA

Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo shutters

Important Diagnostics:
Standard set, with ECE

-------------------------------------------------------------------------------
ICRF Setup: RF ready to run but not on by 08:30 as it will be used later in the day
-------------------------------------------------------------------------------
Run Plan for the first half run MP#398

q95=3.2 (I=0.81MA, B=4.1T, "JET shape") 1050415011 is a good reference
With (+Bbot +Dtop -Gbot -Jtop) trying to get LM data at low field (4T):

1. Repeat 1050415011 with density of n114=1.1e20. With full current square
wave in A-coil from 0.8s to 1.28s. And then vary A-coil current down to
find LM threshold. (This will give us 3 different quadrature phases of
locked mode and allow a direct determination of the intrinsic error).

2. Depending on the result of 1. repeat with density of n114=1.4e20 or
0.8e20. With 3kA square wave in A-coil from 0.8s to 1.28s. And then vary
A-coil current up and down to refine LM threshold.

3. Repeat with no A-coil and turn off gas at 0.8s to let the density drift
down to find intrinsic threshold


q95=3.2 (I=1.27MA, B=6.3T, "JET shape") 1050415014 is a good reference
With (+Bbot +Dtop -Gbot -Jtop) trying to get LM data at higher field (6.3
T):

4. Repeat 1050415014 but at nl14=1.8e20. With 2kA square wave in A-coil
from 0.8s to 1.28s. And then vary A-coil current up and down to refine LM
threshold.

5. Repeat 4. but at nl14=2.2e20

If time allows (possible but not too likely) repeat a 2004 pulse at 6.3T
data with -(Btop -Dbot -Gtop +Jbot) to check result is reproducible

6. Repeat 1040413029 exactly. With 1kA square wave in A-coil from 0.8s to
1.28s. And then vary A-coil current up and down to refine LM threshold.


For the second half of the run, we will run MP#419 D retention (1/2d)
SL: Bruce Lipschultz
PO: Joseph Snipes

Additional gas change:
fill B-side upper with 15 psi He3 Hybrid enabled (PG2)

RF needs to be turned on for this half of the run:
RF operator will decide whether to use E or J for long pulses.
Will need 1. to 1.5 MW.

We will begin with shot 1050804001 at 5.1 T for J-port but with a current of 1 MA.
***This half run requires putting the A-coil configuration back to normal +Dtop -Dbot -Jtop +Jbot ***
and will require -30 kA current limits on the OH coils to go to higher current and long pulse.
The coil invert times will all
need to be set to 2.4 s except TF, which needs to be set to 2.0 s. The fizzle detector will need to be set
to 2.2 s. We will then compare wall pumping at 0.8 MA with that at 1 MA and then decide whether to do the
long pulse experiments at 1 MA or 0.8 MA. See the second session leader plan for more details.

Dignostics: If possible monitor the divertor surface temperatures with IR camera.

***gate valves closed for 5 minutes to allow for pumping studies***

1) Start shot 1050804001 and density of nl_04=1.0
2) Lower the current to 0.8MA & nl_04 to 0.4.
3-8) nl_04 =0.6,0.8,1.0,1.4
9-10) Decide whether to go to long pulse with 0.8 or 1.0 MA. Extend flattop to 1.8-2 sec depending on the current selected. Density will be nl_04=0.9 for 1.0 MA, lower valued determined in shots 2-8 for 0.8 MA.
11 - 14) flattop at 1.5, 1.0, 0.5 seconds and then back to 1.5 seconds.
14) Back to shot 1
15) Sweep the strike point over the divertor plate

Session Leader Summaries
Entered: Aug 5 2005 06:08:30:767PM
Author: Bruce Lipschultz
MP319 D retention

SL B. Lipschultz
PO J. Snipes

Accomplished most of what we attempted today - namely a density scan at 800 kA and a scan of flattop of the current at a fixed density.

We found that the 800 kA shots also pumped at levels in excess of the 1 MA shots. At low densities the amount pumped was small, rising to larger values at higer densities as seen for 1MA. The density that led to this rise was similar to 1MA shots although we appeared to be observing higher levels of pumping for 800kA than for 1MA.

We ran varying length shots with nl04 = 0.8 and 800 kA. We picked the lowest density so as to minimize the loop voltage. We had mixed results in the sense that the longest length shot disrupted - leading to outgassing. We then ran shots with rampdown at 1.0 and 0.5 seconds. The wall pumping decreased to a lower level than for the rampdown at 1.5s done earlier in the shot sequence. The same level of pumping was found for current inversion at 1.0 and 0.55s.

We ran to high enough densities at 800kA such that the divertor was detached. This did not decrease the pumping.. If anything it increased it.

Shot list

1MA
17 nl04=1, long pulse, disrupts
19 nl04=1, current inversion 1.5s, 9tl pumped
20 nl04=0.4, 1tl pumped
21 nl04=0.4, 5tl pumped
22 nl04=0.6, 12.3 tl pumped
23 nl04=0.8, 21tl pumped
24 nl04=1.0, 23 tl pumped
25 nl04=1.4, 30-40tl pumped
27 nl04=1.2, 25tl pumped
28 nl04=0.8, Ip iversion @2.0, disrupt, 5tl outgassed
29 nl04=0.8, Ip iversion @1.0, 5tl pumped
30 nl04=0.8, Ip iversion @0.55, disrupt, 3.5tl pumped
31 nl04=0.8, Ip iversion @0.55, 5.5tl pumped

Entered: Aug 8 2005 03:55:40:047AM
Author: T.C. Hender
MP#398 Complete identity experiments with JET on error field locked mode thresholds

SL: Hender/Wolfe

PO: Snipes

Run began at 9:00 and ended at 13:00 (or just after)

A good session.

With Acoil configuration (+Bbot +Dtop -Gbot -Jtop) we found the locked mode threshold at 4.1T (shot 8). This completes a set of 3 phases [+/-(+Bbot +Dtop -Gbot -Jtop) and â??Btop+Dbot+Gtop-Jbot)] at 4.1T which will allow us to deduce the intrinsic error.

With (+Bbot +Dtop -Gbot -Jtop) we were unable to make a locked mode at 6.3T. But with the inverted phase we got good locked mode data at 6.3T (shot 16). This data will allow to check the Bt scaling for the -(+Bbot +Dtop -Gbot -Jtop) Acoil configuration (we already have equivalent data for â??Btop+Dbot+Gtop-Jbot)

We also showed at 6.3T that the intrinsic error field density limit is close to the 2004 result (shot 11)

Physics Operator Summaries
Entered: Aug 5 2005 05:22:37:220PM
Author: Joseph Snipes
The machine ran pretty well though there were a couple of shots with issues. On shot 1, the magnetics data
acquisition failed making that shot useless. Then, on shot 5, a breaker pulled out at the start of the shot
on OH2L. Both Br0 and Bz tended to drift during the day so they needed to be watched and compensated for to
maintain sustained breakdowns. Then, for the second half of the run, gate valves were closed for wall pumping
studies for 5 minutes after the shot and that made the prefill difficult to predict and led to a number of
fizzles. Nonetheless, a number of results were obtained for both MPs. See the session leaders summaries for
more details.

Shot,Duration(s),Ipmax(MA),Result Shot,Duration(s),Ipmax,Result
| 1 No Ip data | 02 1.852 0.826 Plasma |
| 03 1.941 0.822 Plasma | 04 1.957 0.824 Plasma |
| 05 0.000 0.016 Dud | 06 0.293 0.861 Plasma |
| 07 1.491 0.830 Plasma | 08 1.383 0.903 Plasma |
| 09 1.745 1.276 Plasma | 10 1.772 1.277 Plasma |
| 11 1.453 1.278 Plasma | 12 1.388 1.276 Plasma |
| 13 1.523 1.277 Plasma | 14 0.000 0.038 Fizzle |
| 15 1.449 1.276 Plasma | 16 1.497 1.278 Plasma |
| 17 1.898 1.055 Plasma | 18 0.000 0.037 Fizzle |
| 19 1.977 1.058 Plasma | 20 1.985 0.815 Plasma |
| 21 1.984 0.824 Plasma | 22 1.980 0.827 Plasma |
| 23 1.971 0.815 Plasma | 24 1.973 0.808 Plasma |
| 25 1.833 0.797 Plasma | 26 0.000 0.040 Fizzle |
| 27 1.894 0.799 Plasma | 28 2.390 0.812 Plasma |
| 29 1.482 0.813 Plasma | 30 0.957 0.813 Plasma |
| 31 1.235 0.805 Plasma
Date 1050805: 31 shots. 27 plasmas. 3 fizzles. 1 power supply failure. 1 Data System Error.

Session Leader Comments
Aug 5 2005 09:29:29:207AM1050805001T.C. HenderDisrupted at t=0.99sec. No obvious sign of a locked mode beforehand, sawteeth continue all the way through the shot. A coil current=3500A. Some data lost, including density and magnetics signals.
Aug 5 2005 09:50:12:707AM1050805002T.C. HenderNo disruption, no locked mode. density nl_04=1.1e20, q95=3.2 as requested. Acoil current=3700A. Looks like we will have to drop the density to get a locked mode with this Acoil combination.

Aug 5 2005 10:17:07:020AM1050805003T.C. HenderNo disruption, no locked mode. density nl_04=0.85e20, q95=3.2 as requested. Acoil current=3700A. Next shot, switch off Acoil and let density drop to find intrinsic locked mode threshold.
Aug 5 2005 10:18:20:050AM1050805004T.C. HenderGas feed switched off at 0.85sec. Density reached as low as 0.7e20 without getting a locked mode.
Aug 5 2005 10:18:50:050AM1050805005T.C. HenderSwitch off gas earlier, with a lower initial density.

Dud.

Aug 5 2005 10:42:07:190AM1050805006T.C. HenderTry again. Shot finished early, at 0.29sec.


Aug 5 2005 10:57:00:673AM1050805007T.C. HenderSuccess. Got a locked mode at 1.32sec, nl_04=0.49e20. No Acoil current.


Aug 5 2005 11:11:01:377AM1050805008T.C. HenderGot a locked mode at 1.26sec, nl_04=0.63e20. Acoil current=3700A +Bbot +Dtop -Gbot -Jtop




Aug 5 2005 11:26:11:660AM1050805009T.C. HenderChange to 6.3T, +Bbot +Dtop -Gbot -Jtop. nl_04=1.5e20. Acoil current=3700A. No locked mode.
Aug 5 2005 11:43:11:363AM1050805010T.C. HenderLower density to nl_04=1.2e20, +Bbot +Dtop -Gbot -Jtop. No locked mode at Acoil current=3700A.
Aug 5 2005 11:54:26:220AM1050805011T.C. HenderRepeat with no Acoil current, and turn off gas at 0.8sec. Locked mode at 0.93sec. nl_04=1.15e20.
Aug 5 2005 12:22:38:817PM1050805012T.C. HenderChange Acoil configuration to -Bbot -Dtop +Gbot +Jtop. Locked mode at t=0.93sec. Acoil current=3300A, nl_04=1.43e20
Aug 5 2005 12:35:34:160PM1050805013T.C. HenderRaise density to nl_04=1.59e20 Locked mode at t=0.95sec. Acoil current=3400A.
Aug 5 2005 12:43:07:237PM1050805014T.C. HenderLower Acoil current by 1000A and repeat.

Dud.

Aug 5 2005 12:43:20:770PM1050805014T.C. HenderLower Acoil current by 1000A and repeat.

Fizzle.

Aug 5 2005 12:59:57:143PM1050805015T.C. HenderTry again. Got locked mode at t=0.95sec again. nl_04=1.63e20, Acoil current = 2700A.
Aug 5 2005 01:13:06:940PM1050805016T.C. HenderStart Acoil current 0.1sec earlier, and lower current. Great shot, got locked mode at 1.2sec, nl_04=1.85e20, Acoil current=1650A.
Aug 5 2005 02:44:01:160PM1050805019Bruce Lipschultzshot went fine.

1MA nl_04 = 0.9

13.9 Tl injected
4.7 remaining
~ 9Tl pumped by the walls

Next shot go to the density scan with the lowest density and 800kA
Aug 5 2005 02:50:12:843PM1050805020Bruce Lipschultzshot went fine.

800kA nl_04 = 0.4 dropping through the shot.

3.7 Tl injected
2.6 remaining
~ 1Tl pumped by the walls

Repeat this next shot to make sure we have come to equilibrium with the changes in current and density.
Aug 5 2005 03:15:46:000PM1050805022Bruce Lipschultzshot went fine.

800kA nl_04 = 0.6

15 Tl injected
2.6Tl remaining
~ 12.4Tl pumped by the walls



Aug 5 2005 03:28:41:703PM1050805023Bruce Lipschultzshot went fine.

800kA nl_04 = 0.8

24.5 Tl injected
4.1Tl remaining
~ 20.3Tl pumped by the walls



Aug 5 2005 03:56:34:530PM1050805024Bruce Lipschultzshot went fine.

800kA nl_04 = 1.0

28.3 Tl injected
5.0Tl remaining
~ 22Tl pumped by the walls

Partial detachment at the outer divertor



Aug 5 2005 03:56:55:390PM1050805025Bruce Lipschultzshot disrupted on rampdown at 300kA

800kA nl_04 = 1.4

60 Tl injected
32-22Tl remaining (dropping with time!
~ 28-38Tl pumped by the walls

Very detached!

Next shot to lower density at 1.2


Aug 5 2005 04:12:29:190PM1050805026Bruce Lipschultzfizzle
Aug 5 2005 04:21:36:720PM1050805027Bruce Lipschultznl04 = 1.2 still disrupting during rampdown

42Tl of gas injected
21-15 TL of gas remaining, dropping with time
21-27 tl pumped by wall

outer divertor detached again

Aug 5 2005 04:35:32:547PM1050805028Bruce Lipschultznl04 = 0.8 for long pulse. 2.0 s at rampdown, makes it to 200 kA

11.3Tl of gas injected
16 TL of gas remaining, dropping with time
5 tl given up by wall

Is there an issue with following a high ensity shot?
Aug 5 2005 04:47:12:720PM1050805029Bruce Lipschultznl04 = 0.8, rampdown at 1.0 seconds

10.3Tl of gas injected
5 TL of gas remaining, dropping with time
5 tl pumped by wall


Aug 5 2005 05:01:26:797PM1050805030Bruce Lipschultznl04 = 0.8, rampdown at 0.55 seconds, disruption at 300 kA

10.3Tl of gas injected
6.22 TL of gas remaining, dropping with time
4.1 tl pumped by wall


Aug 5 2005 05:20:16:110PM1050805031Bruce Lipschultznl04 = 0.8, rampdown at 0.55 seconds, no disruption

8.9Tl of gas injected
3.2 TL of gas remaining, dropping with time
5.7 tl pumped by wall


Physics Operator Comments
Aug 5 2005 08:43:25:597AM1050805001Joseph SnipesShot 1: Copied shot 1050415011 and then loaded segment 1 from shot 1050525002, which is the canonical IHH
startup. Then, changed nl04 to 1.1 x 10^20 m^-2 and the A-coil current to 4000 A from 0.8 to 1.28 s. This
should be the "JET shape".
Aug 5 2005 09:11:12:363AM1050805001Joseph SnipesShot 1: Disrupted at 1.0 s. Problems with the data system.
Aug 5 2005 09:36:44:893AM1050805002Joseph SnipesShot 2: Increased prepuff by 4 ms to 25 ms duration. PCDAQMHD1 had to be rebooted to reset the magnetics
data acquisition before this shot. Magnetics data lost for shot 1.
Aug 5 2005 09:42:43:223AM1050805002Joseph SnipesShot 2: Good full length shot.
Aug 5 2005 09:45:05:597AM1050805003Joseph SnipesShot 3: nl04 reduced to 8 x 10^19 m^-2.
Aug 5 2005 09:52:23:690AM1050805003Joseph SnipesShot 3: nl04 reduced to 8 x 10^19 m^-2. Good full length shot.
Aug 5 2005 10:01:34:753AM1050805004Joseph SnipesShot 4: Turned off A-coil. Programmed a ramp in nl04 from 8 x 10^19 m^-2 to 0 from 0.8 s to 1.5 s.
Aug 5 2005 10:08:22:940AM1050805004Joseph SnipesShot 4: Good full length shot. Density did not fall as requested.
Aug 5 2005 10:11:29:330AM1050805005Joseph SnipesShot 5: Programmed nl04 to 6 x 10^19 m^-2 and then zero after 0.4 s.
Aug 5 2005 10:19:19:207AM1050805005Joseph SnipesShot 5: Breaker pulled out during the start of the pulse. It seems OH2L failed. Dud.
Aug 5 2005 10:47:59:520AM1050805006Joseph SnipesShot 6: Try again. Disrupted early at 0.29 s.
Aug 5 2005 10:50:49:910AM1050805007Joseph SnipesShot 7: One more time . . . Good shot. Disrupted late at 1.49 s.
Aug 5 2005 11:05:22:207AM1050805008Joseph SnipesShot 8: Set nl04 to 6.5 x 10^19 m^-2 out to 1.5 s and turned on the A-coil from 0.8 to 1.5 s at 4000 A.
Good shot. Disrupted at 1.38 s. ECE gate valve was closed after the disruption so there is no ECE data.
Aug 5 2005 11:18:27:520AM1050805009Joseph SnipesShot 9: Loaded segment 2 from 1050415014 to go to 6.3 T. Changed nl04 to 1.5 x 10^20 m^-2. Set the A-coil
current to 4000 from 0.8 to 1.5 s. Good shot.
Aug 5 2005 11:30:01:363AM1050805010Joseph SnipesShot 10: Reduced nl04 to 1.2 x 10^20 m^-2. Corrected power supply settings for the shot we copied. Changed the
A-coil current to turn off at 1.28 s as before. Good shot.
Aug 5 2005 11:38:09:597AM1050805011Joseph SnipesShot 11: Turned off the A-coil. Turned off nl04 after 0.8 s.
Aug 5 2005 11:44:38:940AM1050805011Joseph SnipesShot 11: Good shot. Disrupted at 1.45 s.
Aug 5 2005 11:58:50:660AM1050805012Joseph SnipesShot 12: Reduced EF4 current by 10 A to -1320 A. Reduced prepuff by 4 ms to 21 ms duration. Reverse the
polarity of the A-coils. Turned A-coil on at 4000 from 0.8 to 1.28 s. Set nl04 to 1.5 x 10^20 m^-2.
Aug 5 2005 12:19:49:080PM1050805012Joseph SnipesShot 12: Got runaways but otherwise a good shot. Disrupted at 1.385 s.
Aug 5 2005 12:30:46:987PM1050805013Joseph SnipesShot 13: Increased prepuff to 28 ms duration. Raised nl04 to 1.8 x 10^20 m^-2. Added PG3 pre-programmed gas
puff in segment 2 from 0.3 to 0.4 at 100 V and then from 0.4 to 1.5 s at 50 V. Good shot. Late disruption
at 1.515 s.
Aug 5 2005 12:34:19:143PM1050805014Joseph SnipesShot 14: Set A-coil current to 3000 A.
Aug 5 2005 12:42:43:143PM1050805014Joseph SnipesShot 14: Fizzle!
Aug 5 2005 12:55:46:923PM1050805015Joseph SnipesShot 15: Reduced prepuff by 3 ms to 25 ms duration. Reduced Br0 by 0.5 mT to -0.5 mT. Good shot but with a few
runaways to start with. Disrupted at 1.44 s.
Aug 5 2005 01:08:18:800PM1050805016Joseph SnipesShot 16: Increased prepuff by 2 ms to 27 ms duration. Reduced Br0 by 0.2 mT to -0.7 mT. Good shot.
Disrupted at 1.49 s.
Aug 5 2005 02:06:58:300PM1050805017Joseph SnipesShot 17: Changeover to MP419 D Retention. Copied segment 2 of shot 1050804001 and changed nl04 to 1.0 x 10^20 m^-2
and changed all waveforms to go out to 2.5 s with a flattop out to 2.0 s. Disrupted at 1.9 ran out of Vs.
Aug 5 2005 02:19:29:957PM1050805018Joseph SnipesShot 18: No, the session leader wanted to start with flattop to 1.5 s. So, I've reduced Ip, TF current, nl04,
and A-coil currents to rampdown after 1.5 s except nl04 turns off at 1.3 s. nl04 set to 0.9 x 10^20 m^-2.
Fizzle because the gate valves were closed for 5 minutes after the shot and the machine remained full of gas so
there was too much gas at breakdown.
Aug 5 2005 02:27:43:380PM1050805019Joseph SnipesShot 19: Reduced prepuff to 19 ms duration. Good shot. Startup bounced twice just barely went.
Aug 5 2005 02:41:19:737PM1050805020Joseph SnipesShot 20: Reduced Ip to 0.8 MA. Reduced nl04 to 4 x 10^19 m^-2. Good shot. Some runaways.
Aug 5 2005 03:01:47:343PM1050805021Joseph SnipesShot 21: Increased prepuff by 3 ms to 24 ms duration. Ramped RXL inward by 0.5 cm to -1 cm from 1 to 1.5 s then
left it there through the rampdown. Good shot with some runaways.
Aug 5 2005 03:05:27:017PM1050805022Joseph SnipesShot 22: Disabled 3He puff. Set nl04 to 0.6 x 10^20 m^-2. Reduced EF4 current by 5 A to -1325 A. Good shot
with some runaways.
Aug 5 2005 03:21:39:267PM1050805023Joseph SnipesShot 23: Raised prepuff by 2 ms to 26 ms duration. Reduced EF4 current by another 5 A to -1330 A. Raised
nl04 to 8 x 10^19 m^-2. Good shot.
Aug 5 2005 03:38:58:017PM1050805024Joseph SnipesShot 24: Raised nl04 to 1 x 10^20 m^-2. Good shot. Finally a decent startup.
Aug 5 2005 03:44:07:580PM1050805025Joseph SnipesShot 25: Raised nl04 to 1.4 x 10^20 m^-2. Good shot.
Aug 5 2005 03:57:27:483PM1050805026Joseph SnipesShot 26: Decreased prepuff by 3 ms to 23 ms duration. Set nl04 to 1.2 x 10^20 m^-2. Fizzle!
Aug 5 2005 04:08:59:250PM1050805027Joseph SnipesShot 27: Decreased prepuff by 2 ms to 21 ms duration. Good shot.
Aug 5 2005 04:21:35:470PM1050805028Joseph SnipesShot 28: Long pulse flattop out to 2.0 s. Ip at 0.8 MA, nl04 at 0.8 x 10^20 m^-2. A-coil and TF current also
extended out to 2.0 sec for the flattop. Reduce EF4 current by another 5 A to -1335 A. Increased prepuff by
1 ms to 22 ms duration. Good shot.
Aug 5 2005 04:35:28:390PM1050805029Joseph SnipesShot 29: Short pulse out to 1.0 s flattop for nl04, Ip, TF, and A-coils. Good shot.
Aug 5 2005 04:59:21:190PM1050805030Joseph SnipesShot 30: Short pulse out to 0.55 s flattop for nl04, Ip, TF, and A-coils. Disrupted at 0.95 s.
Aug 5 2005 05:05:13:110PM1050805031Joseph SnipesShot 31: Repeat short pulse out to 0.55 s flattop and reduce Ip gain after 0.65 s. Extend the Ip rampdown
by another 0.15 s. Good shot.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:07:04:097AMPlasmaOk
209:38:06:533AMPlasmaOk
309:50:53:610AMPlasmaOk
410:03:25:080AMPlasmaOk
510:16:25:533AMPlasmaBadOH2lcom fault fuse OK
610:36:42:110AMPlasmaOk
710:49:06:160AMPlasmaOk
811:01:32:003AMPlasmaOk
911:14:22:580AMPlasmaOk
1011:28:06:987AMPlasmaOk
1111:42:45:503AMPlasmaOk
1212:15:56:300PMPlasmaOk
1312:28:31:300PMPlasmaOk
1412:41:01:673PMPlasmaOk
1512:53:38:690PMPlasmaOk
1601:06:23:830PMPlasmaOk
1701:57:28:283PMPlasmaOk
1802:10:53:080PMPlasmaOk
1902:24:16:753PMPlasmaOk
2002:37:07:253PMPlasmaOk
2102:49:44:250PMPlasmaOk
2203:03:28:673PMPlasmaOk
2303:15:53:297PMPlasmaOk
2403:28:16:220PMPlasmaOk
2503:42:46:297PMPlasmaOk
2603:55:16:860PMPlasmaOk
2704:07:38:690PMPlasmaOk
2804:20:13:500PMPlasmaOk
2904:34:04:733PMPlasmaOk
3004:46:42:847PMPlasmaOk
3105:03:34:220PMPlasmaOk