Alcator C-Mod Run 960822 Information

Miniproposals

Miniproposal: 156a

Date Filed: 7/22/1996

Title: Raise plasma current to 1.5 MA.

First Author: Robert Granetz

Session Leader: Robert Granetz (shots 1-57)

Operators
Session leader(s):	Robert Granetz
Physics operator(s):	Joseph Snipes
Engineering operator(s):	Frank Silva

Engineering Operator Run Comment
Snipe/ Commissioning

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:15:930PM

Author: To Be Determined

Session leader's summary for run 960822

MP #156A, Raise plasma current to 1.5 MA

SL: R. Granetz
PO: J. Snipes
EC: F. Silva

Primary goal: Increase plasma current to 1.5 MA without damaging machine. In
order to reduce disruption probability, The high current shots will be
carried out at 8 tesla.

-------------------------------------------------------------------------------
Summary: Yesterday there was an accidently leak which completely backfilled
the machine with room air. Since the divertor cryopump was at LN2 temperature,
there was probably some ice formed. Overnight the machine was baked at 60 C,
with simultaneous ECDC in D2. However, it was clear from the beginning that
plasma operation had been badly compromised. By lunch time we had had only
a few brief plasmas, each followed by very high readings on the torus pressure
gauge. In addition, the level of hydrogen was about equal to deuterium, pre-
sumably symptomatic of water vapor or ice in the machine.
It was decided that the original run plans for both the afternoon
and evening would be abandoned. At that point (around 13:00), Ian volunteered
to take over as phys op so he could try getting plasmas at 5.3 tesla. This
proved quite successful, and afforded the RF some conditioning time. Since
we had no prescribed run plan anymore, but had scheduled a late run, Ian
decided to forge on and try a few other things, such as RF mode conversion
studies (since the H levels were so high). In addition, there were two
non-plasma gas calibration shots (with both TF and PF enabled), with shot 032
being particularly useful. During the evening hours the divertor cryopump
was again cooled down, and even some lowering of the triangularity was tried.

-------------------------------------------------------------------------------
Shot sequence plan:

Start with a typical 6.3/5.4 tesla shot from earlier this week. (This is
to see if we can re-establish plasma operation after yesterday's accident.

If plasmas are obtained, go to 7.9 tesla and raise Ip in 0.1 MA increments

When 1.5 MA plasmas are achieved, try running several different prescribed
densities for the dimensionless scaling program (J. Schacter). Also let
the ICRF bang away.

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

Shot 01 -- Fizzle. Null is okay. Lower the gas for the next shot.

Shot 02 -- Fizzle.

Shot 03 -- Fizzle.

Shot 04 -- Fizzle.

Shot 05 -- Fizzle.

Shot 06 -- Plasma, sort of. Dirty disruptive short plasma. Ip=0.25 MA,
duration=0.13 s.

Shot 07 -- Plasma, sort of. Ip=0.31 MA, duration=0.15 s.

Shot 08 -- Dud!

Shot 09 -- Dud again.

Shot 10 -- Fizzle.

Shot 11 -- Fizzle.

Shot 12 -- Dud

Shot 13 -- Fizzle.

Shot 14 -- Dud

Shot 15 -- Fizzle.

Shot 16 -- Dud. Let's stop fooling around. For the next shot increase the
TF by 5 kA and start it 0.1 s earlier.

Shot 17 -- Plasma. Ip=0.8 MA, terminated by disruption at 0.42 s. The higher
field worked again.

Shot 18 -- Fizzle.

Shot 19 -- Plasma. Very resistive, Ip=0.33 MA, duration=0.37 s. Base
pressure is extremely high (1.4e-6 torr at the beginning of
Shot 20 init).

Shot 20 -- Dud.

Change of plans. Because of the obvious vacuum/cleanliness problems due to
yesterday's accident, it has been decided to abandon the run. However, for
a couple of hours Ian would like to takeover as physop and try to get
breakdown at 5.3 tesla. In addition, we will also run a gas calibration shot
for the ratiomatics, etc.

Reduce TF to 5.3 tesla

Shot 21 -- Dud.

Shot 22 -- Fizzle.

Shot 23 -- Dud.

Shot 24 -- Plasma. Ip=0.66 MA, duration=0.36 s. This was a plasma at 5.3 T.

Shot 25 -- Fizzle.

Shot 26 -- Plasma, nearly 1 sec long. Ip=0.8 MA. Density kept rising to
nl_04=2.e20 m-2.

Shot 27 -- Fizzle

Shot 28 -- Plasma. Ip=0.8 MA, disrupted at 1.01 s. Prf=1.2 MW.

The next shot will be a gas calibration shot. It should be a dud.

Shot 29 -- Dud (on purpose). Gas calibration shot.

Shot 30 -- Fizzle.

Shot 31 -- Plasma. Ip=0.8 MA, disrupted at 0.76 s. Prf=1.1 MW.

Shot 32 -- Dud (on purpose). Another gas calibration shot.

Another change of plans. Since Ian has been successful at getting plasmas at
5.3 tesla (alternating shot/fizzle), we've decided to extend the run until
21:00 and do a variety of things (in lieu of the original plans).

Shot 33 -- Fizzle.

Shot 34 -- Plasma. Ip=0.8 MA, disrupted at 0.82 s. Prf=1.3 MW.

Shot 35 -- Dud.

Shot 36 -- Dud.

Shot 37 -- Plasma. Good shot. Ip=0.8 MA, duration=1.33 s. Made it part way
down the ramp. RF was turned off on purpose. It may be causing
the plasma to disrupt during the flattop.

Shot 38 -- Fizzle.

Shot 39 -- Dud.

Shot 40 -- Plasma. Ip=0.8 MA, disrupted at 0.89 s, probably because the
RF was turned on again.

Shot 41 -- Dud.

Shot 42 -- Dud.

Shot 43 -- Plasma. Ip=0.8 MA, disrupted at 0.84 s. Prf=1.5 MW

Shot 44 -- Dud.

Shot 45 -- Plasma. Ip=0.8 MA, duration=0.76 s.

Shot 46 -- Fizzle.

Shot 47 -- Plasma. Ip=0.8 MA, duration=0.93 s. Prf=1 MW.

Shot 48 -- Dud.

Shot 49 -- Fizzle.

Shot 50 -- Plasma. Ip=0.8 MA, duration=0.74 s.

Shot 51 -- Plasma...two in a row. Ip=0.8 MA, duration=0.93 s.

Shot 52 -- Plasma...three in a row. Ip=0.8 MA, duration=0.91 s.

Shot 53 -- Dud.

Shot 54 -- Fizzle.

Shot 55 -- Dud (power supplies faulted at -0.66 s)

Shot 56 -- Fizzle.

Shot 57 -- Fizzle.

End of run.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:56:630PM

Author: To Be Determined

MP 156 A 1.5 MA plasma operation at 8 T
Engineer in Charge: Frank Silva
Session Leader: Bob Granetz
Physics Operator: Joseph Snipes

Overnight ECDC in deuterium with 60 C bake following yesterday's vacuum
accident. Pressure at 6.8 x 10^-7 torr on the machine gauge just before the
run, mostly water on the RGA. We will attempt to get plasmas by starting with
shot 960820004 before trying the high field, high current shots.

Shot 1: Copied 960820004 with hybrid control of the TF going to 6.2 T at 0.2
sec then dropping to 5.4 T by 0.6 sec. Pre-puff set to 15 msec. Fizzle!
Shot 2: Try again with 13 msec pre-puff. Later breakdown at about 10 msec.
Shot 3: Try again with 17 msec pre-puff. Earlier breakdown at 6 msec.
Shot 4: Try again with 20 msec pre-puff. Fizzle. About the same.
Shot 5: Try again with 23 msec pre-puff. Fizzle. Later breakdown at 8 msec.
Shot 6: Try again with 17 msec pre-puff. Reduced Br from 4 to 3.5 mT.
Got plasma that lasted 130 msec just over 0.2 MA.
Shot 7: Reduced pre-puff to 13 msec. Plasma up to 0.3 MA and 150 msec.
Breakdown delayed to 7 msec.
Shot 8: Pre-puff set to 15 msec. Dud.
Shot 9: Repeat. Dud.
Shot 10: Pre-puff set to 19 msec. Fizzle. Late breakdown at 8 msec.
Shot 11: Tweaked Br up to 3.75 mT. Fizzle. Late breakdown at 8 msec.
Shot 12: Pre-puff set to 21 msec. Dud!
Shot 13: Pre-puff set to 22 msec. OH1 voltage increased by 10V at at 5 and
10 msec. Also increased OH2L and OH2U by 2V at 5 and 10 msec.
Late fizzle at 12 msec.
Shot 14: Pre-puff set to 12 msec. Dud!
Shot 15: Increased OH1 voltage by 50V at 5 and 10 msec. Increased OH2U and L
voltages by 10V at 5 and 10 msec. Pre-puff set to 17 msec.
Fizzle.
Shot 16: Increased OH1 voltage by 50 V from 1 to 10 msec. Increased OH2U and L
by 10V from 1 to 10 msec. Dud!
Shot 17: Increased TF to 180 kA and started it at -1.2 sec. Rampdown starts
at 0.2 sec. Got plasma. Disrupted at 0.4 sec. Forgot to copy the
TF waveform from segment 1 to segment 2.
Shot 18: Copied the TF waveform from segment 1 to segment 2. Try again.
Fizzle!
Shot 19: Plasma up to 0.3 MA, but very disruptive, lasting to nearly 0.4 sec.

Run turned over to Ian Hutchinson to do breakdown studies at 5.3 T.

Entered: Jul 7 2004 04:36:56:647PM

Author: To Be Determined

Physop Report. 960822 part 2.
PO Hutch, SL Granetz, EO various.

Late run till 9pm.

Attempts for breakdown at 5.3T Successful.
RF Conditioning. Some done.
High Minority fraction ICRF experiments Some but not wonderful.
Gauge calibration. Done.
Cryopump commissioning Done.
Lower Triangularity. Begun.

Overview
________
At 1 pm after a difficult morning and very dirty plasmas. It was
decided to devote 2 hours to demonstrating initiation at 5.3T. This
proved to be successful almost immediately and entered a plasma/fizzle
alternation sequence. Towards the end of the run, 50-52 were 3 plasmas
in a row. Clean-up was gradually taking place. The 6T superstition is
laid to rest (again).

Since the plasmas were long enough to be useful, we decided to
continue past 3 pm for RF conditioning at least. RF up to 1.5MW was
launched, although still showing strong evidence of impurity problems
and showing no heating.

The charge-exchange and the Maryland spectrometer reported very high levels
of hydrogen, around 50% at shot 20 and still 30% around shot 40. This
probably explains the lack of minority heating. Therefore it was decided to
scan the toroidal field upward, in search of mode-conversion heating.
One shot (I forget which) showed some ECE modulation in phase with the
ICRF modulation but not impressive.

Two shots were taken for gauge calibration: 29 and 32. The latter gave enough
pressure to verify good agreement between the different gauges.

The divertor cryopump was commissioned. It showed clearly the ability to
lower the vessel pressure. More serious analysis and experiments are needed
to figure out what it actually does for the plasma.

From 38 on, a triangularity sweep was installed using Rxl. And at shot
52 Rxu was increased to reduce the upper triangularity, giving .3
upper, .45 lower.

The last hour we experienced problems with torvac and OH2 which broke our
rhythm. No plasmas were obtained.

Scorecard
_________
Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax
1 0.000 0.021 2 0.000 0.021
3 0.000 0.031 4 0.000 0.028
5 0.000 0.018 6 0.132 0.267
7 0.153 0.321 8 0.000 0.013
9 0.000 0.013 10 0.000 0.018
11 0.000 0.021 12 0.000 0.019
13 0.000 0.019 14 0.000 0.016
15 0.000 0.044 16 0.000 0.019
17 0.424 0.797 18 0.000 0.027
19 0.370 0.350 20 0.000 0.019
21 0.000 0.021 22 0.000 0.021
23 0.000 0.019 24 0.365 0.701
25 0.000 0.021 26 0.970 0.802
27 0.000 0.024 28 1.011 0.802
29 0.000 0.021 30 0.000 0.021
31 0.766 0.794 32 0.000 0.019
33 0.000 0.024 34 0.827 0.786
35 0.000 0.019 36 0.000 0.016
37 1.337 0.786 38 0.000 0.024
39 0.000 0.021 40 0.893 0.786
41 0.000 0.021 42 0.000 0.019
43 0.849 0.787 44 0.000 0.024
45 0.766 0.790 46 0.000 0.026
47 0.932 0.793 48 0.000 0.021
49 0.000 0.026 50 0.750 0.791
51 0.932 0.791 52 0.916 0.791
53 0.000 0.016 54 0.000 0.026
55 0.000 0.011 56 0.000 0.019
57 0.000 0.032
Finished summary for 960822 Total of 57 shots.
57 shots. 17 plasmas. 34 fizzles. 6 duds.
Fizzle = gt 17 lt 50kA.

Details
_______
See Snipes report for the first part of the run.
Hybrid control 151kA drawn, with PLC limit at 165kA.
Gas fill to 16ms.
21 Dud Currents very close to shot 19.

Lower Br 1mT to .0025. Increase gas to 18ms.
22 Fiz Bdwn at 8.4ms. 27kA current. OH2L increases 150A. OH2U decreases 100A.

Br offset to .003. EF2 to -2130 from -2100
23 Dud mflux looks ok.

Br offset to .0025. EF3 to 2600V from 2800 at t=-1ms.
24 Pla Resistive the whole way. Too much density/Gas in the ramp.
Bdown at 6.1ms.

Puff to 6V from 100V at 32ms.
25 Fiz Bdown at 5.3ms.

No changes.
26 Pla Disrupts at .9..s

Argon pulse to 40ms from 30ms.
27 Fiz Bdwn 5.8ms

EF4 ramp down speeded up after ~30ms.
28 Pla Bdwn at 6.9ms. Disrupts at 1s.

29 Test gas calibration shot. Prfill puff is -1.68 to -1.5s.

Reload 28. Ramp zcur to -.015 at 1s. (from -.02)
30 Fiz Bdown at 5.8 ms.

31 Pla Disrupts at .76s. Gets a lot of radiation.

32 Gas test with PG3 set for -1.7 to -1.5s.

33 Fiz Reload 31. It looks as if the EF4 change was not loaded.

EF4 to 0 at .12s after 30ms.
34 Pla Disrupts at .8s. Gas coming from antenna is not so great but we still
have an impurity injection.

EF2 voltage at its crowbar given a 150V step to compensate.
35 Dud

36 Dud Repeat

Br to .003T offset.
37 Pla Disrupts at 1.3s. RF kept off. Ran longer.

Clearin to 0. from -.005m. Adjust Rcur and Ip in rampdown.
38 Fiz

EF4 current demand increased at .2s.
RXL drawn to .01 at .9s. (from .005).
39 Dud

OH2s set to 27700 from 277500
40 Pla Disrupts at .9s. Evidence of bad effects from RF.

Install B_t ramp after .5s to 180kA.
41 Dud

OH2s to 27650A.
42 Dud

Br to 2.5mT. EF4 to -1450 from -1460
43 Pla Disrupt at .85s. Got the TF ramp. Bdwn at 5.8ms no hesitation.

No changes
44 Dud

OH2s to 27600. TF ramp started earlier.
45 Pla Bdwn at 6.3ms disrupta at .76s.

Gas to 100V at 70ms. Increase the Rxl ramp. Rmove the -2cm zcur point
so it is -.015m throughout.
46 Fiz Bdown at 6.9ms

47 Pla Bdown at 8ms. Disrupts at .93s.

Increase Rxl to 1.7cm at .9s, and somewhat earlier.
48 Dud

OH2s to 27550
49 Fiz Bdwn at 6.5ms

OH2s to 27500
50 Pla Bdwn at 5.5ms. Disrupts at .75s. Still radiative events.

Raise early gas at 30ms. Move Rcur in by 2mm to .667m.
51 Pla Disrupts at .95x

Draw Rxu to 0 instead of -.015. Increase Rxl to .02 max.
52 Pla Disrupts at .92s. There seems to be a hybrid offset in Rxl of
about -.007m.

EF4 plc limit to 9 from 8. Rxl to .025m max. RF to 100kW.
Long pause because of torvac problem.
53 Dud Fill pressure has drifted down to .032 mtorr.

Raise fill puff to 21ms. Wait again on torvac.
54 Fiz Got .04 mtorr. Bdwn at 6.8ms. Nearly went.

Fill puff to 20ms.
55 PSDud OH2L crowbars at -.66s.

Long pause for fuse replacement. nl04 to 0.9e20.
56 Fiz Bdown at 8.5ms. OHs show larger currents. Probably extra cold.
zcur is getting too low.

No changes.
57 Fiz Bdwn at 7.3s. Nearly went.

Session Leader Comments

Aug 22 1996 08:20:39:480AM Robert Granetz MP #156A, Raise plasma current to 1.5 MA

SL: R. Granetz
PO: J. Snipes
EC: F. Silva

Primary goal: Increase plasma current to 1.5 MA without damaging machine. In
order to reduce disruption probability, The high current shots will be
carried out at 8 tesla.

Aug 22 1996 08:21:15:800AM Robert Granetz Shot sequence plan:

Start with a typical 6.3/5.4 tesla shot from earlier this week. (This is
to see if we can re-establish plasma operation after yesterday's accident.

If plasmas are obtained, go to 7.9 tesla and raise Ip in 0.1 MA increments

When 1.5 MA plasmas are achieved, try running several different prescribed
densities for the dimensionless scaling program (J. Schacter). Also let
the ICRF bang away.

Aug 22 1996 08:48:41:110AM 960822001 Robert Granetz Shot 01 -- Fizzle. Null is okay. Lower the gas for the next shot.

Aug 22 1996 10:18:00:370AM 960822006 Robert Granetz Shot 06 -- Plasma, sort of. Dirty disruptive short plasma. Ip=0.25 MA,
duration=0.13 s.

Aug 22 1996 10:18:15:600AM 960822007 Robert Granetz Shot 07 -- Plasma, sort of. Ip=0.31 MA, duration=0.15 s.

Aug 22 1996 12:35:39:710PM 960822016 Robert Granetz Shot 16 -- Dud. Let's stop fooling around. For the next shot increase the
TF by 5 kA and start it 0.1 s earlier.

Aug 22 1996 12:39:21:470PM 960822017 Robert Granetz Shot 17 -- Plasma. Ip=0.8 MA, terminated by disruption at 0.42 s. The higher
field worked again.

Aug 22 1996 01:17:04:170PM 960822019 Robert Granetz Shot 19 -- Plasma. Very resistive, Ip=0.33 MA, duration=0.37 s. Base
pressure is extremely high (1.4e-6 torr at the beginning of
Shot 20 init).

Aug 22 1996 01:17:28:230PM 960822020 Robert Granetz Shot 20 -- Dud.

Change of plans. Because of the obvious vacuum/cleanliness problems due to
yesterday's accident, it has been decided to abandon the run. However, for
a couple of hours Ian would like to takeover as physop and try to get
breakdown at 5.3 tesla. In addition, we will also run a gas calibration shot
for the ratiomatics, etc.

Aug 22 1996 01:18:24:220PM 960822021 Robert Granetz Reduce TF to 5.3 tesla

Shot 21 -- Dud.

Aug 22 1996 02:02:46:790PM 960822024 Robert Granetz Shot 24 -- Plasma. Ip=0.66 MA, duration=0.36 s. This was a plasma at 5.3 T.Shot 24 -- Plasma. Ip=0.66 MA, duration=0.36 s. This was a plasma at 5.3 T.

Aug 22 1996 02:18:34:590PM 960822026 Robert Granetz Shot 26 -- Plasma, nearly 1 sec long. Ip=0.8 MA. Density kept rising to
nl_04=2.e20 m-2.

Aug 22 1996 02:35:59:120PM 960822028 Robert Granetz Shot 28 -- Plasma. Ip=0.8 MA, disrupted at 1.01 s. Prf=1.2 MW.

Aug 22 1996 02:50:57:900PM 960822029 Robert Granetz Shot 29 -- Dud (on purpose). Gas calibration shot.

Aug 22 1996 03:10:57:730PM 960822031 Robert Granetz Shot 31 -- Plasma. Ip=0.8 MA, disrupted at 0.76 s.

Aug 22 1996 03:23:30:910PM 960822032 Robert Granetz Shot 32 -- Dud (on purpose). Another gas calibration shot.

Another change of plans. Since Ian has been successful at getting plasmas at
5.3 tesla (alternating shot/fizzle), we've decided to extend the run until
21:00 and do a variety of things (in lieu of the original plans).

Aug 22 1996 03:54:33:660PM 960822034 Robert Granetz Shot 34 -- Plasma. Ip=0.8 MA, disrupted at 0.82 s. Prf=1.3 MW.

Aug 22 1996 04:10:27:990PM 960822037 Robert Granetz Shot 37 -- Plasma. Good shot. Ip=0.8 MA, duration=1.33 s. Made it part way
down the ramp. RF was turned off on purpose. It may be causing
the plasma to disrupt during the flattop.

Aug 22 1996 05:00:52:730PM 960822040 Robert Granetz Shot 40 -- Plasma. Ip=0.8 MA, disrupted at 0.89 s, probably because the
RF was turned on again.

Aug 22 1996 06:36:02:700PM 960822043 Robert Granetz Shot 43 -- Plasma. Ip=0.8 MA, disrupted at 0.84 s.

Aug 22 1996 06:37:47:690PM 960822045 Robert Granetz Shot 45 -- Plasma. Ip=0.8 MA, duration=0.76 s.

Aug 22 1996 06:43:15:510PM 960822047 Robert Granetz Shot 47 -- Plasma. Ip=0.8 MA, duration=0.93 s. Prf=1 MW.

Aug 22 1996 06:57:09:130PM 960822050 Robert Granetz Shot 50 -- Plasma. Ip=0.8 MA, duration=0.74 s.

Aug 22 1996 07:01:43:510PM 960822051 Robert Granetz Shot 51 -- Plasma...two in a row. Ip=0.8 MA, duration=0.93 s.

Aug 22 1996 07:17:06:080PM 960822052 Robert Granetz Shot 52 -- Plasma...three in a row. Ip=0.8 MA, duration=0.91 s.

Physics Operator Comments

Aug 22 1996 08:51:58:440AM Joseph Snipes MP 156 A 1.5 MA plasma operation at 8 T
Engineer in Charge: Frank Silva
Session Leader: Bob Granetz
Physics Operator: Joseph Snipes

Overnight ECDC in deuterium with 60 C bake following yesterday's vacuum
accident. Pressure at 6.8 x 10^-7 torr on the machine gauge just before the
run, mostly water on the RGA. We will attempt to get plasmas by starting with
shot 960820004 before trying the high field, high current shots.

Aug 22 1996 08:52:42:380AM 960822001 Joseph Snipes Shot 1:
Copied 960820004 with hybrid control of the TF going to 6.2 T at 0.2 sec then
dropping to 5.4 T by 0.6 sec. Pre-puff set to 15 msec. Fizzle!

Aug 22 1996 09:01:27:450AM 960822002 Joseph Snipes Shot 2: Try again with 13 msec pre-puff. Later breakdown at about
10 msec.

Aug 22 1996 09:15:01:560AM 960822003 Joseph Snipes Shot 3: Try again with 17 msec pre-puff. Earlier breakdown at 6 msec.

Aug 22 1996 09:28:13:460AM 960822004 Joseph Snipes Shot 4: Try again with 20 msec pre-puff. Fizzle. About the same.

Aug 22 1996 09:55:41:510AM 960822005 Joseph Snipes Shot 5: Try again with 23 msec pre-puff. Fizzle! Later breakdown at
8 msec.

Aug 22 1996 10:10:55:580AM 960822006 Joseph Snipes Shot 6: Try again with 17 msec pre-puff. Reduced Br from 4 to 3.5 mT.
Got plasma that lasted 130 msec just over 0.2 MA.

Aug 22 1996 10:30:58:890AM 960822007 Joseph Snipes Shot 7: Reduced pre-puff to 13 msec. Plasma up to 0.3 MA and 150 msec.

Aug 22 1996 10:34:50:590AM 960822007 Joseph Snipes Shot 7: Reduced pre-puff to 13 msec. Plasma up to 0.3 MA and 150 msec.
Breakdown delayed to 7 msec.

Aug 22 1996 11:16:11:450AM 960822008 Joseph Snipes Shot 8: Pre-puff set to 15 msec. Dud!

Aug 22 1996 11:16:31:370AM 960822009 Joseph Snipes Shot 8: Pre-puff at 15 msec. Dud!

Aug 22 1996 11:17:01:700AM 960822010 Joseph Snipes Shot 10: Pre-puff at 19 msec. Fizzle. Late breakdown at 8 msec.

Aug 22 1996 11:31:25:770AM 960822011 Joseph Snipes Shot 11: Tweaked Br up to 3.75 mT. Fizzle. Late breakdown at 8 msec.

Aug 22 1996 11:31:44:430AM 960822012 Joseph Snipes Shot 12: Pre-puff set to 21 msec. Dud!

Aug 22 1996 11:45:06:160AM 960822013 Joseph Snipes Shot 13: Pre-puff set to 22 msec. OH1 voltage increased by 10V at at 5 and
10 msec. Also increased OH2L and OH2U by 2V at 5 and 10 msec. Late fizzle
at 12 msec.

Aug 22 1996 11:59:56:580AM 960822014 Joseph Snipes Shot 14: Pre-puff set to 12 msec. Dud!

Aug 22 1996 12:13:36:260PM 960822015 Joseph Snipes Shot 15: Increased OH1 voltage by 50V at 5 and 10 msec. Increased OH2U and L
voltages by 10V at 5 and 10 msec. Pre-puff set to 17 msec.
Fizzle. Still late breakdown at 8.5 msec.

Aug 22 1996 01:02:23:280PM 960822016 Joseph Snipes Shot 16: Increased OH1 voltage by 50 V from 1 to 10 msec. Increased
OH2U and L by 10V from 1 to 10 msec. Dud!

Aug 22 1996 01:03:17:250PM 960822017 Joseph Snipes Shot 17: Increased TF to 180 kA and started it at -1.2 sec. Rampdown starts
at 0.2 sec. Got plasma. Disrupted at 0.4 sec. Forgot to copy the
TF waveform from segment 1 to segment 2.

Aug 22 1996 01:03:35:930PM 960822018 Joseph Snipes Shot 18: Copied the TF waveform from segment 1 to segment 2. Try again.
Fizzle!

Aug 22 1996 01:04:43:530PM 960822019 Joseph Snipes Shot 19: Plasma up to 0.3 MA, but very disruptive, lasting to nearly 0.4 sec.

Aug 22 1996 01:06:23:410PM 960822020 Joseph Snipes Shot 20: Repeat. Dud! Run turned over to Ian Hutchinson.

Engineering Operator Comments

Shot Time Type Status Comment

1 08:36:19:830AM Plasma Ok no faults

2 08:52:01:970AM Plasma Ok oh2u comm. fault pf breaker out

3 09:03:39:730AM Plasma Ok oh2 upper comm fault breaker pulled (pf)

4 09:17:54:040AM Plasma Ok oh2u comm fault

5 09:45:09:020AM Plasma Ok oh2u comm fault pf breaker pulled

6 09:58:35:630AM Plasma Ok oh2u ioc, comm fault/ oh1 self powered fired bypass

7 10:12:47:660AM Plasma Ok oh2u comm fault /aoc breaker pulled

8 10:38:24:820AM Plasma Ok no faults

9 10:56:06:990AM Plasma Ok no faults

10 11:09:16:160AM Plasma Ok no faults

11 11:21:07:760AM Plasma Ok no faults

12 11:28:49:540AM Plasma Ok no faults

13 11:41:06:020AM Plasma Ok no faults

14 11:51:42:590AM Plasma Ok no faults

15 12:02:22:240PM Plasma Ok no faults

16 12:14:44:120PM Plasma Ok no faults

17 12:26:25:970PM Plasma Ok tf start to -1.2 from -1.1 /no faults

18 12:39:28:940PM Plasma Ok no faults

19 12:50:24:080PM Plasma Ok no faults

20 01:04:09:780PM Plasma Ok

21 01:16:48:190PM Plasma Ok

22 01:27:30:400PM Plasma Ok

23 01:39:23:740PM Plasma Ok

24 01:49:23:750PM Plasma Ok

25 02:00:56:340PM Plasma Ok

26 02:11:30:160PM Plasma Ok

27 02:22:56:440PM Plasma Ok

28 02:32:31:180PM Plasma Ok

29 02:45:52:820PM Plasma Ok

30 02:53:56:570PM Plasma Ok

31 03:01:48:480PM Plasma Ok

32 03:14:35:170PM Plasma Ok

33 03:23:13:320PM Plasma Ok

34 03:31:42:850PM Plasma Ok

35 03:47:41:880PM Plasma Ok

36 03:55:31:370PM Plasma Ok

37 04:05:08:360PM Plasma Ok

38 04:19:24:030PM Plasma Ok

39 04:30:53:960PM Plasma Ok

40 04:41:37:680PM Plasma Ok

41 04:55:51:090PM Plasma Ok

42 05:06:04:290PM Plasma Ok

43 05:15:14:470PM Plasma Ok

44 05:28:43:760PM Plasma Ok

45 05:40:36:430PM Plasma Ok

46 05:56:24:050PM Plasma Ok

47 06:07:45:580PM Plasma Ok

48 06:20:59:800PM Plasma Ok

49 06:30:49:740PM Plasma Ok

50 06:41:44:470PM Plasma Ok

51 06:55:29:710PM Plasma Ok

52 07:08:44:980PM Plasma Ok

53 07:51:24:300PM Plasma Ok

54 08:13:38:780PM Plasma Ok

55 08:21:36:170PM Plasma Bad Convertter Comm Fault OH2u&l, OH1, EF1 U&L

56 08:48:13:570PM Plasma Ok

57 08:55:32:030PM Plasma Ok

Session Leader Comments
Aug 22 1996 08:20:39:480AM		Robert Granetz	MP #156A, Raise plasma current to 1.5 MA SL: R. Granetz PO: J. Snipes EC: F. Silva Primary goal: Increase plasma current to 1.5 MA without damaging machine. In order to reduce disruption probability, The high current shots will be carried out at 8 tesla.
Aug 22 1996 08:21:15:800AM		Robert Granetz	Shot sequence plan: Start with a typical 6.3/5.4 tesla shot from earlier this week. (This is to see if we can re-establish plasma operation after yesterday's accident. If plasmas are obtained, go to 7.9 tesla and raise Ip in 0.1 MA increments When 1.5 MA plasmas are achieved, try running several different prescribed densities for the dimensionless scaling program (J. Schacter). Also let the ICRF bang away.
Aug 22 1996 08:48:41:110AM	960822001	Robert Granetz	Shot 01 -- Fizzle. Null is okay. Lower the gas for the next shot.
Aug 22 1996 10:18:00:370AM	960822006	Robert Granetz	Shot 06 -- Plasma, sort of. Dirty disruptive short plasma. Ip=0.25 MA, duration=0.13 s.
Aug 22 1996 10:18:15:600AM	960822007	Robert Granetz	Shot 07 -- Plasma, sort of. Ip=0.31 MA, duration=0.15 s.
Aug 22 1996 12:35:39:710PM	960822016	Robert Granetz	Shot 16 -- Dud. Let's stop fooling around. For the next shot increase the TF by 5 kA and start it 0.1 s earlier.
Aug 22 1996 12:39:21:470PM	960822017	Robert Granetz	Shot 17 -- Plasma. Ip=0.8 MA, terminated by disruption at 0.42 s. The higher field worked again.
Aug 22 1996 01:17:04:170PM	960822019	Robert Granetz	Shot 19 -- Plasma. Very resistive, Ip=0.33 MA, duration=0.37 s. Base pressure is extremely high (1.4e-6 torr at the beginning of Shot 20 init).
Aug 22 1996 01:17:28:230PM	960822020	Robert Granetz	Shot 20 -- Dud. Change of plans. Because of the obvious vacuum/cleanliness problems due to yesterday's accident, it has been decided to abandon the run. However, for a couple of hours Ian would like to takeover as physop and try to get breakdown at 5.3 tesla. In addition, we will also run a gas calibration shot for the ratiomatics, etc.
Aug 22 1996 01:18:24:220PM	960822021	Robert Granetz	Reduce TF to 5.3 tesla Shot 21 -- Dud.
Aug 22 1996 02:02:46:790PM	960822024	Robert Granetz	Shot 24 -- Plasma. Ip=0.66 MA, duration=0.36 s. This was a plasma at 5.3 T.Shot 24 -- Plasma. Ip=0.66 MA, duration=0.36 s. This was a plasma at 5.3 T.
Aug 22 1996 02:18:34:590PM	960822026	Robert Granetz	Shot 26 -- Plasma, nearly 1 sec long. Ip=0.8 MA. Density kept rising to nl_04=2.e20 m-2.
Aug 22 1996 02:35:59:120PM	960822028	Robert Granetz	Shot 28 -- Plasma. Ip=0.8 MA, disrupted at 1.01 s. Prf=1.2 MW.
Aug 22 1996 02:50:57:900PM	960822029	Robert Granetz	Shot 29 -- Dud (on purpose). Gas calibration shot.
Aug 22 1996 03:10:57:730PM	960822031	Robert Granetz	Shot 31 -- Plasma. Ip=0.8 MA, disrupted at 0.76 s.
Aug 22 1996 03:23:30:910PM	960822032	Robert Granetz	Shot 32 -- Dud (on purpose). Another gas calibration shot. Another change of plans. Since Ian has been successful at getting plasmas at 5.3 tesla (alternating shot/fizzle), we've decided to extend the run until 21:00 and do a variety of things (in lieu of the original plans).
Aug 22 1996 03:54:33:660PM	960822034	Robert Granetz	Shot 34 -- Plasma. Ip=0.8 MA, disrupted at 0.82 s. Prf=1.3 MW.
Aug 22 1996 04:10:27:990PM	960822037	Robert Granetz	Shot 37 -- Plasma. Good shot. Ip=0.8 MA, duration=1.33 s. Made it part way down the ramp. RF was turned off on purpose. It may be causing the plasma to disrupt during the flattop.
Aug 22 1996 05:00:52:730PM	960822040	Robert Granetz	Shot 40 -- Plasma. Ip=0.8 MA, disrupted at 0.89 s, probably because the RF was turned on again.
Aug 22 1996 06:36:02:700PM	960822043	Robert Granetz	Shot 43 -- Plasma. Ip=0.8 MA, disrupted at 0.84 s.
Aug 22 1996 06:37:47:690PM	960822045	Robert Granetz	Shot 45 -- Plasma. Ip=0.8 MA, duration=0.76 s.
Aug 22 1996 06:43:15:510PM	960822047	Robert Granetz	Shot 47 -- Plasma. Ip=0.8 MA, duration=0.93 s. Prf=1 MW.
Aug 22 1996 06:57:09:130PM	960822050	Robert Granetz	Shot 50 -- Plasma. Ip=0.8 MA, duration=0.74 s.
Aug 22 1996 07:01:43:510PM	960822051	Robert Granetz	Shot 51 -- Plasma...two in a row. Ip=0.8 MA, duration=0.93 s.
Aug 22 1996 07:17:06:080PM	960822052	Robert Granetz	Shot 52 -- Plasma...three in a row. Ip=0.8 MA, duration=0.91 s.

Physics Operator Comments
Aug 22 1996 08:51:58:440AM		Joseph Snipes	MP 156 A 1.5 MA plasma operation at 8 T Engineer in Charge: Frank Silva Session Leader: Bob Granetz Physics Operator: Joseph Snipes Overnight ECDC in deuterium with 60 C bake following yesterday's vacuum accident. Pressure at 6.8 x 10^-7 torr on the machine gauge just before the run, mostly water on the RGA. We will attempt to get plasmas by starting with shot 960820004 before trying the high field, high current shots.
Aug 22 1996 08:52:42:380AM	960822001	Joseph Snipes	Shot 1: Copied 960820004 with hybrid control of the TF going to 6.2 T at 0.2 sec then dropping to 5.4 T by 0.6 sec. Pre-puff set to 15 msec. Fizzle!
Aug 22 1996 09:01:27:450AM	960822002	Joseph Snipes	Shot 2: Try again with 13 msec pre-puff. Later breakdown at about 10 msec.
Aug 22 1996 09:15:01:560AM	960822003	Joseph Snipes	Shot 3: Try again with 17 msec pre-puff. Earlier breakdown at 6 msec.
Aug 22 1996 09:28:13:460AM	960822004	Joseph Snipes	Shot 4: Try again with 20 msec pre-puff. Fizzle. About the same.
Aug 22 1996 09:55:41:510AM	960822005	Joseph Snipes	Shot 5: Try again with 23 msec pre-puff. Fizzle! Later breakdown at 8 msec.
Aug 22 1996 10:10:55:580AM	960822006	Joseph Snipes	Shot 6: Try again with 17 msec pre-puff. Reduced Br from 4 to 3.5 mT. Got plasma that lasted 130 msec just over 0.2 MA.
Aug 22 1996 10:30:58:890AM	960822007	Joseph Snipes	Shot 7: Reduced pre-puff to 13 msec. Plasma up to 0.3 MA and 150 msec.
Aug 22 1996 10:34:50:590AM	960822007	Joseph Snipes	Shot 7: Reduced pre-puff to 13 msec. Plasma up to 0.3 MA and 150 msec. Breakdown delayed to 7 msec.
Aug 22 1996 11:16:11:450AM	960822008	Joseph Snipes	Shot 8: Pre-puff set to 15 msec. Dud!
Aug 22 1996 11:16:31:370AM	960822009	Joseph Snipes	Shot 8: Pre-puff at 15 msec. Dud!
Aug 22 1996 11:17:01:700AM	960822010	Joseph Snipes	Shot 10: Pre-puff at 19 msec. Fizzle. Late breakdown at 8 msec.
Aug 22 1996 11:31:25:770AM	960822011	Joseph Snipes	Shot 11: Tweaked Br up to 3.75 mT. Fizzle. Late breakdown at 8 msec.
Aug 22 1996 11:31:44:430AM	960822012	Joseph Snipes	Shot 12: Pre-puff set to 21 msec. Dud!
Aug 22 1996 11:45:06:160AM	960822013	Joseph Snipes	Shot 13: Pre-puff set to 22 msec. OH1 voltage increased by 10V at at 5 and 10 msec. Also increased OH2L and OH2U by 2V at 5 and 10 msec. Late fizzle at 12 msec.
Aug 22 1996 11:59:56:580AM	960822014	Joseph Snipes	Shot 14: Pre-puff set to 12 msec. Dud!
Aug 22 1996 12:13:36:260PM	960822015	Joseph Snipes	Shot 15: Increased OH1 voltage by 50V at 5 and 10 msec. Increased OH2U and L voltages by 10V at 5 and 10 msec. Pre-puff set to 17 msec. Fizzle. Still late breakdown at 8.5 msec.
Aug 22 1996 01:02:23:280PM	960822016	Joseph Snipes	Shot 16: Increased OH1 voltage by 50 V from 1 to 10 msec. Increased OH2U and L by 10V from 1 to 10 msec. Dud!
Aug 22 1996 01:03:17:250PM	960822017	Joseph Snipes	Shot 17: Increased TF to 180 kA and started it at -1.2 sec. Rampdown starts at 0.2 sec. Got plasma. Disrupted at 0.4 sec. Forgot to copy the TF waveform from segment 1 to segment 2.
Aug 22 1996 01:03:35:930PM	960822018	Joseph Snipes	Shot 18: Copied the TF waveform from segment 1 to segment 2. Try again. Fizzle!
Aug 22 1996 01:04:43:530PM	960822019	Joseph Snipes	Shot 19: Plasma up to 0.3 MA, but very disruptive, lasting to nearly 0.4 sec.
Aug 22 1996 01:06:23:410PM	960822020	Joseph Snipes	Shot 20: Repeat. Dud! Run turned over to Ian Hutchinson.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:36:19:830AM	Plasma	Ok	no faults
2	08:52:01:970AM	Plasma	Ok	oh2u comm. fault pf breaker out
3	09:03:39:730AM	Plasma	Ok	oh2 upper comm fault breaker pulled (pf)
4	09:17:54:040AM	Plasma	Ok	oh2u comm fault
5	09:45:09:020AM	Plasma	Ok	oh2u comm fault pf breaker pulled
6	09:58:35:630AM	Plasma	Ok	oh2u ioc, comm fault/ oh1 self powered fired bypass
7	10:12:47:660AM	Plasma	Ok	oh2u comm fault /aoc breaker pulled
8	10:38:24:820AM	Plasma	Ok	no faults
9	10:56:06:990AM	Plasma	Ok	no faults
10	11:09:16:160AM	Plasma	Ok	no faults
11	11:21:07:760AM	Plasma	Ok	no faults
12	11:28:49:540AM	Plasma	Ok	no faults
13	11:41:06:020AM	Plasma	Ok	no faults
14	11:51:42:590AM	Plasma	Ok	no faults
15	12:02:22:240PM	Plasma	Ok	no faults
16	12:14:44:120PM	Plasma	Ok	no faults
17	12:26:25:970PM	Plasma	Ok	tf start to -1.2 from -1.1 /no faults
18	12:39:28:940PM	Plasma	Ok	no faults
19	12:50:24:080PM	Plasma	Ok	no faults
20	01:04:09:780PM	Plasma	Ok
21	01:16:48:190PM	Plasma	Ok
22	01:27:30:400PM	Plasma	Ok
23	01:39:23:740PM	Plasma	Ok
24	01:49:23:750PM	Plasma	Ok
25	02:00:56:340PM	Plasma	Ok
26	02:11:30:160PM	Plasma	Ok
27	02:22:56:440PM	Plasma	Ok
28	02:32:31:180PM	Plasma	Ok
29	02:45:52:820PM	Plasma	Ok
30	02:53:56:570PM	Plasma	Ok
31	03:01:48:480PM	Plasma	Ok
32	03:14:35:170PM	Plasma	Ok
33	03:23:13:320PM	Plasma	Ok
34	03:31:42:850PM	Plasma	Ok
35	03:47:41:880PM	Plasma	Ok
36	03:55:31:370PM	Plasma	Ok
37	04:05:08:360PM	Plasma	Ok
38	04:19:24:030PM	Plasma	Ok
39	04:30:53:960PM	Plasma	Ok
40	04:41:37:680PM	Plasma	Ok
41	04:55:51:090PM	Plasma	Ok
42	05:06:04:290PM	Plasma	Ok
43	05:15:14:470PM	Plasma	Ok
44	05:28:43:760PM	Plasma	Ok
45	05:40:36:430PM	Plasma	Ok
46	05:56:24:050PM	Plasma	Ok
47	06:07:45:580PM	Plasma	Ok
48	06:20:59:800PM	Plasma	Ok
49	06:30:49:740PM	Plasma	Ok
50	06:41:44:470PM	Plasma	Ok
51	06:55:29:710PM	Plasma	Ok
52	07:08:44:980PM	Plasma	Ok
53	07:51:24:300PM	Plasma	Ok
54	08:13:38:780PM	Plasma	Ok
55	08:21:36:170PM	Plasma	Bad	Convertter Comm Fault OH2u&l, OH1, EF1 U&L
56	08:48:13:570PM	Plasma	Ok
57	08:55:32:030PM	Plasma	Ok