Alcator C-Mod Run 1050318 Information

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Miniproposals
Miniproposal:326
Date Filed: 8/26/2002
Title:D, E, and J-port Antenna Evaluation and Comparison
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-35)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Robert Granetz
Engineering operator(s):Sam Pierson,Bill Byford,Ed Fitzgerald

Engineering Operator Run Comment
MP#326 EO Pierson SL Wukitch PO Granetz

Session Leader Plans
Entered: Mar 17 2005 09:39:48:990PM
Author: Steve Wukitch
Plan:

We will start with vanilla discharges to compare the heating
effectiveness (different from heating efficiency) of the 3 antennas. This means separate antenna pulses within each discharge 0.5, 1.0, 1.5 MW. Then combine D and E and increase the total power to 2 MW and 2.5 MW. We will then investigate operation at higher neutral pressure by scanning to higher density. We will
return to more standard density and compare H-mode thresholds via
power ramps and scan current to compare impurity and density
production. We may need one discharge to calibrate the bolometers via impurity puffing depending on diagnostic requirements.
---------------------------------------------------------

Physics Operators Plans
Entered: Mar 17 2005 06:30:24:443PM
Author: Robert Granetz
Engineering setup for Friday, 18 Mar 2005

MP #326 -- D, E, and J-port Antenna Evaluation and Comparison

Session leader: S. Wukitch
Physics operator: R. Granetz

Overnight ECDC in D2, bake at 60 C.

Run begins at 09:00 and ends at 17:00.

Power systems as on 1050316018.

A-coils in standard configuration (lock mode suppression):
+Dtop -Dbot -Jtop +Jbot (same as 1050316)

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 2 psi Ar Hybrid enabled (PG1)
leave B-side upper with He3 Hybrid disabled
fill B-main (C-side) with 30 psi D2 Hybrid enabled (PG3)
leave J-bot Hybrid disabled (PG2)

fill NINJA with 10 psi D2 Leave disabled to begin with

Torvac setup: GV1 closed; bypass to RGA open
Torus gate valves to REMAIN OPEN during and after shot.

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

Necessary diagnostics:
Standard, including bolometry, video cameras.

-------------------------------------------------------------------------------
ICRF Setup: All transmitters in run on at 08:30.

-------------------------------------------------------------------------------
Run plan:

The goal of this run is to retry this past Wednesday's run (1050316), which
was unsuccessful because of problems with the EF3 breaker and with RF
pickup noise throughout the cell. These problems have been fixed

Start with 1050316018 (vanilla shot with 0.8 MA, 5.4 T, and target
nl_04=1.0e20 m-2). Compare heating efficiencies of the three antennas. We
will then investigate operation at higher neutral pressure by scanning to
higher density. We will return to more standard density and compare H-mode
thresholds via power ramps and scan current to compare impurity and density
production.

Session Leader Summaries
Entered: Mar 21 2005 11:43:03:653AM
Author: Steve Wukitch
Run summary

The antenna heating effectiveness appears about the same for all
antennas within 10%. One could argue that J antenna is slightly less
effective than D and E and D may be slightly better than E. From a
few discharges, the heating efficiency was measured from change in
slope in stored energy and the range of efficiencies is from 0.5-0.7.

The J antenna neutral pressure limit appears unchanged from last
campaign (~0.25 mTorr) at 0.8 MA and increased to between 0.7-1 mtorr
at 1 MA. This suggests to condition the antenna after boronization we
should increase the plasma current.

Physics Operator Summaries
Entered: Mar 18 2005 05:34:41:743PM
Author: Robert Granetz
From the physop standpoint, the run when very well today. We had 35 shot cycles, of which only one
was a fizzle, and another one was a no-power shot due to a computer hang. D, E, and J antennas were
all run today at powers up to 2.5 MW. The antennas all seemed to be heating equally well. Despite
the high RF power, we had only marginal, dithering H-modes. Late in the run we tried to do the
bolometry calibration by causing impurity disruptions with argon puffing. This was sort of successful,
except that we couldn't stretch out the timescale as much as we would have liked, despite trying various
valve waveforms and plenum pressures.

Scorecard: 33 plasmas
1 fizzles
0 duds
1 tests or no-power shot cycles
0 beam-into-gas calibration shots with B-field(s)
----------
35 total shot cycles

Session Leader Comments
Mar 18 2005 09:38:15:153AM1050318001Steve Wukitch001 5.4 T, Ip=0.8 MA, nl_04->0.8
D: 0.5 MW [0.6,0.9]sec
E: 0.5 MW [0.9,1.2]sec
J: 0.5 MW [1.2,1.5]sec
result: plasma
D: ran 1 fault
E: ran
J: ran 1 fault
next shot: raise power to 1 MW
Mar 18 2005 09:38:57:530AM1050318002Steve Wukitch002 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.0 MW [0.6,0.9]sec
E: 1.0 MW [0.9,1.2]sec
J: 1.0 MW [1.2,1.5]sec
result: plasma
D: ran
E: ran
J: ran 3 faults
next shot: repeat
cell data is lost
Mar 18 2005 10:14:18:903AM1050318003Steve Wukitch003 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.0 MW [0.6,0.8]sec
E: 1.0 MW [0.9,1.1]sec
J: 1.0 MW [1.2,1.4]sec
result: plasma
D: ran
E: ran
J: ran 1 fault
cell data is lost
next shot: raise power
Mar 18 2005 10:15:00:903AM1050318004Steve Wukitch004 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.4 MW [0.55,0.85]sec
E: 1.4 MW [0.9,1.15]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran
E: ran
J: ran 7 faults
cell data is lost
no spectroscopy data
next shot: repeat
Mar 18 2005 10:31:23:700AM1050318005Steve Wukitch005 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.4 MW [0.55,0.85]sec
E: 1.4 MW [0.9,1.15]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran
E: ran
J: ran 1 fault
cell data is lost
next shot: swap pulse order
Mar 18 2005 11:09:57:620AM1050318006Steve Wukitch006 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.4 MW [0.9,1.15]sec
E: 1.4 MW [0.55,0.85]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran
E: ran
J: ran 4 faults
cell data is lost
next shot: move J to beginning
Mar 18 2005 11:10:44:607AM1050318007Steve Wukitch007 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.4 MW [0.9,1.15]sec
E: 1.4 MW [0.55,0.85]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran
E: ran
J: ran
cell data is lost
next shot: repeat
Mar 18 2005 11:21:21:530AM1050318008Steve Wukitch008 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.4 MW [0.9,1.15]sec
E: 1.4 MW [0.55,0.85]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran
E: ran
J: ran
cell data is present - changed decoder channel, power cycled CAMAC and cPCI
next shot: overlap D and E
Mar 18 2005 11:56:33:167AM1050318009Steve Wukitch009 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.0 MW [1.1,1.5]sec
E: 1.0 MW [1.1,1.5]sec
J: 2 MW [0.55,1.05]sec
result: plasma - H-mode
D: ran
E: ran
J: ran 5 faults
next shot: repeat
Mar 18 2005 11:56:07:450AM1050318010Steve Wukitch010 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.0 MW [1.1,1.5]sec
E: 1.0 MW [1.1,1.5]sec
J: 2.0 MW [0.55,1.05]sec
result: plasma
D: ran
E: ran
J: ran 9 faults
cameras are back
next shot: repeat
Mar 18 2005 11:55:13:167AM1050318011Steve Wukitch011 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.0 MW [1.1,1.5]sec
E: 1.0 MW [1.1,1.5]sec
J: 2 MW [0.55,1.05]sec
result: plasma
D: ran
E: ran
J: ran 6 faults
next shot: repeat
Mar 18 2005 12:17:38:337PM1050318012Steve Wukitch012 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.4 MW [1.1,1.5]sec
E: 1.4 MW [1.1,1.5]sec
J: 1.5 MW [0.55,1.05]sec
result: plasma
D: ran
E: ran
J: ran 2 faults
next shot: move up in power
Mar 18 2005 12:20:29:087PM1050318013Steve Wukitch013 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.25 MW [1.1,1.5]sec
E: 1.25 MW [1.1,1.5]sec
J: 2.5 MW [0.55,1.05]sec
result: plasma
D: ran 3 faults
E: ran 1 fault
J: ran 8 faults
next shot: repeat
Mar 18 2005 12:45:18:057PM1050318014Steve Wukitch014 NTP
Mar 18 2005 12:56:03:587PM1050318015Steve Wukitch015 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.2 MW [1.1,1.5]sec
E: 1.1 MW [1.1,1.5]sec
J: 2.5 MW [0.55,1.05]sec
result: plasma
D: ran
E: ran
J: ran 9 faults
next shot: repeat
Mar 18 2005 01:08:09:413PM1050318016Steve Wukitch016 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.2 MW [1.1,1.5]sec
E: 1.1 MW [1.1,1.5]sec
J: 2.5 MW [0.55,1.05]sec
result: plasma
D: ran 2 faults
E: ran 1 fault
J: ran max faults
next shot: repeat
Mar 18 2005 01:28:53:460PM1050318017Steve Wukitch017 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.2 MW [1.1,1.5]sec
E: 1.1 MW [1.1,1.5]sec
J: 2.5 MW [0.55,1.05]sec
result: plasma
D: ran 2 faults
E: ran 1 fault
J: ran 2 faults
next shot: repeat
Mar 18 2005 01:45:58:523PM1050318018Steve Wukitch018 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.2 MW [1.1,1.5]sec
E: 1.1 MW [1.1,1.5]sec
J: 2.5 MW [0.55,1.05]sec
result: plasma
D: ran 2 faults
E: ran 1 fault
J: ran max faults
next shot: raise density, separate antennas - begin neutral pressure scan
Mar 18 2005 01:55:49:680PM1050318020Steve Wukitch020 5.2 T, Ip=0.8 MA, nl_04->1
D: 1.4 MW [0.9,1.15]sec
E: 1.4 MW [0.55,0.85]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran 1 fault
E: ran clean
J: ran 4 faults
next shot: swap antenna order and raise density
Mar 18 2005 02:13:04:697PM1050318021Steve Wukitch021 5.2 T, Ip=0.8 MA, nl_04->1.2
D: 1.4 MW [0.55,0.85]sec
E: 1.4 MW [0.9,1.15]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran 1 fault
E: ran clean
J: ran max faults - all J4
next shot: repeat


Mar 18 2005 02:26:55:023PM1050318022Steve Wukitch022 5.2 T, Ip=0.8 MA, nl_04->1.2
D: 1.4 MW [0.55,0.85]sec
E: 1.4 MW [0.9,1.15]sec
J: 1.5 MW [1.2,1.5]sec
result: plasma
D: ran 1 fault
E: ran clean
J: ran max faults - all J4

next shot: turn off D and E and run long pulse with J
Mar 18 2005 02:46:37:867PM1050318023Steve Wukitch023 5.2 T, Ip=0.8 MA, nl_04->1.2
J: 1.5 MW [.6,1.5]sec
result: plasma
J: ran max faults
next shot: retune and hope for the best
Mar 18 2005 03:00:19:600PM1050318024Steve Wukitch024 5.2 T, Ip=0.8 MA, nl_04->1.2
J: 1.5 MW [.6,1.5]sec
result: plasma
J: ran max faults
next shot: raise current to 1 MA
Mar 18 2005 03:07:10:103PM1050318025Steve Wukitch025 5.2 T, Ip=0.8 MA, nl_04->1.2
J: 1.5 MW [.6,1.5]sec
result: plasma
J: ran max faults
next shot: repeat with better match
Mar 18 2005 04:04:38:383PM1050318026Steve Wukitch026 5.2 T, Ip=1 MA, nl_04->1.2
J: 1.5 MW [.6,1.5]sec
result: plasma
J: ran
next shot: raise density to 1.5
Mar 18 2005 04:04:20:710PM1050318027Steve Wukitch027 5.2 T, Ip=1 MA, nl_04->1.2
J: 1.5 MW [.6,1.5]sec
result: plasma
J: ran
next shot: raise density to 1.5
Mar 18 2005 03:42:32:883PM1050318028Steve Wukitch028 NTP
Mar 18 2005 04:03:15:023PM1050318029Steve Wukitch029 5.2 T, Ip=1 MA, nl_04->1.2
J: 1.5 MW [.6,1.5]sec
result: plasma
J: ran max fault - still have neutral pressure limit but it is between 0.7 and 1 mtorr
next shot: return to standard shot, with intentional RF trips at 0.8 and 1 sec

Mar 18 2005 04:07:15:413PM1050318030Steve Wukitch030 5.2 T, Ip=0.8 MA, nl_04->0.8
J: 1.5 MW [0.55,1.0]sec
result: plasma
J: ran 1 fault
next: repeat without disruption
Mar 18 2005 04:25:52:633PM1050318031Steve Wukitch031 5.2 T, Ip=0.8 MA, nl_04->0.8
J: 1.5 MW [0.55,1.0]sec
result: plasma
J: ran. good

DW/dT at the two shut-offs (0.8 and 1.0 sec) gave efficiency at 0.5 and 0.64, respectively
Mar 18 2005 04:53:59:807PM1050318032Steve Wukitch032 5.2 T, Ip=0.8 MA, nl_04->0.8
J: 1.5 MW [0.6,.9]sec
result: plasma
J: ran. good

DW/dT at the two shut-offs (0.8 and .9 sec) gave efficiency at 0.6 and 0.4, respectively
Mar 18 2005 04:54:47:070PM1050318033Steve Wukitch033 5.2 T, Ip=0.8 MA, nl_04->0.8
D: 1.2 MW [0.6,.9]sec
result: plasma
D: ran. good

DW/dT at the two shut-offs (0.8 and .9 sec) gave efficiency at 0.7 and 0.6, respectively
Mar 21 2005 09:23:05:950AM1050318034Steve Wukitch034 5.2 T, Ip=0.8 MA, nl_04->0.8
E: 1.2 MW [0.6,.9]sec
result: plasma
E: ran. good

DW/dT at the two shut-offs (0.8 and .9 sec) gave efficiency at about 0.55
Mar 21 2005 09:22:55:513AM1050318035Steve Wukitch035 5.2 T, Ip=0.8 MA, nl_04->0.8
E: 1.2 MW [0.6,.9]sec
result: plasma
E: ran. good

DW/dT at the two shut-offs (0.8 and .9 sec) gave efficiency at about 0.5

Physics Operator Comments
Mar 18 2005 09:27:14:450AM1050318001Robert GranetzPlasma. Good standard shot, but really ratty startup. Lots of runaways until they suddenly
all went away at 0.24 s, possibly due to an injection at that time. The rest of the shot looked
okay. Video cameras had a problem with data acquisition. All three antennas
were on (not simultaneously) at about a half-MW each.

Next shot: adjust RCUR offset in segment 1 (1500 -> 2000). Also reduce Btor from
5.4 to 5.2 T (144 kA).
Mar 18 2005 09:44:59:857AM1050318002Robert GranetzPlasma. Good shot. Good startup. Btor=5.2 T, as requested. Ip=0.8 MA, nl_04=0.9e20 m-2.
All three antennas fired individually. Problem with the RF data.

Next shot: repeat, no changes.
Mar 18 2005 10:00:55:573AM1050318003Robert GranetzPlasma. Good shot. Good startup, but there are lots of runaways. Got some
RF data this time...about 1 MW in each antenna.

Next shot: increase early density pre-programmed gas. Also fill NINJA plenum
with 5 psi of helium-4.
Mar 18 2005 10:21:44:763AM1050318004Robert GranetzPlasma. Good shot. Great startup. Much fewer hard x-rays.
All antennas fired, but there are still data acquisition problems.
1.5 MW from each antenna. Amanda reports that early Te(r) profiles
are back to their normal, peaked shape. (Yesterday they were strongly
hollow.)

Next shot: no changes
Mar 18 2005 10:30:34:920AM1050318005Robert GranetzPlasma. Good shot.
All antennas fired, but there are still data acquisition problems.
1.5 MW from each antenna. Heating effectiveness seems to drop with
time during the shot, or with D -> E -> J sequency.

Next shot: no changes, except change the order of antenna firing
Mar 18 2005 10:45:22:373AM1050318006Robert GranetzPlasma. Good shot.
All antennas fired at 1.55-1.8 MW, but J-port had numerous trips.
Sequence was E -> D -> J

Next shot: tweak up the early pre-programmed gas puff some more
Mar 18 2005 10:53:47:543AM1050318007Robert GranetzPlasma. Good shot.
All antennas fired at 1.5-1.8 MW. Sequence was J -> E -> D.
Good equal heating by all antennas, but still no H-modes.
H/(H+D) is remaining down at 5-6%. Zeff is 1.4-1.5.

Next shot: no PCS changes. D and E will be overlapped.
Mar 18 2005 11:20:02:543AM1050318008Robert GranetzPlasma. Good shot.
All antennas fired at 1.5-1.7 MW. Sequence was J -> E -> D.
D and E were NOT overlapped.
Approximately equal heating by all antennas, but still no H-modes.
H/(H+D) is remaining down at 5-6%. Zeff is 1.4-1.5.

Next shot: no PCS changes. D and E will be overlapped.
Mar 18 2005 11:30:03:513AM1050318009Robert GranetzPlasma. Good shot. D and E were overlapped, giving 2.2 MW total, and an
EDA H-mode (finally). J-port fired first, but had some faulting problems
early on and then settled down to 1.9 MW.
H/(H+D) is remaining down at 5%. Zeff is 1.2-1.3.

Next shot: no PCS changes. Repeat to get better J-port performance.
Mar 18 2005 12:41:27:760PM1050318009Robert GranetzEarl points out that this was not an EDA H-mode, but rather a dithery, barely H-mode
plasma. (Type III ELM's ?)
Mar 18 2005 11:46:47:227AM1050318010Robert GranetzPlasma. Good shot. D and E were overlapped, giving 2.2 MW total, and an
EDA H-mode. J-port fired first, but had faulting problems.
H/(H+D) is remaining down at 6%.

Next shot: no PCS changes. Repeat to get better J-port performance.
Mar 18 2005 11:59:27:980AM1050318011Robert GranetzPlasma. Good shot. D and E were overlapped, giving 2.2 MW total, and an
EDA H-mode. J-port fired first, got 2.0 MW with a few faults. J-port also
produced a few short L-H transitions.
H/(H+D) is remaining down at 6%. Zeff=1.3-1.5

Next shot: no PCS changes.
Mar 18 2005 12:11:02:197PM1050318012Robert GranetzPlasma. Good shot. D and E were overlapped, giving 2.2 MW total, and an
EDA H-mode. J-port fired first, got 2.0 MW with only a couple of faults. J-port also
produced a short L-H transition.
H/(H+D) is remaining down at 6%. Zeff=1.5

Next shot: no PCS changes. Raise J-port to 2.5 MW
Mar 18 2005 12:23:44:960PM1050318013Robert GranetzPlasma. Good shot. RF power was raised. J=2.4, D+E=2.8 MW,
but lots of faulting. H/(H+D) gets up to 8-9%.

Next shot: tweak up early pre-programmed gas some more.
Mar 18 2005 12:34:57:197PM1050318014Robert GranetzNo power shot due to computer problems in init.
Mar 18 2005 01:00:28:773PM1050318015Robert GranetzPlasma. Good shot. J=2.5 MW with lots of faulting, D+E=2.5 MW.
H/(H+D)=6-8%.

Next shot: no PCS changes.
Mar 18 2005 01:08:02:103PM1050318015Robert GranetzPlasma. Good shot. J didn't stay on. D+E=2.5 MW.
H/(H+D)=6-7%.

Next shot: more early pre-programmed gas puffing.
Mar 18 2005 01:24:22:883PM1050318015Robert GranetzPlasma. Good shot. J=2.4 MW, D+E=2.5 MW.
H/(H+D)=7-9%.

Next shot: one more repeat, then we'll start a density scan.
Mar 18 2005 01:35:00:040PM1050318015Robert GranetzPlasma. Good shot. J=2.4 MW, D+E=2.4 MW. Short dithery H-modes.
H/(H+D)=6-8%. Zeff=1.6

Next shot: Start a density scan. Increase nl_04 to 1.0e20 m-2 (from 0.8)
Mar 18 2005 01:48:54:400PM1050318015Robert GranetzPlasma. Good shot. Got the requested density of nl_04=1.0e20 m-2.
J=1.4 MW, E=1.4 MW, but D didn't stay on. No H-modes.
H/(H+D)=6-7%. Zeff=1.6

Next shot: no PCS changes
Mar 18 2005 02:04:32:977PM1050318020Robert GranetzPlasma. Good shot. About 1.5 MW from each antenna. Got a couple of dithery
H-modes. H/(H+D)=5-7%. Zeff=1.3

Next shot: raise nl_04 to 1.2e20 m-2.
Mar 18 2005 02:10:11:743PM1050318021Robert GranetzPlasma. Good shot, although it disrupted during rampdown. Antenna sequence was
changed around: D -> E -> J. Prf=1.65 MW from each of D and E, but J failed to stay on.
No H-modes.

Next shot: no PCS changes.
Mar 18 2005 02:26:04:697PM1050318022Robert GranetzPlasma. Good shot, although again it disrupted during rampdown.
Prf=1.65 MW from each of D and E, but J failed to stay on again.
No H-modes. H/(H+D)=4-5%. Zeff=1.2

Next shot: no PCS changes.
Mar 18 2005 02:36:40:523PM1050318023Robert GranetzPlasma. Good shot, although again it disrupted during rampdown.
Tried for J only this time, but it didn't do too well.

Next shot: no PCS changes.
Mar 18 2005 02:57:38:540PM1050318024Robert GranetzPlasma. Good shot, although again it disrupted during rampdown.
Tried for J only this time, but it didn't do too well on this shot either.

Next shot: raise Ip to 1.0 MA (from 0.8)
Mar 18 2005 03:11:47:290PM1050318025Robert GranetzPlasma. Good shot, Got the 1.0 MA. There's a mysterious density increase
from t=0.35 to 0.62 s due to a big marfe. J-port ran much better at this higher
plasma current.

Next shot: no PCS changes.
Mar 18 2005 03:18:50:460PM1050318026Robert GranetzPlasma. Good shot, Same early marfe and density bump. J-port had 1.5 MW for 0.9 s.

Next shot: raise nl_04 to 1.5e20 m-2 (from 1.2)
Mar 18 2005 03:32:07:510PM1050318027Robert GranetzPlasma. Good shot, but disrupted early in rampdown at 0.8 MA. I_Halo_L=177 kA.
Got the density, actually even a little more: nl_04=1.6e20 m-2. J-port is still
looking very good, with 1.4 MW for 0.9 s.

Next shot: raise nl_04 to 1.8e20 m-2
Mar 18 2005 03:40:35:197PM1050318028Robert GranetzFizzle. Maybe it was the preceding rampdown disruption.

Next shot: reduce pre-fill by 2 ms.
Mar 18 2005 04:02:12:447PM1050318029Robert GranetzPlasma. Disrupted at t=1.47 s. Current was dropping before it was supposed
to. J-port didn't stay on. Startup looked ratty.

Next shot: return to conditions of shot 18 (0.8 MA, nl_04=0.8e20 m-2), but add
a 100 ms argon puff starting at t=0.95 s. This is the start of our bolometry
calibration portion of the run.
Mar 18 2005 04:11:19:413PM1050318030Robert GranetzPlasma. Disrupted at t=0.94 s, just BEFORE the 2nd argon puff was supposed to
begin. So I don't know what caused that disruption. We got the requested plasma
current (0.8 MA) and density (nl_04=0.8e20 m-2).

H/(H+D) is still down at 5%. J-port gave 1.5 MW.

Next shot: increase pre-fill by 2 ms.
Mar 18 2005 04:25:36:977PM1050318031Robert GranetzPlasma. Made it into rampdown. J-port had 1.5 MW until t=1.0 s, then it turned
off quickly in order to get an absorption measurement from the EFIT diamagnetic
signal. 2pi foil signal doesn't show any increase due to the 2nd argon puff.

Next shot: raise argon plenum pressure to 10 psi (from 2 psi) and turn off the
early puff (normally for JR).
Mar 18 2005 04:44:56:913PM1050318032Robert GranetzPlasma. Disrupted at t=1.05 s, definitely due to the argon puff (as confirmed
by John Rice). Interestingly, the argon takes 40+ ms to get in.

Next shot: change argon puff to be 30 volts starting at t=0.95 s and going until
t=1.5 s
Mar 18 2005 04:50:50:400PM1050318033Robert GranetzPlasma. Best shot of the day. Unfortunately there wasn't any argon visible. John Rice
tells us that we have to run that valve at 100 volts.

Next shot: raise B-side-lower voltage to 100 V, from t=0.95 to 1.5 s, but reduce the
plenum pressure to 5 psi.
Mar 18 2005 05:01:28:133PM1050318034Robert GranetzPlasma. Disrupted at t=1.06 s definitely due to argon radiation. But it's still
occurring too fast.

Next shot: reduce argon plenum pressure to 3 psi.
Mar 18 2005 05:17:41:853PM1050318035Robert GranetzPlasma. Disrupted at 1.10 s, again due to argon radiation (and maybe some non-linear
MHD triggered by the argon).

End of run

Engineering Operator Comments
ShotTimeTypeStatusComment
109:07:40:607AMPlasmaOk
209:28:43:060AMPlasmaOk
309:43:38:480AMPlasmaOk
410:01:48:620AMPlasmaOk
510:17:59:887AMPlasmaOk
610:30:55:107AMPlasmaOk
710:45:28:390AMPlasmaOk
811:07:32:107AMPlasmaOk
911:21:19:920AMPlasmaOk
1011:35:58:043AMPlasmaOk
1111:48:39:317AMPlasmaOk
1212:01:44:477PMPlasmaOk
1312:16:40:383PMPlasmaOk
1412:29:12:570PMPlasmaBadComputer problem
1512:46:25:587PMPlasmaOk
1601:00:37:040PMPlasmaOk
1701:12:57:460PMPlasmaOk
1801:27:04:790PMPlasmaOk
1901:39:32:150PMPlasmaOk
2001:52:13:477PMPlasmaOk
2102:04:56:930PMPlasmaOk
2202:17:53:260PMPlasmaOk
2302:31:09:087PMPlasmaOk
2402:46:35:680PMPlasmaOk
2502:59:23:367PMPlasmaOk
2603:12:31:353PMPlasmaOk
2703:25:02:430PMPlasmaOk
2803:37:28:663PMPlasmaOk
2903:49:53:913PMPlasmaOk
3004:03:24:040PMPlasmaOk
3104:15:50:477PMPlasmaOk
3204:28:10:900PMPlasmaOk
3304:43:55:290PMPlasmaOk
3404:56:18:227PMPlasmaOk
3505:08:50:307PMPlasmaOk