Alcator C-Mod Run 1051205 Information

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Miniproposals
Miniproposal:441
Date Filed:11/18/2005
Title:ICRF Coupling studies on J-port antenna
First Author:Steve Wukitch
Session Leader:Alexandre Parisot (shots 1-35)

Operators
Session leader(s):Alexandre Parisot
Physics operator(s):Joseph Snipes
Engineering operator(s):Bill Cochran,Ed Fitzgerald,Bill Byford

Engineering Operator Run Comment
MP 441 ICRF Coupling studies on J-port antenna

Session Leader Plans
Entered: Dec 2 2005 03:59:34:443PM
Author: Alexandre Parisot
SL-plan Monday 05-Dec-2005

MP 441 ICRF Coupling studies on J-port antenna

Session leader: A. Parisot
Physics operator: J. Snipes

ICRF Setup: All transmitters to run-on by 8:30 am.

Important Diagnostics: A-port, F-port scanning probes, edge and core Thomson.

Goal:
Simultanously obtain ICRF coupling measurements for J-port antenna and radial density profiles in the core, edge, and SOL, in low ICRF power discharges. This experiment is similar to that run with D and E antennas in 1031120.

Plan:
Start with LSN 1031120030.
1. L-mode discharges: 5.4T, scan current and density (9 discharges),
ip = 600 kA, 900 kA, 1.2 MA ; nl04 = .7, .9, 1.1 (e20 m-2)
with J-port in (0,pi,0,pi) 500 kW total, and probes insertions at 0.75, 0.95 and 1.15 sec
2. Repeat ip = 900 kA, nl04 = .9 with
(i) (0,0,0,0) phasing for J-port,
(ii) J3 only (500 kW)
(iii) J4 only (500 kW)
3. H-mode discharges: change field to 5.2 T, scan current and density (9 discharges),
ip = 600 kA, 900 kA, 1.2 MA ; nl04 = .7, .9, 1.1 (e20 m-2)
with J-port in (0,pi,0,pi) 500 kW total, D and E antennas 500 kW total,
and probes insertions at 0.75, 0.95 and 1.15 sec
4. Repeat ip = 900 kA, nl04 = .9 with
(i) (0,0,0,0) phasing for J-port,
(ii) J3 only (500 kW)
(iii) J4 only (500 kW)

Time after 1.2 sec will be used for J-port antenna conditionning.
The shot sequence may be changed during the day as we equally want to collect data for all 4 topics.
In particular:
(i) No repeats if we have any trouble with a particular target - just move on to the next set of parameters. We will only repeat to adjust probe insertion and/or retune the RF.
(ii) In (3), we can tweak parameters or adjust the shot sequence depending on our ability to get H-mode at 1 MW RF power for the chosen targets. (4) will then be run with the best H-mode target we obtained.

Physics Operators Plans
Entered: Dec 2 2005 04:16:36:977PM
Author: Joseph Snipes
Engineering setup for Monday 5 Dec 2005

MP 441 ICRF Coupling studies on J-port antenna

Session leader: A. Parisot
Physics operator: J. Snipes

Overnight ECDC in ** HELIUM ** and bake at 60 C from Saturday night until two hours
before the run.

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

Power systems as on 1031120030 except C_COIL start time needs to be set to 0.3 s.

A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar + 2 psi Ne Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
fill NINJA with 10 psi D2 Leave DISABLED

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

Torvac setup: Gate valves open

No between-shot boronization.

Key diagnostics: A-port, F-port scanning probes, edge and core Thomson.


-------------------------------------------------------------------------------
ICRF Setup: All transmitters to run-on by 8:30 am.
-------------------------------------------------------------------------------
Run plan: Start by copying 1031120030 a lower single null discharge.
Then, run a series of low RF power L-mode plasmas varying Ip and nel.
Then, run a series of low power H-mode plasmas and again vary Ip and nel.
J-port phasing will also be changed from (0,pi,0,pi) to (0,0,0,0).
Compare J-port, D and E port coupling measurements and density profiles
in the core, edge, and SOL.

Session Leader Summaries
Entered: Dec 5 2005 05:25:42:820PM
Author: Alexandre Parisot
We covered most of the parameter space requested by the miniproposal today, despite a somewhat limited number of plasmas. Good data was collected from the probes and the Thomson, with J-port on and in L-mode and H-mode. We also obtained good data with (0,0,0,0) phasing, which will be useful to characterize the impedance matrix for the antenna.

We skipped over the low density/low current discharges as we ran into MARFEs and J-port was not running due to high neutral pressure. We obtained the desired targets for 900 kA and 1.2 MA and of the plasmas went to H-mode with only 500 kW from J-port. Having collected some good L-mode and H-mode data by shot 13, we decided to obtain more data points with (0,0,0,0) phasing than originally planned.

In the second half of the run, we obtained comparison shots between (0,0,0,0) and (0,pi,0,pi) phasings at 1.2 MA and 900 kA for low and high target densities. Plasmas went in and out of H-mode at higher currents, so that the profiles will have to be analyzed with care. Good L-mode comparisons were obtained. On most of those shots, D and E were also on, so that we can analyze the same discharges for D/E for comparison

Shot Ip nl04 L/H mode J-port phasing D&E
002 600kA 0.7 L L L (0,pi,0,pi)
004 900kA 0.7 L L H (0,pi,0,pi)
005 900kA 0.9 L L L (0,pi,0,pi)
007 900kA 1.1 L L L (0,pi,0,pi)
008 1.2MA 0.7 L * * (0,pi,0,pi)
010 1.2MA 0.7 L H H (0,pi,0,pi)
012 1.2MA 0.9 L H H (0,pi,0,pi)
013 1.2MA 1.1 L L L (0,pi,0,pi)
015 1.2MA 1.1 L L H (0,pi,0,pi) 500 kW
017 1.2MA 1.1 L L L J4 only 500 kW
019 1.2MA 1.1 L L L (0,0,0,0) 500 kW
022 1.2MA 0.7 L * * (0,0,0,0) 500 kW
024 1.2MA 0.7 L H ? (0,0,0,0) 500 kW
028 1.2MA 0.7 L H H (0,pi,0,pi) 500 kW
029 900kA 0.7 L H ? (0,pi,0,pi) 500 kW
030 900kA 0.7 L L L (0,0,0,0) 500 kW
031 900kA 1.1 L L L (0,0,0,0) 250 kW
034 900kA 1.1 L L L (0,pi,0,pi) 250 kW








Physics Operator Summaries
Entered: Dec 5 2005 05:05:45:257PM
Author: Joseph Snipes
The run started out fine, but then there were a series of fizzles and duds that plagued the run. Nonetheless,
a number of physics results were obtained. See the session leader's summary for those results. It was not
clear why there were so many fizzles and duds, but the machine seemed to be very sensitive to the gas evolving
from the walls after disruptions and there were also some unexplained changes in Bz that were difficult to
anticipate. A number of shots had large OH resistance values in the range of
2.5 to 2.8 uOhms when following a fizzle or dud. Since the values did not get
worse during the run, we decided to proceed with caution.
Despite these difficulties, we managed to get 22 plasmas out of 35 shots.
Shot,Duration(s),Ipmax(MA),Result Shot,Duration(s),Ipmax,Result
| 01 1.988 0.680 Plasma | 02 1.989 0.684 Plasma |
| 03 1.464 0.700 Plasma | 04 1.987 0.910 Plasma |
| 05 1.957 0.905 Plasma | 06 0.000 0.033 Fizzle |
| 07 1.948 0.905 Plasma | 08 1.981 1.206 Plasma |
| 09 0.036 0.108 Fizzle | 10 1.515 1.207 Plasma |
| 11 0.000 0.025 Fizzle | 12 1.968 1.203 Plasma |
| 13 1.908 1.193 Plasma | 14 0.000 0.025 Fizzle |
| 15 1.904 1.197 Plasma | 16 0.000 0.024 Fizzle |
| 17 1.897 1.194 Plasma | 18 1.897 1.193 Plasma |
| 19 1.594 1.193 Plasma | 20 0.000 0.024 Dud |
| 21 0.000 0.024 Fizzle | 22 1.986 1.206 Plasma |
| 23 1.978 1.206 Plasma | 24 1.982 1.204 Plasma |
| 25 0.000 0.026 Dud | 26 0.000 0.023 Dud |
| 27 0.000 0.023 Fizzle | 28 1.981 1.209 Plasma |
| 29 1.972 0.913 Plasma | 30 1.977 0.909 Plasma |
| 31 1.890 0.899 Plasma | 32 0.000 0.025 Fizzle |
| 33 0.000 0.024 Fizzle | 34 1.475 0.940 Plasma |
| 35 0.000 0.027 Fizzle
Date 1051205: 35 shots. 22 plasmas. 10 fizzles. 3 duds. 0 System Error.

Session Leader Comments
Dec 5 2005 09:28:00:100AM1051205001Alexandre ParisotRequest: LSN, 5.1T, 600kA, nl04 = 0.7 (copy from shot 1031120030)

Plasma. Lots of runaways. J ran all the way at 500 kW. nl04 at 0.6.
This is a good target.

Next: Change Bt to 5.3T to put J-port on axis. Now we can put the probes in.


Dec 5 2005 09:47:04:257AM1051205002Alexandre ParisotRequest: LSN, 5.3T, 600kA, nl04 = 0.7, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP)

Plasma. Probe data looks OK.

Next: Go to nl04 ~ 0.9
Dec 5 2005 10:01:22:490AM1051205003Alexandre ParisotRequest: LSN, 5.3T, 600kA, nl04 = 0.9, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP)

Plasma. Big MARFE. J-port did not run, neutral pressure exceeded limit.
There is no point trying higher densities, so we just skip the two high density 600kA targets and move on to the next target.

Next: Go to 900 kA, nl04 = 0.7
Dec 5 2005 10:15:59:223AM1051205004Alexandre ParisotRequest: LSN, 5.3T, 900kA, nl04 = 0.7, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Plasma. 2 H-modes before 1.2 sec.
Good probe data from ASP. 1.15sec insertion is in H-mode.
Gap trace is flatter.

Next: Go to 900 kA, nl04 = 0.9
Dec 5 2005 10:24:19:833AM1051205005Alexandre ParisotRequest: LSN, 5.3T, 900kA, nl04 = 0.9, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Plasma. Good probe data.

Next: Go to 900 kA, nl04 = 1.1
Dec 5 2005 10:48:12:007AM1051205007Alexandre ParisotRequest: LSN, 5.3T, 900kA, nl04 = 1.1, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. J ran.

Next: 1.2 MA, nl04 = 0.7
Dec 5 2005 11:07:39:053AM1051205008Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.7, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. H-modes after 0.77 sec. RF has multiple faults.
.95 and 1.15 insertions are in H-mode, RF was off at this time.
The gap is bigger than in earlier shots. Probe and Thomson profiles connect but don't overlap at .75 sec.

Next: Repeat. Retune the RF and reduce the gap to 1.5 cm flat.
Dec 5 2005 11:38:58:193AM1051205010Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.7, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data.
.95 and 1.15s insertions are in H-mode.

Next: Go to nl04 = 0.9
Dec 5 2005 11:58:00:710AM1051205012Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.9, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data.
.95 and 1.15s insertions are in H-mode.

Next: Go to nl04 = 1.1
Dec 5 2005 12:13:28:723PM1051205013Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.9, J-port @ 500 kW .7 - 1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data.

Next: Repeat with D&E on at 250 kW each from .8 to 1.2sec.
Starting with next shot, we will work our way backwards in the scan we just did.
For each target, we will repeat with J at (0,0,0,0) phasing.
Dec 5 2005 12:34:41:600PM1051205015Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.9,
J-port @ 500 kW .7 - 1.2 sec
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data. J ran all the way.
1.15sec insertion is in H-mode

Next: Go to (0,0,0,0) phasing.

Dec 5 2005 01:02:47:647PM1051205017Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 1.1,
J-port @ 500 kW .7 - 1.2 sec
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. J-port faulted out, mismatched. No data for this shot.
The phasing is (0,~30deg,0,~30deg).

Next: Repeat. Retune J-port and try to set the digital phase so that
we have (0,0,0,0)

Dec 5 2005 01:18:11:117PM1051205018Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 1.1,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. J3 faulted out, mismatched. J4 runs alone 0.86 - 1.2 sec.

Next: Repeat. Retune J3.

Dec 5 2005 01:32:38:007PM1051205019Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 1.1,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Disrupted in rampdown.
J ran. Good probe data but no H-modes.

Next: Go to nl04 = 0.7, still with (0,0,0,0)

Dec 5 2005 02:18:18:067PM1051205022Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.7,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. 0.75sec insertion is OK.
Plasma goes in and out of H-mode after 0.83sec, RF has multiple faults.
No useful data for 0.95sec and 1.15sec.

Next: Repeat.

Dec 5 2005 02:33:14:757PM1051205023Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.7,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data but no Thomson (laser did not fire)
J-port has a couple of trips, but is on for the 3 probe insertions.
.95 and 1.15 are in H-mode.

Next: Repeat again, still with (0,0,0,0)

Dec 5 2005 02:42:53:583PM1051205024Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.7,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data for .75 and .95sec
J-port has a couple of trips, but is on for the 3 probe insertions.
.95 is in H-mode.

Next: Repeat with (0,pi,0,pi)

Dec 5 2005 03:33:38:223PM1051205028Alexandre ParisotRequest: LSN, 5.3T, 1.2 MA, nl04 = 0.7,
J-port @ 500 kW .7 - 1.2 sec (0,pi,0,pi) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good probe data for .75 and .95sec.

Next: Go to ip = 900 kA.

Dec 5 2005 03:45:36:473PM1051205029Alexandre ParisotRequest: LSN, 5.3T, 900 kA, nl04 = 0.7,
J-port @ 500 kW .7 - 1.2 sec (0,pi,0,pi) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. H-modes are longer.
Probe data looks ok for .75 and .95sec.
.95sec is in H-mode

Next: Repeat with (0,0,0,0) phasing.

Dec 5 2005 04:01:26:113PM1051205030Alexandre ParisotRequest: LSN, 5.3T, 900 kA, nl04 = 0.7,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. Good data, but the probe insertions are in L-mode.

Next: Go to nl04 = 1.1
Dec 5 2005 04:11:07:913PM1051205031Alexandre ParisotRequest: LSN, 5.3T, 900 kA, nl04 = 1.1,
J-port @ 500 kW .7 - 1.2 sec (0,0,0,0) phasing
D&E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. L-mode. D did not run.
Good probe data.

Next: Repeat with (0,pi,0,pi) phasing, with D off to have a similar shot.
Dec 5 2005 05:22:31:990PM1051205034Alexandre ParisotRequest: LSN, 5.3T, 900 kA, nl04 = 1.1,
J-port @ 500 kW .7 - 1.2 sec (0,pi,0,pi) phasing
E @ 250 kW each .8-1.2 sec
Probe insertion times: .75, .95, 1.15 sec (ASP and FSP)

Result: Plasma. L-mode.
Good probe data.

Next: Go to 600 kA, nl04 = 0.7, J-port at (0,0,0,0) phasing and D back on.

End of run.

Physics Operator Comments
Dec 5 2005 09:24:36:850AM1051205001Joseph SnipesShot 1: Copied shot 1031120030 then called all the wires involving BP coils or rogowskis including the first 8
wires and the plasma current. Set all offsets to zero. Added A-coil feedback to wire 11 and zeroed out the
A-coil preprogrammed waveform. Set Ip to -0.6 MA and nl04 to 7 x 10^19 m^-2.
Copied segment 1 from shot 1051202020. DNB is on. Got some runaways on startup, but otherwise a good shot.
The baseline of BP22_GHK did not return to zero as it should, so Wolfe is
removing it from the EFIT calculation and then re-running EFIT.
Dec 5 2005 09:40:13:067AM1051205002Joseph SnipesShot 2: Increased TF current to 147 kA. Increased prepuff by 5 ms to 37 ms duration. Good shot.
Dec 5 2005 10:02:27:117AM1051205003Joseph SnipesShot 3: Reduced prepuff by 3 ms to 34 ms duration. Changed RCUR at 1.5 s from 0.6598 m to 0.6558 m to flatten
out the outer gap at 1.5 cm. Good shot but already getting a MARFE at this density so we will move on to higher
current for shot 4.
Dec 5 2005 10:06:14:427AM1051205004Joseph SnipesShot 4: Increased Ip to -0.9 MA and reduced nl04 to 7 x 10^19 m^-2. Good shot.
Dec 5 2005 10:19:39:677AM1051205005Joseph SnipesShot 5: Increased nl04 to 9 x 10^19 m^-2. Good shot.
Dec 5 2005 10:31:47:490AM1051205006Joseph SnipesShot 6: Increased nl04 to 1.1 x 10^20 m^-2. Fizzle!
Dec 5 2005 10:44:20:020AM1051205007Joseph SnipesShot 7: Reduced prepuff by 2 ms to 32 ms duration. Good shot.
Dec 5 2005 10:56:28:740AM1051205008Joseph SnipesShot 8: Increased Ip to 1.2 MA and reduced nl04 to 7 x 10^19 m^-2. Good shot.
Dec 5 2005 11:13:59:867AM1051205009Joseph SnipesShot 9: Increased RCUR by a few mm to try to return the outer gap to 1.5 cm. Added Ar+Ne puff at 0.3 s for
35 ms duration. Fizzle!
Dec 5 2005 11:27:44:410AM1051205010Joseph SnipesShot 10: Increased prepuff by 2 ms to 34 ms duration. Still a few runaways
early, but a decent shot except that it disrupted right at the beginning
of rampdown.
Dec 5 2005 11:45:24:163AM1051205011Joseph SnipesShot 11: Increased prepuff by 2 ms to 36 ms duration. Increased nl04 to 9 x 10^19 m^-2. Fizzle!
Shots 3 and 10 had OH resistance warnings of 2.82 and 2.83 uOhm, respectively.
We've decided to proceed cautiously.
Dec 5 2005 11:55:59:820AM1051205012Joseph SnipesShot 12: Repeat. Good shot. Got another OH resistance warning at 2.77 uOhm.
Dec 5 2005 12:17:17:537PM1051205014Joseph SnipesShot 14: Repeat. Fizzle!
Dec 5 2005 12:29:11:397PM1051205015Joseph SnipesShot 15: Reduced prepuff by 2 ms to 34 ms duration. Good shot.
Dec 5 2005 12:46:06:897PM1051205016Joseph SnipesShot 16: Repeat. Fizzle!
Dec 5 2005 01:02:22:567PM1051205017Joseph SnipesShot 17: Repeat. Good shot. Only E port RF at 0.2 MW. Another OH resistance
warning at 2.777 uOhm.
Dec 5 2005 01:10:46:223PM1051205018Joseph SnipesShot 18: Reduced prepuff by 2 ms to 32 ms duration. Good shot.
Dec 5 2005 01:24:15:180PM1051205019Joseph SnipesShot 19: Changed rampdown RCUR, ZCUR, CLEARIN, RXL, ZXL, RXU, and ZXU to remain diverted into rampdown to see if
we can ramp all the way down. Did not make it through rampdown. I'll go back to what was there before.
Dec 5 2005 01:47:30:397PM1051205020Joseph SnipesShot 20: Reloaded shot 18 to get the rampdown back. Reduced nl04 to 7 x 10^19 m^-2. Dud!
Dec 5 2005 02:05:09:177PM1051205021Joseph SnipesShot 21: Increased prepuff by 2 ms to 34 ms duration. Try again. Fizzle!
OH resistance warning at 2.709 uOhms.
Dec 5 2005 02:15:44:817PM1051205022Joseph SnipesShot 22: Reduced EF4 current from -1330 A to -1340 A because Bz seems to have jumped up on the last shot. Good
shot. OH resistance warning at 2.85 uOhm.
Dec 5 2005 02:24:47:210PM1051205023Joseph SnipesShot 23: Decreased prepuff by 1 ms to 33 ms duration. Good shot.
Dec 5 2005 02:37:28:647PM1051205024Joseph SnipesShot 24: Repeat. Good shot.
Dec 5 2005 02:50:04:303PM1051205025Joseph SnipesShot 25: Repeat. Dud!
Dec 5 2005 03:02:25:723PM1051205026Joseph SnipesShot 26: Increased prepuff by 2 ms to 35 ms duration. Reduced Br0 by 0.3 mT to -0.3 mT. Try again. Dud!
Dec 5 2005 03:14:58:710PM1051205027Joseph SnipesShot 27: Bz appears to have jumped up again. So, I'm lowering the EF4 current by another 10 A to -1350 A.
Returned Br0 to 0. One more time . . . Fizzle!
Dec 5 2005 03:27:32:693PM1051205028Joseph SnipesShot 28: Very late breakdown on shot 27. Try increasing the prepuff by 2 ms to 37 ms duration. Good shot.
Dec 5 2005 03:40:07:507PM1051205029Joseph SnipesShot 29: Reduced Ip to 0.9 MA. Good shot.
Dec 5 2005 03:52:44:927PM1051205030Joseph SnipesShot 30: Increased EF4 current by 10 A to -1340 A. Good shot.
Dec 5 2005 04:06:49:210PM1051205031Joseph SnipesShot 31: Increased nl04 to 1.1 x 10^20 m^-2. Good shot. Runaways early.
Dec 5 2005 04:17:57:113PM1051205032Joseph SnipesShot 32: Repeat. Fizzle!
Dec 5 2005 04:30:44:113PM1051205033Joseph SnipesShot 33: Increase prepuff by 1 ms to 38 ms duration. Fizzle!
Dec 5 2005 04:44:01:053PM1051205034Joseph SnipesShot 34: Reduced prepuff by 3 ms to 35 ms duration. Reduced EF4 current by 10 A to -1350 A. Good shot.
Disrupted at 1.5 s.
Dec 5 2005 04:57:02:270PM1051205035Joseph SnipesShot 35: Reduced prepuff by 2 ms to 33 ms duration. Reduced Ip to 0.6 MA and reduced nl04 to 7 x 10^19 m^-2.
Fizzle!

Engineering Operator Comments
ShotTimeTypeStatusComment
109:04:00:210AMPlasmaOk
209:37:13:303AMPlasmaOk
309:51:33:833AMPlasmaOk
410:04:36:880AMPlasmaOk
510:17:20:537AMPlasmaOk
610:29:57:443AMPlasmaOk
710:42:30:930AMPlasmaOk
810:55:00:367AMPlasmaOk
911:12:28:397AMPlasmaOk
1011:24:56:350AMPlasmaOk
1111:38:07:880AMPlasmaOk
1211:50:29:787AMPlasmaOk
1312:02:53:223PMPlasmaOk
1412:15:17:130PMPlasmaOk
1512:27:36:960PMPlasmaOk
1612:44:08:333PMPlasmaOk
1712:56:32:473PMPlasmaOk
1801:09:01:537PMPlasmaOk
1901:21:34:613PMPlasmaOk
2001:45:33:007PMPlasmaOk
2101:58:02:867PMPlasmaOk
2202:10:30:020PMPlasmaOk
2302:23:16:083PMPlasmaOk
2402:35:43:553PMPlasmaOk
2502:48:19:943PMPlasmaOk
2603:00:46:287PMPlasmaOk
2703:13:24:410PMPlasmaOk
2803:25:56:990PMPlasmaOk
2903:38:37:317PMPlasmaOk
3003:51:10:723PMPlasmaOk
3104:03:50:740PMPlasmaOk
3204:16:25:037PMPlasmaOk
3304:29:10:193PMPlasmaOk
3404:41:44:053PMPlasmaOk
3504:55:29:710PMPlasmaOk