Alcator C-Mod Run 1051108 Information

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Miniproposals
Miniproposal:265
Date Filed: 4/7/2000
Title:CXRS Commissioning
First Author:E.C. Eisner
Session Leader:Bill Rowan (shots 1-32)
Miniproposal:431
Date Filed: 7/28/2005
Title:Measurement of Faraday Rotation in MSE Optics Using Invessel Polarizer
First Author:Jin-Seok Ko
Session Leader:Steve Scott (shots 15-32)

Operators
Session leader(s):Bill Rowan,Steve Scott
Physics operator(s):Bill Rowan
Engineering operator(s):Bill Cochran,Bill Parkin

Engineering Operator Run Comment
MP 265 CXRS Commissioning. MP 431 Faraday Rotation in MSE Optics.

Session Leader Plans

Physics Operators Plans
Entered: Nov 7 2005 05:15:29:730PM
Author: Bill Rowan
Engineering Setup and Run Plan for Tuesday 8-Nov-2005

MP 265 CXRS Commissioning. Session Leader: Rowan
MP 431 Faraday Rotation in MSE Optics. Session Leader: Ko/Scott

Physics operator: Rowan

Overnight ECDC in D2, and bake at 60 C.

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

Power systems as on 1051104028 (1.0 MA fiducial, 5.4 T, lower single null)

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 Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
leave NINJA as is DISABLED

Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters

Torvac setup: Gate valves open

DNB WILL BE REQUIRED FOR THIS RUN

Start with MP 265. Vary density over the nl_04 range 0.5 to 1.0E+20.
Vary the DNB voltage from 40 kV to 50 kV. The goal is to verify the photon
emission cross sections that are used for inference of B+5 density from
CXRS emission. This will be completed in less than 10 shots.

Continue with MP 431.
BT ramps based on the setup for shot 1050718004
IP ramps based on the setup for shot 1050629023

Session Leader Summaries
Entered: Nov 8 2005 06:26:23:910PM
Author: Bill Rowan
For MP 265, the cxrs photon emission cross section dependence on beam energy
was measured. The initial, rough analysis of the beam energy scan is that the
cross section for charge exchange recombination between the beam neutrals and
BVI is not simply described by an interaction of fully stripped boron with full
energy hydrogen neutrals in the n=1 state. At least at the high energy end of
the scan, other energy components contribute. From the lower energy part of the
scan it is appears that hydrogen beam neutrals in states with n>1 contribute to
the emission. Of course, this interpretation may change somewhat when a
quantitative analysis replaces this qualitative one.

During this experiment, the beam ran well over the energy range from 30 kV to
50 kV. After the neutralizer but before entering the duct, the main energy
component density is approximately 19%. The water component seems high at
approximately 36% but the beam runs well (that is, without faults) in spite of
that.

Entered: Nov 17 2005 10:01:06:603AM
Author: Steve Scott
We successfully completed MP431 to measure the Faraday rotation (or lack of it) in the MSE optics.
The procedure is simple: position a linear polarizer immediately in front of MSE's plasma-facing
lens, and illuminate it with light from an Ohmic plasma.

The light incident on MSE therefore has a
fixed polarization direction. So any changes in the measured polarization direction are presumably
due to Faraday rotation. In this miniproposal, we created plasmas with a Bt ramp at constant Ip,
an Ip ramp at constant Bt, and also reference plasmas with a long flattop on both Bt and Ip.

Shots 20 and 24 have a BT ramp at constant Ip, to look for Faraday rotation in lens L1 due to the
toroidal field. Shots 27 and 29 have an Ip ramp at constant Bt, to look for Faraday rotation in the other
optical elements due to the vertical and/or radial field. Shots 18 and 19 are reference shots
with a long Ip and Bt flattop.

The initial results seem to indicate that there is very little, if any, Faraday rotation in the
MSE optical sytem.

Physics Operator Summaries
Entered: Nov 8 2005 06:07:14:220PM
Author: Bill Rowan
The goals of both miniproposals were accomplished. For MP 265, the cxrs photon
emission cross section dependence on beam energy was measured. During
this experiment, the beam ran well over the energy range of 30 kV to 50 kV.
After the neutralizer and before entering the duct, the water component density
is approximately 36% and the main energy component density is approximately
19%. The water component seems high but the beam runs well in spite of that.
For MP 431, the Faraday rotation in the MSE optics was measured. For both, see
the SL summaries. The last few shots were used to look at the sensitivity of
Alex Ince-Cushman's poloidal rotation diagnostic.

There were problems with duds and fizzles although fields (BR and BZ) looked
okay. By the end of the run, the prefill pulse had been increased to 40 ms to
get full length discharges. The prefill was increased first in response to
duds and then in responsed to fizzles with bounces.

Score card

Plasmas: 19 (001,003,004,006,011,012,013,014,015,016,018,019,020,024,025,027,
029,031,032)
Fizzles: 6 (017,021,022,023,028,030)
Duds: 6 (002,005,007,008,009,010)
No power: 1 (026, action monitor fault)
---------
Total: 32


Session Leader Comments
Nov 8 2005 03:20:47:220PMSteve Scottgood Bt ramp shot (condition #2 in the miniproposal).
We will take one repeat.
Note that this shot doesn't have quite the same Bt waveform as shot 20.
Nov 8 2005 12:39:23:100PM1051108015Steve ScottWe will be starting with condition "1" of table 1 of MP431 (page 8). This will be a
5.4 Tesla, 0.5 MA shot with a long Ip and BT flattop.
Nov 8 2005 12:51:58:380PM1051108016Steve ScottTry again for condition "1": flattop Bt + Ip 5.4 T, 0.5 MA
Nov 8 2005 01:22:28:990PM1051108017Steve ScottTrying again for condition "1", but got a fizzle.
Nov 8 2005 02:10:10:003PM1051108019Steve Scottrepeat condition #1 after a cell access to adjust position of the MSE
wire grid polarizer. nominally this should be a repeat of shot 18.
This shot had lots of runaways.
Nov 8 2005 02:42:40:973PM1051108021Steve ScottAttempt repeat of the condition #2 = Bt ramp at fixed Ip. got a fizzle.
Nov 8 2005 04:32:48:940PM1051108022Steve ScottFizzle.
Nov 8 2005 04:33:46:067PM1051108024Steve ScottGood Bt ramp shot
Nov 8 2005 03:30:57:877PM1051108025Steve ScottTried for a third shot with the Bt ramp, but got another fizzle. So we'll declare
victory here, and for the next shot we'll try an Ip ramp at fixed Bt.
Nov 8 2005 04:44:07:660PM1051108029Steve Scottgood shot with Ip ramp. this is the nominal end of the MP431 ... now take a few shots
for neon puffing studies.
Nov 8 2005 04:56:03:503PM1051108031Steve Scottgood 1MA shot.

Physics Operator Comments
Nov 8 2005 08:32:02:837AMBill RowanBefore the run, a heater cable was found to be damaged. The connector was burned. We will procede without that heater.

loaded 1051104028

Nov 8 2005 09:16:23:117AM1051108001Bill Rowan001. Plasma. full length. nel_04=1.0. beam at 0.5 s

Next shot. Move the beam to 1.0s
No pcs changes

Nov 8 2005 09:39:49:930AM1051108002Bill Rowan002. Dud

Next shot. Add 1 ms to prefill puff. now 26 ms

Nov 8 2005 09:51:52:117AM1051108003Bill Rowan
003. Plasma.

Next shot. Attempt to reduce density to nl_04=8e+19

Nov 8 2005 10:08:57:337AM1051108004Bill Rowan004. Plasma. nl_04 = 0.77e+20

Next shot. Attempt to reduce the density again to nl_04=0.6e+20

Nov 8 2005 10:20:52:490AM1051108005Bill Rowan005. Dud.

Next shot. Add 1 ms to prefill puff. Now 27 ms

Nov 8 2005 10:39:48:163AM1051108006Bill Rowan006. Plasma. nel04=0.57e+20

Next shot. nl_04=0.8e+20


Nov 8 2005 10:57:33:040AM1051108007Bill Rowan007. Dud

Next shot. EF4 more positive. change from -1340 to -1335

Nov 8 2005 11:09:35:303AM1051108008Bill Rowan008. Dud

Next shot. Add 1 ms to prefill puff. Now 28 ms

Nov 8 2005 11:24:43:460AM1051108009Bill Rowan009. Dud

Next shot. EF4 more negative. change from -1335 to -1340 (starting value for the day)
Add 1 ms to prefill puff. Now 29 ms.

Nov 8 2005 11:39:01:180AM1051108010Bill Rowan010. dud

Next shot. Increase prefill puff to 32 ms

Nov 8 2005 11:57:37:740AM1051108011Bill Rowan011. Plasma

Next shot. Increase prefill puff to 34 ms
Enabled B-side lower. PG1. On at 0.3 s for 40 ms

Nov 8 2005 12:04:39:397PM1051108012Bill Rowan012. Plasma

Next shot. Increase prefill puff to 35 ms

Nov 8 2005 12:32:12:337PM1051108013Bill Rowan013. Plasma

Next shot. No pcs changes

Nov 8 2005 12:44:06:290PM1051108014Bill Rowan014. Plasma

Last shot for this experiment.

Next shot.
start mp 431
Steve Scott is SL
reloaded segment 2 from 1050718004
recalculated the magnetics predictors as required
load/clean

Nov 8 2005 01:13:32:587PM1051108015Bill Rowan015. Plasma

Next shot.
BT=5.4T
IP=500 kA

Nov 8 2005 01:13:11:773PM1051108016Bill Rowan016. IP reduced to 500 kA
BT flattened at 5.4 T
Disruption at 0.5 s.

Next shot.
Reduce the density demand to 0.5e+20
Disable B-side lower

Nov 8 2005 01:18:19:397PM1051108017Bill Rowan017. Fizzle.
Post disruption fizzle.

Next shot.
Reduce the prefill by 1 ms to 34 ms

Nov 8 2005 01:38:30:170PM1051108018Bill Rowan018. Plasma

Cell access after this shot for MSE

Next shot. No PCS changes

Nov 8 2005 02:19:52:847PM1051108019Bill Rowan019. Plasma

Next shot. Increase prefill by 1 ms to 35 ms
BT to 6.5 T at the beginning of segment 2. Then ramp to 3 T by 1.5 s


Nov 8 2005 02:28:30:300PM1051108020Bill Rowan020. Plasma

Next shot.
Trim the BT ramping. Obtain 6.5 T early the shot and then ramp to 2.5 T by 1.5 s

Nov 8 2005 02:30:27:957PM1051108020Bill RowanIncrease prefill by 1 ms to 36 ms

Nov 8 2005 02:37:13:190PM1051108021Bill Rowan021. Fizzle

Next shot.
Reduce the prefill by 1 ms to 35 ms

Nov 8 2005 02:51:52:800PM1051108022Bill Rowan022. Fizzle

Next shot.
Increase the prefill by 3 ms to 38 ms.

Nov 8 2005 03:11:36:923PM1051108023Bill Rowan023. Fizzle

Next shot.
Increase the prefill by 2 ms to 40 ms

Nov 8 2005 03:17:17:893PM1051108024Bill Rowan024. Plasma

Next shot: No pcs changes

Nov 8 2005 03:37:56:127PM1051108025Bill Rowan025. Plasma

Next shot.
Bt constant at 5.4 T
IP ramp from 1 MA down to 0.3 MA at 1.5 s
Reload 1051108014 and put in the IP ramp

Nov 8 2005 03:51:48:393PM1051108026Bill Rowan026. No power shot. Action monitor did not start

Next shot. No pcs changes

Nov 8 2005 03:58:46:237PM1051108027Bill Rowan027, Plasma

Next shot. No PCS changes.

Nov 8 2005 04:13:49:207PM1051108028Bill Rowan028. Fizzle

Next shot. No PCS changes

Nov 8 2005 06:04:25:940PM1051108029Bill Rowan029. Plasma.

End of the MSE run.
Nov 8 2005 04:39:58:347PM1051108030Bill Rowan030. Fizzle

Next shot.
EF4: -1340 to -1330


Nov 8 2005 04:53:03:033PM1051108031Bill Rowan031. Plasma

Next shot.
Increase PG1 to 120 ms

Nov 8 2005 05:50:27:393PM1051108032Bill Rowan032. Plasma

End of the run

Engineering Operator Comments
ShotTimeTypeStatusComment
109:04:23:757AMPlasmaOk
209:26:46:257AMPlasmaOk
309:41:26:790AMPlasmaOk
409:58:27:930AMPlasmaOk
510:14:10:837AMPlasmaOk
610:27:49:710AMPlasmaOk
710:52:18:257AMPlasmaOk
811:05:56:320AMPlasmaOk
911:19:02:617AMPlasmaOk
1011:33:00:490AMPlasmaOk
1111:46:05:663AMPlasmaOk
1211:59:26:837AMPlasmaOk
1312:14:13:193PMPlasmaOk
1412:29:35:663PMPlasmaOk
1512:45:29:087PMPlasmaOk
1612:58:39:117PMPlasmaOk
1701:13:30:710PMPlasmaOk
1801:26:36:290PMPlasmaOk
1902:04:24:707PMPlasmaOk
2002:20:37:783PMPlasmaOk
2102:34:06:207PMPlasmaOk
2202:47:17:800PMPlasmaOk
2303:00:23:473PMPlasmaOk
2403:13:29:470PMPlasmaOk
2503:26:53:847PMPlasmaOk
2603:44:33:723PMPlasmaBadno power shot, actiom monitor hung up.
2703:56:04:940PMPlasmaOk
2804:09:28:020PMPlasmaOk
2904:22:26:363PMPlasmaOk
3004:35:39:267PMPlasmaOk
3104:48:25:143PMPlasmaOk
3205:01:11:817PMPlasmaOk