Readme.txt

Title of Paper: Massive Gas Injection Valve Development for NSTX-U 
Authors: R. Raman, G.J. Plunkett, W-S. Lay
Name of Journal: IEEE Transactions on Plasma Science
Key Words: MGI, disruption mitigation, electromagnetic, eddy current

Figure 1
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Primary components of an electromagnetic valve.


Figure 2
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Internal component drawing of the double solenoid MGI valve for NSTX-U. The valve uses two solenoids, with currents driven in opposite directions so that there is no net J x B force on the valve when it is operated in an external magnetic field.


Figure 3
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Photo showing the MGI valve for NSTX-U and the valve undergoing off-line tests on a University of Washington test stand.


Figure 4
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MGI valve installation locations on NSTX-U. Initially three valves would be installed (shown by locations 1, 2 and 3). The fourth valve at location 4 is planned for a future installation. These locations are: (1a) private flux region injection, (1b) lower scrape-off-layer and lower diverter injection, (2) conventional mid-plane injection, (3) upper diverter injection, and (4) additional location for further variations in the poloidal gas injection location.


Figure 5
MGI coil current measurements for series and parallel connection configurations. AL24: A 15 feet cable is connected to 10 feet of wire from the coil. The coils are connected in series. AL38: Same as AL24, but with the coils connected in parallel. AL08: Coils connected in series but without the 15 feet cable. The operating voltage is different for each case. A twisted pair, 14 AWG STRD 19 wire is used as the cable. The coil uses 21 turns of 1.4 mm diameter magnet wire.

The data field in each row is separated by a blank space.
There are 4 data points on each row. These are:
Time in seconds
Current through MGI valve (Amps/100) ? Configuration AL08
Current through MGI valve (Amps/100) ? Configuration AL38
Current through MGI valve (Amps/100) ? Configuration AL24


Figure 6
Nitrogen gas pressure increase in a 1.3 m3 test chamber for coils in a series configuration (AL24). The operating voltage for each case is shown next to the pressure trace and varies from 600 to 697 Volts.

The data field in each row is separated by a blank space.
There are 6 data points on each row. These are:
Time in seconds
Current through MGI valve (kA/10) at 600V
Pressure in chamber at V=600V (mTorr/100)
Pressure in chamber at V=648V (mTorr/100)
Pressure in chamber at V=697V (mTorr/100)
Pressure in chamber at V=699V (mTorr/100)


Figure 7
Nitrogen gas pressure increase in a 1.3 m3 test chamber for coils in a series configuration (AL38). The operating voltage for each case is shown next to the pressure trace and varies from 699 to 881 Volts.

The data field in each row is separated by a blank space.
There are 8 data points on each row. These are:
Time in seconds
Current through MGI valve (kA/10) at 699V
Pressure in chamber at V=699V (mTorr/100)
Pressure in chamber at V=750V (mTorr/100)
Pressure in chamber at V=799V (mTorr/100)
Pressure in chamber at V=827V (mTorr/100)
Pressure in chamber at V=853V (mTorr/100)
Pressure in chamber at V=881V (mTorr/100)


Figure 8
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Setup used for MGI valve testing in an external magnetic field. The valve is located between two solenoid coils.


Figure 9
Experimental traces from the operation of the valve with and without the presence of an external magnetic field. Shown are the current pulse duration through the solenoid and the current pulse through the gas valve pancake coils. The gas valve is discharged 10 ms after the solenoid discharge is initiated. Shown are two gas pressure traces for cases in which there was no external magnetic field. Shown also are four gas pressure traces during the presence of a 1 T external magnetic field in a configuration in which the field is parallel to the pancake solenoid surface.

The data field in each row is separated by a blank space.
There are 8 data points on each row. These are:
Time in seconds
Current through solenoid (AU) 
Current through MGI valve (AU) 
Pressure in chamber (AU) ? No magnetic field
Pressure in chamber (AU) ? No magnetic filed
Pressure in chamber (AU) -  With 1T magnetic field
Pressure in chamber (AU) -  With 1T magnetic field
Pressure in chamber (AU) -  With 1T magnetic field