High Power Helicon (HPH) - University of...
Transcript of High Power Helicon (HPH) - University of...
High Power Helicon (HPH)J. Prager*; T. Ziemba; R. Winglee; J. Slough; J. Carscadden
*Department of Earth and Space SciencesUniversity of WashingtonSeattle, WA 98195-1310
- 14 Isolated Gate Bipolar Transistors (IGBTs) in parallel- IGBT rating: 250 A and 1200 V- Peak Antenna currents > 2 kA- Frequency range: 0.3 - 1.1 MHz- Standard Operation: 600 kHz- Charging Capacity: 7.9 mF- Shot length: 35 - 400 µs
Antenna Current
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0
1000
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-50.00 0.00 50.00 100.00 150.00 200.00time (us)
Curre
nt (A
)
- m = +1 antenna- diameter = 7 cm- length = 15 cm- Six magnets produce DC field (typical: 130, 260, 390 G)- Gas: H, He, N, Ar, Xe, Ne (Ar typical)- Plasma accelerated in downstream direction only
HPH Source
HPH Power Supply
DC Magnetic field
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Int. Langmuir Face Planar Midstream Planar
DownstreamPlanar
RFA
Magnetic Field - Side View
Magnetic Field - Top View
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Impacts Side of ChamberConnects to Ambient Earth Magnetic Field
On Axis Magnetic Field (Axial Direction)
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0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8Distance (meters)
Mag
net
ic F
ield
(G
)
390 Gauss260 Gauss130 Gauss
Face Planar Midstream Planar cm
DownstreamPlanar
RFA
Power Deposition Data
Radial Planar Probe Data
Face Planar Peak Density
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Prob
e C
urre
nt
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Midstream Radial Profile
0.000
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0.010
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0.035
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-5.0 0.0 5.0 10.0 15.0 20.0 25.0Distance (cm)
Prob
e C
urre
nt
130 Gauss260 Gauss390 Gauss
Boron nitride cover and back plateTungsten stinger
Tungsten ion collector
- Distribution peaked on axis- FWHM decreases with field strength
Future WorkFuture Work- Measure thrust of HPH on a thrust stand- Measure power and downstream properties in dual coil mode- Design gas feed for more efficient gas handling in DC or amplitude modulated operation- Continue optimization and performance characterization- Test and characterize pre-ionizer-Study downstream magnetic properties
- Measure thrust of HPH on a thrust stand- Measure power and downstream properties in dual coil mode- Design gas feed for more efficient gas handling in DC or amplitude modulated operation- Continue optimization and performance characterization- Test and characterize pre-ionizer-Study downstream magnetic properties
This presentation includes contributions from Race Roberson, Nathan Stobie, Gregory Quetin, and Joni DeBoever
This presentation includes contributions from Race Roberson, Nathan Stobie, Gregory Quetin, and Joni DeBoever
100 us
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Discriminator Voltage
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115 us
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130 us
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rgy
Dis
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utio
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145 us
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rgy
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160 us
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rgy
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utio
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175 us
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Retarding Field Analyzer (RFA) Data
- Data at 390 G & 75 kW peak power- Dual peak energy distribution- Average energy = 35 eV (for Ar)
- 5 nickel grids (55% transparency)- 24.9 mm x 19.5 mm x12 mm- Orafice 2.6 mm in diameter
Peak Power
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100 150 200 250 300 350 400 450 500 550Charging Voltage (V)
Peak
Pow
er (k
W)
130 G260 G390 G
Peak Power vs. Field
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0 50 100 150 200 250 300 350 400 450Magnetic Field (gauss)
Inpu
t Pow
er (K
W)
400 V450 V500 V425 V475 V
Source Plasma Density
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0 20 40 60 80 100 120Peak Power (kW)
Peak
Den
sity
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020 m
-3)
130 G260 G390 G
Isp Measurement: Time of Flight (130 G)
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0 10 20 30 40 50 60 70 80Power (kW)
Isp
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- Input power is calculated from a direct measurement of the antenna current and voltage- 100 kW peak power deposition into the plasma- Source density > 1020 m-3
- Isp increases with increasing power; no saturation has been observed- Input power scales with base magentic field strength- Source density saturates as power increases
Charging CapIGBT Switch
Gate Switch
Antenna Tuning Caps
Plasma
DumpResistor
Charging Supply
SnubbingCircuit
HPH Power Supply
RFA Probe Current: Time Profile
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Time (us)
Prob
e C
urre
nt 0 V18 V36 V54 V70 V