Energy Conversion & Loss Processes of Heavy gas FRCs Heavy-gas FRCs D J h LR Dr. Joshua L. Rovey Assistant Professor of Aerospace Engineering Mi iU i it fSi &T h l Missouri University of Science & T echnology (formerly University of Missouri-Rolla) Presented to: AFOSR Contractors Meeting, Arlington, VA May 12 th , 2010
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Energy Conversion & Loss Processes of Heavy gas FRCsHeavy-gas FRCs
D J h L RDr. Joshua L. RoveyAssistant Professor of Aerospace EngineeringMi i U i it f S i & T h lMissouri University of Science & Technology
(formerly University of Missouri-Rolla)
Presented to:AFOSR Contractors Meeting, Arlington, VA
May 12th, 2010
Project Main Focus
M i F Pl id f ti h i i h
Plasmoid Propelled Spacecraft
• Main Focus: Plasmoid formation physics in heavy gases– What are the collisional, radiative, transport properties during
formation of heavy-gas plasmoids?formation of heavy gas plasmoids?– How do they evolve during formation?– What are the major loss mechanisms, limiting ion production?– Methods or design features to reduce losses?
Motivation
• Higher Power Thruster10’s 100’s of kW– 10 s – 100 s of kW
– We have the technology– Costs mass
100
1000
10 MW
• Lower Specific Alpha0 1
1
10
Thru
st (N
) 1 MW
HET Ion100 kW
Plasmoid Thruster
– less kg mass per unit power
0 001
0.01
0.1T
1 kW
Ion10 kW
0.1 kWP 0.001
1032 3 4 5 6 7
1042 3 4 5 6 7
105
Specific Impulse (sec)
jet
input
PP
input jet ionization therm lossP P P P P
Plan of Attack
1. Design & develop a device that repeatably forms heavy-gas plasmoidsy g p
– No need for expulsion– Cylindrical theta pinch geometry
2 Characteri e sing time resol ed diagnostics2. Characterize using time-resolved diagnostics– Standard diagnostics: triple probe, Bdot, flux loops, wall
• Snowplow Model– As plasma compressed, mass entrained– Equation of motion includes pressure and magnetic force
Magnetic force d e to changing ind ctance both M and L– Magnetic force due to changing inductance, both M and L– Initial assumption, adiabatic compression
d d 2magd drm f p rdt dt
rdW dr
rdWFmag
constpV
Future Research Plan
• Focus : Plasmoid formation processes in heavy gases
• Ionization, excitationC i h i• Compression, heating
• Radiation, transport
E t bli h d t di f h l id• Establish understanding of heavy gas plasmoid energy conversion and loss processes
• Ion production efficiency • Efficient conversion of electrical energy to
thrust; minimize Etherm and Elosses
Overall Program Approach
Plasmoid Program
Experiment Numerical Modeling
i S CMPX Test Article
Plasma Properties
PrismSPECTcollisional-radiative
MOQUI?pTriple probe MOQUI?
Emission SpectraFast spectrometer
Dynamic Circuit-Plasma ModelsFast spectrometer
Total Radiation FluxPhotodiodes
Plasma Models
APLab Research Program Goal:Determine the major formation
Plasma TransportElectrostatic wall probes
physics for heavy gas plasmoids and the main loss mechanisms
– Photodiode/bolometer• Analysis of spectra using y p g
PrismSPECT• Abel inversion technique
l i di l filanalysis – radial profiles• Symmetry? Radial
variation using topvariation using top chords agree with bottom?
Timeline
• Year 1 – device design, setup, operation with standard probes• Year 2 spectroscopy techniques & analysis development• Year 2 – spectroscopy techniques & analysis development• Year 3 – data comparison with models, effects of heavy gas