COMPUTATIONAL SIMULATION OF EM ATTENUATION BY PLASMAS FORMED IN HYPERVELOCITY ATMOSPHERIC FLIGHT

The attenuation of an electromagnetic wave propagating through the hypervelocity flow field generated by an aerodynamic vehicle, is numerically investigated. The reacting flow field consisting of nitric oxide ions, free electrons, and other species is simulated using computational fluid dynamics. The Navier-Stokes equations, including a nonequilibrium air kinetics model consisting of seven species and twenty-six reactions, are solved. An electromagnet ic wave, originating from within the vehicle, is attenuated by the free electrons (plasma) in the chemically reacting flow. Attenuation analysis is performed separately (uncoupled) from the gasdynamic analysis using a series solution of Maxwell's equations valid for a long- wavelength plane wave and a thin (i.e., in comparison to wavelength) inhomogeneous plasma layer. The magnetic field, generated by the moving electrons in the plasma, is included in the analysis. The results of this study demonstrate that significant signal attenuation can occur for even weakly ionized air flows. C c

[1]  Michael G. Dunn,et al.  Theoretical and Experimental Studies of Reentry Plasmas , 1973 .

[2]  C. Park,et al.  Nonequilibrium Hypersonic Aerothermodynamics , 1989 .

[3]  Michael J. Nusca.  Numerical simulation of electromagnetic wave attenuation in nonequilibrium chemically reacting flows , 1998 .

[4]  G. Widhopf,et al.  A TVD finite-volume technique for nonequilibrium chemically reacting flows , 1988 .

[5]  Glick.  Interaction of electromagnetic waves with the plasmas of hypersonic flows , 1962 .

[6]  Harold P. Furth,et al.  Plasma diagnostics with microwaves , 1965 .

[7]  F. Albini,et al.  Reflection and transmission of electromagnetic waves at electron density gradients , 1961 .

[8]  R. Reid,et al.  The Properties of Gases and Liquids , 1977 .

[9]  Graham V. Candler,et al.  Computation of weakly ionized hypersonic flows in thermochemical nonequilibrium , 1991 .

[10]  Richard A. Thompson,et al.  A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K , 1989 .

[11]  J. Galejs.  Slot antenna impedance for plasma layers , 1964 .

[12]  J. Teare,et al.  A STREAMTUBE APPROXIMATION FOR CALCULATION OF REACTION RATES IN THE INVISCID FLOW FIELD OF HYPERSONIC OBJECTS , 1961 .

[13]  T. G. Cowling,et al.  The mathematical theory of non-uniform gases , 1939 .

[14]  Michael J. Nusca.  COMPUTATIONAL SIMULATION OF THE RAM ACCELERATOR USING A COUPLED CFD/INTERIOR-BALLISTICS APPROACH , 1997 .

[15]  C. R. Peterson,et al.  Mechanics And Thermodynamics Of Propulsion , 1965 .

[16]  J. Galejs.  Admittance of a waveguide radiating into stratified plasma , 1965 .

[17]  J. Marion,et al.  Classical Electromagnetic Radiation , 1965 .

[18]  Michael J. Nusca,et al.  ELECTROMAGNETIC WAVE ATTENUATION IN HYPERVELOCITY CHEMICALLY REACTING FLOWS , 1997 .

[19]  C. Papas.  Theory of electromagnetic wave propagation , 1965 .