The Current and Field Distribution of a High Power Satellite Antenna Affected by Nonlinear Plasma Sheath Phenomena,
DEUTSCHE FORSCHUNGS- UND VERSUCHSANSTALT FUER LUFT- UND RAUMFAHRT E V OBERPFAF FENHOFEN (GERMANY F R)
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For electromagnetic adn acoustic radiation from antennas in a plasma environment the fundamental electro- and hydrodynamic equations are presented involving nonlinear source terms up to the third order. A perturbation procedure is applied to derive a numerical solution from a set of coupled integral equations for the linearized first-order magnetic field and electron density describing the dipole radiation into a homogeneous compressible plasma. The solution is given in terms of an equivalent surface current density based on a Greens function representation. An electron absorption coefficient is introduced to account for plasma-antenna surface interactions. Due to nonlinear ponderomotive forces an inhomogeneous plasma sheath is shown to build up around the dipole, where the antenna-to-plasma coupling turns out to be strongest in the near-field feeding zone of a high power transmitting antenna. The linearized field and density are taken along with the nonlinear source terms to determine the higher-order fields for antenna characteristics such as the input impedance. Numerical results are discussed for an electrically short dipole embedded in an ionospheric plasma.
- Unmanned Spacecraft