
Accession Number : ADP005707
Title : The Current and Field Distribution of a High Power Satellite Antenna Affected by Nonlinear Plasma Sheath Phenomena,
Corporate Author : DEUTSCHE FORSCHUNGS UND VERSUCHSANSTALT FUER LUFT UND RAUMFAHRT E V OBERPFAF FENHOFEN (GERMANY F R)
Personal Author(s) : Bethke, K. H. ; Edenhofer, P.
Report Date : MAY 1987
Pagination or Media Count : 10
Abstract : 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 (firstorder) 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 Green's function representation. An electron absorption coefficient is introduced to account for plasmaantenna surface interactions. Due to nonlinear ponderomotive forces an inhomogeneous plasma sheath is shown to build up around the dipole, where the antennatoplasma coupling turns out to be strongest in the nearfield (feeding zone) of a high power transmitting antenna. The linearized field and density are taken along with the nonlinear source terms to determine the higherorder fields for antenna characteristics such as the input impedance. Numerical results are discussed for an electrically short dipole embedded in an ionospheric plasma.
Descriptors : *SPACECRAFT ANTENNAS, *PLASMA SHEATHS, DIPOLES, IONOSPHERE, ELECTRIC FIELDS, NEAR FIELD, NONLINEAR ANALYSIS, INTEGRAL EQUATIONS, MAGNETIC FIELDS, ELECTRON DENSITY, ABSORPTION COEFFICIENTS, ELECTRONS, COUPLING(INTERACTION), WEST GERMANY.
Subject Categories : Unmanned Spacecraft
Distribution Statement : APPROVED FOR PUBLIC RELEASE