Premium
Polarization of auroral backscatter at 50 MHz
Author(s) -
Hussey G. C.,
Koehler J. A.,
Sofko G. J.
Publication year - 1997
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/96rs03315
Subject(s) - scattering , polarization (electrochemistry) , physics , linear polarization , optics , faraday effect , coherent backscattering , backscatter (email) , incoherent scatter , computational physics , radar , polarimetry , stokes parameters , magnetic field , telecommunications , chemistry , computer science , wireless , laser , quantum mechanics
Auroral backscatter from the lower E region was studied using two 50 MHz bistatic, continuous wave radar links which shared a common polarimetric receiver. The polarization parameters were defined in terms of the polarization ellipse, which is described by the ellipticity angle χ orientation angle ψ , and polarization ratio m . Spectral analysis was applied to the intensity measurements and its corresponding polarization parameters. Observations of typical auroral spectral types 1, 2, and 3 indicated that the scattering of a linearly polarized incident wave produced an essentially linear and highly polarized scattered wave. These results imply a small scattering volume and/or a small number of discrete scatterers located close to one another, “scatterer” referring to a volume where radar waves are scattered according to weak coherent scattering theory, and also reaffirms that the scattering process is a weak coherent one. These results are typical of most observations, but not all; an otherwise typical intensity spectrum may also exhibit variable polarization parameters with an appreciable reduction in the polarization ratio and/or signals of significant ellipticity. These anomalous properties can be explained as scatter coming from a number of individual scattering volumes within the scattering region (i.e., the effective radar viewing region), which are each influenced differently by Faraday rotation to and from the scattering region.