Polarization dependency of transverse scattering and collisional coupling to the ambient atmosphere from meteor trails - theory and observations

Kurzfassung

Quantitative analyses of transverse scatter meteors to derive physically consistent solutions of the ambipolar diffusion coefficient, electron line density, and initial trail radius have been rare. In this manuscript, we present simulations using a full-wave scatter treatment of the transverse scatter meteor echo profiles for different background collision frequencies to account for the increase in ion-neutral and electron-neutral collisions over the typical specular meteor layer between 75-110 km. The altitude dependency of the ionneutral collision frequency was adapted from recent multi-frequency radar observations by the European Incoherent Scatter Scientific Association (EISCAT). We generate look-up tables with parallel and transverse reflection coefficients for various collision frequencies in order to investigate how this quantity alters the meteor echo profile observed at different altitudes. We analyze 33 specular meteor observations collected with the Southern Argentina Agile Meteor Radar Orbital System (SAAMER-OS). Typical detections provide information about the meteor trajectory, enabling computation of both scattering angles, as well as the determination of precise meteoroid velocities. However, with the addition of two recently installed antennas which receive each polarization direction separately, we were able to also determine the ambipolar diffusion coefficient, electron line density, and initial trail radius, by performing a qualitative fit to the collected data. Finally, we demonstrate that utilizing the polarization information of a given echo produces a similar result to that of the triple-frequency observations made using the Canadian Meteor Orbit Radar (CMOR).