Seminar
Dr Charles Carrano, Boston College ISR.
2:00pm December 2, 2014
Title: The Roles of Diffractive and Refractive Scattering in the Generation of Ionospheric Scintillation
Abstract: The purpose of this talk is to characterize the roles of refractive and diffractive processes that
contribute to the scintillation of trans-ionospheric signals, so that their signatures can be identified in
experimental measurements and used to infer the statistical structure of the random ionospheric
medium. We will begin by discussing the differences between refraction and diffraction in the context
of scintillation, and review their relative contributions to the weak and strong scattering of transionospheric satellite signals. Using ray-tracing and parabolic methods, we will quantify the
contributions from refraction and diffraction for propagation through power-law irregularities and
demonstrate the perhaps counter-intuitive notion that the erosion of small scale ionospheric structure
through diffusive processes can increase the scintillation index measured on the ground. Finally, we
will discuss a recent generalization of the statistical theory of scintillation, and demonstrate how it may
be used to infer the statistical structure of the irregularities from scintillation measurements in both the
unsaturated and saturated regimes.