SPRG Seminars
January 24, 2012:
"Determination of Elecrtomagnetic Source Direction as an Eigenvalue Problem"
Juan Carlos Martinez Oliveros, Space Science Laboratory, University of California, Berkeley
Low frequency solar and interplanetary radio bursts are generated at frequencies below the ionospheric plasma cutoff and must therefore be measured in space, with deployable antenna systems. The problem of measuring both the general direction and polarization of an electro-magnetic source is commonly solved by iterative fitting methods such as linear regression that deal simultaneously with both directional and polarization parameters. We have developed a scheme that separates the problem of deriving the source direction from that of a determination of polarization, avoiding iteration in a multi-dimensional manifold. The crux of the method is to first determine the source direction independently of concerns as to its polarization. Once the source direction is known, its direct characterization in terms of Stokes vectors in a single iteration, if desired, is relatively simple. We show the applicability of this technique in the study of type II and type-III bursts and their associated phenomena.