Gyrosynchrotron Emission from Anisotropic Electron Distributions

We present numerical calculations of the intensity, degree of polarization, and spectral index of gyrosynchrotron emission produced by fast electrons with anisotropic pitch-angle distributions. The anisotropy is found to affect the emission substantially. The emission intensity can change up to a few orders of magnitude at the optically thin region compared with the isotropic case. The local value of spectral index changes considerably with the anisotropy. X -mode polarization increases for loss cone distributions and decreases for beamlike distributions. Moreover, the sense of polarization can correspond to the ordinary wave mode at the optically thin region for a certain range of view angles for beamlike distributions. We discuss possible applications and observability of the effects obtained.