PROPAGATION CHARACTERISTICS OF AURORAL HISS OBSERVED BY AKEBONO SATELLITE

V-shaped hiss and saucer emission observed by the Akebono satellite in the auroral region in the altitude range between 3,000 km and 5,000 km were studied on their wave normal directions using 5 components of electric and magnetic field wave data by Phillips-Tikhonov regularization method. It was found that the V-shaped hiss come down to the spacecraft and their azimuthal direction of wave normal is anti-symmetric with respect to the location of V-shaped frequency minimum. Ray tracing study is made to see how the frequency versus time characteristics and wave normal direction of the emissions should be at the satellite level. The results by ray tracing shows good agreement with the observation, under the assumption that the initial wave normal direction is circularly symmetric around the magnetic field, with the resonance cone angle.