Wavelike Structure of Magnetic Field-Aligned Irregularities Detected by Phase Interferometry

Abstract

Recordings of scintillations in the angle of arrival of satellite beacon transmissions at 136.410 MHz, by means of a modified phase interferometer, show relatively slow, periodic increases in angular variations. These increases are associated with occurrences of magnetic field-aligned irregularities at the height of the F region. The periodic component of scintillations is thought to arise from a wavelike form of distribution of irregularities. The wavelength most frequently found is in a 3–4 km range. No similar wave structure was found in simultaneous recordings of amplitude scintillations, possibly because of the difference between amplitude and phase scale sizes of irregularities. The existence of magnetic field-aligned irregularities, characterized by the periodic angular structure, could be evidence of a ducted mode of propagation of hydromagnetic waves originating in the auroral zone.