Observations of equatorial plasma bubbles using broadcast VHF radio waves

Abstract

The propagation of VHF radio waves affected by field‐aligned irregularities within equatorial plasma bubbles is examined. Continuous observation of VHF radio waves at Tateyama, Japan, shows that broadcast radio waves transmitted from Southeast Asia propagate to Japan. Using a ray‐tracing calculation combined with a model of scattering by field‐aligned irregularities, we determined scatter points suitable for the reception of these radio waves. The results of the calculation show that radio waves transmitted from the Philippines can propagate to Japan owing to field‐aligned irregularities within equatorial plasma bubbles located west of Japan. Comparing with all‐sky imager data observed at Sata, Japan, we found that the radio waves are received at Tateyama when the plasma bubbles are observed at Sata. The results of this study show that the reception of these radio waves is closely correlated with the equatorial plasma bubbles.