Filament Oscillations and Moreton Waves Associated with EIT Waves

Abstract

In this paper we compare EUV Imaging Telescope (EIT) waves with simultaneous phenomena seen in Ha in order to address the question of what an BIT wave is. We surveyed the events associated with solar flares larger than GOES M-class in 1999-2002. The Ha data are taken with the Flare-monitoring Telescope (FMT) at the Hida Observatory of Kyoto University. Among 14 simultaneous observations of BIT waves and Ha, 11 were found to have filament eruptions, three were associated with Moreton waves, and one was found to have only filament oscillations. This shows that we cannot see clear wave fronts in Ha even if BIT waves exist, but that it is possible to recognize invisible waves by means of filament oscillations. The nature of filament oscillations and Moreton waves associated with BIT waves is examined in detail, and it is found that the filament oscillations were caused by EIT waves.