Abstract

On the basis of microwave solar images from Nobeyama Radiohelograph (NoRH), we report on statistical features of solar eruptive events. In microwaves (17 GHz), most of eruptive events are originated from polar crown filament or far from active regions, and not associated with flares. This tendency, which is contrary to what seen in soft X-rays by Yohkoh/SXT, probably reflects a temperature dependency in this wavelength. By using 17GHz synoptic maps from NoRH, we discuss i) where the microwave eruptions tend to occur and ii) its spatial relation with magnetic structures above (e.g., streamers) that can be seen in LASCO coronagraph images.