Solar microwave combined type-III bursts

We call a "microwave combined type III burst" when there is a microwave com mon type III burst at the low frequency end and a simultaneous microwave co ntinuous type U burst at the high frequency end. The latter is the result o f further evolution of single microwave type U bursts in one and the same m agnetic ring, and, as such, is still a subtype of type III bursts. Hence th e whole combined type III burst is also a subtype of type III bursts. The s ource of radiation of the microwave combined type III burst (i.e. high-ener gy electron beams) comes from one and the same region of acceleration. But in its interaction with magnetic rings in low coronal regions an electron b eam is divided into two beams, one of captured electrons and one of escapin g electrons. These beams have different trajectories of motion and give ris e to simultaneous continuous type III burst at the high frequency end and c ommon type III burst at the low frequency end. The formation of the combine d burst is closely related to the structure of magnetic rings in the low co ronal regions, so it is peculiar to the microwave range.