This chapter discusses ionospheric modes. Both single-hop and multiple-hop echoes from the ionosphere are frequently seen in records made with vertical-incidence sounders (ionosondes) radiating short pulses. It is convenient to regard the region of the ionosphere in which reflection occurs as a well-marked layer; that is to say, the D-, E-, and F-regions of ionospheric physics tend to be visualised as discrete layers in ray-tracing applications. The surface of the earth and the reflecting layer act very much like a pair of parallel mirrors in optics, and the separate returns correspond to multiple images of the transmitter.

Inspec keywords: ray tracing; echo; ionospheric electromagnetic wave propagation

Other keywords: ray tracing; single hop echo; ionospheric mode; vertical incidence sounder; radiating short pulse; multiple hop echo

Subjects: Ionospheric electromagnetic wave propagation