A Review of MU Radar Observations of the Thermosphere and Ionosphere.

The MU radar is situated in a longitude sector very different from those of the American and European incoherent scatter radars. Its location, together with its unique operating characteristics, gives it a particular importance to worldwide studies of the thermosphere and ionosphere. This paper summarizes the MU radar's capability for studying the ionosphere at heights above 100 km (Section 1), and broadly reviews the principal results obtained in the first ten years of operation on the large-scale structure of the ionospheric E- and F-layers (Section 2); thermospheric winds, electric fields and gravity waves (Section 3); and field-aligned irregularities (Section 4). Data from other instruments in Japan, such as ionosondes and magnetometers, have proved vital to the interpretation of MU radar data.