Distinct MLT asymmetry of auroral kilometric radiation observed by the FAST satellite

Auroral Kilometric Radiation (AKR) is a common radio emission, which can contribute to the magnetosphere−ionosphere−atmosphere coupling. Similar emissions have been observed in all magnetic planet magnetospheres of the solar system. In this study, using observations from the FAST satellite from 30 August 1996 to 9 September 2001, the distribution of AKR in altitude = 500−4500 km and invariant latitude (|ILAT|) = 60°−80° has been analyzed. 63045 AKR samples have been identified with ~48% (52%) samples on the dayside (nightside). Of considerable interest, there is a distinct MLT asymmetry with the high occurrence rate in MLT = 05−08 and 18−22 (02−05 and 12−17) in the northern (southern) hemisphere. The distinct MLT asymmetry is associated with the direction of B_x of the interplanetary magnetic field. In addition, the occurrence rate on the nightside clearly increases as the AE^* index increases. This study further enriches the information and understanding of AKR in the magnetosphere as well as other similar radio emissions.