Statistical Characteristics of EMIC Waves Observed at Geosynchronous Orbit during Quiet Geomagnetic Conditions

Thursday, 18 December 2014
Jong-Sun Park1, Khan-Hyuk Kim1, Dong-Hun Lee1, Ensang Lee2 and Ho Jin2, (1)Kyung Hee University, Yongin, South Korea, (2)Kyung Hee University, School of Space Research, Yongin, South Korea
It is generally accepted that the electromagnetic ion cyclotron (EMIC) waves can be generated under the conditions of anisotropic (T > T) and energetic (larger than a few tens keV) ion population. Such conditions are expected when the magnetospheric convection is enhanced or when the magnetosphere is compressed by solar wind dynamic pressure enhancement. Even in the absence of strong magnetospheric convection or strong solar wind dynamic pressure enhancements, we have observed EMIC waves at geosynchronous orbit. In this study, we report the GOES observations of the EMIC waves excited during quiet geomagnetic conditions (Kp ≤ 1) in the period from January 2007 to December in 2008. Unlike previous studies, the occurrence rate of quiet time EMIC waves is dominant in morning-to-afternoon sector. We will examine the source of free energy to excite quiet time EMIC waves and also examine wave’s characteristics.