Importance of E-F Region Coupling on Low and Mid-Latitude Ionospheric Irregularities

Tuesday, 16 December 2014
Tatsuhiro Yokoyama, National Institute of Information and Communications Technology, Tokyo, Japan
It is well known that ionospheric conductivity has a strong anisotropy so that even a relatively small-scale electrostatic polarization electric field can be easily mapped along geomagnetic field lines. As well as the conjugate characteristics between the northern and southern henmispheres, the electrodynamical coupling between the E and F region plays an important role in the formation of the ionospheric irregularities in low and mid-latitude: equatorial plasma bubbles (EPBs) and medium-scale traveling ionospheric disturbances (MSTIDs). Although they are characterized as the F-region plasma density irregularities, they are substantially controlled by the E-region effect such as the conductivity gradient in the evening and patchy sporadic-E layers. Recent observations and numerical studies of EPBs and MSTIDs will be presented.