Latitudinal dependence of static mesospheric E fields above thunderstorms

Abstract

Electrostatic fields generated by thunderclouds can significantly heat and modify the lower ionospheric electrons at altitudes of 70-80km. These fields can map to higher altitudes along the geomagnetic field lines and have been proposed as the mechanism for generation of whistler ducts. Previous 2-D modeling of these fields have been limited to azimuthally symmetric cases which requires a vertical magnetic field. We have developed a 3-D model of the electrostatic thundercloud fields which allows the consideration of effects of the geomagnetic field dip angle on the mapping of the fields to high altitudes. The results show stronger electric fields at altitudes of 70-110km with an equatorward and eastward shift of tens of kilometers at lower geomagnetic latitudes. These stronger fields are mapped into the magnetosphere and may therefore be important for whistler duct generation. The fields also indicate a more significant contribution of the quiescent heating on VLF early/fast events.