Oral Presentation

Dayside cusp aurorae and ionospheric convection under radial interplanetary magnetic fields

Author(s): Hsien-Ming Li (Institute of Space Science, National Central University, Taoyuan, Taiwan, R.O.C.) Jih-Hong Shue (Institute of Space Science, National Central University, Taoyuan, Taiwan, R.O.C.)

Presenter: Hsien-Ming Li (Institute of Space Science and Engineering, NCU)

Dayside cusp aurorae are created from particles precipitating into the cusp and ionospheric convection driven by solar wind electric fields. Dayside cusp aurorae and ionospheric convection for radial interplanetary magnetic fields (IMFs) have not been the main subjects of many studies. In this study, we coordinated observations obtained from the all-sky camera on Svalbard, the Super Dual Auroral Radar Network, and far ultraviolet imagers on board Defense Meteorological Satellite Program satellites on 4 January 2014 to examine the morphology of aurorae and the patterns of ionospheric convection for the radial IMF. During the event, a poleward-moving auroral form, which typically relates to magnetic reconnection on the dayside for the southward IMF, was observed when the IMF turned toward a pure radial orientation. Moreover, both antisunward and sunward convection was observed near the footprint of the cusp at different times during the radial IMF period. Antisunward and sunward convection is typically an indicator of the reconnection on the dayside for the southward IMF and behind the cusp for the northward IMF, respectively. All observations supported the two reconnection sites proposed by Pi et al. (2017) in the magnetospheric configuration for the radial IMF. However, this study proposes that the two types of reconnection were not necessary for the radial IMF to occur simultaneously.