Optical Signature of Polar Cusp During Southward IMF Bz Observed by TIMED/GUVI and DMSP

The GUVI instrument on board the TIMED satellite provides unique multi-wavelength observations of polar region emissions. In this study we focus on the identification of the polar cusp region during southward IMF conditions. Using simultaneous DMSP particle observations, the optical signatures and dynamics of the polar cusp region are investigated. We will address which of the five GUVI wavelengths can best be used for optical identification of the cusp precipitation by comparing images of various wavelengths. These new GUVI observations suggest that cusp aurora in the FUV extends over a relatively wide MLT range during a large southward IMF Bz. Characteristics and morphology of the cusp auroras in the FUV will also be discussed.