Magnetic and optical measurements and signatures of reconnection in the cusp and vicinity

The study of geophysical processes in the cusp and its nearby magnetospheric regions — the mantle and the low-latitude boundary layer — is a crucial link in the chain of understanding the mechanism of the solar-terrestrial relationship. The magnetic conjugation of these regions with the high-latitude ionosphere permits the study of the solar wind-dayside magnetopause interaction via ground-observed ionospheric phenomena. The major topics covered are the dayside aurora in Spitsbergen and the Alfv$\acute {\rm e}$n waves detected by an induction magnetometer as high-latitude geomagnetic Pc1 pulsations. The results presented establish a relation between the aurora and pulsation dynamics and the reconnection phenomenon which occurs at negative IMF ${B}_{\rm z}$ values and which is commonly accepted to be the most likely way for solar wind energy to penetrate into the inner magnetosphere. The results also suggest that the Spitsbergen optical and magnetic measurements provide an opportunity for the world scientific community to solve the major space weather problem of monitoring the replenishment of the energy expended in the course of magnetospheric substorms.