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The Space Plasma Exploration by Active Radar (SPEAR) facility has\udsuccessfully operated in the high-power heater and low-power radar modes and\udhas returned its first results. The high-power results include observations\udof SPEAR-induced ion and plasma line spectral enhancements recorded by the\udEISCAT Svalbard UHF incoherent scatter radar system (ESR), which is\udcollocated with SPEAR. These SPEAR-enhanced spectra possess features that\udare consistent with excitation of both the purely growing mode and the\udparametric decay instability. In this paper, we present observations of\udupper and lower E-region SPEAR-induced ion and plasma line enhancements,\udtogether with F-region spectral enhancements, which indicate excitation of\udboth instabilities and which are consistent with previous theoretical\udtreatments of instability excitation in sporadic E-layers. In agreement with\udprevious observations, spectra from the lower E-region have the\udsingle-peaked form characteristic of collisional plasma. Our observations of\udthe SPEAR-enhanced E-region spectra suggest the presence of variable\uddrifting regions of patchy overdense plasma, which is a finding also\udconsistent with previous results

EISCAT Svalbard radar observations of SPEAR-induced E- and F-region spectral enhancements in the polar cap ionosphere