Plasma parameter estimation from multistatic, multibeam incoherent scatter data

Multistatic incoherent scatter radars are superior to monostatic facilities in the sense that multistatic systems can measure plasma parameters from multiple directions in volumes limited by beam dimensions and measurement range resolution. We propose a new incoherent scatter analysis technique that uses data from all receiver beams of a multistatic, multibeam radar system and produces, in addition to the plasma parameters typically measured with monostatic radars, estimates of ion velocity vectors and ion temperature anisotropies. Because the total scattered energy collected with remote receivers of a modern multistatic, multibeam radar system may even exceed the energy collected with the core transmit‐and‐receive site, the remote data improve the accuracy of all plasma parameter estimates, including those that could be measured with the core site alone. We apply the new multistatic analysis method for data measured by the tristatic European Incoherent Scatter VHF radar and the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) multibeam receiver and show that a significant improvement in accuracy is obtained by adding KAIRA data in the multistatic analysis. We also demonstrate the development of a pronounced ion temperature anisotropy during high‐speed ionospheric plasma flows in substorm conditions.