ICI 2011-2013: Investigation of cusp irregularities and GNSS scintillations by sounding rockets

There is a well documented phenomenological relationship between the northern lights, polar cap patches, and scatter of HF radio waves, but the underlying processes remain to be understood. GHz frequencies used in critical infrastructure, for satellite co mmunication and navigation systems, are also affected. Improved knowledge is the key for progress in ionospheric modelling for more reliable predictions of ionospheric radio wave conditions and for corrections to GPS navigation signals. The ionospheric cu sp, seen by naked eye as the daytime auroras over Svalbard, is a very complex region of the ionosphere. Our hypothesis is that there are several cusp phenomena that individually or together may have important roles in plasma irregularity formation (flow c hannels, flow shears, electron beams, and polar cap patches). In-situ sounding rocket measurements with high spatial resolution, is the most feasible approach to study the generation mechanisms of HF backscatter targets, and with the ICI-series of rockets , we aim to describe the nature of the plasma structures under various conditions and to provide the plasma parameters needed to properly evaluate existing models for plasma instabilities. The rocket data will also be used in analyzing and modelling the p hysics of plasma irregularities that lead to GNSS scintillations, of which aim is to improving GNSS integrity at polar latitudes under scintillating conditions. Because scintillations occur under a variety of physical conditions, and the physical processe s leading to the formation and evolution of scintillation causing irregularities are still poorly understood, it is important that multiple rockets are used to investigate the broadest range of conditions possible. Notably ICI-4 will cover solar maximum c onditions.