STEREO/PLASTIC determines three-dimensional distributions of solar wind iron ions with unprecedented time resolution. Typically 300 to 1000 counts are registered within each 5 min time interval. For the present study we use the information contained in these distributions to characterize CIRs (Corotating Interaction Regions) in two test cases. We perform a consistency test for both the derived physical parameters and for the analytical model of CIRs of Lee (2000). At 1 AU we find that apart from compositional changes the most indicative parameter for marking the time when a CIR passes a spacecraft is the angular deflection of the flow vector of particles. Changes in particle densities and the changes in magnitudes of speeds are apparently less reliable indicators of stream interfaces.
Bochsler, P., Lee, M. A., Karrer, R., Jian, L. K., Ellis, L., Farrugia, C. J., … Opitz, A. (2010). Diagnostics of corotating interaction regions with the kinetic properties of iron ions as determined with STEREO/PLASTIC. Annales Geophysicae, 28(2), 491–497. https://doi.org/10.5194/angeo-28-491-2010