Wind speed and typical expansion properties of the f-subsonic and f-supersonic solutions. Panel a: Same as panel a of Fig. 2 but colored (black or red) by the type of identified solutions (f-subsonic or f-supersonic, respectively) after computing isopoly models including f(r) from PFSS. The isopoly parameters are interpolated from the five populations’ isopoly parameters, from Dakeyo et al. (2022). The modeled observations include 42% and 58% of f-subsonic and f-supersonic solutions, respectively. Panel b: Typical expansion radius from Eq. (11) of the data presented in panel a classified by solution type. The f-subsonic and f-supersonic solutions are represented in black and red, respectively.