SolO/EPT ion observations in a frame moving with the solar wind for a radial speed w = 350 km s⁻¹, at proton speeds between 3000 and 5000 km s⁻¹, respectively. Here v′ and μ′ are the ion speed and pitch-angle cosine in the moving frame of reference, respectively. The time interval is 7:00 to 8:00 UT on April 19, 2020, covering the increase of energetic ion fluxes within the mini flux rope (see Figs. 4 and 5 and discussion in Sect. 3.3.3).