Fig. 5: Pitch angle distributions before and after the crash.

Alpha particle tracers were loaded in the whole range of pitch angles defined by \(\alpha ={\sin }^{-1}({v}_{\parallel }/v)\) with initial energies a, b 35 keV, c, d 350 keV, e, f 3.5 MeV. These data were obtained in simulations of the entire plasma in order to capture all orbits, including those near the trapped-passing boundary, which traverse both the plasma core and the periphery³⁶. Spatial integration was performed separately for the inner region \(\overline{r}\, < \, 0.18\,{{{{{\rm{m}}}}}}\) (left) and the outer region \(\overline{r}\, > \, 0.18\,{{{{{\rm{m}}}}}}\) (right), whose border is near the initial q = 1 radius \({\overline{r}}_{1}\approx 0.19\,{{{{{\rm{m}}}}}}\). More complete views of the velocity distributions are shown in Supplementary Figs. 7 and 8.