Abstract. We study the interaction of solar wind protons with the Earth's quasi-parallel bow shock using a hybrid-Vlasov simulation. We employ the high-fidelity global hybrid model Vlasiator to include effects due to bow shock curvature, tenuous upstream populations, and foreshock waves. We investigate the local uncertainty of the position of the quasi-parallel bow shock as a function of several plasma properties, and find that for a significant portion of time, the local bow shock position is challenging to define. Our results support the notion of upstream structures causing patchwork reconstruction of the quasi-parallel shock front in a non-uniform manner. We propose a novel method for spacecraft data to be used to analyze this quasi-parallel reformation. We combine our hybrid-Vlasov results with test-particle studies and show that shock non-locality appears to have little direct efficient on particle injection. We show that proton energization, which is required for injection, takes place throughout a larger shock transition zone. Non-local energization of particles is found regardless of the instantaneous non-locality of the shock front. Distortion of magnetic fields in front of and at the shock is shown to have a significant effect on proton injection. We additionally show that the density of suprathermal reflected particles upstream of the shock may not be a useful metric for the probability of injection at the shock, as foreshock dynamics and particle trapping appear to have a greater effect on energetic particle accumulation at a given position in space. Our results have significant implications for statistical and spacecraft studies of the shock injection problem.
Non-locality of the Earth's quasi-parallel bow shock: injection of thermal protons in a hybrid-Vlasov simulation
