© Diana Morosan

Energetic particle populations are ubiquitous throughout the Universe and often found to be accelerated by astrophysical shocks. One of the most prominent sources for energetic particles in our solar system are huge eruptions of magnetized plasma from the Sun called coronal mass ejections (CMEs), which usually drive shocks that accelerate charged particles up to relativistic energies. Accelerated electrons can be observed remotely as low-frequency radio bursts or in situ at spacecraft. However, it is currently unknown where electrons accelerated in the early phases of such eruptions propagate and when they escape the solar atmosphere. New results from the field now use a three-dimensional representation of radio emission locations from ground-based observatories to relate it to the overlying coronal magnetic field, shock wave propagation, magneto-hydrodynamic (MHD) models of the solar corona, and in situ electron observations at spacecraft. Our results indicate that if the in situ electrons are shock-accelerated, the most likely origin of the first arriving electrons is located near the acceleration site of electrons beams producing type II and herringbone radio bursts. These are regions during the early evolution of the CME where there is clear evidence of shock-electron acceleration and intersection of the CME shock with open field lines that can connect to the observing spacecraft.