Using the Structure of Heliospheric Collisionless Shock Waves in Modeling Lepton Injection into the Supernova Shock Acceleration Process

Abstract:

Collisionless shock waves have been observed in the Heliosphere for over 50 years. In situ observation of heliospheric shock micro and macro processes provides valuable information for modeling processes associated with the injection and subsequent acceleration of ambient leptons to cosmic ray energies by distant astrophysical shocks waves. The motivation for this talk is the observations of an “anomalous” cosmic ray positron abundance observed at 1 AU. Positrons were originally thought to be secondaries produced by the collisions of primary cosmic rays with interstellar media. However, recent observations at 1 AU of the energy spectra galactic cosmic ray leptons in the ~ 100 - 1000 GeV energy range now strongly suggest that positrons in the energy range are primary cosmic rays coming from an astrophysical source or the annihilation of dark matter. Observations of radio, X-ray and Gamma-ray emissions from supernova remnants show that supernova shock waves accelerate electrons to 100s GeV energies. The supernova shock acceleration process is assumed not to significantly change the relative abundances of ions. This talk extends the model of electron injection into the shock acceleration process to include positrons. This extended injection model suggests that for many shock geometries the relative abundances of positrons to electrons could be substantially enhanced, and, perhaps, make a significant contribution to the observed cosmic ray positron to electron ratio.