21st June 2021: Non-thermal element abundances at astrophysical shocks

Speaker: Björn Eichmann (Ruhr University Bochum, Germany). Location: Virtually; 3 pm

The non-thermal source abundances of elements play a crucial role in the
understanding of cosmic ray phenomena from a few GeV up to several tens of
EeV. In this presentation a first systematic approach is shown that describes
the change of the abundances from the thermal to the non-thermal state via
diffusive shock acceleration by a temporally evolving shock. Hereby, not only
time-dependent ionization states of elements contained in the ambient gas are
considered, but also elements condensed on solid, charged dust grains which
can be injected into the acceleration process as well. This generic parametrized
model is then applied to the case of particle acceleration by supernova remnants
in various ISM phases as well as Wolf-Rayet wind environments. The resulting
predictions for low energy cosmic ray (LECR) source abundances are compared
with the data obtained by various experiments revealing the importance of dust
grains as well as the possible contribution of different ISM environments to the
observed LECR flux.

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