Kavli Affiliate: Igor Moskalenko
| First 5 Authors: Mikhail Malkov, Patrick Diamond, Mingyun Cao, Igor Moskalenko,
| Summary:
Recent measurements of primary and secondary CR spectra, their arrival
directions, and our improved knowledge of the magnetic field geometry around
the heliosphere allow us to set a bound on the distance beyond which a puzzling
10-TeV "bump" cannot originate. The sharpness of the spectral breaks associated
with the bump, the abrupt change of the CR intensity across the local magnetic
equator ($90^{circ}$ pitch angle), and the similarity between the primary and
secondary CR spectral patterns point to a local reacceleration of the bump
particles out of the background CRs. We argue that a nearby shock may generate
such a bump by increasing the rigidity of the preexisting CRs below 50 TV by a
mere factor of ~1.5. Reaccelerated particles below ~0.5 TV are convected with
the interstellar medium flow and do not reach the Sun, thus creating the bump.
This single universal process is responsible for the observed spectra of all CR
species in the rigidity range below 100 TV. We propose that one viable
candidate is the system of shocks associated with Epsilon Eridani star at 3.2
pc of the Sun, which is well aligned with the direction of the local magnetic
field. Other shocks, such as old supernova shells, may produce a similar
effect. We provide a simple formula that reproduces the spectra of all CR
species with only three parameters uniquely derived from the CR proton data. We
show how our formalism predicts helium and carbon spectra and the B/C ratio.
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