Particle transport, composition, and acceleration at shocks
in the inner heliosphere
J. Giacalone
University of Arizona, Tucson, Arizona, USA
The transport and acceleration of charged particles at shocks in the
inner heliosphere is discussed with particular emphasis on the connection
to anomalous cosmic rays and the outer heliosphere. A synthesis of
recent insights regarding the acceleration of pickup ions (both of
interstellar and "inner source" origin) will be given in the context
of spacecraft observations. I will focus on variations in composition
of energetic nuclei associated with the passage of propagating shocks.
For instance, the spatial distribution of accelerated particles at corotating
interaction regions (CIRs) provides constraints on possible acceleration
mechanisms and sources. It will be shown that the acceleration of pickup
ions is strongly favored at the reverse shock (of the two shock-pair which
bounds the CIR) over the forward shock. Moreover, recent cosmic-ray
observations suggest that pickup ions from the so-called "inner source" may
have a noticeable effect on the abundance of anomalous cosmic rays. I will
discuss the importance of the preacceleration of these pickup ions, in the
inner heliosphere, prior to their acceleration at the termination shock of
the solar wind. I will also discuss the propagation of energetic nuclei
associated with impulsive solar flares.