Acceleration of solar wind and pickup ions by shocks

Document Type

Conference Proceeding

Publication Date

12-1-2005

Abstract

Distribution functions of H+, He++ and He+ up- and downstream of shocks are examined to learn about the acceleration of solar wind and pickup ions by various types of shocks. We combine data from the SWICS and HISCALE instruments on Ulysses to obtain continuous spectra over the wide energy range from ∼0.6 keV to almost 5 MeV for our detailed study of two different types of shock crossings, a reverse shock of a Corotating Interaction Region (CIR) and Jupiter's bow shock. Ion velocity distributions have suprathermal tails extending to MeV energies upstream of and far removed from shocks. Downstream distributions have spectral shapes similar to those upstream but higher particle densities in the tails. Injection/acceleration efficiencies show the strongest correlation with the shock compression ratio. Applying observations made from ∼1.6 to 5.4 AU to the heliospheric termination shock we find that simply heating the upstream pickup and solar wind distributions provides excellent fits to the measured ion spectra and is consistent with all other available observations by Voyager 1.

Identifier

32644433103 (Scopus)

Publication Title

European Space Agency Special Publication ESA SP

ISSN

03796566

First Page

107

Last Page

112

Issue

592

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