1. Formation of Power Law Tail with Spectral Index-5 Inside and Beyond the Heliosphere
- Author
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Gloeckler, G., Fisk, L. A., Mason, G. M., Matthew Hill, Li, G., Lin, Rp, Luhmann, J., Hu, Q., Verkhoglyadova, O., and Zank, Gp
- Subjects
Physics ,Particle acceleration ,Spectral index ,Solar wind ,Solar flare ,Physics::Space Physics ,Astrophysics::Solar and Stellar Astrophysics ,Cosmic ray ,Astrophysics ,Power law ,Heliosphere ,Spectral line - Abstract
Suprathermal power law tails, with the unique spectral index of −5, on the velocity distributions (or equivalently of −1.5 on differential intensity) of solar wind and pickup ions are commonly observed in the heliosphere as well as the heliosheath. Here we present additional observations of velocity distributions and differential energy spectra of protons and heavier ions in the heliosheath, and in the heliosphere both during quiet times and in Corotating Ion Events. In particular we examine the energy range where the suprathermal tails roll over and find good agreement with the measured tails using isotropic solar wind frame differential spectra of the form E−1.5 exp[−(m/q)γ•(E/Ec)(1+γ)/2], with only two free parameters that depend on ambient solar wind conditions. We apply these concepts to particle acceleration in the heliosheath and show that the unmodulated Anomalous Cosmic Ray spectra near the heliopause are consistent with being E−1.5(ν−5) tails with a roll‐over at Ec = 25 MeV/nucleon.
- Published
- 2008