Letter to the Editor
Ion acceleration in connection with a modulated solar wind termination shock: phase space propagation and complete energy spectra
Andreas Dworsky and
Hans J. Fahr
Received 28 July 1999 / Accepted 17 November 1999
Using the general kinetic transport equation for cosmic ray particles the energization of heliospheric pick-up ions (PUI's) to Anomalous Cosmic Ray particles (ACR's) by means of non-linear wave-particle interactions is described. After creation of PUI's with initial energies of 1 keV/nuc they undergo phase space diffusion by Fermi-1 and Fermi-2 scattering processes in the heliosphere and at the termination shock and eventually appear as ACR's in the 10 MeV/nuc energy regime for which spatial diffusion becomes important. We present ion energy spectra derived from a fully consistent theoretical context and covering the range from 1 keV/nuc to 100 MeV/nuc. Our solutions of the kinetic transport equation reflect the effect of simultaneous operations of convective and diffusive transport processes in heliospheric phase space. As demonstrated in our calculations the kick-up from pick-up's to ACR's in our approach completely works on known physical grounds with no need to prescribe a specific injection of seed ACR's at the shock. The spectra resulting near the termination shock are far from being pure power-laws as is expected in classical shock acceleration theories. Thus the idea to start from measured VOYAGER ACR spectra and to apply a necessary demodulation up to a pure power-law cannot be used to find the shock location.
Key words: Sun: solar wind inteplanetary medium ISM: cosmic rays acceleration of particles shock waves turbulence
Send offprint requests to: Hans J. Fahr
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© European Southern Observatory (ESO) 2000
Online publication: December 8, 1999