Signature of a three-dimensional heliosphere in the spectra of anomalous cosmic rays

A steady-state transport model of the Anomalous component of Cosmic Rays (ACRs) that takes into account convection, spatial diffusion and adiabatic deceleration in a three-dimensional heliosphere is applied to compute ACR spectra in the kinetic energy range 2 keV to several GeV. The spectra are investigated with respect to their longitudinal gradients due to the three-dimensional structure of the heliosphere, defined by a latitudinally varying solar wind that is terminated by a heliospheric shock. The results significantly refine earlier studies based on the integrated spectra, i.e. the cosmic ray pressure. With the full spectral information at our disposal, we can identify the spectral regimes exhibiting the largest longitudinal gradients. (C)1999 COSPAR. Published by Elsevier Science Ltd.