Time-dependent cosmic ray modulation using a modified compound approach
Abstract
A modified two-dimensional, time-dependent transport model is presented for the global modulation of cosmic rays in the heliosphere. Computations are compared to spacecraft observations in the inner and outer heliosphere. Time-dependence in the transport parameters are introduced by utilizing recent advances in transport theory. This new approach, based on the original compound approach of Ferreira and Potgieter (2004) gives better compatibility to observations on a global scale. Numerical solutions are presented for protons at 200 MeV and 1.8 GeV. The study of cosmic ray modulation along the Voyager 1 and 2 trajectories shows that both spacecraft had still been under the influence of solar activity between the termination shock and the heliopause. A time-dependence in the position of the termination shock is also implemented to show the effect of such a dynamic structure on the heliospheric modulation of galactic cosmic rays.
- Publication:
-
39th COSPAR Scientific Assembly
- Pub Date:
- July 2012
- Bibcode:
- 2012cosp...39.1182M