We implemented a 2D Monte Carlo model to simulate the solar modulation of galactic cosmic rays. The model is based on the Parker’s transport equation which contains diffusion, convection, particle drift and energy loss. Following the evolution in time of the solar activity, we are able to modulate a local interstellar spectrum (LIS), that we assumed isotropic beyond the termination shock, down to the Earth position inside the heliosphere. In this work we focused our attention to the cosmic ray positron fraction at energy below 10 GeV, showing how the particle drift processes could explain different results for AMS-01 and PAMELA. We compare our modulated spectra with observations at Earth, and then make a prediction of the cosmic ray positron fraction for the AMS-02 experiment.
Della Torre, S., Bobik, P., Boschini, M., Consolandi, C., Gervasi, M., Grandi, D., et al. (2012). Effects of solar modulation on the cosmic ray positron fraction. ADVANCES IN SPACE RESEARCH, 49(11), 1587-1592 [10.1016/j.asr.2012.02.017].
Effects of solar modulation on the cosmic ray positron fraction
CONSOLANDI, CRISTINA;GERVASI, MASSIMO;Grandi, D;PENSOTTI, SIMONETTA;ROZZA, DAVIDE;TACCONI, MAURO
2012
Abstract
We implemented a 2D Monte Carlo model to simulate the solar modulation of galactic cosmic rays. The model is based on the Parker’s transport equation which contains diffusion, convection, particle drift and energy loss. Following the evolution in time of the solar activity, we are able to modulate a local interstellar spectrum (LIS), that we assumed isotropic beyond the termination shock, down to the Earth position inside the heliosphere. In this work we focused our attention to the cosmic ray positron fraction at energy below 10 GeV, showing how the particle drift processes could explain different results for AMS-01 and PAMELA. We compare our modulated spectra with observations at Earth, and then make a prediction of the cosmic ray positron fraction for the AMS-02 experiment.
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