Project:

In this project a comprehensive two-dimensional numerical drift model based on Parker’s (1965) time-dependent transport equation is used to compute the modulation of cosmic ray protons and anti-protons in the heliosphere. This is done using the latest developments in the elements of the diffusion tensor, heliospheric boundaries and cosmic ray interstellar spectra. The main focus of this project is on the effects of the spatial and rigidity dependence of the scattering parameter (ωτ), with ω the gyro-frequency and τ a time scale defined by diffusive scattering, on the drift coefficient in the modulation of the mentioned species. A comparison of the numerical modelling of the ratio of anti-protons to protons obtained from different scenarios of ωτ is made over a solar cycle. The modelling results will be compared with PAMELA observations. This charge-sign-dependent modulation study should assist in establishing the amount of drifts present at the Earth from solar minimum to maximum solar activity in both magnetic cycles.