Solar modulation in a very quiet heliosphere

24 Apr 2017, 15:15
25m
Other Institutes

Other Institutes

Hyatt Arlington, Washington DC

Speaker

Prof. Marius Potgieter (North-West University)

Description

Solar activity was at its lowest level since the beginning of the space exploration era from 2006 to 2009. During this period, the PAMELA space experiment observed spectra for galactic protons and electrons down to 70 MV and 400 MV, respectively, during what is called an A < 0 solar magnetic polarity cycle. This provides the opportunity to study charge-sign-dependent modulation under very quiet heliospheric conditions. Drift theory for the solar modulation of cosmic rays predicts that the intensity of protons at the Earth is expected to show a different rate of recovery towards solar minimum when compared to electrons during A < 0 cycles. The solutions of a comprehensive three-dimensional drift model are compared to PAMELA spectra to authenticate the modelling approach and then it is used to make predictions of how cosmic rays are differently modulated. Computations are done down to 1 MeV for the mentioned period and are based on new very local interstellar spectra.

Primary author

Prof. Marius Potgieter (North-West University)

Co-authors

Mr Jan-Louis Raath (North-West University) Dr Etienne Vos (North-West University)

Presentation materials