报告题目：A global perspective of the modulation of cosmic rays in the heliosphere
报告人：Prof. Marius Potgieter（South African）
It is possible, now for the first time, to describe reasonably well the total, global modulation of cosmic rays in the heliosphere using comprehensive numerical models together with observations from the two Voyager spacecraft, from Ulysses, PAMELA, AMS2 and other space missions. The very local interstellar spectra for several cosmic ray species have become much better known so that together with knowledge of where the solar wind termination shock and heliopause is located, comprehensive modelling has taken a step forward. Of particular interest to solar modulation studies is that the onset of solar cycle 24 was expected to start at the end of 2008, following the familiar 11-year solar activity cycle. However, minimum modulation conditions were prolonged until the end of 2009, producing a remarkable decrease in the heliospheric magnetic field magnitude and modulation conditions significantly different from previous minimum epochs. This unique minimum has been well observed by the PAMELA detector in terms of cosmic ray electrons and positrons, among others. This allows a good assessment of the theory for charge-sign dependent modulation. The role and importance of all modulation processes and their complicated interplay will be highlighted. Major observations together with theoretical and numerical modelling approaches to the acceleration, transport and modulation of cosmic rays in the heliosphere will be reviewed in this presentation.