The book contains courses taught to a public of Ph.D. students, post-docs and confirmed researchers in all fields of heliospheric plasma physics. It aims at identifying physical issues which are common to two different fields of astronomy: solar and magnetospheric physics. Emphasis is given to basic processes of transport and conversion of energy: magnetic reconnection is discussed in detail from the viewpoints of MHD and kinetic physics. Processes of charged particle acceleration are reviewed and compared with recent observations. The subject is introduced by a summary of MHD, and the basic structures and parameters of the solar atmosphere, terrestrial ionosphere and magnetosphere are reviewed. The book combines a pedagogic and comprehensive presentation of physical issues and raises fully open questions, with the complementary and sometimes conflicting views of geophysicists and solar physicists. The book's focus, while basic, opens new avenues.