Major unsolved problems in space plasma physics (Q5952706)

With the general thoughts of the title the author gives a view for the audience of the Paris 2000 conference mentioning the main problems of plasma physics in the branches where he is mainly interested. These concern the interplanetary turbulence in the first line, the problems are mentioned in connection with the space observations of Alfvén waves. This is combined with turbulence observations. The symmetries of interplanetary fluctuations are then discussed, and consequences for charged particle propagation are mentioned. The dissipation range is modelled on a subgrid-scale level, here the hyperdissipation is mentioned in a subchapter with nonlinear operators and MHD-Hall terms. The heating problem is equally introduced in the corona and solar wind acceleration context, the heating by Alfvén waves (in a three-dimensional model with wave acceleration) and the reconnection scenarios are mentioned. Finally, the nature of complex problems is discussed in connection with Alfvén waves in the outer heliosphere. This is rather an opening lecture with interesting problems than a smaller contributed paper with more or less important questions. The question marks raised by the text are made expecially intriguing by the list of referred papers: they count 80 items!