An important part of the sun's influence on the Earth and planets, and on processes throughout interplanetary space, is exerted by the solar wind and its embedded magnetic field. Although significant progress has been made toward understanding these effects, wide gaps remain which provide fertile areas for theoretical research to complement the many ongoing experimental programs. The growing collection of observational data is leading to the discovery of new, subtle, and apparently fundamental relationships between the terrestrial environment and the state of the interplanetary medium. For example, possible influences of cosmic rays on global electricity have been proposed. A second example is the existence of solar-cycle effects on Earth's environment. It is not yet precisely clear just which of the sun's emissions vary over the course of a solar cycle nor is it clear how they vary. For this reason, continued investigation of the behavior of the interplanetary medium is central to a firm understanding of solar-terrestrial relationships. This grant will support continuation of a program of theoretical investigations into the properties and behavior of the interplanetary medium, with emphasis on solar-terrestrial relationships. Emphasis will be placed on the large-scale structure of the solar wind, its magnetic field, and the various manifestations of its fluctuations and turbulence. In particular, the effect of large scale magnetic field structure on cosmic ray acceleration, propagation and anisotropies will be studied. As part of this effort a Sun workstation will be acquired to facilitate supercomputer access and hence large scale numerical modelling of particle propagation in the interplanetary medium. The investigators are highly qualified in this research area.
