Heliophysics: Physics of Explosive Events Within the Heliosphere

The heliosphere, permeated by plasma and magnetic field, exhibits very interesting explosive dynamics. Some common examples are eruptions in the Sun's corona, or substorms in the Earth's and other planetary magnetospheres. The interplay of ingenious experimental observations, sophisticated theory, and well-designed numerical simulations (the third leg of discovery) has enabled us to arrive at our current understanding of such explosive events. The underlying physics is often described by fluid models (and their generalizations) governing plasma dynamics in the presence of magnetic fields, analogous to the fluid equations obeyed by neutral fluids that provide the underpinnings of the science of meteorology. Much can be learned about these explosive events from interdisciplinary perspectives, illustrated in this talk by describing mechanisms that involve magnetic reconnection (analogous to vortex reconnection in neutral fluids) and nonlinear Rayleigh-Taylor-like instabilities.