For the physics journal, see Solar Physics (journal)
Solar physics is the study of our Sun. It is a branch of astrophysics that specializes in exploiting and explaining the detailed measurements that are possible only for our closest star. It intersects with many disciplines of pure physics, astrophysics, and computer science, including fluid dynamics, plasma physics including magnetohydrodynamics, seismology, particle physics, atomic physics, nuclear physics, stellar evolution, space physics, spectroscopy, radiative transfer, applied optics, signal processing, computer vision, and computational physics.
Because the Sun is uniquely situated for close-range observing (other stars cannot be resolved with anything like the spatial or temporal resolution that the Sun can), there is a split between the related discipline of observational astrophysics (of distant stars) and observational solar physics. The Solar Physics Division of the American Astronomical Society boasts about 600 members (in 2008), compared to several thousand in the parent organization.
A major thrust of current (2009) effort in the field of solar physics is integrated understanding of the entire solar system including the Sun and its effects throughout interplanetary space within the heliosphere and on planets and planetary atmospheres. Studies of phenomena that affect multiple systems in the heliosphere, or that are considered to fit within a heliospheric context, are called heliophysics, a new coinage that entered usage in the early years of the current millennium.