Division E Sun and Heliosphere
Division E encompasses the study of the Sun, its variability, activity, and dynamics, as well as its impact on the Earth and other bodies located within the heliosphere. The Division aims to advance knowledge and enhance understanding of the Sun-heliosphere system.
Compared with other stars, the proximity of the Sun enables detailed scientific investigations into its structure, the dynamo operating within the solar interior, and the radiation and solar wind that propagate into the heliosphere. More dynamic phenomena include flares, mass ejections, the propagation of shock fronts, and the acceleration of particles within the solar wind. If directed toward Earth, such dynamic events may disrupt critical systems on which society depends, including satellite operations, communication pathways, and power distribution systems. On longer time scales, variations in the solar irradiance (both total and spectral) contribute to changes in the Earth's climate. The common thread connecting many of these diverse solar phenomena is the magnetic field, and thus the understanding of its evolution in the interior, photosphere, corona, and outer atmosphere of the Sun is of great importance.
Many of the physical processes on the Sun are of broader astrophysical interest. The ability to observe these processes in great detail in the solar system provides insight toward what is happening around other stars. These processes include the structure and flows within the solar interior, as inferred via helioseismology; the operation of the solar dynamo; the reconnection of magnetic fields in the solar atmosphere; the mechanisms by which electrons, protons, and ions are accelerated by flares and within the magnetized solar wind; the interaction of this magnetized wind with the atmospheres surrounding both terrestrial and gaseous planets; and understanding brightness variations of the Sun, especially in the context of determining limiting factors involving the detection of planets orbiting other stars.
In addition to these cross-disciplinary research activities, Division E seeks to engage a broad community. As examples of this engagement, working groups affiliated with the Division are dedicated to calibrating the long-term historical record of synoptic observations of the Sun, to facilitating comparisons between studies of solar and stellar magnetic activity, and to promoting the benefits of viewing of solar eclipses by both astronomers and the general public alike.