DivE: The Sun & Heliosphere

After several successful manoeuvers, Parker Solar Probe is primed to get some gravitational assists from Venus, & come within about 8.86 solar radii of the Sun’s surface on its closest approach in 2024. (NASA / Johns Hopkins APL / Steve Gribben)

High-Resolution Interferometric Imaging of a Sunspot Observed at Band 3 around 100 GHz with ALMA. (Shimojo et al. (2017) Solar Physics, 292, p28)

IAU 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. This field will have a great variety of opportunities through new generations of observations from ground- and space-based facilities across the electromagnetic spectrum, including both instruments fully dedicated to solar / heliospheric physics or and those with multiple purposes. For example, the recently launched Parker Solar Probe (PSP) will approach within 8.5 solar radii of the Sun’s surface and will help solve long standing mysteries of solar-wind acceleration and coronal heating; Solar Orbiter (SO) will provide close-up, high-latitude observations of the Sun to examine how it creates and controls the heliosphere; the world’s largest solar telescope, Daniel K Inouye Solar Telescope (DKIST), will image the surface of the Sun in unprecedented detail.

High-performance computing will enable an analysis of the as-yet-unexplored physical regimes and help tackle Grand Challenge problems by bringing together multidisciplinary teams of theorists, observers and data scientists. Specifically, connections between solar / heliospheric science and geospace / atmospheric science will aid in systematically understanding the basic processes of space weather and space climate. Connections with stellar physics will help understand the stellar dynamos, and planetary habitability. The new generation of observational data will stimulate theoretical developments to answer fundamental questions of astrophysics and plasma physics, such as the origin of solar and stellar magnetic activity cycles, the triggering mechanism for solar and stellar eruptions, the processes underlying magnetic reconnection, the heating mechanisms of the chromosphere and corona, the acceleration and propagation of energetic particles, as well as the potentially disastrous impacts that solar disturbances may have on the solar-terrestrial space environment, etc.

The challenges this field faces are complex.  There is a need to ensure continuity of solar and heliospheric observations and to preserve data and make it accessible. We must also develop new methods for using heterogeneous and high-volume data in driving and optimizing models, and further enhance dialogue with the astrophysicists from other Divisions who are challenged by similar basic physics problems. Finally, we must build bridges between basic and applied science, industry and the general public for the common benefit. In particular, the Sun via its activity influences the Earth’s environment and human activity in space and on the ground, requiring the Division to work more closely with the space-weather operations community to better understand both the physics and the risks of extreme space weather events.

Division E coordinates the above wide range of scientific activities, mainly performed within the Commissions and Working Groups:

Since the IAU GA started Division Days in Honolulu, Division E Meeting has been a scientific meeting on “Solar and Heliospheric Physics” covering all research fields relevant for Division E. The scientific developments on key scientific problems in a wide spectra are addressed either through theory, data-processing or observationally with stereo and close-up observations by a variety of facilities, including continued space-based facilities (RHESSI, Hinode, IRIS, SDO, STEREO, SOHO) and ground-based major facilities (1m SST, NVST, 1.5m GREGOR, 1.6m GST). We also take advantage of non-solar dedicated radio facilities (ALMA, EVLA, LWA, MWA, LOFAR, GURT) and solar dedicated radio facilities (MUSER, SRH, ICCON, and future projects ASO-S, SKA).

The IAU PhD Prize winners for 2016 and 2017, a new category of IAU Prizes to recognize outstanding scientific achievements in solar and heliospheric physics around the world for young PhDs, are invited to present their work at the Division E Days.

YIHUA YAN is President of IAU Division E Sun and Heliosphere. He is presently Director of Solar Physics Division, and Director of CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing. He is also a Professor at University of Chinese Academy of Sciences, Beijing.