Letters of Intent received in 2022

LoI 2024-2194
A 4π view of the Sun: advances in solar observations and in space weather understanding

Date: 1 August 2024 to 7 August 2024
Category: GA Symposium
Location: CapeTown, South Africa
Contact: Marco Romoli (marco.romoli@unifi.it)
Coordinating division: Division E Sun and Heliosphere
Other divisions: Division B Facilities, Technologies and Data Science
Division C Education, Outreach and Heritage
Division F Planetary Systems and Astrobiology
Division G Stars and Stellar Physics
Chair of SOC: Li Feng (Purple Mountain Observatory, Nanjing)
Chair of LOC: None (None)



1. The Sun under a 4π observation: the multi-point of view synergies, new challenges in our physical understanding of:
- the magnetic field between the photosphere and the heliosphere;
- the sources and acceleration of the solar wind;
- the magnetic connectivity from the Sun to the heliosphere;
- the physics of the dynamical corona and eruptive events
2. Results from the new space and ground-based observatories
3. How Sun and heliosphere contribute to determine space weather: awareness, forecasting, and data access:
- cross-disciplinary open-data frameworks in space weather
- global collaboration in space weather forecasting
4. Synergies between solar observations and space weather studies
5. How solar and heliophysics science contributes to stellar physics and the star-exoplanets connection.
6. Machine learning techniques for handling large data volume for solar physics and space weather
7. The future of solar physics research: new ground-based and space observatories, data centers, and space weather facilities



Never before has the study and monitoring of the Sun been able to take advantage of so many observatories, both space and ground based. The Sun is studied not only from an earth-based perspective, but also from heliocentric orbits. The NASA Parker Solar Probe (PSP) encounter mission launched in 2018 and the ESA/NASA Solar Orbiter (SolO) launched in 2020, are monitoring the Sun and the heliosphere from privileged points-of-view as close to the Sun as 10 solar radii for PSP and 0.28 au for SolO. The largest ever optical/NIR telescope, the 4-meter Daniel K Inouye Solar Telescope (DKIST), will have all its focal plane instrumentation operational. In addition, the first national Chinese and Indian missions, respectively the Advanced Space-based Solar Observatory (ASO-S) and Aditya-L1 (Sun divinity in Sanskrit), will be launched in October 2022 and in 2023, and will have completed their commissioning activities.

By the time of the IAU 2024 General Assembly, these facilities will have produced large quantities of unique data and exciting science addressing the big questions of solar physics - solar corona heating and magnetic structure, where and how the solar wind is accelerated, and how eruptive events like coronal mass ejections (CME) - affect and shape the heliosphere. SolO will start to achieve the orbital tilt necessary to uncover the secrets of the solar poles.

This comprehensive study of the Sun and its heliosphere will provide important inputs to the development of the knowledge of the processes that govern the Sun and the heliosphere and their interaction with the Earth environment, and serve as a template for similar processes around other stars and their planets.

These facilities and their synergies with their unprecedented performance (high resolution, special mutual positions like quadratures and conjunctions), although not specifically designed for space weather monitoring, will provide an important data pool that will improve the space weather forecasting techniques necessary to make the earth a safer place for life.
The space weather community is heavily involved in turning research results into operational data products (R2O). In addition, modelling of the corona and heliosphere, in particular connectivity models, that have been traditionally designed to help space weather forecasts are now also turning into essential tools to plan coordinated observations on missions like Solar Orbiter and PSP. A symposium such as the one we propose is key to making new research results available to operational space weather science.

Another important issue is the strategy to archive and handle a large amount of data sets produced by very different instrumentation, from plasma data to spectral, high resolution and synoptic images to which the traditional astrophysical classification based on astronomical objects cannot work.
The volume and complexity of the resulting data sets will require continued efforts to develop novel techniques for data analysis, based on machine learning, data mining and modeling, and necessitate a large level of cooperation between facilities in order to best exploit their combined diagnostic potential.
All of these aspects will be addressed during the Symposium.
Several solar-related IAU symposia have been held in the last decade, on the new facilities capabilities, and on the science with large telescopes, so it is now time to show how the efforts put by the international communities and the national and international funding agencies in this first part of the century have yielded a large return in terms of knowledge of our star, awareness of the influence that the Sun has and can have on the Earth and on the capability of facing the risks that extreme eruptive events can pose to the environment and our technology.
A General Assembly symposium is a privileged place where to discuss the results of the investigations and how to operate at best the present facilities, to establish new broad collaborations and to optimize the existing ones, and, last but not least, to direct the future of the solar research.

A plenary lecture will be proposed on interdisciplinary aspects of Sun and heliosphere, space weather, and stars influences on planetary systems.

SOC: The following colleagues have agreed to be part of the SOC. We are further discussing with a number of colleagues to define a wider regional (including the host country) and thematic representation.

Martin Snow (SANSA, Hermanus, South Africa),
Anik De Groof (ESA/ESAC, Spain)
Clementina Sasso (INAF, Italy)
Durgesh Tripathi (IUCAA, India)
Gianna Cauzzi (NSO, USA)
Lisa Upton (JHUAPL, USA)