The Action Thématique Soleil-Terre (ATST) is a component of the Programme National Astrophysique (PN Astro) of the CNRS Terre et Univers (INSU). It is the result of a recent reform of INSU’s structure, implemented during the latest community “prospective” exercise (https://www.insu.cnrs.fr/fr/identifier-les-enjeux-futurs-les-prospectives-scientifiques). The ATST corresponds to the former Programme National Soleil-Terre (PNST), which had been in operation since 1998 (following on from the GdR Plasmae and GdR Magnétodynamique Solaire et Stellaire that existed before that).
ATST is a community of around 250 people (employed researchers, contract workers and doctoral students), including around 130 permanent staff. The ATST’s aim is to fund research projects and lead the national scientific community in the field of heliospheric plasma physics. The main themes of this “Action Thématique” relate to the study of the Sun-Earth system, from the generation of the solar magnetic field to the effects on the terrestrial magnetosphere, ionosphere and thermosphere, via the dynamics of the solar wind, the environments of the other planets in the Solar System, and all the way to the confines of the heliosphere.
Since the 2024 reform, ATST has been organized around two coordinators, who represent the community in its relations with supervisory authorities, and a Scientific Expert Committee (CES) of 13 researchers whose skills cover the community’s various themes. Two INSU representatives (“chargé de mission” and administrative representative) are permanently invited to the CES as well as representatives of the partners who contribute to the financing of the ATST: one for the Sun – Heliosphere – Magnetospheres thematic group (GT SHM ) for CNES, one for the AIM laboratory of the CEA, and one for ONERA.
Other members of the scientific community may also be invited to attend meetings, depending on the topics under discussion. The CES meets on average two or three times a year. One of its meetings is dedicated to the distribution of the budget following responses to a call for tenders. The ATST budget is about 130 kEuros (with a variable distribution from year to year depending on partners contributions: CNES, INSU, CEA and ONERA).
The current composition of the Scientific Expert Committee can be found here.