From Solar Jets to Inner-Heliospheric Switchbacks – JET2SB

During its unprecedented approaches of the Sun, the Parker Solar Probe (PSP, NASA) mission has made the puzzling discovery of very frequent and abrupt deflections of the magnetic field, the switchbacks (SBs) in the solar wind. Because of their ubiquity in the inner heliosphere, SBs are considered as a key ingredient on the complex generation mechanisms of the solar wind. A family of scenarios place the origin of these event in solar jets, an intermediate-scale form of solar activity occurring continuously at the base of the Sun’s atmosphere. The objectives of JET2SB are to investigate how solar jets can induce the formation of SBs and whether/how they participate to the generation, acceleration and structuration of the solar wind.
The JET2SB project will build on the complementary expertise of three different French solar physics teams and assets, using both space and ground-based observations of the solar atmosphere, most notably using the renewed THEMIS solar telescope, in-situ measurements from PSP, in synergy with comprehensive 3D MHD numerical modeling of the generation and propagation of solar jets from the solar atmosphere to the inner heliosphere. New observations of the solar atmosphere will be used to better understand the properties of jet-like events, as well as constrain numerical models. The deterministic link between solar observations and inner-heliosphere measurements will be done thanks to 3D MHD simulations of the propagation of jets. They will produce synthetic in-situ measurements to be compared with observed ones. This will allow for a breakthrough in the interpretation and understanding of in-situ observations of SBs, in which the 3D context is absent.
JET2SB will not only strengthen the French expertise in a highly competitive field, but also put it at the forefront of projects that aim at better understanding the societal impacts of solar activity, thanks to a better comprehension of the fundamental properties of Sun-Earth relationships.