Understanding how the solar wind gets a magnetic push
 

During total solar eclipses, the Sun’s atmosphere, the corona, can be seen with the naked eye continuously out to 10s of solar radii. In this region, its atmosphere is super-sonically expanding creating a continuous outflow of plasma, the solar wind, that fills and shapes the heliosphere. Depending on where it originates on the Sun, the solar wind can experience different levels of heating as it escapes the corona while being accelerated by varying contributions of its thermal pressure gradient and work done by plasma oscillations. While the heating and acceleration has been studied extensively, observations of the solar wind are largely limited to the corona (remote sensing) or farther out (in situ), with few opportunities where both can be linked contemporaneously.

Last year’s 2024 total solar eclipse over North America offered one of the most detailed views of the Sun and its outflowing solar wind for this purpose. Through a multi-mission coordinated effort, our eclipse team follows a single solar wind stream from near the solar surface to past the orbit of Venus. The results shed light on the mass and energy flow in the atmosphere of our star. More generally, this work offers insights into the physics of magnetized stellar winds and their impact on the surrounding planetary environment.