The European Solar Agency's Solar Orbiter spacecraft has made the first ever direct connection between the solar wind around a spacecraft and where they came from on the Sun.
Understanding where the solar wind originates and how its properties are set has been a long-standing goal for solar physicists.
"Solar Orbiter flew past the coronal hole and the active region, and we saw fast solar wind streams, followed by slow ones.
Graphic: ESA"This result confirms that Solar Orbiter is able to make robust connections between the solar wind and its source regions on the solar surface," said Daniel M¼ller, ESA Solar Orbiter project scientist.
The solar wind is broadly categorised into fast wind, traveling over 500 km/s from coronal holes, and slow wind under 500 km/s whose origins are less understood.
The European Solar Agency's Solar Orbiter spacecraft has made the first ever direct connection between the solar wind around a spacecraft and where they came from on the Sun.
This breakthrough opens a new way for scientists to study the origins of the solar wind.
The solar wind is a constant stream of charged particles flowing outward from the Sun. Understanding where the solar wind originates and how its properties are set has been a long-standing goal for solar physicists. However, by the time the wind reaches Earth, much of the detail linking it to source regions on the Sun has been lost.
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A key objective for Solar Orbiter was to link the solar wind measured in situ by the spacecraft to specific areas on the Sun's surface imaged by its remote sensing instruments. Achieving this required combining data from Solar Orbiter's unique suite of instruments with modeling tools that map the outward propagation of solar wind from the Sun.
The team used the Magnetic Connectivity Tool, developed for the Solar Orbiter mission, to predict when the spacecraft would fly through solar wind streams originating from target surface features like coronal holes or active regions.
Between March 1-9, 2022, when Solar Orbiter was around 75 million km from the Sun, the spacecraft's instruments detected variations in wind speed, composition and temperature tied to those areas.
"Solar Orbiter flew past the coronal hole and the active region, and we saw fast solar wind streams, followed by slow ones. We saw a lot of complexity that we could tie back to the source regions," said Stephanie Yardley of Northumbria University, lead author on the study.
The observations confirmed that "footprints" imparted by different solar source regions can still be detected in the solar wind, allowing it to be traced back to its origins on the Sun's surface. This was a key mission goal for Solar Orbiter. Graphic: ESA
"This result confirms that Solar Orbiter is able to make robust connections between the solar wind and its source regions on the solar surface," said Daniel M¼ller, ESA Solar Orbiter project scientist. "This opens the way for us to study the solar wind's origin in unprecedented detail."
The solar wind is broadly categorised into fast wind, traveling over 500 km/s from coronal holes, and slow wind under 500 km/s whose origins are less understood. Linking slow solar wind streams to active regions like sunspot complexes was a focus of this study.
By flying through the interface of fast and slow solar wind streams, Solar Orbiter could directly observe the transitions between wind types and tie them to the magnetic configurations on the Sun's surface. This allows the poorly-understood sources of the slow solar wind to finally be pinpointed. Solar Orbiter flew past the coronal hole and the active region. (Photo: ESA)
The ability to connect solar wind measurements back to the Sun's surface from close range is a pioneering new capability. It paves the way for future studies combining data from multiple spacecraft like NASA's Parker Solar Probe and ESA's BepiColombo to comprehensively map the solar wind's origins across the Sun.
As the primary driver of space weather affecting Earth and spacecraft, unraveling the solar wind's sources and physics is a critical goal for solar science and space exploration. Solar Orbiter's breakthrough provides a powerful new tool for achieving this.
