Fast’ solar wind moves with speeds above 500 km/s. Curiously, this wind exits the Sun’s corona with lower speeds, so something speeds it up as it moves farther away. The million-degree wind naturally cools down as it expands into a larger volume and becomes less dense, much like the air on Earth as you climb a mountain. And yet, it cools more slowly than expected from this effect alone.
So, what provides the necessary energy to accelerate and heat the fastest parts of the solar wind?
Data from our Solar Orbiter and NASA’s Parker Solar Probe have provided conclusive evidence that the answer is large-scale oscillations in the Sun’s magnetic field, known as Alfvén waves.
📹 ESA – European Space Agency
📸 ESA/NASA
#ESA #Sun #SolarWinds
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