NASA’s Parker Solar Probe has flown close enough to the Sun to detect the fine structure of the solar wind close to where it is generated at the solar surface, revealing details that are lost as the wind exits the solar corona as a uniform blast of charged particles.
The solar wind forms the heliosphere, a giant magnetic bubble that protects planets in our Solar System from a barrage of high-energy cosmic rays.
However, the solar wind also carries plasma and part of the Sun’s magnetic field, which can crash into Earth’s magnetosphere and cause disturbances, including geomagnetic storms.
These storms occur when the Sun experiences more turbulent activity, including solar flares and enormous expulsions of plasma into space, known as coronal mass ejections.
Geomagnetic storms are responsible for spectacular aurora light shows that can be seen near the Earth’s poles, but at their most powerful, they can knock out a city’s power grid and potentially even disrupt global communications.
Previous studies revealed that the Sun’s magnetic field was somehow driving the solar wind, but researchers didn’t know the underlying mechanism.
In an earlier paper, University of Maryland’s Professor James Drake and colleagues argued that the heating and acceleration of the solar wind is driven by magnetic reconnection.
They explained that the entire surface of the Sun is covered in small jetlets of hot plasma that are propelled upward by magnetic reconnection, which occurs when magnetic fields pointing in opposite directions cross-connect. In turn, this triggers the release of massive amounts of energy.
“Two things pointing in opposite directions often wind up annihilating each other, and in this case doing so releases magnetic energy,” Professor Drake said.
“These explosions that happen on the Sun are all driven by that mechanism. It’s the annihilation of a magnetic field.”
To better understand these processes, the astronomers used data from NASA’s…
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