The Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. For the most part, the magnetosphere acts as a shield to protect the Earth from this high-energy solar activity.
But when this field comes into contact with the sun’s magnetic field — a process called “magnetic reconnection” — powerful electrical currents from the sun can stream into Earth’s atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.
Scientists have now identified a process that happens in the Earth’s magnetosphere that reinforces this shielding effect preventing harmful solar radiation from reaching us.
A plume of low-energy plasma particles follow the Earth’s magnetic field lines where the magnetic field connects with the sun’s. In this “merging point,” the presence of cold, dense plasma slows magnetic reconnection, blunting the sun’s effects on Earth.
“The Earth’s magnetic field protects life on the surface from the full impact of these solar outbursts,” says John Foster, of MIT’s Haystack Observatory. “Reconnection strips away some of our magnetic shield and lets energy leak in, giving us large, violent storms. These plasmas get pulled into space and slow down the reconnection process, so the impact of the sun on the Earth is less violent.”
For more than a decade, scientists at Haystack Observatory have studied this plasma plume phenomena.
This information could be used to predict future solar storms, which could avert damage to satellites and other radiation sensitive devices (like my cell phone).
– Ex astris, scientia –
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