Plasma ‘shield’ protects Earth from high-energy solar activity

The magnetosphere stretches from Earth’s core out into space, where it meets the solar wind. It acts as a shield to protect our planet from this high-energy solar activity. When the Earth’s magnetic field comes into contact with the Sun’s magnetic field — a process known as “magnetic reconnection” — powerful electrical currents from the solar furnace can stream into our planet’s atmosphere, creating space weather that can impact high-altitude aircraft and astronauts on the space station. Now MIT and NASA astronomers have pinpointed a process in the Earth’s magnetic field that bolsters its shielding effect. Ground- and space-based observations helped the astronomers spot a plume of low-energy plasma particles that “joins” the magnetic field lines as they stream from our planet’s lower atmosphere up to the point where the magnetosphere meets with the Sun’s magnetic field. The presence of cold, dense plasma curbs magnetic reconnection, undermining the Sun’s effects on Earth. “The Earth’s magnetic field protects life on the surface from the full impact of these solar outbursts,” notes John Foster, associate director 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.” The study’s findings are described in greater detail in the journal Science.

News Source: Science