Scientists working with a NASA probe that investigates how the Sun's and Earth's magnetic fields connect and disconnect have uncovered a new type of magnetic event in our near-Earth environment
Scientists working with a NASA probe that investigates how the Sun’s and Earth’s magnetic fields connect and disconnect have uncovered a new type of magnetic event in our near-Earth environment. Launched in 2015, the Magnetospheric Multiscale, or MMS, consists of four identical spacecraft that orbit around Earth through the dynamic magnetic system surrounding our planet to study a little-understood phenomenon called magnetic reconnection. Magnetic reconnection is a phenomenon unique to plasma, that is, the mix of positively and negatively charged particles that make up the stars, fill space and account for an estimated 99 percent of the observable universe.
The new discovery, detailed in the journal Nature, found reconnection where it has never been seen before – in turbulent plasma. For the study, the scientists used an innovative technique to squeeze extra information out of the data. “In the plasma universe, there are two important phenomena: magnetic reconnection and turbulence,” said Tai Phan, a senior fellow at the University of California, Berkeley, and lead author on the paper. “This discovery bridges these two processes,” Phan said.
The finding of reconnection in turbulence has implications, for example, for studies on the Sun. It may help scientists understand the role magnetic reconnection plays in heating the inexplicably hot solar corona – the Sun’s outer atmosphere – and accelerating the supersonic solar wind. Magnetic reconnection is one of the most important processes in the space around Earth.
This fundamental process dissipates magnetic energy and propels charged particles, both of which contribute to a dynamic space weather system that scientists want to better understand, and even someday predict. Reconnection occurs when crossed magnetic field lines snap, explosively flinging away nearby particles at high speeds. Magnetic reconnection has been observed innumerable times in the magnetosphere – the magnetic environment around Earth – but usually under calm conditions.
The new event occurred in a region called the magnetosheath, just outside the outer boundary of the magnetosphere, where the solar wind is extremely turbulent. Previously, scientists did not know if reconnection could even occur there, as the plasma is highly chaotic in that region. MMS found it does.