Researchers from the US Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) announced on Wednesday that they had discovered a new mechanisms that could help prevent a potentially deadly solar eruption before it even leaves the sun.
Solar eruptions, they explain, are massive explosions that fire tons of plasma gas and radiation into space. Had the members of the original moon-landing crew encountered one, it likely would have killed them on the spot. Furthermore, the phenomenon can cause a geomagnetic storm to occur in the Earth’s atmosphere, damaging satellites and disrupting power grids.
As NASA prepares to send astronauts to Mars, it has stepped up efforts to identify solar eruption events so in attempts to protect satellites, power systems, and other equipment. As part of the US space agency’s efforts, PPPL physicist Clayton Myers and his colleagues have discovered a way to differentiate between potentially dangerous explosions and similar, harmless events.
The eruptions, better known as coronal mass ejections, occur when magnetic energy stored in the sun’s outer layer (corona) is suddenly released. That energy, Myers’ team reported in this week’s edition of the journal Nature, is typically stored in arched structures called magnetic flux ropes.
Experiments reveal why would-be eruptions sometime fail
As these long-lived flux ropes become twisted and destabilize, one of two things happens: they either erupt out into the solar system, producing a coronal mass ejection, or they fail and collapse back into the sun. Failures occur due to a force running along the flux rope, known as the guide magnetic field, which is strong enough to keep it from destabilizing fully.
In these instances, the guide field interacts with electric currents in the flux rope, causing a force that halts the eruptions. This force, known as the “toroidal field tension force,” is missing from existing models of solar eruptions, Myers and his fellow researchers found through the use of a special device known as the Magnetic Reconnection Experiment (MRX).
The MRX, they explained, is used to study how magnetic fields in plasma converge and separate violently. They used it to produce a flux rope and a “potential magnetic field” similar to the ones that enclose the rope in the solar corona, and discovered that the guide field, which may believed had been of little importance, plays a key role in preventing eruptions from occurring.
Once the flux rope begins to move outwards in the presence of a powerful enough guide field, the plasma essentially reorganizes itself. This process causes it to lose energy and collapse, said Myers, adding that “the presence of a substantial guide field should therefore indicate a reduced probability of eruption.”
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Image credit: NASA
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