High Speed Electrons’ Energy Source Found

U.S. researchers say they’ve discovered how ultra high-speed electrons produced by solar flares and magnetospheric storms get their high energy.

A team of scientists led by University of Maryland physics Professor James Drake have solved a key remaining mystery about how the interaction of magnetic fields produce the explosive releases of energy seen in solar flares, storms in the Earth’s magnetosphere and many other powerful cosmic events.

Large numbers of such low-mass particles travel at speeds far higher than can be explained by the widely accepted slingshot model for how reconnecting magnetic field lines accelerate charged particles.

Now the researchers appear to have found the answer. In the October 5 edition of the journal Nature, Drake and colleagues show electrons gain speed by repeatedly bouncing off of the ends of contracting magnetic islands that form as the magnetic field lines reconnect.

Ours is the first mechanism that explains why electrons gain so much energy during magnetic reconnection, said Drake, And from a practical standpoint, these new findings can help scientists to better predict which solar storms pose the greatest threat to communications and other satellites.