| March 21, 2019

When 'killer electrons' shook Earth in flat 60 seconds

WASHINGTON, March 10: A team of scientists has observed in detail for the first time the effects of a solar shockwave on the Earth's radiation belts from the beginning to the end.

The shockwave struck a massive blow to the Earth's magnetic field, setting off a magnetised sound pulse around the planet on October 8, 2013.

The resulting magnetosonic pulse, lasting just 60 seconds, reverberated through the Earth's radiation belts, accelerating certain particles to ultrahigh energies.

"These are very lightweight particles, 'killer electrons' - electrons that can go right through a satellite," said John Foster, associate director of Massachusetts Institute of Technology's (MIT) Haystack Observatory.

These particles are accelerated, and their number goes up by a factor of 10 in just one minute.

"We were able to see this entire process taking place and it is exciting. We see something that, in terms of the radiation belt, is really quick," he added.

Solar shockwaves can impact Earth's radiation belts a couple of times each month.

"The event in 2013 was a relatively minor one," Foster noted.

On October 8, 2013, an explosion on the Sun's surface sent a supersonic blast wave of solar wind out into space.

This shockwave tore past Mercury and Venus, blitzing by the moon before streaming towards Earth.

NASA's Van Allen Probes, twin spacecraft orbiting within the radiation belts deep inside Earth's magnetic field, captured the effects of the solar shockwave just before and after it struck.

Scientists at MIT's Haystack Observatory, the University of Colorado and elsewhere analysed the probes' data and observed a sudden and dramatic effect in the shockwave's aftermath.

The findings were published in the Journal of Geophysical Research.