Plasma Vortices and Spacequakes

This sort of thing fits right in with the Plasma Cosmology view.

Researchers using NASA’s fleet of five THEMIS spacecraft have discovered a form of space weather that packs the punch of an earthquake and plays a key role in sparking bright Northern Lights. They call it “the spacequake.”

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“Magnetic reverberations have been detected at ground stations all around the globe, much like seismic detectors measure a large earthquake,” says THEMIS principal investigator Vassilis Angelopoulos of UCLA.

It’s an apt analogy because “the total energy in a spacequake can rival that of a magnitude 5 or 6 earthquake,” according to Evgeny Panov of the Space Research Institute in Austria. Panov is first author of a paper reporting the results in the April 2010 issue of Geophysical Research Letters (GRL).

In 2007, THEMIS discovered the precursors of spacequakes. The action begins in Earth’s magnetic tail, which is stretched out like a windsock by the million mph solar wind. Sometimes the tail can become so stretched and tension-filled, it snaps back like an over-torqued rubber band. Solar wind plasma trapped in the tail hurtles toward Earth. On more than one occasion, the five THEMIS spacecraft were in the line of fire when these “plasma jets” swept by. Clearly, the jets were going to hit Earth. But what would happen then? The fleet moved closer to the planet to find out.

“Now we know,” says THEMIS project scientist David Sibeck of the Goddard Space Flight Center. “Plasma jets trigger spacequakes.”

Spacequakes (vortices, 200px)

A THEMIS map of plasma flows during a spacequake. The axes are labeled in Earth radii, so each swirl is about the size of Earth.

“When plasma jets hit the inner magnetosphere, vortices with opposite sense of rotation appear and reappear on either side of the plasma jet,” explains Rumi Nakamura of the Space Research Institute in Austria, a co-author of the study. “We believe the vortices can generate substantial electrical currents in the near-Earth environment.”

Acting together, vortices and spacequakes could have a noticeable effect on Earth. The tails of vortices may funnel particles into Earth’s atmosphere, sparking auroras and making waves of ionization that disturb radio communications and GPS. By tugging on surface magnetic fields, spacequakes generate currents in the very ground we walk on. Ground current surges can have profound consequences, in extreme cases bringing down power grids over a wide area.

Lately I've been seeing more mention of electricity in space science news, which is to the good - but one possibility that the THEMIS scientists don't seem to be considering is that electrical forces are generating the magnetic fields.  You can't have one without the other - something that solar scientists and cosmologists, and in fact anyone who uses the phrase "magnetic lines reconnecting" fails to grasp.

Posted by Buckethead Buckethead on   |   § 0

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