Secrets of exploding plasma clouds on Sun

Scientists sheds light on the explosion of plasma clouds on the Sun.

Last Updated: Nov 09, 2010, 17:47 PM IST

Washington: Scientists have shed light on the explosion of plasma clouds on the Sun.
The Sun sporadically expels trillions of tons of million-degree hydrogen gas in explosions called coronal mass ejections (CMEs).

Such clouds are enormous in size and are made up of magnetized plasma gases, so hot that hydrogen atoms are ionized.

CMEs are rapidly accelerated by magnetic forces to speeds of hundreds of kilometres per second to upwards of 2,000 kilometres per second in several tens of minutes.

CMEs are closely related to solar flares and, when they impinge on the Earth, can trigger spectacular auroral displays.

They also induce strong electric currents in the Earth``s plasma atmosphere (i.e., the magnetosphere and ionosphere), leading to outages in telecommunications and GPS systems and even the collapse of electric power grids if the disturbances are very severe.

In 2006, an international twin-satellite mission called STEREO was launched to continuously observe the erupting plasma structures from the Sun to the Earth.

Now, using the data from STEREO, new research by scientists at the Naval Research Laboratory (NRL), has demonstrated for the first time that the observed motion of erupting plasma clouds driven by magnetic forces can be correctly explained by a theoretical model.

The theory is based on the concept that an erupting plasma cloud is a giant "magnetic flux rope," a rope of "twisted" magnetic field lines shaped like a partial donut.

The findings will be presented at the 52nd Annual Meeting of the APS Plasma Physics Division.