Plasma and Magnetic Fields

16 Dec 2010

NASA has another story to delight - the Cassini spacecraft took images of enormous clouds of plasma periodically blooming around Saturn, moving the planet 'like an unbalanced load of laundry on a spin cycle' and words to that effect. The hot plasma, they continue, producing a repeating signature like a thump in the rotating magnetic field. The big question now being asked - why are these plasma explosions happening in such a periodic manner? Data analysed by NASA shows plasma injections, electrical currents, and Saturn's magnetic field are all involved in the process - and an animation can be seen at www.nasa.gov/cassini and at http://saturn.jpl.nasa.gov The story is at www.jpl.nasa.gov/news/news.cfm?release=2010-417&cid=release_2010-417 . Somewhat later, we are told, we all know that changing rotation sequences have been observed at pulsars, millions of light years from our solar system, and now we find a similar phenomenon is happening right here on Saturn.

At www.physorg.com/print211566169.html a paper in the Journal of Geophysical Research which is based on images taken from the IBEX spacecraft, has brought renewed attention to the magnetosphere of the earth - the region of space that ebbs and flows in response to the amount of charged particles emitted from the sun. The link includes a video clip of IBEX images of a plasma sheet event, a component of the magnetosphere made up of magnetic field lines that attach to the earth at both ends, bottling up denser plasma (or ionised gas) within the magnetotail, the trailing portion of the magnetosphere. The various images also show a piece of the plasma sheet break away and being ejected down the tail - magnetic disconnection. This has never been seen before.

At www.physorg.com/news/2010-12-esa-sun.html ... new software developed by the European Space Agency makes available to anyone and everyone a library of images taken from the SOHO solar and heliospheric observatory - up to a million images with new ones being added each day - just one click away. There is also a web site to facilitate understanding of just what it is you are looking at - see http://jhelioviewer.org

Further, at www.physorg.com/print211555084.html a new research spacecraft was launched on December 12th from Norway, a rocket that rose up 200 miles into the aurorae and came down some 900 miles away. The short flight was a success - but the information has yet to be analysed. The hope is that it will shed new light on aurora.

At www.physorg.com/print211561407.html we learn that images of X-rays streaming from a stroke of lightning have been taken in an attempt to understand the behaviour of lightning, a glaring streak of electrically altered ionised air. How the spark is initiated is not understood. Electrical fields in clouds appear to be way too small. However, researchers have found they can produce lightning by shooting a rocket trailing copper wire into a thunderstorm.