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Don Scott

27 June 2015

SIS member Adam Stuart has been keeping some of us up to mode on the current Thunderbolts conference in the US. He has forwarded links to www.ptep-online.com/index_files/2015/PP-41-13.PDF and https://m.youtube.com/watch?v=fVsON1c3OUY

The first is to an article by Don Scott which has been published in the journal Progress in Physics. The video is a recording of aurora over northern Scotland which I've passed on to various people as it is pretty dramatic. See what you think.

Don Scott begins by saying that in 1908 Birkeland suggested auroras were powered by corpuscular rays emanating from the Sun – what we now call the solar wind. These he said, became deflected into Earth's polar regions by the magnetic field. The existence of such a magnetic field was disputed, based on the idea, or partially so, that currents could not cross the presumed vacuum of space. Birkeland was unable to expand on his theory because of the nature of the magnetic field (which has multiple strands) and therefore his ideas had a tendency to languish – although many people were sympathetic.

In 1950 Lundquist investigated whether  magnetic fields could exist in an electrically conducting liquid. In 1957 Chandrasekhar and Kendall applied a similar analysis to the spherical geometry of the Sun. NASA scientists and others have been working on Birkeland currents and flux rope observations since the mid 1960s. Later, it was concluded that Birkeland currents and Alfven waves are fundamental to understanding the Earth's plasma environment. In 2009 the space probe Themis discovered a flux rope pumping a huge current down into the Arctic  auroral region, providing observational evidence for the existence of Birkeland currents. They were no longer hypothetical. Scott then goes on to spell out a Lundquist like model of a cylindrical force free field aligned current. He uses a NASA video which clearly displays counter rotation – and various other elements in the argument taken from images from the Cassini mission to Saturn, as well as the Hourglass or Butterfly planetary nebula, M2-9, which has a z-pinch etc. Well worth a download and browse. 

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