Aurora as seen from the international space station

[Tzunamii]

http://www.wimp.com/auroraborealis/
Absolutely beautiful.

[robinson]

Very cool.

[MGmirkin]

Speaking of auroras and cool stuff, you guys should check out some of the papers by Bengt Hultqvist...

(On the importance of auroral processes in the Universe; not free unfortunately, I think it costs like $30-something unless you have a subscription or access through an institution?)
http://adsabs.harvard.edu/abs/2008JASTP..70.2235H

Acceleration of charged particles in magnetic field-aligned electric potential differences at Earth and at the outer planets in the solar system is summarized and its general importance in the Universe is briefly discussed. The role of field-aligned currents, driven by parallel electric fields, in causing filamentary structure in stellar atmospheres is briefly reviewed. The differences between auroral optical emissions at various planets are summarized. The important role of field-aligned potential differences in the generation of AKR and corresponding emissions from other objects is discussed. Finally, aurora-associated processes for ejection of planetary plasma into space are briefly reviewed.

(Downward ion acceleration at auroral latitudes: cause of parallel electric field)
http://adsabs.harvard.edu/abs/2002AnGeo..20.1117H
http://www.ann-geophys.net/20/1117/2002 ... 7-2002.pdf

Observations with the Freja satellite at about 1700 km altitude of downward accelerated ions in the keV and sub-keV energy range are described and analysed. The observations show the following: (1) Processes involving velocity dispersion are not important; (2) Ion pitch-angle distributions are mostly somewhat field aligned but not far from isotropic, so the ions are effectively spread in pitch-angle; (3) As all ion species, H +, O +, and He +, are found to be accelerated to the same energy, the only possible known acceleration mechanism is a potential difference along the magnetic field lines; (4) No significant Birkeland current features are associated with the ion precipitation; (5) Precipitation of energetic electrons from the plasma sheet is always present when the downward accelerated ions are observed; (6) Ion precipitation is generally not seen in regions with primary auroral Birkeland currents associated with electron inverted-V distributions; (7) Precipitated ions are mostly observed at low and medium disturbance levels, but they are also found in strongly disturbed conditions; (8) Downward accelerated ions occur fairly frequently at auroral latitudes near Freja apogee altitudes and are seen at all local times. The present investigation is limited to the nightside. The above observational results are found to be consistent with the physical mechanism for producing a downward-pointing parallel electric field proposed by Hultqvist (1971). That mechanism is basically one of an ambipolar potential difference set up by the energetic electrons from the plasma sheet.

(Parallel electric fields accelerating ions and electrons in the same direction)
http://adsabs.harvard.edu/abs/1988Ap%26SS.144..149H
http://articles.adsabs.harvard.edu/cgi- ... e=PDF_HIGH

In this contribution Viking observations of electrons and positive ions which move upward along the magnetic field lines with energies of the same order of magnitude are presented. It is proposed that both ions and electrons are accelerated by an electric field which has low-frequency temporal variations such that the ions experience an average electrostatic potential drop along the magnetic field lines whereas the upward streaming electrons are accelerated in periods of downward pointing electric field which is quasi-static for the electrons and forces them to beam out of the field region before the field changes direction.

It's amusing to the note that apparently back on March 20th, 1989 Boston Globe ran a story entitled "Alfven: Universe Is An Electric Place Nobel Physicist Sees Cosmos As A Big Aurora; Recent Perplexing Findings Give His Idea A Boost." The article is available for a fee from the Globe's archives online. I haven't read it though. I was just amused considering the title of Hultqvist's paper ("On the importance of auroral processes in the Universe") was so strikingly similar almost exactly 20 years later... Don't know if that was intentional or not. May have just been a big whopping coincidence. If I believed in coincidences anymore, that is. First THEMIS publishes on magnetic ropes a hundred years after Birkeland predicted "pencil" cathode rays flowing in filaments from he sun to the Earth. Now Hultqvist publishes this paper on auroral phenomena 20 years after Alfvén gets noticed with his "Electric Universe"-ish mention talking about how auroral processes may be important in understanding how the universe works...

Good times...
~Michael Gmirkin

[MGmirkin]

I wonder how this latest finding about the Auroral Kilometric Radiation reflects on the Bengt Hultqvist paper?

(Satellites Pinpoint Earth's Auroral Radio Chatter)
http://www.scientificamerican.com/artic ... oint-earth

(On the importance of auroral processes in the Universe)
http://dx.doi.org/10.1016/j.jastp.2008.03.023

Best,
~Michael Gmirkin

[mharratsc]

Next we'll have to 'patent' scientific discoveries