This indicates the presence of major geomagnetic activity liable to be associated with an auroral storm.
Observers in southern England who would like to know if a big magnetic and auroral storm is likely and could become visible in their locality should visit the useful American website www.spaceweather.com.
Solar physicists think the auroral storm
observed on August 28th was also generated by an enormous CME that probably cleared a path in the solar wind, thereby facilitating the great speed of the September 2nd event.
That space, Yumoto says, contains vast quantities of electric currents generated by sharp changes in the earth's electromagnetic field and supplies the electrons needed to trigger an auroral storm.
Auroral storms -- the ghostly and etheral phenomenon that now and then whips up the polar skies -- probably originate in the outer space about 60,000 kilometers from the nocturnal face of the earth, according to scientists at Kyushu University.
Auroral storms are generated by larger than usual quantities of electrons interacting in the mix.
Auroras vary throughout the night during an auroral storm
, yet seem best about midnight.
"The tail is supposedly the region that supplies the first steps toward providing the energy for an auroral storm."
In the meantime, researchers continue to comb through the Galileo data, tracking down intriguing hints of links between auroral storms observed from Earth and activity in the magnetotail.
, Southern Style Nikon 35-mm camera, 50-mm f/2 lens, 1-minute exposure on Fujicolor Superia 400 color-negative film.
Jovian auroral storms
, like those on Earth, develop when electrically charged particles crash into the magnetic field surrounding the planet and then spiral inward toward the north and south magnetic poles.
Generally such conditions produce substorms rather than large auroral storms
. A substorm is defined by University of Alaska scientist Syun-Ichi Akasofu as "an auroral brightening that spreads in latitude and longitude to cover large distances." Many visually detected auroras are actually generated by substorms, explains Newell.