The dynamic aurora

Journal Article · Mon May 01 00:00:00 EDT 1989 · Scientific American; (USA)

DOI:https://doi.org/10.1038/scientificamerican0589-90· OSTI ID:6485913

Akasofu, Syunichi ^[1]

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1. Univ. of Alaska, Fairbanks (USA)

Auroral physicists today know that auroras are lights emitted when atoms and molecules in the ionosphere are struck by electrons blowing in from the sun. The apparent motion of the auroral curtain is caused not by atmospheric turbulence but by changes in the electromagnetic conditions that propel the electrons, just as motion on a television screen is an illusion created by changes in the magnetic field that directs electrons from a cathode tube onto the screen. In the case of the aurora, what serves as the cathode tube Where is its power supply Why does that power seem to fluctuate from time to time, causing the aurora to ebb and flow across the polar sky More than 20 years ago it was determined that auroral emissions occur because the ionosphere is bombarded by electron beams generated by a complex interaction between the solar wind and the earth's magnetic envelope. The geomagnetic nature of the aurora can be seen clearly from outer space. Centered on each of the geomagnetic poles is a great luminous oval that is a permanent feature of the planet. The one around the North Pole is the aurora borealis. Its counterpart in the south is the aurora australis. The authors and his colleagues have now found a numerical relation between the solar wind and the generation of the power that drives the aurora, as well as other disturbances of the geomagnetic field. They are also gaining a better idea of how the sun's activity affects the solar wind. This progress raises the interesting possibility of developing a computer method to predict the intensity of auroral activity. Because auroras can interfere significantly with radio and satellite communications, as well as with power lines and some defense systems, the ability to predict auroral intensity has become increasingly important as human activity expands into polar regions and into space.

• OSTI ID: 6485913
• Journal Information: Scientific American; (USA), Journal Name: Scientific American; (USA) Vol. 260:5; ISSN SCAMA; ISSN 0036-8733
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATOMS
AURORAE
AURORAL OVAL
CURRENTS
DYNAMICS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
EARTH PLANET
ELECTRIC CURRENTS
ELECTROJETS
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
GEOMAGNETIC FIELD
INTERACTIONS
IONOSPHERE
LEPTONS
MAGNETIC BAYS
MAGNETIC FIELDS
MAGNETIC STORMS
MECHANICS
MOLECULES
PLANETARY IONOSPHERES
PLANETS
SOLAR ACTIVITY
SOLAR FLARES
SOLAR WIND