Photo from the Nobel Foundation archive.
Hannes Olof Gösta Alfvén
Born: 30 May 1908, Norrköping, Sweden
Died: 2 April 1995, Djursholm, Sweden
Affiliation at the time of the award: Royal Institute of Technology, Stockholm, Sweden
Prize motivation: "for fundamental work and discoveries in magnetohydro-dynamics with fruitful applications in different parts of plasma physics."
Prize share: 1/2
The phenomenon of aurora borealis occurs when bursts of charged particles from the sun collide with the earth's magnetic field. These jets of particles are an example of a special state of matter - plasma. Plasma is a gas comprised of electrons and ions (electrically charged atoms) that forms at high temperatures. From the late 1930s onward, Hannes Alfvén developed a theory about aurora borealis, which led to magneto-hydrodynamics; the theory of the relationships between a plasma's movements, electric currents and fields, and magnetic fields.