Hannes Alfvén

Hannes Olof Gösta Alfvén was a Swedish electrical engineer and plasma physicist who single-handedly founded the field of magnetohydrodynamics (MHD)—the study of how electrically conducting fluids interact with magnetic fields. Educated at Uppsala University and later a professor at the Royal Institute of Technology (KTH) in Stockholm and UC San Diego, Alfvén realized that ninety-nine percent of the observable universe exists in the plasma state.

In 1942, Alfvén predicted that magnetic fields in ionized plasma can propagate transverse low-frequency waves, in which ions oscillate in response to restoring tension in magnetic field lines. Now known worldwide as Alfvén waves, these plasma waves explain aurora borealis dynamics, geomagnetic storms, solar flares, and coronal heating. For his fundamental work in magnetohydrodynamics with fruitful applications in different parts of plasma physics, Alfvén was awarded the 1970 Nobel Prize in Physics—the only plasma physicist ever so honored.