Hannes Alfvén

Biography

Hannes Alfvén was a Swedish scientist who won the Nobel Prize in Physics in 1970 for opening up the field of magnetohydrodynamics (hydromagnetic waves) and developing ways to apply it to the study the physics of the magnetosphere, the solar system and interstellar space.

Alfvén was born in Norrköping, Sweden, in 1908 to a family of doctors. His mother, Anna-Clara Romanus, was among Sweden’s first female physicians, and his parents encouraged Alfvén’s early interest in astronomy and radio electronics. Alfvén attended the University of Uppsala, where he studied mathematics and physics.

Displaying a contrarian streak that ran throughout his academic career, Alfvén chose to study what would now be considered nuclear physics and electronics, in contrast to his department’s focus on spectroscopy. His doctoral thesis on “Ultra-Short Electromagnetic Waves” (1932) also pushed against the current, as he was pursuing research in astronomy and electronics at a time when many scientists were looking into nuclear physics.

After earning his doctorate, Alfvén worked at the University of Uppsala and then at the Nobel Institute in Stockholm. In 1940, at age 32, he was appointed Professor of Electromagnetic Theory and Electric Measurements at the Royal Institute of Technology in Stockholm, where he helped lead an institutional expansion that created three new departments, including the Alfvén Laboratory in 1990. He also mentored future innovators in physics. In 1967, he accepted a dual appointment at the University of San Diego (which holds his papers), and he divided his time seasonally between Sweden and the United States until 1988.

Alfvén was consistently ahead of his time in his theories about the movement of electricity in space. Contemporary physicists (including the editors of various peer-reviewed journals) initially doubted many of his innovations, but they have since been accepted as critical tools in the study of plasma physics. He made it far simpler to analyze charged particle motion in electric and magnetic fields through his idea of the guiding center. Concepts named after him, including Alfvén waves and velocity, Alfvén number, Alfvén layers, Alfvén critical points, Alfvén radii, and Alfvén distances, have all become part of the lexicon of this field.

He broke with the scientific consensus when he proposed the phenomenon that would later be called Alfvén waves: electromagnetic waves in which tension on the magnetic field lines provides a restoring force that causes the ions to oscillate . Before he tried to develop a mathematical model of these waves, he had to overcome skepticism that electromagnetic waves could propagate more than a skin depth into a good conductor. He also had to convince his peers that even if, as was then believed, interstellar space was a vacuum, it contained sufficient plasma to carry electric currents that could locally produce the magnetic field.

Alfvén also sought to develop practical applications for his ideas. His study of the solar atmosphere, for example, inspired him to invent a new kind of vacuum tube, the Trochotron, which used an electron beam in crossed electric and magnetic fields. He was an early proponent of nuclear power, but would become one of its leading critics in Sweden as the dangers became better known.

If he was often an outsider in the profession, some of his ideas remain controversial, such as his research into symmetric cosmology. It remains disputed whether the universe is made of equal amounts of matter and anti-matter separated by thin boundary layers. In fact, Alfvén created a medal that may one day be awarded to the first person who can determine whether the Alpha-Centauri star is made of matter or anti-matter.

In addition to sharing the 1970 Nobel Prize in Physics, Alfvén was a lifetime fellow of the IEEE and earned numerous awards in his field. The Hannes Alfvén Prize is awarded annually by the European Physical Society for outstanding work in plasma physics.

Hannes Alfvén

Biography

Further Reading