World of Scientific Discovery on Hannes Olof Gösta Alfvén

Hannes Olof Gösta Alfvén made a number of important discoveries in the fields of plasma physics, space physics, and astrophysics, and is considered the founder of magnetohydrodynamics (MHD), a field of study whose applications are as diverse as the properties of stars and the production of fusion power by artificial means. In 1970, he was awarded the Nobel Prize with Louis Néel in physics for his achievements in MHD and their practical uses in plasma physics. MHD deals with the behavior of electrically conducting gases and liquids as they interact with magnetic fields. The first space scientist to receive the Nobel, Alfvén's discoveries grew out of his research in sunspots.

Hannes Olof Gösta Alfvén was born in Norrköping, Sweden, May 30, 1908. His parents, Johannes Alfvén and Anna-Clara (Romanus) Alfvén, were both physicians. After completing elementary and secondary school in Norrköping, Alfvén enrolled at the University of Uppsala and received his Ph.D. in physics in 1934. He became a lecturer in physics at Uppsala, and three years later was appointed research physicist at the Nobel Institute of Physics. In 1940, he became a member of the faculty at the Royal Institute of Technology in Stockholm where he held successively the titles of professor of the theory of electricity from 1940 to 1945, professor of electronics from 1945 to 1963, and professor of plasma physics from 1963 to 1967.

Alfvén's primary research interest was the application of physical principles to astronomical phenomena. In the early 1940s, he began a long-term study of sunspots. One of the consequences of his research was his discovery of hydromagnetic waves (named Alfvén waves in his honor), which challenged some long-held and widely accepted physical concepts, including James Clerk Maxwell's electromagnetic theory. Traditionally, electromagnetic waves were believed to be incapable of penetrating a conductor to any significant degree. For example, light (a form of electromagnetic radiation) is almost perfectly reflected by a conductor such as copper or silver metal.

During his study of sunspots, Alfvén hypothesized that electromagnetic waves were very good conductors, able to extend through the highly ionized solar gas. In 1942, he published a detailed and elegant demonstration of his theory; however, his observations were either ignored or rejected by most of his colleagues. Six years later, when he presented his ideas in a lecture at the University of Chicago. Enrico Fermi is said to have nodded in approval after Alfvén had delivered his paper; soon after, the physics community followed suit.

Alfvén continued to work for the most part in private, publishing a relatively small number of papers on his discoveries. Out of that work, however, grew an important new field of physics now known as magnetohydrodynamics (MHD).

An important aspect of Alfvén's work in MHD has been his study of plasma, sometimes referred to as the fourth state of matter. A gas-like mixture of electrons and positively-charged ions, plasma exists only at very high temperatures, such as those found in stars. At such extreme temperatures, atoms and molecules are completely ionized. Most of Alfvén's early research on plasma was based on studies of sunspots, magnetic storms, and other stellar phenomena. One of his most important discoveries in this area came in the 1930s, when he proposed the concept of magnetic field lines that become "frozen" within a plasma. He showed that under certain circumstances in which a plasma moves, the magnetic field associated with it moves as well. The primary goal of Alfvén's work with plasma and MHD has been to better understand the origin of the universe, which he believes was formed from plasma. By studying properties of primordial plasma through exploration of asteroids, for example, Alfvén felt more could be learned about how stars, planets, and other astronomical bodies were formed. Consequently, he was a strong supporter of space research programs, such as those carried out by the U.S. National Aeronautics and Space Administration. Such programs, he believes, provide an invaluable way of testing theoretical concepts like those he developed.

Although Alfvén's own research has centered on outer space, many of his discoveries have had important practical applications. For example, developing fusion power plants that can supply energy on a commercial basis depends on the ability to produce and contain very hot masses of material within which fusion reactions can occur. At the high temperatures inside a fusion reactor, these materials exist in the form of plasma, inviting the many important applications of Alfvén's discoveries.

Alfvén left Sweden in 1967 to accept an appointment as professor of physics at the University of California at San Diego. His decision to leave his native country was supposedly based on disagreements with the Swedish government over certain policies, particularly those involving education and nuclear power. For instance, although he had originally been a strong supporter of the construction of nuclear power plants, he later developed concerns about the environmental risks posed by such plants. He argued against the increasing dependence on nuclear power in Sweden, and eventually decided that all applications of nuclear power--both peaceful and military--were dangerous. He became active in the anti-nuclear movement of the 1970s and 1980s. At the time of his death, Alfvén was teaching part-time at the University of California in San Diego. He died at his home in Djursholm, Sweden. In addition to his Nobel Prize, Alfvén received the Gold Medal of the Royal Astronomical Society in 1967, the Lomonosov Gold Medal of the Soviet Academy of Sciences in 1971, the Franklin Medal of the Franklin Institute in 1971, and the Bowie Gold Medal in 1987. Alfvén's memberships included the National Academy of Sciences and the Royal Society.