Alfvén’s approach to physics:
Alfvén’s approach to physics was based on insight and intuition. He was quick to understand how nature works and he was able to place new observations into a framework larger than that required to explain the observations themselves. For example, in the early 1930’s, cosmic rays were commonly thought to be gamma rays filling the entire universe. However, when they were discovered to be charged particles, Alfvén offered in 1937 the novel suggestion that the galaxy contained a large-scale magnetic field and that the cosmic rays moved in spiral orbits within the galaxy, owing to the forces exerted by the magnetic field. He argued that there could be a magnetic field pervading the entire galaxy if plasma was spread throughout the galaxy. This plasma could carry the electrical currents that would then create the galactic magnetic field.