... The concept of continuous solar wind developed in 1950's. First, Biermann (1951, 1957) observed comet tails as they passed close to the Sun , and explained the observed tail deflection by a continuous flux of protons from the Sun. Then Parker (1959) showed that the solar corona must expand, and called the outward streaming coronal gas 'solar wind'. ... The expanding solar wind drags also the solar magnetic field outward, forming what is called the interplanetary magnetic field (IMF) . ...