The godfather of the solar wind: E. Parker

posted: Feb 10, 2009

We have the honor to welcome E. Parker in June 2009 at the Solar-Terrestrial Center of Excellence. This will be an occasion to speak to the world's top expert on the solar wind. It was in the 1950s that Parker developed his theory about the solar wind. In the perception of many, his name is a synonym for solar wind.

Parker suggested that the corona, the exterior part of the solar atmosphere is continuously expanding. This spherically symmetric expansion is called the solar wind. This wind is an ever lasting plasma stream. By the time the wind reaches Earth, it has become supersonic and leads to the typical form of the dipolar Earth magnetosphere, our magnetic protection with the stretched tail at the night-side and compressed bulb at the day-side. The solar wind is associated with open magnetic field lines. Coronal holes are solar structures with this typical open magnetic field configuration. The wind drags with it the solar magnetic field lines. The plasma and the magnetic field stick together. Thinking further, Parker understood how the Sun's magnetic field should look in space. He came to the concept of a spiral, the famous Parker spiral. The spiral is a way to picture the open magnetic field lines emanating from the Sun, how they reach out in space and how they are bended because of the solar rotation.

It was also Parker who proposed a solution for the heating problem of the corona. The corona is much hotter compared with for example, the solar surface. Nano-flares could be the key in solving this problem. Parker was born in 1927. His science dates from before and after the space age. His theories developed before the space age, were confirmed by spacecrafts, contrary to all the skepticism. No magic or crystal ball, but clever and open for new ideas. We are looking forward to his visit and his talk!