February 25, 2011, 12:00 pm - 1:00 pm

February 25, 2011, 12:00 pm - 1:00 pm

The Source of the Slow Solar Wind

Dr. Spiro Antiochos (NASA Goddard Space Flight Center)

Since the pioneering theoretical work of Parker, which was later confirmed by direct satellite observations, it has been known that the Sun's atmosphere streams continuously outward as a supersonic wind. At a basic level the origin of the wind is straightforward: the difference in gas pressure between the Sun's million-degree corona and the tenuous interstellar plasma causes the corona to expand outward. The Sun's intense magnetic field, however, adds both structure and dynamics to this simple 1D picture. The field divides the X-ray corona into regions that are "open" (i.e., connect to the heliosphere and "closed" (confined to the Sun). Furthermore, the field structures the heliosphere into quasi-steady "fast" wind and fully dynamic "slow" wind. The fast wind has been clearly identified as originating from open "coronal hole" regions, but the source of the slow wind has long been one of the major problems in solar/heliospheric physics. I will present a brief review of recent observations and models of the corona and wind, and then discuss a new theory, the S-Web model, that may explain the source of the slow wind.