Dartmouth Events

Abstract: The universe is filled with plasmas, which make up 99.9% of matter in the visible universe. The Sun, the primary source of energy for the solar system through radiation, also blows out a “solar wind” in the form of a hot tenuous plasma. The solar wind plasma fills interplanetary space, creating a vast bubble called the heliosphere, the only natural laboratory available for the direct exploration of fundamental processes in plasma physics. The solar wind is super-fast (300-800 km/s, Mach number reaching 10 and over) and extremely hot (close to one million degrees) and originates from the outermost layer of the Sun’s atmosphere, the solar corona, visible to the naked eye during total solar eclipses. In this colloquium, I will first review the discovery of the solar wind and the fundamental theories explaining its acceleration. However, early theories are unable to produce fast solar wind speed with the observed temperature profile, highlighting the need to incorporate additional physics, that is, the electromagnetic processes occurring in the solar atmosphere, such as magnetic reconnection and plasma turbulence. The presentation will underscore the most recent progress made in understanding the heating and acceleration of solar corona and solar wind, using the cutting-edge modeling efforts and the latest observations made by Parker Solar Probe, which was launched in 2018 with the goal of understanding the sources and dynamic processes behind the formation of the heliosphere. Last, I will discuss future research opportunities in the field of heliophysics.

***Join before the Colloquium at 3:00 pm for coffee, cookies and brownies from Lou's in Wilder 103!***

Hosted by Professor Yi-Hsin Liu