Heating and acceleration of the solar wind: turbulence, waves, and instabilities

Описание: Physics & Astronomy Colloquium
Professor Leon Ofman
2015 08 31
Catholic University of America and NASA Goddard Space Flight Center


The solar wind is a continuous and variable stream of magnetized plasma from the Sun that shapes the heliospheric environment and the Earth's magnetosphere. It is the background state of the interplanetary space that affect the propagation of Coronal Mass Ejections that can cause geomagnetic storms. Therefore, the observation and modeling of the solar wind is important for accurate space weather prediction. The existence of the solar wind was inferred theoretically and later discovered in spacecraft measurements. However, some key aspects in the physics of the solar wind formation, heating, and acceleration are still debated and intensively studied. The task is complicated by the facts that the solar wind plasma is non-Maxwellian (non-equilibrium), and contains evidence of kinetic instabilities. The magnetic and velocity fluctuations are often Alfvenic, exhibiting turbulent power-law scalings, and show evidence of dissipation. I will discuss the possible processes that lead to the heating and the acceleration of the solar wind, and review recent progress in the modeling of the solar wind plasma. I will discuss the relation of the modeling results to recent ACE/Wind satellite observations, as well as upcoming Solar Probe Plus and the Solar Orbiter missions.