Space Physics Seminar fall-2016

The Origin of the Slow Solar Wind

The solar wind is one of the major drivers of Space Weather activity producing a variable stream of plasma that impacts the earth’s magnetosphere. The solar wind is classified into the fast and slow solar wind streams, with the slow wind reaching ~400 km/s and the fast wind is about twice faster and half denser near Earths’ orbit. While major advances were made in solar wind research, the origin and formation of the slow solar wind (SSW) are still outstanding questions in solar physics. The wealth of present day remote sensing observations and models provide important clues on the magnetic structure and the possible acceleration mechanics of the SSW. Understanding the origin of the SSW is a major objective of the planned Solar Probe Plus and Solar Orbiter spacecraft missions. I will review the important outstanding questions requiring further analysis: What are the source regions on the Sun and their contributions to the SSW? What is the role of the magnetic topology in the corona for the origin, acceleration and energy deposition of the SSW? What are the possible acceleration and heating mechanisms for the SSW? I will discuss the present status of our understanding of the origin and formation of the SSW, and review the significant progress that has been made recently in the study of SSW thanks to spacecraft observations, such as Ulysses, Wind, ACE, and STEREO. I will present the results of advanced numerical models of the SSW that address the above open questions.