The Principal Investigator (PI) will investigate discontinuities in the solar wind near the Sun and at the Earth, and use these structures to study magnetic reconnection events at the Sun. His team will catalog discontinuity types, calculate discontinuity occurrence frequency as a function of solar wind characteristics and solar source region, and develop a capability to predict the types of plasma structures that arrive at Earth.
The PI's team will statistically analyze high-resolution plasma and magnetic field data from the Wind, ACE, Helios-1, and Helios-2 spacecraft to develop criteria to identify the various types of discontinuities existing in the solar wind. The team will then use the Wang-Sheeley-Arge (WSA) model to map the solar wind at L1 back to the solar surface, and thus determine from which type of solar-surface region (for example, center of coronal hole, coronal-hole edge, small coronal hole, or active region) each discontinuity in their catalog originated.
Using their discontinuity catalog, the PI's team will identify plasma boundaries and suprathermal-electron boundaries, and then calculate the amount of magnetic flux between each boundary pair using magnetic field and plasma data collected at 1 AU. From this amount of flux and the calculated transit time of the solar wind, the will estimate the reconnection rate at the solar surface.
The data needed for this project are accessible online. The PI expects this effort to lead to a better understanding of the origin of plasma structure in the heliosphere and the physical processes acting in the solar wind. This project will train a postdoctoral scientist and the research results will be incorporated into an educational outreach program.
