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Physics and Astronomy Space Plasma Seminar - Toshi Nishimura - Boston University

Title: "Remote Sensing of Earth's Dayside Reconnection Processes by Imagers and Radars"

Tuesday, January 31, 2017
3:30pm – 4:30pm
Wilder 202
Intended Audience(s): Public
Categories: Lectures & Seminars
Abstract: Dayside magnetic reconnection in the Earth’s magnetosphere plays an important role in energy transport from the solar wind to the Earth’s magnetosphere-ionosphere system. Understanding of dayside reconnection is important for plasma dynamics in its ionospheric footprint (cusp), including plasma transport and heating. While in-situ measurements by satellites can determine local behavior of reconnection, it is difficult to address its spatial extent and time evolution. On the other hand, remote-sensing from the ground by imagers and radars provides 2-d measurements of electron precipitation from the reconnection region, allowing to find spatial and temporal evolution of dayside reconnection and its connection to ionospheric phenomena.
 
Recently a new incoherent scatter radar located at Resolute Bay, Canada (RISR-C), started its science operation. In combination with the existing north-facing radar (RISR-N), the pair of radars provides the highest resolution of data in the cusp region over 10 degree latitudes. These data were used to address (1) spatial extent, timing, and duration of dayside reconnection, (2) ionospheric plasma transport and heating associated with dayside reconnection, and (3) their dependence on upstream solar wind conditions. As expected, dayside reconnection is found overall correlated with the southward interplanetary magnetic field. In such situations, the azimuthal extent of reconnection is ~3 h MLT and ionospheric plasma propagating into the open magnetic field region originates on closed magnetic field lines. On the other hand, dayside reconnection is also enhanced in other solar wind conditions including cone angle changes. In such situations, dayside reconnection is more localized (~1 h MLT) and ionospheric plasma is mostly generated by precipitation into the cusp. We also identified 2-d structures of plasma transport along magnetic field lines (upflow) associated with cusp heating processes.
For more information, contact:
Tressena Manning
tressena.a.manning@dartmouth.edu
603-646-2854
Permanent URL to this event: https://physics.dartmouth.edu/events/event?event=43263

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