Dartmouth Events

Physics & Astronomy/Thayer Plasma Seminar - Evan Thomas, Dartmouth College

Title: "Global Magnetosphere-Ionosphere Response to Varying Timescales of Solar Wind Driving and Long-Term Trends in Arctic Sea Ice Cover: New Results from the SuperDARN.

Tuesday, September 25, 2018
3:30pm-4:30pm
Wilder 202
Intended Audience(s): Public
Categories: Lectures & Seminars

Abstract:  Electrodynamics of the dayside high-latitude ionosphere are known to be governed by solar wind-magnetosphere coupling processes.  The nightside ionosphere however is dominated by tail reconnection processes (e.g., substorms) which do not necessarily have a one-to-one relationship with solar wind driving.  Statistical characterizations of ionospheric electrodynamics often assume a quasi-steady state is approached following a 10-40 min reconfiguration from one set of driving conditions to another.  We test this approximation by calculating statistical patterns of ionospheric convection using 7 years of velocity measurements from the Super Dual Auroral Radar Network (SuperDARN) for varying solar wind electric field, IMF clock angle, and solar wind steadiness criteria.  Average descriptions of the region 1 (R1) Birkeland current oval are calculated for the same time intervals and solar wind conditions using Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) observations of the high-latitude field-aligned current (FAC) system.  We examine the evolution of the R1 oval boundary under varying timescales of solar wind steadiness to infer the balance between dayside and nightside reconnection processes.  This context is used to describe the variations in ionospheric convection observed under strongly northward and southward IMF conditions for increasing solar wind steadiness.  Finally, a new and unique project using SuperDARN ground backscatter observations to detect Arctic sea ice characteristics will be introduced.

For more information, contact:
Tressena Manning
603-646-2854

Events are free and open to the public unless otherwise noted.