Date: 2025-11-14 00:00:00
Time: 3:30 – 4:30pm
Location: 3853 Slichter Hall
Presented By:
Dr. Yangyang Shen
Abstract:
Magnetosphere and ionosphere coupling is largely driven by electromagnetic waves (e.g., Alfven waves) and particle precipitation in the polar cusp and auroral region. This coupling is inherently dynamic, nonlinear, and multiscale. Ionosphere magnetic perturbations (δB) span scales from >1,000 km across the auroral zone—associated with Region-1 and Region-2 field-aligned currents (FACs)—down to <1 km, approaching the electron inertial length and corresponding to fine-scale auroral arcs (~100 m). These smaller scale δB are often linked to inertial Alfven waves that carry parallel electric fields, accelerate electrons, and produce dynamic auroral structures. During geomagnetic storms and substorms, transient currents associated with these small-scale δB can exceed several hundred μA/m2, leading to ionosphere total electron content (TEC) perturbations and plasma irregularities that cause GPS scintillations and disrupt communication. Characterizing these small-scale δB and their space weather effects remains challenging due to Doppler shift from spacecraft motion (~7.8 km/s) and the scarcity of tandem spacecraft observations of electric and magnetic field measurements necessary to distinguish DC and wave components. NASA’s TRACERS mission, launched on 24 July 2025, offers new opportunities to investigate these processes. Here we present initial results from TRACERS MAG observations of a coincident small-scale δB and GPS scintillation event.