2025 THEMIS SCIENCE NUGGETS

SUMMARIES OF THEMIS RESEARCH

By utilizing in-situ measurements of multiple spacecraft together with THEMIS ground-based magnetometers, we for the first time determine the extreme compression of the magnetopause from higher than 10 R E down to 5 R E . This observation of such severe deformation is also consistent with the prediction of the theoretical model. Read more.

We conducted a statistical investigation of the dayside magnetopause reconnection extent using 39 space–ground conjugate observations. The azimuthal extent of reconnection exhibits substantial variability, ranging from ~1.5 hr to ~6.5 hr in magnetic local time (MLT), and is influenced by the solar wind speed. Read more.

While numerous studies have explored fast and slow ion flows and dawn-dusk asymmetries in the plasma parameters within the plasma sheet, questions remain about how these flows and plasma properties evolve throughout the substorm cycle, particularly the statistical distributions of earthward and tailward flows and asymmetries in ion density and pressure during different phases. Read more.

In this study, we examine how different types of solar wind and the presence of an upstream foreshock might explain why the real observed magnetopause sometimes does not match model predictions, using data from spacecraft missions in near-Earth space (Cluster, THEMIS and MMS). Read more.

In this study we combine THEMIS satellite measurements above the ionosphere with GPS receiver and magnetometer measurements below the ionosphere, along with lists of earthquakes and other surface disturbances, to isolate and study conditions when plasma waves above the ionosphere affect electron dynamics in the ionosphere. Read more.

This study establishes the first direct linkage between streamer-like meso-scale red-line auroras and plasma sheet electron pitch-angle scattering by TDSs, underscoring the importance of wave-driven diffuse auroral processes in generating low-energy auroral streamers, distinct from the conventional streamer quasi-electrostatic coupling paradigm. High correlations between observed and forward modeled auroral intensity help establish high-fidelity magnetic mapping during geomagnetically active periods. Read more.