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Abstract Flux transfer events (FTEs) are transient magnetic flux ropes at Earth's dayside magnetopause formed due to magnetic reconnection. As they move across the magnetopause surface, they can generate disturbances in the ultralow frequency (ULF) range, which then propagate into the magnetosphere. This study provides evidence of ULF waves in the Pc2 wave frequency range (>0.1 Hz) caused by FTEs during dayside reconnection using a global 3D hybrid‐Vlasov simulation (Vlasiator). These waves resulted from FTE formation and propagation at the magnetopause are particularly associated with large, rapidly moving FTEs. The wave power is stronger in the morning than afternoon, showing local time asymmetry. In the pre and postnoon equatorial regions, significant poloidal and toroidal components are present alongside the compressional component. The noon sector, with fewer FTEs, has lower wave power and limited magnetospheric propagation.

Geospace plasma simulations have progressed toward more realistic descriptions of the solar wind-magnetosphere interaction from magnetohydrodynamic to hybrid ion-kinetic, such as the state-of-the-art Vlasiator model. Despite computational advances, electron scales have been out of reach in a global setting. eVlasiator, a novel Vlasiator submodule, shows for the first time how electromagnetic fields driven by global hybrid-ion kinetics influence electrons, resulting in kinetic signatures. We analyze simulated electron distributions associated with reconnection sites and compare them with Magnetospheric Multiscale (MMS) spacecraft observations. Comparison with MMS shows that key electron features, such as reconnection inflows, heated outflows, flat-top distributions, and bidirectional streaming, are in remarkable agreement. Thus, we show that many reconnection-related features can be reproduced despite strongly truncated electron physics and an ion-scale spatial resolution. Ion-scale dynamics and ion-driven magnetic fields are shown to be significantly responsible for the environment that produces electron dynamics observed by spacecraft in near-Earth plasmas., (© 2022. The Authors.)

Shock waves in collisionless plasmas are among the most efficient particle accelerators in space. Shock reformation is a process important to plasma heating and acceleration, but direct observations of reformation at quasi-parallel shocks have been lacking. Here, we investigate Earth's quasi-parallel bow shock with observations by the four Magnetospheric Multiscale spacecraft. The multi-spacecraft observations provide evidence of short large-amplitude magnetic structures (SLAMS) causing reformation of the quasi-parallel shock. We perform an ion-kinetic Vlasiator simulation of the bow shock and show that SLAMS reforming the bow shock recreates the multi-spacecraft measurements. This provides a method for identifying shock reformation in the future., (© 2022. The Authors.)