Journal Article

Dayside Pc2 Waves Associated With Flux Transfer Events in a 3D Hybrid‐Vlasov Simulation

Turc, L., Pfau‐Kempf, Y., Zaitsev, I., Cozzani, G., Tarvus, V., Ganse, U., Grandin, M., Workayehu, A., Papadakis, K., Zhou, H., Alho, M., Tesema, F., Battarbee, M., Horaites, K., Palmroth, M., Suni, J., Dubart, M.

2024

Overview

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. Plain Language Summary The Earth's magnetosphere is a dynamic region shaped by the interplay between the solar wind and Earth's magnetic field. This interaction occurs at the boundary of the magnetosphere (magnetopause) through a process known as magnetic reconnection, giving rise to Flux Transfer Events (FTEs), which are magnetic structures that carry flux and energy into the magnetosphere. These FTEs form either in sudden bursts, patchy patterns or in a continuous, and relatively stable way making the magnetopause surface dynamic. As the FTEs move along the boundary of the magnetosphere, they create compressed regions and lead to wave generation that can extend into the magnetosphere. The study uses an advanced 3D hybrid‐Vlasov simulation model to analyze waves originated from FTE formation and propagation at the magnetopause. We find that rapidly moving and large FTEs have a significant impact on the magnetopause, leading to the generation of ULF waves with frequency above 0.1 Hz. This shows first direct evidence supporting previous theoretical speculations regarding the ability of FTEs to generate waves near the magnetopause. Key Points Dayside Pc2 waves (>0.1 Hz) have been detected in a 3D hybrid‐Vlasov simulation These waves exhibit lower intensity within the magnetosphere at noon, compared to the prenoon and postnoon sectors Pc2 waves observed in the simulation are associated with largest and fast moving flux transfer events initiated by subsolar reconnection

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Earth / Earth magnetosphere / Equatorial regions / Extremely low frequencies / Fluctuations / Flux transfer events / Frequency ranges / Geomagnetic field / Jupiter / Magnetic field / Magnetic fields / Magnetic flux / Magnetic reconnection / Magnetopause / Propagation / Ropes / Simulation / Simulation models / Solar magnetic field / Solar wind / ULF waves / Wave frequency / Wave generation / Wave power