Petrova, E. ; Van Doorsselaere, T. ; Berghmans, D. ; Parenti, S. ; Valori, G. ; Plowman, J.

published in Solar Orbiter Science Nugget, 19/02/2025 (2025)

Abstract: Alfvén waves are of significant interest in the coronal heating problem due to their ability to transport energy from the lower layers of the Sun’s atmosphere to the corona [1]. However, their detection remains challenging because they are essentially rotational perturbations in plasma velocity and azimuthal components of the magnetic field, and are incompressible, and do not produce significant structural displacements [2]. As a result, they have primarily been observed using spectrometers across different layers of the solar atmosphere [4-8], while imaging instruments have struggled to capture them directly [3]. Recent advancements in solar imaging technology have drastically improved spatial and temporal resolution, enabling the detection of previously unresolved phenomena. In this study, we present new observations of propagating rotational motions within a fan-spine magnetic topology—a configuration consisting of a dome and a spine, formed when a magnetic bipole emerges into a preexisting unipolar field [9]. Numerical simulations suggest that this topology favours magnetic reconnection, which in turn generates propagating Alfvén waves [10-13]. Here, we use multiple instruments onboard Solar Orbiter to detect an event that has been extensively modelled in numerical studies.

Keyword(s): Solar Orbiter ; EUI ; waves
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