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EP: Fachverband Extraterrestrische Physik
EP 6: Sun and Heliosphere III
EP 6.3: Vortrag
Dienstag, 1. April 2025, 17:00–17:15, ZHG101
Rapid Coronal Variability — •Abhas Pradhan1, Lakshmi Pradeep Chitta1, and Hardi Peter1,2 — 1Max Planck Institute for Solar System Research, Goettingen, Germany — 2Institut für Sonnenphysik (KIS) , Freiburg , Germany
Solar coronal loops are heated to temperatures exceeding 1 MK, despite the photosphere being only ∼5700K. The mechanisms sustaining such extreme temperatures in the corona remain unclear. One hypothesis is that nanoflares, small-scale transient magnetic reconnection events, heat the corona. These nanoflares are thought to create rapid UV/EUV variability at the footpoints of coronal loops. High-resolution observations are required to quantify this variability, which in turn will inform us the occurence and energy contribution of nanoflares to coronal heating. Solar Orbiter’s EUI offers higher-resolution coronal observations over several hours, complemented by PHI magnetograms providing photospheric magnetic field data at matching resolution. We analyzed high-resolution EUI 174 Å images (180km/pixel, 5s cadence) of an active region core, along with bright points and the diffuse corona, to detect these rapidly varying events. We find frequent occurrences of such rapid events in moss regions and bright points, typically every 3 to 5 minutes, while diffuse regions show almost no rapid activity. The lifetimes and wait-times of rapid events in bright points and moss show similar patterns, remaining consistent despite changes in the underlying magnetic topology. Our study offers better insights to constrain nanoflare-based heating models and processes responsible for mass and energy injection into the hot loops.
Keywords: astrophysics; solar physics; corona; nanoflare; solar orbiter