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EP: Fachverband Extraterrestrische Physik

EP 5: Sun and heliosphere I

EP 5.3: Talk

Wednesday, March 22, 2023, 11:45–12:00, ZEU/0160

Picoflares in the Quiet Solar Corona Observed by the Solar Orbiter — •Olena Podladchikova^1,2, Alexander Warmuth¹, Francis Verbeeck³, Marco Velli⁴, Susanna Parenti⁵, Frederic Auchere⁵, Astrid Veronig⁶, Stefan Purkhart⁶, Stefan Hofmeister¹, Udo Schuehle⁷, Luca Teriaca⁷, Aznar Cuadrado⁷, Andrea Battaglia⁸, Frederic Schuller¹, and Anik De Groof⁹ — ¹AIP, Potsdam, Germany — ²Kiev Polytechnic University, Ukraine — ³ROB, Belgium — ⁴UCLA, USA — ⁵IAS, France — ⁶University of Graz, Austria — ⁷MPS, Germany — ⁸ETH, Switzerland — ⁹ESA, Madrid, Spain

On May 30, 2020, the Solar Orbiter High-Resolution Imager (HRIEUV) operating in 174 A being for the first time approximately at 0.5AU to the Sun, registered a large number of sudden heating events so-called campfires with rich morphology and smaller space-time characteristics than nanoflares. We found that campfires emit thermal energy in the picoflares range of 3.4 × 10²⁰ − 9.8 × 10²³ ergs per event. The relationship between the emission measure and the temperature of campfires can be fitted by the power law covering 1 - 2.7 MK temperature range similar to large X-Ray flares. Their frequency distribution can be fitted by power-law f(E) ≈ E^{2.82 ± 0.11}, but at higher than nanoflares frequencies and lower energy range. The additional previously unaccounted energy input of ≥ 3 σ is 1.0075 percent of the total required power to sustain a quiet solar corona. The observed power law would have to continue to about 1.25 × 10¹⁸ ergs in order to fulfill the observed coronal heating requirement.