UDK 523.985.7
UDK 523.987
UDK 52
UDK 53
UDK 520
UDK 521
UDK 523
UDK 524
UDK 52-1
UDK 52-6
GRNTI 41.21
GRNTI 41.00
GRNTI 29.35
GRNTI 29.31
GRNTI 29.33
GRNTI 29.27
GRNTI 29.05
OKSO 03.06.01
OKSO 03.05.01
OKSO 03.04.03
BBK 2
BBK 223
TBK 614
TBK 6135
BISAC SCI004000 Astronomy
BISAC SCI005000 Physics / Astrophysics
We present results of the analysis of multiwavelength observations of the M3.4 eruptive flare that occurred near the western limb of the Sun on September 2, 2023 (SOL2023-09-02T06:33). We use observations from the near-Earth spacecraft ASO-S/HXI, SDO/AIA, HMI, GOES/XRS, and Fermi/GBM. X-ray observations by the STIX telescope-spectrometer on board the Solar Orbiter from the opposite side of the Sun are also used. The flare was associated with a two-stage inclined ( $\approx 40-50^{\circ}$ to the radial direction) eruption, the second stage of which was accompanied by the impulsive flare phase and quasi-periodic pulsations (QPPs) of hard X-rays with a characteristic time scale $P\approx1.56$ min. HXI observed hard X-ray sources located above the apex of a coronal Y-shaped structure, visible in the ``hot'' 94 and 131 Å EUV channels, behind a drop-shaped erupting plasmoid/prominence. Hard X-ray sources near the foot of the flare loops and flare ribbons were also observed, mainly after the peak of the impulsive phase. The HXI and STIX observations from different locations in the heliosphere are consistent with each other. Temporal dynamics of the spectral index of nonthermal electron flux had a ``soft-hard-soft'' behavior during QPPs. The observational results do not contradict the ``standard'' model of eruptive two-ribbon flares, where populations of electrons are accelerated episodically due to magnetic reconnection in a current sheet in the corona behind an erupting structure. However, understanding the quasi-periodicity of electron acceleration/injection requires further studies.
Sun: flares; X-rays, gamma rays; UV radiation; coronal mass ejections (CMEs)
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