523.985.7
523.987
52
53
520
521
523
524
52-1
52-6
41.21
41.00
29.35
29.31
29.33
29.27
29.05
03.06.01
03.05.01
03.04.03
2
223
614
6135
SCI004000
SCI005000
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)
1. Gan W.-Q., Zhu C., Deng Y.-Y., et al., 2019, Research in Astronomy & Astrophysics, 19, 11, id. 156
2. Kupriyanova E.G., Kolotkov D.Yu., Nakariakov V.M., et al., 2020, Solar-Terrestrial Physics, 6, 1, p. 3
3. Krucker S., Hurford G.J., Grimm O., et al., 2020, Astronomy & Astrophysics, 642, id. A15
4. Lemen J.R., Title A.M., Akin D.J., et al., 2012, Solar Physics, 275, 1-2, p. 17
5. Meegan C., Lichti G., Bhat P.N., et al., 2009, Astrophysical Journal, 702, p. 791
6. Scherrer P.H., Schou J., Bush R.I., et al., 2012, Solar Physics, 275, 1-2, p. 207
7. Zimovets I.V., McLaughlin J.A., Srivastava A.K., et al., 2021, Space Science Reviews, 217, 5, id. 66
8. Zhang Z., Chen D.-Y., Wu J., et al., 2019, Research in Astronomy and Astrophysics, 19, 11, id. 160
