Homologous Microflares with Mass Ejection and Plasma Heating on the Quiet Sun

Study of microflares on the quiet Sun is extremely important in learning the physics of both solar flare and atmospheric heating. Here, for the first time, we report the detailed observations of two homologous microflares from Atmospheric Imager Assembly (AIA) images and Heliospheric Magnetic Imager magnetograms in a very quiet region. The two microflares are observed clearly in the extreme ultraviolet and faintly in the ultraviolet in AIA images. They have an area of ∼59 Mm² and ∼46 Mm², and a duration of 25 minutes and 22 minutes. The magnetic cancellation continuously takes place during the microflares, and the magnetic flux decrease is apparent, with a value of ∼4 × 10¹⁸ Mx. The obvious mass ejections are observed during the microflares, and dimming occurs during and after the microflares. The velocity of mass ejection is up to 160 km s⁻¹. For the two microflares, the time of peak intensity in λ 30.4 nm precedes that of the coronal peak emission, up to 2.4–3.3 minutes. Their thermal energy is estimated to be 1.3 × 10²⁷ erg and 2.5 × 10²⁶ erg, respectively, which heats the corona up to 5.8 MK and 2.8 MK. There are many similarities of microflares on the quiet Sun to major flares in the active regions.