Two Homologous Quasi-periodic Fast-mode Propagating Wave Trains Induced by Two Small-scale Filament Eruptions

We present two homologous quasi-periodic fast-mode propagating (QFP) wave trains excited by two small-scale filament eruptions nearby a sunspot on 2017 September 12. By using observations from several ground-based and space-based instruments, it is found that the eruptions of two small-scale filaments resulted in some accompanying solar phenomena/activities (such as radio bursts, GOES C-class flares, coronal bright fronts, and QFP wave trains). The QFP wave trains run behind the main coronal bright fronts with a constant propagating speed of about 800 km s−1, while two main coronal bright fronts traveled away from the flare kernel obeying the power-law functions of $S(t)=894.9\ast {\left(t-7.43\right)}^{0.60}+76.8$ and S(t) = 705.3 ∗ (t − 19.12)0.47 + 57.5, respectively. The period of the first QFP wave train was estimated to be about 59 s, while the second QFP wave train has two periods of about 70 and 37 s. On the other hand, the intensity peaks of 94 and 335 Å passbands in the flare kernel exhibit some perturbations during the occurrences of the QFP wave trains. With the wavelet analysis and their synchronization, these perturbations and the QFP wave trains are tightly related phenomena, which suggests that they have a common exciting mechanism. Furthermore, we find that the emissions of the intensity peak mainly originate from the one footpoint of flare loops during the occurrence of the QFP wave trains. According to the above features, we conclude that the QFP wave trains are excited in the energy release process associated with magnetic reconnection and are closely related to the outflow of the magnetic reconnection.