Context. High-resolution observations of the Sun reveal a multitude of small-scale striations throughout the photosphere. While these features are well observed in broad-band intensity images, spectropolarimetric observations remain rare. Aims. In this study, we characterize small dark striations at the pore-granulation boundary and bright grains moving along them. We seek to describe their magneto-convective nature. Methods. We analyzed restored context images and many-line Stokes inversions of a restored spectropolarimetric scan from GST/FISS-SP with a spatial resolution of 0.068″. In the inversion, we used 85 solar absorption lines within a 33 Å wide spectral window in the 5250 Å region. We compare the observations with a MURaM simulation to discern the magneto-convective nature of striations and grains. Results. We find multiple dark striations in the vicinity of pores or active region intergranular lanes with a typical width of 0.09″ and moving bright grains that migrate along some of those striations toward the adjacent pore. Grains forming in a high-resolution MURaM simulation of a pore show similar lifetimes of about 70 s. A comparison of the atmospheric configurations of simulated and observed grains reveals good qualitative agreement in structure, dynamics, thermal, and magnetic stratification. The simulation shows that the dark striations form at the top of a convective plume confined by the surrounding field, and that their dark appearance is caused by plasma trapped in the field cusp at optical depth unity. The moving bright grains are composed of hot plasma pulled upwards by turbulent flows at the tip of the striation. Conclusions. By combining high resolution spectro-polarimetry, many-line inversions, and MURaM simulations, we present the first analysis of the 3D fine structure of small-scale striations and moving bright grains in the vicinity of a pore and describe their magneto-convective nature.

Light bridges (LBs), embedded in sunspots, appear as elongated narrow bright features, in contrast to the surrounding dark sunspot umbra or penumbra. Under high-resolution observations, dark lanes were reported along the spine of LBs. Although numerical modeling explains the basic physical properties of LBs , how and where the dark lanes form remain incomprehensible from the observational aspect. The multiwavelength observations obtained by the Goode Solar Telescope (GST) at Big Bear Solar Observatory (BBSO), show that the dark lanes are prominent in the H$$\alpha $$, visible continuum and near infrared (NIR) line core. However, they are absent from the NIR continuum, which is formed about 30 km below the photosphere. These results provide altitude data for the layered structure and suggest that the dark lanes located above this region originate in the deep photosphere.

Context. For the analysis of highly resolved solar spectra the simultaneous observation and interpretation (inversion) of only a few (often only one) spectral lines is still the norm. With modern instruments spatially highly resolved spectropolarimetric data covering many lines are available. Aims. For the first time we combine the information from 85 simultaneously observed absorption lines in spatially highly resolved data to test a proposed solar many-line inversion strategy. Methods. We inverted full Stokes spectra recorded with the FISS spectro-polarimeter (FISS-SP) at the 1.6-m Goode Solar Telescope in California, using the SPINOR code. We contrasted two different setups: one following the traditional approach of using a line doublet, and a new method inverting many-lines simultaneously. Results. Compared to results from an inversion using two lines of a line doublet, we discovered more fine-structure and better constrained values using the many-line technique. An average quiet Sun spectrum was successfully reproduced using a model atmosphere, but when inverting spatially resolved data, uncertainties in line parameters and blend configurations did not average out. Thus, a deliberate selection process of lines and line blends was required, in order to make the many-line case converge to a physically expected and coherent atmosphere. We successfully developed and tested such a selection method. Conclusions. Our results highlight that the many-line inversions method delivers more coherent results with superior line of sight (LOS) resolution of the atmospheric structure. Moreover, it effectively detects and utilizes even weak polarimetric signals in noisy data and thereby partly circumvents low noise requirements. It reveals uncertainties in atomic parameters of individual spectral lines and models, as the degree of freedom to compensate for these uncertainties by compromising the inferred atmospheric parameters is considerably reduced. It is thereby pointing to a need for improved atomic data, including log(gf) values, of many lines in the solar spectrum. The many-line method presents significant potential for solar physics and may become the preferred option for future observations with upcoming spectrographs.

Solar active region 11283 produced an X2.1 flare associated with a solar eruption on 2011 September 6. Observations revealed a preflare sigmoidal structure and a circular flare ribbon surrounding the typical two-ribbon structure, along with remote brightenings located at a considerable distance from the main flare site. To interpret these observations in terms of the dynamics of the three-dimensional coronal magnetic field, we conducted data-constrained magnetohydrodynamic simulations. Using a nonlinear force-free field as the initial condition, we reconstructed a realistic preflare magnetic environment, capturing a sheared sigmoid above the polarity inversion line surmounted by a fan–spine structure. Our simulations revealed that reconnection between the sigmoidal field, the adjacent fan–dome field lines, and the neighboring large loops facilitated the transfer of magnetic twist and led to the formation of a large magnetic flux rope (MFR). This transfer and propagation of twist are clearly visible throughout the MFR. As reconnection progresses, the entire fan–spine structure expands along with the evolving MFR. A notable outcome of the simulation is that the footpoints of the newly formed MFR align closely with the observed circular flare ribbon and the remote brightening region. Our findings suggest that a large MFR formed during the X2.1 flare, providing a coherent explanation for the observed phenomena.

Our study of H alpha line profiles of rapid blue- and redshifted excursions measured with Goode Solar Telescope revealed an asymmetrical three-peak structure present in the blue wing of the H alpha line, suggesting complex internal velocity fields that may include bidirectional flows and transverse and torsional motions. Blueshifted plasma predominates across the field of view (FOV), correlating with higher temperatures (>10(4) K) and extending to greater heights. Conversely, redshifts are less spread over the FOV, are localized near network magnetic fields, and diminish rapidly with altitude. The frequency distribution associated with blueshifted events displays a bimodal structure with peaks centered at 7200 and 8800 K. The redshifted events display a much weaker and wide peak centered at about 9000 K. No significant difference in temperature distributions for blue- and redshifted events is observed in the range above 10,000 K. Variations of H alpha line profiles with height seem to indicate that the line-of-sight integration effects may be most significant within the 0-6 Mm layer above the photosphere, and it decreases with height.

We introduce MVPinn, a Physics-Informed Neural Network (PINN) approach tailored for solving the Milne-Eddington (ME) inversion problem, specifically applied to spectropolarimetric observations from the Big Bear Solar Observatory's Near-InfraRed Imaging Spectropolarimeter (BBSO/NIRIS) at the Fe I 1.56 μm lines. Traditional ME inversion methods, though widely used, are computationally intensive, sensitive to noise, and often struggle to accurately capture complex profile asymmetries resulting from gradients in magnetic field strength, orientation, and line-of-sight velocities. By embedding the ME radiative transfer equations directly into the neural network training as physics-informed constraints, our MVPinn method robustly and efficiently retrieves magnetic field parameters, significantly outperforming traditional inversion methods in accuracy, noise resilience, and the ability to handle asymmetric and weak polarization signals. After training, MVPinn infers one magnetogram in about 15 seconds, compared to tens of minutes required by traditional ME inversion on high-resolution spectropolarimetric data. Quantitative comparisons demonstrate excellent agreement with well-established magnetic field measurements from the SDO/HMI and Hinode/SOT-SP instruments, with correlation coefficients of approximately 90

Despite decades of research, the fundamental processes involved in the initiation and acceleration of solar eruptions remain not fully understood, making them long-standing and challenging problems in solar physics. Recent high-resolution observations by the Goode Solar Telescope have revealed small-scale magnetic flux emergence in localized regions of solar active areas prior to eruptions. Although much smaller in size than the entire active region, these emerging fluxes reached strengths of up to 2000 G. To investigate their impact, we performed data-constrained magnetohydrodynamic simulations. We find that while the small-scale emerging flux does not significantly alter the preeruption evolution, it dramatically accelerates the eruption during the main phase by enhancing the growth of torus instability, which emerges in the nonlinear stage. This enhancement occurs independently of the decay index profile. Our analysis indicates that even subtle differences in the preeruption evolution can strongly influence the subsequent dynamics, suggesting that small-scale emerging flux can play a critical role in accelerating solar eruptions.

We analyze high-resolution observations of an X-1.0 white-light flare, triggered by a filament eruption, on 2022 October 2. The full process of filament formation and subsequent eruption was captured in the H α passband by the Visible Imaging Spectrograph (VIS) on board the Goode Solar Telescope (GST) within its center field of view. White-light emissions appear in flare ribbons following the filament eruption and H α ribbon brightening. GST Broadband Filter Imager data show that the continuum intensity, as compared to the nearby quiet-Sun area, has increased by up to 20% in the photospheric TiO band around 7057 Å. The Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory reported 10% contrast enhancement in the continuum near Fe i 6173 Å line. The separation motion of two white-light kernels is recorded by the high-cadence GST/TiO images and is well accompanied by the motion of the VIS H α flare ribbon leading edge. One kernel, located in a 150 Gauss field within a granulation area, exhibited an average apparent motion speed of 55 km s ^−1 , which is the highest average speed ever reported. The other kernel drifted at 9 km s ^−1 in an 800 Gauss magnetic field area. Hard X-ray (HXR) emissions reaching up to 300 keV have been observed for this flare. The simultaneous occurrence of high-cadence HXR, microwave, and white-light emissions strongly suggests that the energetic particles from the flare directly contribute to the heating. The inverted HXR energy flux density corresponding to 10% TiO brightening is 2.07 ± 0.23 × 10 ^11 erg cm ^−2 s ^−1 during the flare peak.

The increasing demand for high-resolution solar observations has driven the development of advanced data processing and enhancement techniques for ground-based solar telescopes. This study focuses on developing a python-based package (GT-scopy) for data processing and enhancing for giant solar telescopes, with application to the 1.6 m Goode Solar Telescope (GST) at Big Bear Solar Observatory. The objective is to develop a modern data processing software for refining existing data acquisition, processing, and enhancement methodologies to achieve atmospheric effect removal and accurate alignment at the sub-pixel level, particularly within the processing levels 1.0-1.5. In this research, we implemented an integrated and comprehensive data processing procedure that includes image de-rotation, zone-of-interest selection, coarse alignment, correction for atmospheric distortions, and fine alignment at the sub-pixel level with an advanced algorithm. The results demonstrate a significant improvement in image quality, with enhanced visibility of fine solar structures both in sunspots and quiet-Sun regions. The enhanced data processing package developed in this study significantly improves the utility of data obtained from the GST, paving the way for more precise solar research and contributing to a better understanding of solar dynamics. This package can be adapted for other ground-based solar telescopes, such as the Daniel K. Inouye Solar Telescope (DKIST), the European Solar Telescope (EST), and the 8 m Chinese Giant Solar Telescope, potentially benefiting the broader solar physics community.

Recently, intermittent and aperiodic fan-shaped chromospheric surges have attracted significant attention, though their related photospheric dynamic signals remain unclear. This study examines seven such surges and their potential photospheric signals along a light bridge (LB) in NOAA AR 12371 over a period of 100 min using BBSO/GST observations. Each surge displays as dark, jet-like structures with nearly uniform amplitudes, aligned closely along the LB to form a long smooth upper edge. Simultaneously, the photospheric LB exhibits dynamic grains, including bright points and granules. Adjacent grains brighten, expand, and merge into a ‘grain group’ (GG), which span LB’s cross-section. As GG moves along the LB, its leading edge develops an arched structure. During GG formation, the local horizontal magnetic field direction undergoes significant deflection. Within the 100-min interval, 10 GGs were recorded, occurring intermittently and aperiodically. Notably, three photospheric GG-free intervals corresponded to three chromospheric surge-free intervals, with a temporal delay (80–712 s) between GG reappearance and surge recurrence. Our findings suggest that meso-scale photospheric GGs, larger than individual granules but smaller than the full extent of the LB, are closely related to chromospheric surges. A conceptual model integrating inverse turbulent cascades and flux tube interactions is proposed, unifying multi-scale energy transfer from photospheric convection to chromospheric reconnection.

We present a unique observation of the X6.4-class flare SOL2024-02-22T22:34 using the Mid-InfraRed Imager (MIRI) at the Goode Solar Telescope. Three ribbon-like flare sources and one unidentified source were detected in MIRI’s two mid-infrared (mid-IR) bands at 5.2 and 8.2 μ m. The two stronger ribbons displayed maximum mid-IR enhancements of 21% and 18% above quiet-Sun levels and 10% in Helioseismic and Magnetic Imager (HMI) continuum intensity ( I _c ). The weak ribbon and the unidentified source had maximum mid-IR enhancements of 7% but showed HMI/ I _c dimmings, instead of excess emissions. Our result suggests that mid-IR emission forms in a higher layer during the flare and is more sensitive to flare heating than HMI/ I _c emission. The MIRI observations have high temporal resolution (2.6 s cadence in these observations) and show apparent source motions. One flare ribbon extends along weak vertical magnetic-field channels in the sunspot umbra, light bridge, and penumbra, with an approximately 30 s delay between HMI/ I _c and 8.2 μ m emissions. Meanwhile, the unidentified source moved at an apparent speed of 130 km s ^−1 from a mixed-polarity area to one flare ribbon with a strong HMI/ I _c enhancement. We studied available hard X-ray/microwave imaging spectroscopy and used nonlinear force-free field extrapolation modeling to identify flare structures. The observational evidence strongly favors the chromospheric origin of the unidentified mid-IR source. Comparison with the X1.0 flare SOL2022-10-02T20:25 indicates that the total amount of high-energy electron (>60 keV) flux density is a key factor in determining the total brightening area and the maximum intensity enhancement in HMI/ I _c emissions.

On 2024 July 25, while observing the solar active region NOAA 13762 with the high-resolution 1.6 m Goode Solar Telescope at the Big Bear Solar Observatory, we witnessed two mysterious phenomena: the partial detachment of filament strands from its main body in the chromosphere and the sudden disappearance of a sunspot penumbra in the photosphere, the former accompanied by small flares. Our analysis reveals a spatiotemporal correlation between the filament peeling process and the penumbral disappearance. To understand the above observations physically, we performed a magnetohydrodynamic simulation that successfully replicated the disappearance of the penumbra as a consequence of weakened horizontal magnetic field. The simulations demonstrate that both the filament peeling and the penumbral decay are driven by the same underlying process: the upward expansion of the magnetic flux rope induced by null point magnetic reconnection. These results suggest a novel mechanism by which the Sun sheds magnetic flux to interplanetary space in the form of filament peeling and penumbral disappearance.

The dynamic structures of solar filaments prior to solar flares provide important physical clues about the onset of solar eruptions. Observations of those structures under subarcsecond resolution with high cadence are rare. We present high-resolution observations covering preeruptive and eruptive phases of two C-class solar flares, C5.1 (SOL2022-11-14T17:29) and C5.1 (SOL2022-11-14T19:29), obtained by the Goode Solar Telescope at Big Bear Solar Observatory. Both flares are ejective, i.e., accompanied by coronal mass ejections (CMEs). High-resolution H α observations reveal details of the flares and some striking features, such as a filament peeling process: individual strands of thin flux tubes are separated from the main filament, followed shortly thereafter by a flare. The estimated flux of rising strands is in the order of 10 17 Mx, versus the 10 19 Mx of the entire filament. Our new finding may explain why photospheric magnetic fields and overall active region and filament structures as a whole do not have obvious changes after a flare, and why some CMEs have been traced back to the solar active regions with only nonerupting filaments, as the magnetic reconnection may only involve a very small amount of flux in the active region, requiring no significant filament eruptions. We suggest internal reconnection between filament threads, instead of reconnection to external loops, as the process responsible for triggering this peeling of threads that results in the two flares and their subsequent CMEs.

Context. The interaction between magnetic fields and convection in sunspots during their decay process remains poorly understood, whereas the formation of sunspots is relatively well studied and fully modeled. Works on the velocity scales at the solar surface have pointed to the existence of the family of granules, whose interaction with the magnetic field leads to the formation of supergranules and their networks, which are visible at the solar surface. Aims. The aim of this paper is to consider relationship between the decay of sunspots and convection via the motion of the family of granules and how the diffusion mechanism of magnetic field operates in a decaying sunspot. Methods. We report the decay of a sunspot observed by the 1.6 m Goode Solar Telescope (GST) with the TiO Broadband Filter Imager (BFI) and the Near-InfraRed Imaging Spectropolarimeter (NIRIS). The analysis was aided by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamic Observatory (SDO). In the first step, we followed the decay of the sunspot with HMI data over three days by constructing its evolving area and total magnetic flux. In the second step, the high spatial and temporal resolution of the GST instruments allowed us to analyze the causes of the decay of the sunspot. Afterward, we followed the emergence of granules in the moat region around the sunspot over six hours. The evolution of the trees of fragmenting granules (TFGs) was derived based on their relationship with the horizontal surface flows. Results. We find that the area and total magnetic flux display an exponential decrease over the course of the sunspot decay. We identified 22 moving magnetic features (MMFs) in the moats of pores, which is a signature of sunspot decay through diffusion. We note that the MMFs were constrained to follow the borders of TFGs during their journey away from the sunspot. Conclusions. The TFGs and their development contribute to the diffusion of the magnetic field outside the sunspot. The conclusion of our analysis shows the important role of the TFGs in sunspot decay. Finally, the family of granules evacuates the magnetic field.

Solar images are critically important for studying solar activities and features. Today, many observatories rely on CMOS sensors to acquire these images. However, these sensors often introduce column fixed-pattern noise (CFPN), seriously affecting image quality. Therefore, we proposed a two-way filtering algorithm to remove CFPN. Firstly, in the horizontal direction, we used the one-dimensional global weighted least squares filter and the efficient bilateral filter to obtain a coarse denoised image. Then, we utilized the weighted guided filter in the vertical direction to estimate the CFPN components, thereby obtaining a clean solar image. We selected three different solar observation images to compare and evaluate our results to those obtained by three comparative methods. The images are observed by the Solar Upper Transition Region Imager aboard the SATech-01 satellite. Additionally, we further used two quantitative metrics, photo response non-uniformity and mean relative deviation, to quantify the denoised results. The results demonstrate that our proposed method removes the CFPN better and preserves the image features in a more balanced way.

Aims. Recurring jets are observed in the solar atmosphere. They can erupt intermittently over a long period of time. By the observation of intermittent jets, we wish to understand what causes the characteristics of the periodic eruptions. Methods. We report intermittent jets observed by the Goode Solar Telescope (GST) with the TiO Broadband Filter Imager (BFI), the Visible Imaging Spectrometer (VIS) in H α , and the Near-InfraRed Imaging Spectropolarimeter (NIRIS). The analysis was aided and complemented by 1400 Å and 2796 Å data from the Interface Region Imaging Spectrograph (IRIS). These observational instruments allowed us to analyze the temporal characteristics of the jet events. By constructing the H α dopplergrams, we found that the plasma first moves upward, but during the second phase of the jet, the plasma flows back. Working with time slice diagrams, we investigated the characteristics of the jet dynamics. Results. The jet continued for up to 4 h. The time-distance diagram shows that the peak of the jet has clear periodic-eruption characteristics (5 min) during 18:00 UT–18:50 UT. We also found a periodic brightening phenomenon (5 min) during the jet bursts in the observed bands in the transition region (1400 Å and 2796 Å), which may be a response to intermittent jets in the upper solar atmosphere. The time lag is 3 min. Evolutionary images in the TiO band revealed a horizontal movement of the granulation at the location of the jet. By comparison to the quiet region of the Sun, we found that the footpoint of the jet is enhanced at the center of the H α spectral line profile, without significant changes in the line wings. This suggests prolonged heating at the footpoint of the jet. In the mixed-polarity magnetic field region of the jet, we observed the emergence of magnetic flux, its cancellation, and shear, indicating possible intermittent magnetic reconnection. This is confirmed by the nonlinear force-free field model, which was reconstructed using the magneto-friction method. Conclusions. The multiwavelength analysis indicates that the events we studied were triggered by magnetic reconnection that was caused by mixed-polarity magnetic fields. We suggest that the horizontal motion of the granulation in the photosphere drives the magnetic reconnection, which is modulated by p -mode oscillations.

We used 29 high-resolution line-of-sight magnetograms acquired with the Goode Solar Telescope (GST) in a quiet-Sun area to extrapolate a series of potential field configurations and study their time variations. The study showed that there are regions that consistently exhibit changes in loop connectivity, whereas other vast areas do not show such changes. Analysis of the topological features of the potential fields indicates that the photospheric footprint of the separatrix between open- and closed-loop systems closely matches the roots of rapid blue- and redshifted excursions, which are disk counterparts of type II spicules. There is a tendency for the footpoints of the observed H _α features to be cospatial with the footpoints of the loops that most frequently change their connectivity, while the area occupied by the open fields that did not show any significant and persistent connectivity changes is void of prominent jet and spicular activity. We also detected and tracked magnetic elements using the Southwest Automatic Magnetic Identification Suite and GST magnetograms, which allowed us to construct artificial magnetograms and calculate the corresponding potential field configurations. Analysis of the artificial data showed tendencies similar to those found for the observed data. The present study suggests that a significant amount of chromospheric activity observed in the far wings of the H _α spectral line may be generated by reconnecting closed-loop systems and canopy fields consisting of “open” field lines.

Three-minute oscillations are a common phenomenon in the solar chromosphere above a sunspot. Oscillations can be affected by the energy release process related to solar flares. In this paper, we report on an enhanced oscillation in flare event SOL2012-07-05T21:42 with a period of around 3 minutes that occurred at the location of a flare ribbon at a sunspot umbral–penumbral boundary and was observed in both chromospheric and coronal passbands. An analysis of this oscillation was carried out using simultaneous ground-based observations from the Goode Solar Telescope at the Big Bear Solar Observatory and space-based observations from the Solar Dynamics Observatory. A frequency shift was observed before and after the flare, with the running penumbral wave that was present with a period of about 200 s before the flare coexisting with a strengthened oscillation with a period of 180 s at the same locations after the flare. We also found a phase difference between different passbands, with the oscillation occurring from high-temperature to low-temperature passbands. Theoretically, the change in frequency was strongly dependent on the variation of the inclination of the magnetic field and the chromospheric temperature. Following an analysis of the properties of the region, we found the frequency change was caused by a slight decrease of the magnetic inclination angle with respect to the local vertical. In addition, we suggest that the enhanced 3 minute oscillation was related to the additional heating, maybe due to the downflow, during the EUV late phase of the flare.

With the aid of high-resolution spatial and temporal observations from the Goode Solar Telescope, we present an investigation of the emergence, coalescence, and submergence of a moving magnetic feature (MMF) in the region surrounding a magnetic pore located at the periphery of a large sunspot. The results show that the MMF has a magnetic field strength greater than 500 G and is dominated by the horizontal magnetic component. We observe upflow at the inner part and downflow at the outer part, indicating a pattern of Evershed flow. The MMF emergence is accompanied by the expansion of a granule, which has several striations inside just like the twisted features found in the penumbra filament. Our analysis shows that although these striations have different properties of magnetic field and kinematics during the expansion of the granule, the overall magnetic and dynamic properties of the MMF remain stable. We find that the region where the MMF emerges and submerges becomes more penumbra-like, i.e., adjacent positive and negative values of elongated magnetic features that are parallel to each other, while the optical penumbra-like features are not apparent at the same time. Our work indicates that the dynamics of the MMF near the magnetic pore is important for the development of filamentary structure. The magnetic configuration produced by an MMF together with the elongation of a granule could thus be key to understand the formation of penumbra filaments.

Minifilament (MF) eruption producing small jets and micro-flares is regarded as an important source for coronal heating and the solar wind transients through studies mostly based on coronal observations in the extreme ultraviolet (EUV) and X-ray wavelengths. In this study, we focus on the chromospheric plasma diagnostics of a tiny minifilament in quiet Sun located at [71'', 450''] on 2021--08--07 at 19:11 UT observed as part of the ninth encounter of the PSP campaign. Main data obtained are the high cadence, high resolution spectroscopy from the Fast Imaging Solar Spectrograph (FISS) and high-resolution magnetograms from the Near InfraRed Imaging Spectropolarimeter (NIRIS) on the 1.6~m Goode Solar Telescope (GST) at Big Bear Solar Observatory (BBSO). The mini-filament with size $\sim$1''$\times$5'' and a micro-flare are detected in both the H$\alpha$ line center and SDO/AIA 193, 304~\AA\ images. On the NIRIS magnetogram, we found that the cancellation of a magnetic bipole in the footpoints of the minifilament triggered its eruption in a sigmoidal shape. By inversion of the \ha\ and Ca {\sc ii} spectra under the embedded cloud model, we found a temperature increase of 3,800 K in the brightening region, associated with rising speed average of MF increased by 18~$km~s^{-1}$. This cool plasma is also found in the EUV images. We estimate the kinetic energy change of the rising filament as 1.5$\times$$10^{25}$~ergs, and thermal energy accumulation in the MF, 1.4$\times$$10^{25}$~ergs. From the photospheric magnetograms, we find the magnetic energy change is 1.6$\times$$10^{26}$~ergs across the PIL of converging opposite magnetic elements, which amounts to the energy release in the chromosphere in this smallest two-ribbon flare ever observed.