Solar Physics最新文献

{"title":"Multi-Wavelength View of a Confined C2.2 Flare: From Compact Two-Ribbon Emission to a Tailed C-Shaped Ribbon Morphology","authors":"Shilpa Patra,&nbsp;Kamlesh Bora,&nbsp;Lakshmi Pradeep Chitta,&nbsp;V. S. Pandey,&nbsp;Yajie Chen,&nbsp;Shakti Singh","doi":"10.1007/s11207-026-02749-4","DOIUrl":"10.1007/s11207-026-02749-4","url":null,"abstract":"<div><p>Flare ribbon morphology is often used as an observational proxy for magnetic reconnection and the underlying coronal magnetic topology. However, complex ribbon shapes do not necessarily imply a specific large-scale topology, particularly when different atmospheric diagnostics sample different parts of the same event. We examine this problem using an apparently confined C2.2 flare in NOAA active region (AR) 13078 on 2022 August 16, observed with the Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI), New Vacuum Solar Telescope (NVST) H<span>(alpha )</span> imaging, and a non-force-free Field (NFFF) extrapolation.</p><p>The flare shows a strongly wavelength-dependent ribbon morphology. In lower-atmospheric diagnostics, especially AIA 1600 Å and NVST H<span>(alpha )</span>, it appears mainly as a compact two-ribbon flare rooted around a polarity inversion line (PIL). In contrast, AIA 304 Å reveals a C-shaped ribbon with an extended tail linking the compact flaring core to nearby pores and plage. The extended AIA 304 Å morphology appears to develop through the progressive brightening of connected, low-lying magnetic loops, rather than representing a separate ribbon system. The pre-flare phase shows localized ultraviolet (UV)/extreme-ultraviolet (EUV) brightenings together with loops in hot AIA channels. Hot AIA channels reveal a sigmoid-like structure associated with the same low-lying magnetic system that hosts the active-region filament and nearby arch filament system. During the flare, the H<span>(alpha )</span> filamentary material becomes less visible in places, most likely due to heating, enhanced background emission, and opacity changes, rather than complete disappearance or eruption.</p><p>The extrapolated field contains a coronal null point at higher altitude; however, its fan and spine footpoints are not co-spatial with the observed flare ribbons or with the extended tail brightening. This suggests that the large-scale null-point topology is unlikely to be the primary cause of the C-shaped ribbon morphology. Nevertheless, the extrapolation does reproduce the low-lying magnetic connectivity associated with the active-region filament, the arch filament system, and loops linking the positive-polarity sunspot to surrounding negative-polarity pores and plage. Together, the observations and extrapolated magnetic field topology support a scenario in which the extended tail of the C-shaped ribbon results from the progressive formation or successive heating of the loops connecting the sunspot and plage, rather than from reconnection at the higher coronal null.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Signature of the Saturated Hanle Effect in the Linearly Polarized Coronal Fe XIV Emission Line","authors":"Hervé Haudemand,&nbsp;Silvano Fineschi,&nbsp;Lucia Abbo,&nbsp;Gerardo Capobianco,&nbsp;Luca Zangrilli,&nbsp;Riccardo Chiartano,&nbsp;Joan Burkepile,&nbsp;Michael Galloy,&nbsp;Valeria Caracci,&nbsp;Davide Loreggia,&nbsp;Maurizio Pancrazzi,&nbsp;Joe Zender,&nbsp;Marco Romoli,&nbsp;Giorgio Bergamin,&nbsp;Emanuele Amato,&nbsp;Donata Bonino,&nbsp;Jean-Marc Christille,&nbsp;Paolo Calcidese,&nbsp;Alessandro Liberatore","doi":"10.1007/s11207-026-02753-8","DOIUrl":"10.1007/s11207-026-02753-8","url":null,"abstract":"<div><p>Direct measurements of magnetic fields in the solar corona are an open challenge in solar physics. Information about their topology can be derived from polarized observations of forbidden coronal emission lines through the saturated Hanle effect. In this work, we present the first results from observations of the linearly polarized Fe XIV 530.3 nm line-emission acquired during the total solar eclipse of April 8, 2024. We analyzed polarized images acquired by the Coronal Magnetograph (CorMag) that observed the solar corona from heliocentric distances of 1.05 up to 2 solar radii (<span>(mbox{R}_{odot})</span>). Maps of the linear polarization angle were derived, and interpreted as a signature of the saturated Hanle effect of forbidden lines. This allowed a correlation between the direction of the Fe XIV polarization vector and that of the local magnetic field to be established. Comparisons with a Potential-Field Source-Surface model showed consistency between observed polarization patterns and the topology of modeled magnetic structures, particularly in the regions under study. These results confirmed the diagnostic potential of the saturated Hanle effect in forbidden coronal lines and validated the Coronal Magnetograph as an effective instrument for constraining coronal magnetic field models.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-026-02753-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189139","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Temperature Gradients on Generation of Solar Acoustic Wave Energy Spectra and Fluxes","authors":"S. Routh,&nbsp;Z. E. Musielak","doi":"10.1007/s11207-026-02750-x","DOIUrl":"10.1007/s11207-026-02750-x","url":null,"abstract":"<div><p>The general formula for the acoustic wave energy flux derived for sound generation in non-isothermal turbulent fluids by Routh and Musielak (2025, Fluids 10, 156) is applied, for the first time quantitatively, to the superadiabatic layer of the solar convection zone, using thermodynamic profiles from a standard solar model and an eddy-time correlation function calibrated against three-dimensional (3D) solar convection simulations. Three main results are obtained. First, an exact, closure-independent relation is derived for vertically propagating waves, <span>(F_{m}/F_{q} = 9,Omega _{0}^{4}/(omega ^{2}-Omega _{0}^{2})^{2})</span>, where <span>(F_{m})</span> and <span>(F_{q})</span> are the monopole and quadrupole contributions to the acoustic wave energy flux, <span>(omega )</span> is the angular wave frequency, and <span>(Omega _{0})</span> is the acoustic cutoff frequency of the stratified background medium. This relation is valid for any turbulence spectrum and temporal correlation function; it shows that the temperature-gradient monopole source dominates over the classical Lighthill quadrupole only in a narrow band just above <span>(Omega _{0})</span>. Second, the dipole source term <span>(F_{d})</span> produces a net <i>negative</i> correction to the emitted flux (<span>(-8%)</span> to <span>(-11%)</span>): the temperature gradient partially suppresses, rather than enhances, the emission through this term. Third, the non-isothermal corrections are strongly band-selective: the frequency-integrated total flux changes by only a few percent, but the flux in the chromospherically relevant <span>(0,text{--},20text{ mHz})</span> band is enhanced by <span>(approx 15%)</span> (with the monopole alone contributing <span>(+26%)</span>), precisely the part of the spectrum available for chromospheric heating. The classical quadrupole mechanism remains dominant throughout the source layer, the total fluxes (<span>(5.5,text{--},6.6times 10^{7})</span> erg cm⁻² s⁻¹) agree with the classical benchmarks, and the sensitivity of these results to the assumed turbulence closure is quantified, providing a framework for future calculations based on turbulence statistics extracted from numerical convection simulations.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic Helicity of the Time-Dependent Separator Reconnection","authors":"Mahboub Hosseinpour","doi":"10.1007/s11207-026-02754-7","DOIUrl":"10.1007/s11207-026-02754-7","url":null,"abstract":"<div><p>We present an analytical study of the time-dependent magnetic helicity creation in the separator magnetic reconnection model. The background field connects two 3D null points via a separator, and a localized flux ring perturbation with a linearly growing amplitude drives the reconnection. Using a gauge-invariant formulation, we derive a closed-form expression for the helicity creation rate. The rate scales linearly with the product of the background and perturbation field strengths, the geometric dimensions of the flux ring, and the square of its displacement from the separator axis. For typical coronal parameters, the model yields an analytical scaling law for the helicity source; a realistic reconnection diffusion region creates helicity at a negligible rate compared to the active-region helicity budget. The handedness of the created twist is determined by the sign of the perturbation amplitude, providing a clear observational signature. A comparison with a simple linear null point shows that the separator geometry is essential for a net helicity creation. These results provide the first analytical description of time-dependent helicity variation during separator reconnection and offer testable predictions for spectropolarimetric observations.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Marginal Multi-Object Multi-Frame Blind Deconvolution","authors":"Andrés Asensio Ramos","doi":"10.1007/s11207-026-02752-9","DOIUrl":"10.1007/s11207-026-02752-9","url":null,"abstract":"<div><p>High-resolution ground-based solar imaging relies heavily on multi-object multi-frame blind deconvolution to correct for atmospheric turbulence. However, the traditional joint maximum likelihood estimation methods in which the object and the atmospheric aberrations are estimated together face some problems. In this paper, we introduce a marginal estimator for the multi-object multi-frame blind deconvolution problem. By employing a Bayesian framework to marginalize over the observed objects, we develop a stable reconstruction method that offers several distinct advantages over standard joint estimation. First, the marginalization provides enhanced regularization that naturally accounts for object uncertainty, successfully preventing the reconstruction algorithm from erroneously assigning noise power to high-order aberrations. Second, the marginal estimator yields more robust contrast control, as it is much less sensitive to the hyperparameters dictating the power spectral density (PSD) of the object prior. This robustness allows these hyperparameters to be optimized directly, enabling a “plug-and-play” deployment that removes the need for expert manual tuning. Finally, we demonstrate that the proposed method is highly accessible and simple to implement, requiring only the addition of a log-determinant term to the traditional merit function. With minimal modifications required for existing blind deconvolution pipelines, the marginal estimator has been fully integrated into the open-source <span>torchmfbd</span> package for its use by the solar physics community.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149189043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Variance of Solar Soft X-ray Fluxes","authors":"Hugh S. Hudson","doi":"10.1007/s11207-026-02748-5","DOIUrl":"10.1007/s11207-026-02748-5","url":null,"abstract":"<div><p>The timeseries of GOES soft X-ray data contains clues about the nature of the heating mechanism(s) of the solar corona. This paper focuses on a basic statistical analysis: the correlation of the mean flux <span>(S)</span> and its variance <span>(var(S))</span>. Using Taylor’s law <span>(var(S) = alangle bar{S} rangle ^{alpha })</span>, we can distinguish different degrees of coherence in the variability via the fitted value of the exponent; <span>(alpha = 1)</span> implies Poisson statistics. For the GOES 1 – 8 Å timeseries we find <span>(alpha )</span> to be substantially greater than unity for the entire dynamic range of the observations, which cover an eight-year period embracing both quiet times and flare-active times. A single value of <span>(alpha = 3.06 pm 0.05)</span> characterizes the whole data set, 2018 – 2025, with no evidence for variability in time or any dependence on the base-level flux. This indicates that flares dominate the statistics to well below GOES A-class levels. The fact that the same correlation applies to quiet times as well as active times suggests that there is no need for a different physics to explain the heating of the quiescent corona. This finding does not exclude episodic heating mechanisms, but the heating events do not occur randomly.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Doppler Velocity Variation Near the Solar Limb in the Solar Photosphere Observed with Hinode","authors":"Akie Moritsuka,&nbsp;Yukio Katsukawa,&nbsp;Ryohtaroh T. Ishikawa","doi":"10.1007/s11207-026-02747-6","DOIUrl":"10.1007/s11207-026-02747-6","url":null,"abstract":"<div><p>The Doppler velocity and bisector of photospheric lines show significant center-to-limb variation. This variation has been considered to be caused by the projection angle of the granular convection which has a corrugated surface. This study aimed to show the spectral line shifts up to the limb and investigate how these shifts are caused by granular convection. We analyzed the Fe <span>i</span> 630.15 nm absorption line by spatially resolving the granulation very close to the limb using datasets of polar observations obtained with the Spectro-Polarimeter (SP) of the Solar Optical Telescope (SOT) on board Hinode. We also analyzed the Fe <span>i</span> 630.15 nm emission line, which was observed within <span>(1^{prime prime })</span> above the limb. This study revealed the following: 1) the spatially averaged spectral lines showed an increase in redshift toward the limb, then became constant, and finally became nearly zero, 2) the Doppler velocities of granules, which were classified as bright and non-magnetic regions, showed as increase in redshifts toward the limb, 3) the bisector of granules changed more than that of the intergranules, and 4) the emission lines showed small blueshifts. These results indicate that the increase in redshift toward the limb is caused by the increase in the redshift of granules. Because the bisector reflects the atmospheric velocity along the line-of-sight, our observations can be interpreted as suggesting that the line-forming region in granules is geometrically thicker than that in intergranules.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-026-02747-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coronal Cooling: Rain, Prominences, and Eruptions – Editorial","authors":"Seray Şahin,&nbsp;Malcolm Keith Druett,&nbsp;Valeriia Liakh,&nbsp;Beatrice Popescu Braileanu,&nbsp;Thomas Rees-Crockford","doi":"10.1007/s11207-026-02746-7","DOIUrl":"10.1007/s11207-026-02746-7","url":null,"abstract":"","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multi-Scale Cascade to Initiate Solar Flares","authors":"Huseyin Cavus,&nbsp;Eric R. Priest,&nbsp;L. P. Chitta,&nbsp;Philippa K. Browning","doi":"10.1007/s11207-026-02742-x","DOIUrl":"10.1007/s11207-026-02742-x","url":null,"abstract":"<div><p>We suggest that the preflare and impulsive phases of a solar flare may be described in terms of a two-stage scenario. Stage I for the preflare phase is the marginally stable and linearly unstable development of a global MHD instability (torus or kink) that causes a magnetic flux rope containing a prominence to begin erupting slowly from equilibrium. It forms a current sheet with weak magnetic reconnection that produces weak EUV and X-ray brightenings and bidirectional outflows. Stage II for the impulsive phase of the flare consists of a transition from linear to nonlinear instability in which there is a multi-scale cascade to produce many small-scale current sheets with fast impulsive bursty reconnection, at which fast particle acceleration is likely to occur. There are two distinct types of flare to which this scenario applies. Type A is a new one suggested by Solar Orbiter observations (Chitta et al. 2026). In this case, Stage I involves kink instability, with weak reconnection at a current sheet within the flux rope. During the nonlinear development of Stage II, the jets expelled by the current sheet spawn a myriad of new current sheets throughout the flux rope. Type B is the usual model in which a torus instability drives weak reconnection at a current sheet below a rising flux rope or vice versa (Stage I), followed by a transition to fast impulsive bursty reconnection in the current sheet (Stage II). If both types occur simultaneously, with reconnection both within and under the flux rope, then four flare ribbons are produced.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Type I Solar Radio Bursts Modulated by Solar Flares","authors":"Yutong Li,&nbsp;Chuanyang Li,&nbsp;Yanke Tang,&nbsp;Ning Gai,&nbsp;Zichuan Li,&nbsp;Zhe Cui,&nbsp;Yang Gao,&nbsp;Yifan Wang,&nbsp;Xiaodong Xu,&nbsp;Xiaodi Huo","doi":"10.1007/s11207-026-02736-9","DOIUrl":"10.1007/s11207-026-02736-9","url":null,"abstract":"<div><p>Type I solar radio bursts (noise storms) are persistent meter-wave nonthermal emissions above active regions, with their occurrence and properties closely related to the local magnetic configuration and nonthermal electron acceleration. This study examines a type I noise storm on 24 December 2023 and its relation to flare activity. The noise-storm source was co-spatial with active region (AR) 3529 and showed frequency-dependent spatial dispersion. The associated M2.9 flare strongly modulated the emission, with the storm intensity decreasing at flare onset, recovering afterward, and shifting to higher frequencies. Based on multiwavelength observations, we suggest that pre-flare small-scale reconnection supplied nonthermal electrons to overlying closed magnetic structures and maintained the storm. During the flare, magnetic reconnection above the active region produced bidirectional plasma ejections and type III bursts with bidirectional frequency drifts; the gradually decreasing starting frequency of these bursts may indicate an upward-moving reconnection site. The resulting magnetic reconfiguration disrupted electron trapping and suppressed the storm, whereas post-flare magnetic recovery allowed the emission to resume. These results show that flares can modulate type I noise storms through magnetic restructuring and provide insight into the generation mechanism of noise storms.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"301 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}