Solar Physics最新文献

{"title":"Short and Intermediate Periodicities in Ca ii K Plage Areas as Seen in Kodaikanal Images for Individual Cycles from 14 to 22","authors":"Partha Chowdhury,&nbsp;V. Muthu Priyal,&nbsp;Jagdev Singh,&nbsp;Belur Ravindra","doi":"10.1007/s11207-025-02545-6","DOIUrl":"10.1007/s11207-025-02545-6","url":null,"abstract":"<div><p>We analyze historical Ca <span>ii</span> K images from the Kodaikanal Observatory (KO) spanning 1907 to 1996, encompassing Solar Cycles 14 through 22. These digitized images were processed using the Equal Contrast Technique (ECT) to ensure uniform data quality for studying long and short-term variations. From these standardized images, we identify and compute the areas of both plages and network regions in both solar hemispheres in every image. We then utilizy this revised, uniform Ca <span>ii</span> K plage area time series for Solar Cycles 14 to 22. Our primary objective is to investigate the presence of short, Rieger-type periods and quasi-biennial oscillations (QBOs), specifically those near ≈ 1.3 years. To achieve this, we employ both Lomb-Scargle periodograms and Morlet wavelet maps. Our power spectrum analysis consistently shows that Rieger-type periods are significant across all solar cycles, in both the northern and southern hemispheres and in the whole disk data. However, the wavelet analysis reveals that both Rieger-type and QBO periodicities are intermittent, exhibiting varying periods in different cycles and hemispheres. This indicates that plages and network areas demonstrate asymmetric behavior between the two hemispheres. We have also discussed the potential reasons behind these observed periodicities.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210652","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":"Application of a Neural Network for Identifying Erroneous Solar Images","authors":"Kiran Jain,&nbsp;Mitchell Creelman","doi":"10.1007/s11207-025-02554-5","DOIUrl":"10.1007/s11207-025-02554-5","url":null,"abstract":"<div><p>For over a century, solar images have been captured across different spectral ranges. Initially, these images were taken on photographic plates, and with the development of CCD cameras, the images transitioned from analogue to digital formats. Analyzing digital images enables us to identify and analyze trends and features on the solar disk more efficiently. However, complications due to instrument malfunction or environmental factors can result in suboptimal images. Traditionally, several statistical parameters are used to check image quality, but these measures do not always yield satisfactory results. In this article, we describe a convolutional classification neural network for near-real time image quality assessment of GONG Dopplergrams. We also present a case study where this approach significantly improved the quality of science data products in an automated data reduction pipeline without any human intervention.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145144815","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":"Role of CME Clusters and CME-CME Interactions in Producing Sustained (gamma )-Ray Emission Events","authors":"Atul Mohan,&nbsp;Pertti Mäkelä,&nbsp;Natchimuthuk Gopalswamy,&nbsp;Sachicko Akiyama,&nbsp;Seiji Yashiro","doi":"10.1007/s11207-025-02535-8","DOIUrl":"10.1007/s11207-025-02535-8","url":null,"abstract":"<div><p>Fast (<span>(mathrm{V}_{mathrm{CME}} &gt; 1000text{ km},text{s}^{-1})</span>) coronal mass ejections (CMEs) capable of accelerating protons beyond 300 MeV are thought to trigger hours-long sustained <span>(gamma )</span>-ray emission (SGRE) after the impulsive flare phase. Meanwhile, CME-CME interactions can cause enhanced proton acceleration, increasing the fluxes of solar energetic particles. This study explores the role of fast CME interactions in SGRE production during CME clusters, which we define as a series of CMEs linked to &gt; C-class flares with waiting times &lt; 1 day from the same active region (AR). We focus on clusters in major CME-productive ARs (major ARs), by defining a major AR as one that produced &gt; 1 CME associated to a major (&gt; M-class) flare. The study identified 76 major ARs between 2011 and 2019, of which 12 produced all SGRE events. SGRE-producing ARs exhibit higher median values for the speed of their fastest CMEs (2013 vs. 775 km s⁻¹) and the class of their strongest flares (X1.8 vs. M5.8), compared to SGRE-lacking ARs. They also produced relatively faster CMEs (median speed: 1418 vs. 1206.5 km s⁻¹), with the SGRE-associated CMEs occurring during periods of higher CME rates than typical fast CME epochs. Twelve of 22 (54.5%) SGRE events and 5 of 7 (71.4%) long-duration (&gt; 10 h) SGRE events occurred during CME clusters, with high chances of CME-CME interactions. A case study on very active major ARs showed that all SGRE-associated CMEs with <span>(mathrm{V}_{mathrm{CME}} lesssim 2000text{ km},text{s}^{-1})</span> underwent CME-CME interactions within ≲ 10 <span>({mathrm{R_{odot }}})</span>, while SGRE-associated CMEs faster than 3000 km s⁻¹ did not undergo interactions.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02535-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145199","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":"Flare Energetics, CME Launch and Heliospheric Propagation for the May 2024 Events, as Derived from Ensemble MHD Modelling","authors":"Brigitte Schmieder,&nbsp;Jinhan Guo,&nbsp;Guillaume Aulanier,&nbsp;Anwesha Maharana,&nbsp;Stefaan Poedts","doi":"10.1007/s11207-025-02553-6","DOIUrl":"10.1007/s11207-025-02553-6","url":null,"abstract":"<div><p>Many questions must be answered before understanding the relationship between the emerging magnetic flux through the solar surface and the extreme geoeffective events. The main ingredients for getting X-ray class flares and large interplanetary Coronal Mass Ejections (CMEs) are the buildup of electric current in the corona, the existence of magnetic free energy, magnetic energy/helicity ratio, twist, and magnetic stress in active regions (ARs). The upper limit of solar energy in the space research era, as well as the potential for experiencing superflares and extreme solar events, can be predicted using MHD simulations of CMEs.</p><p>To address this problem, we consider the recent events of May 2024 and use three MHD models:</p><p>1) OHM (“Observationally driven High order scheme Magnetohydrodynamic code”) for investigating the magnetic evolutions at a synthetic dipole structure.</p><p>2) TMF (time-dependent magneto-friction) for setting up an initial non-potential magnetic field in the active region. A zero-beta MHD model for tracing the magnetic evolution of active regions.</p><p>3) EUHFORIA (“European heliospheric forecasting information asset”) for interplanetary CME propagations.</p><p>For the eruptive flares with CMEs, magnetic solar energy is computed along with data-constrained MHD simulations for the May 2024 events. We show the consistency between the data-initiated, realistic simulation of the May 2024 big event and energy scalings from an idealised simulation of a bipolar eruption using OHM. The estimated free magnetic energy did not surpass <span>(5.2 times 10^{32}text{ erg})</span>. Good arrival time predictions (<span>(&lt;3)</span> hours) are achieved with the EUHFORIA simulation with the cone model. We note the interest in coupling all the chains of codes from the Sun to the Earth and developing different approaches to test the results.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145145200","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":"Observations of Flare Induced Doppler Shifts in the Si iii 1206 Å Line","authors":"Luke H. Majury,&nbsp;Ryan O. Milligan","doi":"10.1007/s11207-025-02548-3","DOIUrl":"10.1007/s11207-025-02548-3","url":null,"abstract":"<div><p>Doppler shifts in chromospheric and transition-region lines during solar flares are often interpreted as chromospheric condensation or evaporation. However, alternative sources of Doppler-shifted emission have been suggested, such as filament eruptions, jets or chromospheric bubbles. We analyse high-cadence scans from SORCE/SOLSTICE, which provide one-minute resolution profiles of the transition-region Si <span>iii</span> (1206 Å, <span>(textrm{T} = 10^{4.6},textrm{K})</span>) line. 11 X-, M-, and C-class events observed during these scans with clear impulsive phase Si <span>iii</span> enhancements were identified. By subtracting a quiet-Sun profile and fitting Gaussian profiles to the Si <span>iii</span> line, measurements of flare-induced Doppler shifts were made. After correcting for a systematic trend in these shifts with solar longitude, two of the 11 events were found to exhibit a significant Doppler shift, one with a <span>(201.36pm 21.94;textrm{km,s}^{-1})</span> redshift and the other with a <span>(-39.75pm 11.00;textrm{km,s}^{-1})</span> blueshift. Intriguingly, SDO/AIA 304 Å and 1600 Å imaging revealed a bright eruption coincident with the event that exhibited a blueshift, suggesting the shift may have resulted from the eruption rather than evaporation alone. Our results highlight Si <span>iii</span> as a useful diagnostic of flaring dynamics at a temperature that has received limited attention to date. Future comparisons of these observations with radiative hydrodynamic simulations, along with new observations from state-of-the-art spectrometers such as SOLAR-C/EUVST and MUSE, should clarify the mechanisms behind the observed shifts in this study.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02548-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110510","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":"Activity-Cycle Variations of Convection Scales in Subsurface Layers of the Sun","authors":"Alexander V. Getling,&nbsp;Alexander G. Kosovichev","doi":"10.1007/s11207-025-02546-5","DOIUrl":"10.1007/s11207-025-02546-5","url":null,"abstract":"<div><p>We use subsurface-flow velocity maps inferred by time–distance helioseismology from Doppler measurements with the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO) to investigate variations of large-scale convection during Solar Cycles 24 and 25 in the 19-Mm-deep layer. The spatial power spectra of the horizontal-flow divergence reveal well-defined characteristic scales of solar supergranulation in the upper 4 Mm layer, while the giant-cell scale is prominent below levels of <span>(d sim 8)</span> Mm. We find that the characteristic scales of supergranulation remain stable while the giant scales increase during the periods of the 11-year activity cycle maxima. The power of the giant-cell scales increases with the enhancement of solar activity. This may be due to large-scale flows around active regions and, presumably, solar-cycle variations of the convection-zone stratification.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073789","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":"MHD Simulations of CME with Associated Prominence Eruption","authors":"Yuhong Fan","doi":"10.1007/s11207-025-02547-4","DOIUrl":"10.1007/s11207-025-02547-4","url":null,"abstract":"<div><p>We present an overview of magnetohydrodynamic (MHD) simulations of prominence-forming coronal flux ropes and the development of coronal mass ejection (CME) with associated prominence eruption. The simulations found the formation of a prominence–cavity system that qualitatively reproduces several observed features including the cavity, the prominence “horns”, and the central “cavity” enclosed in the “horns” above the prominence. We discuss the magnetic structure corresponding to these observed features and the effect of the prominence weight on the stability and eruption of the flux rope.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073899","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":"Aditya-L1 - An Observatory Class Mission: Spacecraft, Mission, and Operations","authors":"Nashiket Premlal Parate,&nbsp;Nigar Shaji,&nbsp;Motamarri Srikanth,&nbsp;K. Sankarasubramanian,&nbsp;Narashimha Murthy Patnaik,&nbsp;S. Narendra,&nbsp;Abhijit Avinash Adoni,&nbsp;Kuldeep Negi,&nbsp;Pragyan Pattanaik,&nbsp;Bharat Kumar G. V. P,&nbsp;Vivek R. Subramanian,&nbsp;Hemanth Kumar Reddy N.,&nbsp;Shree Niwas Sahu,&nbsp;Vishnu Kishore Pai,&nbsp;Sajjade Faisal Mustafa,&nbsp;Richa Pathak,&nbsp;Amit Maji,&nbsp;T. R. Haridas,&nbsp;Anand Raj,&nbsp;Pankaj Agarwal,&nbsp;Arvind Kumar Singh,&nbsp;Smruti Ranjan Panigrahi,&nbsp;A. Ravi","doi":"10.1007/s11207-025-02533-w","DOIUrl":"10.1007/s11207-025-02533-w","url":null,"abstract":"<div><p>Aditya-L1 is an observatory class mission designed and developed by the Indian Space Research Organisation (ISRO) to study the Sun and the inner heliosphere. Aditya-L1, currently orbiting around the first Lagrange point L1, is in a periodic halo orbit located approximately at 1.5 million km from Earth on the Sun–Earth line (about 1% of the Sun-Earth distance and closer to Earth). The orbital parameters of Aditya-L1 around L1 are Ax = 208,951 km, Ay = 670,024 km and Az = 120,000 km, where Ax, Ay and Az are semi-diameters of the orbit with an orbital period of 177.86 days. The primary objective of the Aditya-L1 mission is to understand the coronal and chromospheric dynamics of the Sun along with its influence on the heliosphere, especially at the L1 location. To achieve these goals, the spacecraft is configured to accommodate seven payloads of which four are remote sensing and three are in situ experiments. The scientific payloads are designed and developed by various Indian Research Institutes in close collaboration with different ISRO centers. The spacecraft is configured with the modified Mars orbiter mission (MOM) bus and is a three-axis stabilized spacecraft with a lift of mass of 1480.73 kg and power generation of ≈ 1820 W. Pointing stability will be better than 15 arcsec as required by the coronagraph payload. Aditya-L1 payload produces around 240 Gbits of science data per day (≈ 90% data is from the imaging payloads). Planning, coordination, and operation of the spacecraft and the scientific payloads are conducted from ISRO telemetry, tracking, and command network in Bengaluru, India. Aditya-L1 was launched on board the Polar Satellite Launch Vehicle (PSLV C57) at 11:50 Indian standard time (IST) from the second launch pad of the Satish Dhawan Space Centre (SDSC), Sriharikota, India on 2 September 2023. It was inserted at the L1 point on 6 January 2024, at 4:17 pm IST. The spacecraft, mission, and operation aspects of the Aditya-L1 spacecraft are discussed in this paper.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145062135","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":"Automatic Detection of Ellerman Bombs in the H(alpha ) Line","authors":"Arooj Faryad,&nbsp;Alexander G. M. Pietrow,&nbsp;Meetu Verma,&nbsp;Carsten Denker","doi":"10.1007/s11207-025-02534-9","DOIUrl":"10.1007/s11207-025-02534-9","url":null,"abstract":"<div><p>Ellerman bombs (EBs) are small and short-lived magnetic reconnection events in the lower solar atmosphere, most commonly reported in the line wings of the H<span>(alpha )</span> line. These events are thought to play a role in heating the solar chromosphere and corona, but their size, short lifetime, and similarity to other brightenings make them difficult to detect. We aim to automatically detect and statistically analyze EBs at different heliocentric angles to find trends in their physical properties. We developed an automated EB detection pipeline based on a star-finding algorithm. This pipeline was used on ten high-resolution H<span>(alpha )</span> datasets from the 1-meter Swedish Solar Telescope (SST). This pipeline identifies and tracks EBs in time, while separating them from visually similar pseudo-EBs. It returns key parameters such as size, contrast, lifetime, and occurrence rates based on a dynamic threshold and the more classical static ‘contrast threshold’ of 1.5 times the mean quiet-Sun (QS) intensity. For our dynamic threshold we found a total of 2257 EBs from 28,772 individual detections across our datasets. On average, the full detection set exhibits an area of 0.44 arcsec² (0.37 Mm²), a peak intensity contrast of 1.4 relative to the QS, and a median lifetime of 2.3 min. The stricter threshold yielded 549 EBs from 15,997 detections, with a higher median area of 0.66 arcsec² (0.57 Mm²), an intensity contrast of 1.7, and a median lifetime of 3 min. These comparisons highlight the sensitivity of EB statistics to selection thresholds and motivate further work towards consistent EB definitions. Several long-lived EBs were observed with lifetimes exceeding one hour. While the EB intensity contrast increases towards the limb, no clear trends were found between the other EB parameters and the heliocentric angle, suggesting that the local magnetic complexity and evolutionary stage dominate EB properties.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028157","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":"Incorporating Magnetic-Field Characteristics into EUV-Based Automated Segmentation of Coronal Holes","authors":"Jeremy A. Grajeda,&nbsp;Laura E. Boucheron,&nbsp;Michael S. Kirk,&nbsp;Andrew Leisner,&nbsp;Jaime A. Landeros,&nbsp;C. Nick Arge","doi":"10.1007/s11207-025-02536-7","DOIUrl":"10.1007/s11207-025-02536-7","url":null,"abstract":"<div><p>Coronal holes (CHs) are magnetically open regions that allow hot coronal plasma to escape from the Sun and form the high-speed solar wind. This wind can interact with Earth’s magnetic field. For this reason, developing an accurate understanding of CH regions is vital for understanding space weather and its effects on Earth. The process of identifying CH regions typically relies on extreme ultraviolet (EUV) imagery, leveraging the fact that CHs appear dark at these wavelengths. Accurate identification of CHs in EUV, however, can be difficult due to a variety of factors, including stray light from nearby regions, limb brightening, and the presence of filaments (which also appear dark, but are not sources of solar wind). In order to overcome these issues, this work incorporates photospheric magnetic-field data into a classical EUV-based segmentation algorithm based on the Active Contours Without Edges (ACWE) segmentation method. In this work magnetic-field data are incorporated directly into the segmentation process, serving both as a method for removing non-CH regions in advance, and as a method to constrain evolution of the segmented CH boundary. This reduces the presence of filaments while allowing the segmentation to include CH regions that may be difficult to identify due to inconsistent intensities.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02536-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145011824","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}