Solar Physics最新文献

{"title":"North-South Asymmetry of the Solar Activity at Different Spatial Scales","authors":"V. N. Obridko,&nbsp;A. S. Shibalova,&nbsp;D. D. Sokoloff,&nbsp;I. M. Livshits","doi":"10.1007/s11207-025-02527-8","DOIUrl":"10.1007/s11207-025-02527-8","url":null,"abstract":"<div><p>Solar activity seems quite understandable when considered on the scales comparable with a solar cycle, i.e. about 11 years, and on a short time scale of about a year. A solar cycle looks basically (anti)symmetric with respect to the solar equator, while the sunspot distribution is more or less random. We investigated the difference in the spatial distribution of magnetic structures on both time scales in terms of sunspots and the surface large-scale magnetic field and arrived at the conclusion that the structures of each type are created by a specific mechanism. For long-term structures, it is the mean-field dynamo. For the short-term ones, it is the spot production considered as a separate physical mechanism. The relationship between the mean-field dynamo mechanism and the processes of sunspot formation is a complex problem of current interest. The 11-year cycle itself is created by the mean-field dynamo and is most likely determined by processes in the convection zone. However, the transformation of magnetic flux into spots and active regions occurs, apparently, on significantly shorter time scales and probably develops directly in the subsurface layers, i.e., Near-Surface Shear Layer (NSSL) or leptocline.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144868826","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":"Ion Acceleration in Fermi-LAT Behind-the-Limb Solar Flares: The Role of Coronal Shock Waves","authors":"Alexander Warmuth,&nbsp;Melissa Pesce-Rollins,&nbsp;Nicola Omodei,&nbsp;Song Tan","doi":"10.1007/s11207-025-02522-z","DOIUrl":"10.1007/s11207-025-02522-z","url":null,"abstract":"<div><p>We investigate the relationship between the gamma-ray emission measured with the Large Area Telescope on board Fermi (Fermi-LAT9 and radio signatures of coronal shock waves in four behind-the-limb (BTL) solar flares. All events were associated with metric type II radio bursts. Both start and end times of the radio bursts were synchronized with the gamma-ray emission. The type II bursts associated with the BTL gamma-ray flares had higher speeds and lower formation heights than those of an average sample. These findings support the notion that the highly relativistic ions that produce the gamma-rays in BTL flares are accelerated at CME-driven propagating coronal shock waves rather than in large-scale coronal loops.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144868955","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":"Ground-Level Enhancement of 8 June 2024 (GLE 75) Caused by Solar Energetic Particles","authors":"Stepan Poluianov,&nbsp;Alexander Mishev,&nbsp;Olga Kryakunova,&nbsp;Botakoz Seifullina,&nbsp;Nikolay Nikolayevskiy,&nbsp;Ilya Usoskin","doi":"10.1007/s11207-025-02518-9","DOIUrl":"10.1007/s11207-025-02518-9","url":null,"abstract":"<div><p>Solar eruptive events such as flares and coronal mass ejections can accelerate charged particles up to nearly relativistic energies producing so-called solar energetic particles (SEPs). Some of those SEPs can propagate towards Earth and be registered by, e.g., particle detectors onboard satellites. Favourable acceleration conditions make strong SEP events possible with a high flux of high-energy (&gt; 500 MeV) protons, which can be registered even on the ground by neutron monitors (NMs) as rapid enhancements of their count rate over the background. Such events are accordingly called ground-level enhancements (GLEs). GLEs are rare, with only 73 events registered from 1942 to 2023, and three more GLEs 74 – 76 occurred in 2024, close to the maximum of solar activity. In this work, we report GLE 75 that happened on 8 June 2024, initially missed during real-time monitoring, but identified retrospectively. The SEP event, which induced the GLE, was associated with a flare from the solar active region 13697 (13664 on the previous solar rotation). It caused statistically significant increases in the count rate of NMs Dome C, South Pole, and Peawanuck, as well as in the proton intensity measured by Geostationary Operational Environmental Satellite GOES-16. Here, we show the GLE in NM data, describe the procedure of evaluation of its statistical significance, and present the analysis with reconstruction of the spectral and angular SEP distributions.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02518-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144861435","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":"The Gondola for the Sunrise iii Balloon-Borne Solar Observatory","authors":"Pietro Bernasconi,&nbsp;Michael Carpenter,&nbsp;Harry Eaton,&nbsp;Erich Schulze,&nbsp;Bliss Carkhuff,&nbsp;Geoffrey Palo,&nbsp;Daniel Young,&nbsp;Nour Raouafi,&nbsp;Angelos Vourlidas,&nbsp;Robert Coker,&nbsp;Sami K. Solanki,&nbsp;Andreas Korpi-Lagg,&nbsp;Achim Gandorfer,&nbsp;Alex Feller,&nbsp;Tino L. Riethmüller,&nbsp;H. N. Smitha,&nbsp;Bianca Grauf,&nbsp;Jose Carlos del Toro Iniesta,&nbsp;David Orozco Suárez,&nbsp;Yukio Katsukawa,&nbsp;Masahito Kubo,&nbsp;Thomas Berkefeld,&nbsp;Alexander Bell,&nbsp;Alberto Álvarez-Herrero,&nbsp;Valentín Martínez Pillet","doi":"10.1007/s11207-025-02524-x","DOIUrl":"10.1007/s11207-025-02524-x","url":null,"abstract":"<div><p><span>Sunrise iii</span> is a balloon-borne solar observatory dedicated to investigating the physics governing the magnetism and dynamics in the lower solar atmosphere. The observatory is designed to operate in the stratosphere, at heights around 36 km (above 99% of Earth’s atmosphere), to avoid image degradation due to turbulence in the Earth’s lower atmosphere, to gain access to the NUV wavelengths down to 309 nm, and to enable (when flown during summer solstice) observing the Sun uninterruptedly 24 hours/day. It is composed of a balloon gondola (equivalent to a spacecraft bus) carrying a 1-m aperture telescope (the largest solar telescope to-date to fly in the stratosphere on a balloon) feeding an imaging vector magnetograph and two spectropolarimeters aiming at acquiring high spatial resolution high cadence time series maps of the solar vector magnetic fields, plasma flows, and temperature in the photosphere and chromosphere.</p><p>In July 2024 <span>Sunrise iii</span> successfully completed a six and a half days long stratospheric flight from Kiruna (Sweden) to Northern Canada at an average altitude of 36 km. This was the third successful flight of the <span>Sunrise</span> observatory, which had previously flown in 2009 and 2013. For this flight it was upgraded substantially with a new and improved suite of three instruments carried by a completely new gondola with upgraded pointing control system.</p><p>This article focuses on describing the design and flight performance of the <span>Sunrise iii</span> gondola and all its subsystems. It describes the gondola mechanical structure, its power system, its command and control system, and in particular its pointing control system which was key for achieving high spatial and spectral resolution images of the solar photosphere and chromosphere by the three instruments.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02524-x.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810849","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":"SARD: A YOLOv8-Based System for Solar Active Region Detection with SDO/HMI Magnetograms","authors":"Jinhui Pan,&nbsp;Jiajia Liu,&nbsp;Shaofeng Fang,&nbsp;Rui Liu","doi":"10.1007/s11207-025-02525-w","DOIUrl":"10.1007/s11207-025-02525-w","url":null,"abstract":"<div><p>Solar active regions are where sunspots are located and photospheric magnetic fluxes are concentrated, therefore being the sources of energetic eruptions in the solar atmosphere. The detection and statistics of solar active regions have been forefront topics in solar physics. In this study, we developed a solar active region detector (SARD) based on the advanced object detection model YOLOv8. First, we applied image processing techniques including thresholding and morphological operations to 6975 line-of-sight magnetograms from 2010 to 2019 at a cadence of 12 h, obtained by the Helioseismic and Magnetic Imager onboard the Solar Dynamic Observatory. With manual refinement in accordance with the NOAA catalog, we labeled each individual active regions in the dataset, and obtained a total of 26,531 labels for training and testing the SARD. Without any overlap between the training and test sets, the superior performance of SARD is demonstrated by an average precision rate as high as 94%. We then performed a statistical analysis on the area and magnetic flux of the detected active regions, both of which yield log-normal distributions. This result sheds light on the underlying complexity and multi-scale nature of solar active regions.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162114","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":"Adding Further Pieces to the Synchronization Puzzle: QBO, Bimodality, and Phase Jumps","authors":"F. Stefani,&nbsp;G. M. Horstmann,&nbsp;G. Mamatsashvili,&nbsp;T. Weier","doi":"10.1007/s11207-025-02521-0","DOIUrl":"10.1007/s11207-025-02521-0","url":null,"abstract":"<div><p>This work builds on a recently developed self-consistent synchronization model of the solar dynamo which attempts to explain Rieger-type periods, the Schwabe/Hale cycle, and the Suess-de Vries and Gleissberg cycles in terms of resonances of various wave phenomena with gravitational forces exerted by the orbiting planets. We start again from the basic concept that the spring tides of the three pairs of the tidally dominant planets Venus, Earth, and Jupiter excite magneto-Rossby waves at the solar tachocline. While the quadratic action of the sum of these three waves comprises the secondary beat period of 11.07 years, the main focus is now on the action of the even more pronounced period of 1.723 years. Our dynamo model provides oscillations with exactly that period, which is also typical for the quasi-biennial oscillation (QBO). Most remarkable is its agreement with Ground Level Enhancement (GLE) events which preferentially occur in the positive phase of an oscillation with a period of 1.724 years. While bimodality of the sunspot distribution is shown to be a general feature of synchronization, it becomes most strongly expressed under the influence of the QBO. This may explain the observation that the solar activity is relatively subdued when compared to that of other sun-like stars. We also discuss anomalies of the solar cycle, and subsequent phase jumps by 180^∘. In this connection it is noted that the very 11.07-year beat period is rather sensitive to the time-averaging of the quadratic functional of the waves and prone to phase jumps of 90^∘. On this basis, we propose an alternative explanation of the observed 5.5-year phase jumps in algae-related data from the North Atlantic and Lake Holzmaar that were hitherto attributed to optimal growth conditions.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02521-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145162670","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":"Observation and Modeling of Small Spatial Structures of Solar Radio Noise Storms Using the uGMRT","authors":"Surajit Mondal,&nbsp;Peijin Zhang,&nbsp;Devojyoti Kansabanik,&nbsp;Divya Oberoi,&nbsp;Gillian Pearce","doi":"10.1007/s11207-025-02519-8","DOIUrl":"10.1007/s11207-025-02519-8","url":null,"abstract":"<div><p>One of the most commonly observed solar radio sources in the metric and decametric wavelengths is the solar noise storm. These are generally associated with active regions and are believed to be powered by the plasma emission mechanism. Since plasma emission is emitted primarily at the fundamental and harmonic of the local plasma frequency, it is significantly affected by density inhomogeneities in the solar corona. The source can become significantly scatter-broadened due to the multi-path propagation caused by refraction from the density inhomogeneities. Past observational and theoretical estimates suggest some minimum observable source size in the solar corona. The details of this limit, however, depend on the modeling approach and details of the coronal turbulence model chosen. Hence pushing the minimum observable source size to smaller values can help constrain the plasma environment of the observed sources. In this work, we for the first time, use data from the upgraded Giant Metrewave Radio Telescope in the 250 – 500 MHz band, to determine multiple instances of very small-scale structures in the noise storms. We also find that these structures are stable over timescales of 15 – 30 minutes. By comparing the past observations of type III radio bursts and noise storms, we hypothesize that the primary reason behind the detection of these small sources in noise storm is due to the local environment of the noise storm. We also build an illustrative model and propose some conditions under which the minimum observable source size predicted by theoretical models, can be lowered significantly.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02519-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171737","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":"Multiple Sources of a Type II Radio Burst Within a Coronal Mass Ejection","authors":"Shiwei Feng,&nbsp;Pietro Zucca","doi":"10.1007/s11207-025-02520-1","DOIUrl":"10.1007/s11207-025-02520-1","url":null,"abstract":"<div><p>Solar type II radio bursts are generated through plasma emission caused by energetic electrons that are accelerated by shock waves during solar eruptions. These bursts serve as tracers of shock waves in the corona. However, the complexity of solar eruptions and the lack of radio imaging observations have hampered our understanding of type II bursts. The newly built Daocheng Solar Radio Telescope (DSRT) detected a rare type II burst. Its harmonic shows an initial herringbone (HB), followed by three nearly parallel lanes. These lanes form a framed pattern: a central main lane (termed MAIN) with a higher brightness temperature and wider bandwidth, flanked by two well-defined fringes, F1 and F2. Radio and extreme ultraviolet imaging observations indicate that the sources of the HB are precisely located on the flank of the leading shock wave driven by a coronal mass ejection (CME). In contrast, the MAIN and F2 sources correlate in terms of time, location, electron number density, and propagation velocity with an ascending coronal loop. In contrast, the F1 sources are associated with a nearby but distinct coronal loop. These observations suggest that at least three sources of the type II burst accompany the CME. A scenario involving multiple shock waves within the CME is proposed to explain the presence of the different radio sources.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171323","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":"Differential Rotation of Long-Lived Sunspot Groups in Solar Cycles 22 – 24 Determined by Watukosek Solar Observatory Data","authors":"Nanang Widodo,&nbsp;Johan Muhamad,&nbsp;Ayu Dyah Pangestu,&nbsp;Gerhana Puannandra Putri,&nbsp;Santi Sulistiani,&nbsp;Silmie Vidiya Fani,&nbsp;Tiar Dani,&nbsp;Dhani Herdiwijaya","doi":"10.1007/s11207-025-02516-x","DOIUrl":"10.1007/s11207-025-02516-x","url":null,"abstract":"<div><p>Solar differential rotation (SDR) profile can give an important clue on how the solar dynamo varies from one solar cycle to another. In order to investigate the variability of SDR across multiple solar cycles, we calculated rotation rates of sunspots observed in Solar Cycles 22 – 24 (1987 – 2019) by using sunspot data records from the Watukosek Solar Observatory (WKSO). WKSO has the longest continuous sunspot observation record in Indonesia. Its historical record of sunspot observations provides a unique and valuable dataset for solar physics research. In this paper, we introduced the repository of sunspot observations from WKSO for almost three solar cycles. Using these data, we calculated the rotation rate of each long-lived sunspot group during Solar Cycles 22 – 24 by measuring the linear least-square fitting of daily movements of the sunspot position in various latitudes. The results confirm the well-established pattern of SDR, with a faster rotation at the equator compared to higher latitudes. We also found that the rotation rates of long-lived sunspot groups are slower than the differential rotation rates derived from the entire sunspot data. Furthermore, our analysis of this dataset confirmed that the bipolar sunspot groups rotate faster than unipolar sunspots. These results suggest that unipolar and bipolar sunspots are anchored at different depths beneath the solar surface. These findings are consistent with prior results using older data from different observatories, suggesting the reliability and scientific importance of the sunspot observations from WKSO for understanding solar-dynamo processes and their variability.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171321","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":"Bayesian Modeling of Emerging Bipolar Active Regions from Solar Cycle 23","authors":"Mariano Poisson,&nbsp;Pascal Démoulin,&nbsp;Marcelo López Fuentes,&nbsp;Cristina H. Mandrini","doi":"10.1007/s11207-025-02517-w","DOIUrl":"10.1007/s11207-025-02517-w","url":null,"abstract":"<div><p>Active regions (ARs) are the photospheric manifestations of emerging magnetic flux ropes (FRs) formed in the solar interior. We analyze the emergence of 126 bipolar ARs during Solar Cycle 23 using a flux rope model, whose parameters are inferred through a Bayesian inference method. This approach allows us to estimate key sub-photospheric properties of FRs. We find that the Bayesian method effectively captures the global magnetic characteristics of ARs, with discrepancies primarily arising in the later stages of emergence. We examine the ability of a flux-balanced FR model with a symmetric circular cross-section to reproduce polarity shapes during these late stages. Additionally, we analyze how the inclination of the FR legs provides insight into the emergence stage. We propose an improved method for estimating the separation of polarities, which decreases projection effects and flux distribution biases. Furthermore, we confirm a strong correlation between the AR flux and the distance between the main polarities, as well as the evolution of their separation speed. Finally, we identify a characteristic ratio between the thickness of the FR and its curvature radius, suggesting an underlying physical mechanism governing this ratio.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 8","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171163","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}