Solar Physics最新文献

Long-Term Variation of the Number of Sunspots per Group 每组太阳黑子数量的长期变化

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-15 DOI: 10.1007/s11207-025-02558-1

Alexei A. Pevtsov, Yury A. Nagovitsyn, Kalevi Mursula

{"title":"Long-Term Variation of the Number of Sunspots per Group","authors":"Alexei A. Pevtsov, Yury A. Nagovitsyn, Kalevi Mursula","doi":"10.1007/s11207-025-02558-1","DOIUrl":"10.1007/s11207-025-02558-1","url":null,"abstract":"<div><p>Long-term reconstructions of sunspot number (SSN) and group number (GN) often tacitly assume that the basic characteristics of solar activity remain unchanged even over long times, e.g., that the number of sunspots and the number of sunspot groups now and, say, 100 or 500 years ago have the same relation. However, this assumption needs examination, especially as the long-term homogeneity between sunspots and several other solar activity parameters has recently been challenged (Mursula et al. 2024). Here we use long series of sunspot observations to study if and how the number of sunspots per group varies at different time scales. We use observations from the Kislovodsk Mountain Astronomical Station (KMAS) and the Solar Observing Optical Network (SOON) to create a reference series for the overlapping period of 1982 – 2016. We then scale other historical data to this reference series in order to have a unified time series for 1749 – 2024. We find that the yearly mean number of sunspots per group varies between about 2 and 10 (average of 6.8), closely in phase with the solar cycle over the whole 270-year time interval. We also find that the number of sunspots per group depicts a very similar secular variation as the sunspot number.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02558-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145315861","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}

引用次数: 0

Correction: Bošković’s Spherical Trigonometric Solution for Determining the Axis and Rate of Solar Rotation by Observing Sunspots in 1777 修正：Bošković在1777年通过观测太阳黑子来确定太阳自转轴和速率的球面三角解

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-15 DOI: 10.1007/s11207-025-02542-9

Mirko Husak, Roman Brajša, Dragan Špoljarić, Davor Krajnović, Domagoj Ruždjak, Ivica Skokić, Dragan Roša, Damir Hržina

引用次数: 0

The Role of Photospheric Magnetic Flux Diffusion in Initiation of Solar Eruptions 光球磁通量扩散在太阳爆发起始中的作用

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-14 DOI: 10.1007/s11207-025-02557-2

Xinkai Bian, Chaowei Jiang, Yang Wang, Peng Zou, Xueshang Feng, Pingbing Zuo, Yi Wang

{"title":"The Role of Photospheric Magnetic Flux Diffusion in Initiation of Solar Eruptions","authors":"Xinkai Bian, Chaowei Jiang, Yang Wang, Peng Zou, Xueshang Feng, Pingbing Zuo, Yi Wang","doi":"10.1007/s11207-025-02557-2","DOIUrl":"10.1007/s11207-025-02557-2","url":null,"abstract":"<div><p>Solar eruptions may occur at different evolutionary stages of active regions, during which the photospheric motions manifest in various forms, including flux emergence, sunspot rotation, shearing, converging, and magnetic flux diffusion. However, it remains unclear what the specific roles played by these different motions are in leading to eruptions. Here, we employ high resolution magnetohydrodynamic simulations to demonstrate how solar eruptions can be initiated in a single bipolar configuration, driven by first shearing and then flux diffusion at the bottom surface. Flux diffusion disperses the photospheric magnetic flux, driving portions of it toward the polarity inversion line (PIL). This process leads to the expansion of core field, enhancing the pinching effect to form the current sheet. When magnetic reconnection occurs within this current sheet, the eruption is initiated, characterized by a rapid release of magnetic energy and accompanied by the formation of a erupting flux rope. Additionally, flux diffusion contributes to magnetic cancellation near the PIL, leading to the formation of a weakly twisted magnetic flux rope prior to the eruption. However, this pre-existing flux rope plays a limited role in eruption initiation, as its spatial position remains largely unchanged throughout the eruption. These findings demonstrate that the primary role of flux diffusion is to facilitate current sheet formation, highlighting the critical role of current sheet formation in eruption initiation.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145316007","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}

引用次数: 0

Models of Collisionless Quasineutral Solar Wind Current Sheets 无碰撞的准中性太阳风电流片模型。

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-13 DOI: 10.1007/s11207-025-02551-8

Sophie Boswell, Thomas Neukirch, Anton Artemyev, Ivan Vasko, Oliver Allanson

{"title":"Models of Collisionless Quasineutral Solar Wind Current Sheets","authors":"Sophie Boswell, Thomas Neukirch, Anton Artemyev, Ivan Vasko, Oliver Allanson","doi":"10.1007/s11207-025-02551-8","DOIUrl":"10.1007/s11207-025-02551-8","url":null,"abstract":"<div><p>In situ measurements of kinetic scale current sheets in the solar wind show that they are often approximately force-free although the plasma <span>(beta)</span> is of order one. They frequently display systematic asymmetric and anti-correlated spatial variations of their particle density and temperature across the current sheet, leaving the plasma pressure essentially uniform. These observations of asymmetries have previously been modelled theoretically by adding additional terms to both the ion and electron distribution functions of self-consistent force-free collisionless current sheet models with constant density and temperature profiles. In this article we present the results of a modification of these models in which only the electron distribution function has an additional term, whereas the ion distribution function is kept as a thermal (Maxwellian) distribution function. In this case the nonlinear quasineutrality condition no longer has a simple analytical solution and therefore has to be solved alongside Ampère’s law. We find that while the magnetic field remains approximately force-free, the non-zero quasineutral electric field gives rise to an additional spatial substructure of the plasma density inside the current sheet. We briefly discuss the potential relation between our theoretical findings and current sheet observations.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12518478/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145297814","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}

引用次数: 0

Hot Flare Precursor Events in GOES 1-s Data: Filament Eruptions GOES 1-s中的热耀斑前兆事件数据：长丝喷发

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-10 DOI: 10.1007/s11207-025-02556-3

Hugh Hudson

{"title":"Hot Flare Precursor Events in GOES 1-s Data: Filament Eruptions","authors":"Hugh Hudson","doi":"10.1007/s11207-025-02556-3","DOIUrl":"10.1007/s11207-025-02556-3","url":null,"abstract":"<div><p>Solar flares exhibit precursor soft X-ray emission at high temperatures (the Hot Onset Precursor Event, here HOPE for short). This phenomenon is readily seen for events at or above the GOES C-class, but at present we do not know whether or not a “pure” filament-eruption event, such as one coming from the polar-crown filament zone, also exhibits this property. We study this question using both older and more modern GOES/XRS soft X-ray data. The currently operating GOES-R spacecraft (GOES-16 through GOES-19) have different sensor technology and also higher cadence than in the earlier satellites in the series, and so we devote an Appendix to describing these data from the point of view of a user interested in the detection of faint sources; most GOES/XRS users focus on flare observations, rather than the quiet Sun. Because the HOPE signatures appear at the very beginning of the development of a flare, they require study at the lowest flux levels. Our searches both with GOES-R and earlier data do not detect HOPE in purely filament-eruption events. At a representative HOPE temperature of 10 MK, the emission measure for any HOPE source must be less than about <span>(10^{46}text{ cm}^{-3})</span>.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256220","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}

引用次数: 0

HEL1OS – A Hard X-ray Spectrometer on Board Aditya-L1 HEL1OS - Aditya-L1上的硬x射线光谱仪

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-08 DOI: 10.1007/s11207-025-02543-8

Anuj Nandi, Manju Sudhakar, Srikar Paavan Tadepalli, Anand Jain, Brajpal Singh, Reenu Palawat, Ravishankar B. T., Bhuwan Joshi, Monoj Bug, Anurag Tyagi, Sumit Kumar, Mukund Kumar Thakur, Akanksha Baggan, Srikanth T., Arjun Dey, Veeresha D. R., Abhijit Avinash Adoni, Padmanabhan, Vivechana M. S., Evangelin Leeja Justin, James M. P., Kinshuk Gupta, Shalini Maiya P. R., Lakshmi A., Sajjade Faisal Mustafa, Vivek R. Subramanian, Gayatri Malhotra, Shree Niwas Sahu, Murugiah S., Medasani Thejasree, Narayan Rao G. S., Rethika T., Motamarri Srikanth, Ravi A., Nashiket Premlal Parate, Nigar Shaji

{"title":"HEL1OS – A Hard X-ray Spectrometer on Board Aditya-L1","authors":"Anuj Nandi, Manju Sudhakar, Srikar Paavan Tadepalli, Anand Jain, Brajpal Singh, Reenu Palawat, Ravishankar B. T., Bhuwan Joshi, Monoj Bug, Anurag Tyagi, Sumit Kumar, Mukund Kumar Thakur, Akanksha Baggan, Srikanth T., Arjun Dey, Veeresha D. R., Abhijit Avinash Adoni,  Padmanabhan, Vivechana M. S., Evangelin Leeja Justin, James M. P., Kinshuk Gupta, Shalini Maiya P. R., Lakshmi A., Sajjade Faisal Mustafa, Vivek R. Subramanian, Gayatri Malhotra, Shree Niwas Sahu, Murugiah S., Medasani Thejasree, Narayan Rao G. S., Rethika T., Motamarri Srikanth, Ravi A., Nashiket Premlal Parate, Nigar Shaji","doi":"10.1007/s11207-025-02543-8","DOIUrl":"10.1007/s11207-025-02543-8","url":null,"abstract":"<div><p><b>HEL1OS</b> (<span>(mathbf{H})</span>igh <span>(mathbf{E})</span>nergy <b>L1</b> <span>(mathbf{O})</span>rbiting X-ray <span>(mathbf{S})</span>pectrometer) is one of the remote sensing payloads on board Aditya-L1 mission designed to continuously monitor and measure the time-resolved spectra of solar flares between 8 keV and 150 keV. This broad energy range has been covered by using compound semiconductor detectors: cadmium telluride (CdTe: 8 – 70 keV) and cadmium zinc telluride (CZT: 20 – 150 keV) with geometric areas of 0.5 cm<sup>2</sup> and 32 cm<sup>2</sup>, respectively. A stainless steel collimator provides a field-of-view of 6° × 6° optimized to limit the off-axis response while keeping the design within the instrument mass constraints. The in-house designed low-noise digital pulse processing-based front-end electronics has achieved a spectral resolution of ≈ 1 keV at 14 keV (CdTe) and ≈ 7 keV at 60 keV (CZT). The instrument is also equipped with processing and power electronics to process the signal, drive the electronics, bias the detectors with required low and high voltages for optimal performance of the overall system. In this article, we present design aspects of the instrument, results from the pre-launch ground-based tests, and the in-orbit operations, which have indicated optimal performance in line with that expected.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256646","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}

引用次数: 0

Quasi-Separatrix Layers and Three-Dimensional Magnetic Reconnection: Theory and Observations of Solar Flares (Invited Review) 准分离矩阵层和三维磁重联：太阳耀斑的理论与观测（特邀评论）

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-07 DOI: 10.1007/s11207-025-02549-2

Jaroslav Dudík, Guillaume Aulanier, Juraj Lörinčík, Alena Zemanová

{"title":"Quasi-Separatrix Layers and Three-Dimensional Magnetic Reconnection: Theory and Observations of Solar Flares (Invited Review)","authors":"Jaroslav Dudík, Guillaume Aulanier, Juraj Lörinčík, Alena Zemanová","doi":"10.1007/s11207-025-02549-2","DOIUrl":"10.1007/s11207-025-02549-2","url":null,"abstract":"<div><p>Over the past three decades, models of solar flares and eruptions based on quasi-separatrix layers (QSLs) have made several important, observationally verified predictions regarding how the magnetic reconnection happens in 3D. Thus, they have become the best available theory of how and where solar flares and eruptions happen. We review the properties of QSLs, the close correspondence between QSL traces in the lower atmosphere and flare ribbons, together with their association to electric current enhancements, both modelled and observed ones. Furthermore, we review the slipping and slip-running nature of the magnetic reconnection in QSLs, and the associated apparent footpoint motions of the reconnecting structures, both modelled and observed. In addition, the purely 3D reconnection geometries involving the erupting magnetic flux rope are reviewed as well, along with the observational evidence for these processes. Finally, we discuss the indications that dynamics within the QSLs could play a role in heating the solar corona.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 10","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02549-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256331","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}

引用次数: 0

Sunspot Observations in 1684 – 1702: John Flamsteed and Philippe de La Hire 1684 - 1702年的太阳黑子观测：约翰·弗兰斯蒂德和菲利普·德·拉希尔

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-10-01 DOI: 10.1007/s11207-025-02544-7

Nadezhda Zolotova, Mikhail Vokhmyanin

引用次数: 0

Quantifying Chromosphere Response to Flare Energy Release Using AIA Observations in 1600 Å and 304 Å Passbands 利用AIA观测在1600 Å和304 Å波段量化耀斑能量释放的色球响应

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-09-30 DOI: 10.1007/s11207-025-02550-9

Jiong Qiu, Rhiannon Fleming

{"title":"Quantifying Chromosphere Response to Flare Energy Release Using AIA Observations in 1600 Å and 304 Å Passbands","authors":"Jiong Qiu, Rhiannon Fleming","doi":"10.1007/s11207-025-02550-9","DOIUrl":"10.1007/s11207-025-02550-9","url":null,"abstract":"<div><p>Imaging observations of the solar lower atmosphere by the Atmospheric Imaging Assembly (AIA) have been mostly used as the context, and their quantitative information has been much less explored. The chromosphere responds rapidly to energy release by magnetic reconnection during flares. Furthermore, a flare is a collection of multiple energy release events that can be identified in spatially resolved chromosphere observations. In this paper, we conduct a statistical and semi-quantitative study of the relative photometry in the UV 1600 Å and EUV 304 Å passbands for 18 flares observed by AIA. In each flare, we have identified thousands of flare ribbon pixels in the UV 1600 Å images, and measured their brightness (counts per second) and the rise and decay timescales, which are indicative of heating properties in flare loops. The analysis shows that bright flare pixels, characterized by peak brightness larger than ten times the quiescent brightness, exhibit sharplight curves with the half rise time below 2 min, followed by a two-phase decay with a rapid decay on timescales comparable to the rise time and then a more gradual decay. Flare ribbon pixels identified in both UV 1600 Å and EUV 304 Å images exhibit similar time profiles during the rise, and their peak brightness appear to be related by a power law. Our analysis shows that AIA observed flare brightness in UV 1600 Å relative to the quiescent brightness is a meaningful measurement of the flare chromosphere photometry. AIA observations for over a decade thus provide a unique and extensive database for systematic and semi-quantitative study of flaring chromosphere, either in the context of the Sun as a star, or in spatially resolved manner that helps to probe the nature of flare energy release on elementary scales.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 9","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02550-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145211011","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}

引用次数: 0

Observations of Switchback Chains in a Twin-CME Event 双cme事件中切换链的观测

IF 2.4 3区物理与天体物理

Solar Physics Pub Date : 2025-09-29 DOI: 10.1007/s11207-025-02541-w

Emily McDougall, Bala Poduval, Matthew Argall

{"title":"Observations of Switchback Chains in a Twin-CME Event","authors":"Emily McDougall, Bala Poduval, Matthew Argall","doi":"10.1007/s11207-025-02541-w","DOIUrl":"10.1007/s11207-025-02541-w","url":null,"abstract":"<div><p>Magnetic switchbacks, the localized and abrupt reversals in the magnetic field direction, are prominent features in the solar wind. We present the results of a study of switchbacks and the solar energetic particle (SEP) events associated with a twin-CME scenario – described as sequential eruptions of two coronal mass ejections (CMEs) from the same active region occurring within a short time interval – observed by Parker Solar Probe during August 18 – 19, 2022. The two consecutive CMEs, originating from active region (AR) 13078, displayed overlapping trajectories, and the primary CME traversed the wake of the pre-CME within its predicted turbulence duration window, leading to the formation of a significant solar energetic particle (SEP) event. The interaction of these CMEs was further complicated by their embedding within a high-speed stream emanating from a nearby coronal hole which led to increased solar wind density, plasma temperature, and intensified magnetic field strength. The interaction between the twin-CME event and the high-speed stream results in a compression and subsequent process which forced magnetic reconnection. This reconnection produced a distinct chain of magnetic switchbacks downstream of the CME wake, characterized by sharp directional changes in the magnetic field, enhanced transverse ion current, and suprathermal alpha particle flux. The orientation of the magnetic field of the high-speed stream as it surrounded the twin-CME suggests that interchange reconnection facilitated the emergence of switchback structures in the turbulent CME sheath, aligning with predictions from the model by Zank et al. (2020). In addition to the supportive evidences of interchange reconnection as a plausible explanation for switchbacks, our findings are expected to provide deeper insights into CME evolution in high-speed stream environments and have implications for understanding turbulent plasma processes that contribute to solar wind structuring.</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":"145210655","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}

引用次数: 0