Solar Physics最新文献

{"title":"The High-Energy Protons of the Ground Level Enhancement (GLE74) Event on 11 May 2024","authors":"A. Papaioannou,&nbsp;A. Mishev,&nbsp;I. Usoskin,&nbsp;B. Heber,&nbsp;R. Vainio,&nbsp;N. Larsen,&nbsp;M. Jarry,&nbsp;A. P. Rouillard,&nbsp;N. Talebpour Sheshvan,&nbsp;M. Laurenza,&nbsp;M. Dumbović,&nbsp;G. Vasalos,&nbsp;J. Gieseler,&nbsp;S. Koldobskiy,&nbsp;O. Raukunen,&nbsp;C. Palmroos,&nbsp;M. Hörlöck,&nbsp;M. Köberle,&nbsp;R. F. Wimmer-Schweingruber,&nbsp;A. Anastasiadis,&nbsp;P. Kühl,&nbsp;E. Lavasa","doi":"10.1007/s11207-025-02486-0","DOIUrl":"10.1007/s11207-025-02486-0","url":null,"abstract":"<div><p>High energy solar protons were observed by particle detectors aboard spacecraft in near-Earth orbit on May 11, 2024 and produced the 74^th ground level enhancement (GLE74) event registered by ground-based neutron monitors. This study involves a detailed reconstruction of the neutron monitor response, along with the identification of the solar eruption responsible for the emission of the primary particles, utilizing both in situ and remote-sensing. Observations spanning proton energies from a few MeV to around 1.64 GeV, collected from the Solar and Heliospheric Observatory (SOHO), the Geostationary Operational Environmental Satellite (GOES), the Solar Terrestrial Relations Observatory (STEREO-A), and neutron monitors, were integrated with records of the associated solar soft X-ray flare, coronal mass ejection, and radio bursts, to identify the solar origin of the GLE74. Additionally, a time-shift analysis was conducted to link the detected particles to their solar sources. Finally, a comparison of GLE74 to previous ones is carried out. GLE74 reached a maximum particle rigidity of at least 2.4 GV and was associated with a series of type III, type II, and type IV radio bursts. The release time of the primary solar energetic particles (SEPs) with an energy of 500 MeV was estimated to be around 01:21 UT. A significant SEP flux was observed from the anti-Sun direction with a relatively broad angular distribution, rather than a narrow, beam-like pattern, particularly during the main phase at the particle peak flux. Comparisons with previous GLEs suggest that GLE74 was a typical event in terms of solar eruption dynamics.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02486-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145171515","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":"Sunrise iii: Overview of Observatory and Instruments","authors":"Andreas Korpi-Lagg,&nbsp;Achim Gandorfer,&nbsp;Sami K. Solanki,&nbsp;Jose Carlos del Toro Iniesta,&nbsp;Yukio Katsukawa,&nbsp;Pietro Bernasconi,&nbsp;Thomas Berkefeld,&nbsp;Alex Feller,&nbsp;Tino L. Riethmüller,&nbsp;Alberto Álvarez-Herrero,&nbsp;Masahito Kubo,&nbsp;Valentín Martínez Pillet,&nbsp;H. N. Smitha,&nbsp;David Orozco Suárez,&nbsp;Bianca Grauf,&nbsp;Michael Carpenter,&nbsp;Alexander Bell,&nbsp;María-Teresa Álvarez-Alonso,&nbsp;Daniel Álvarez García,&nbsp;Beatriz Aparicio del Moral,&nbsp;Julia Atiénzar,&nbsp;Daniel Ayoub,&nbsp;Francisco Javier Bailén,&nbsp;Eduardo Bailón Martínez,&nbsp;Maria Balaguer Jiménez,&nbsp;Peter Barthol,&nbsp;Montserrat Bayon Laguna,&nbsp;Luis R. Bellot Rubio,&nbsp;Melani Bergmann,&nbsp;Julian Blanco Rodríguez,&nbsp;Jan Bochmann,&nbsp;Juan Manuel Borrero,&nbsp;Antonio Campos-Jara,&nbsp;Juan Sebastián Castellanos Durán,&nbsp;María Cebollero,&nbsp;Aitor Conde Rodríguez,&nbsp;Werner Deutsch,&nbsp;Harry Eaton,&nbsp;Ana Belen Fernández-Medina,&nbsp;German Fernandez-Rico,&nbsp;Agustin Ferreres,&nbsp;Andrés García,&nbsp;Ramón María García Alarcia,&nbsp;Pilar García Parejo,&nbsp;Daniel Garranzo-García,&nbsp;José Luis Gasent Blesa,&nbsp;Karin Gerber,&nbsp;Dietmar Germerott,&nbsp;David Gilabert Palmer,&nbsp;Laurent Gizon,&nbsp;Miguel Angel Gómez Sánchez-Tirado,&nbsp;David González-Bárcena,&nbsp;Alejandro Gonzalo Melchor,&nbsp;Sam Goodyear,&nbsp;Hirohisa Hara,&nbsp;Edvarda Harnes,&nbsp;Klaus Heerlein,&nbsp;Frank Heidecke,&nbsp;Jan Heinrichs,&nbsp;David Hernández Expósito,&nbsp;Johann Hirzberger,&nbsp;Johannes Hoelken,&nbsp;Sangwon Hyun,&nbsp;Francisco A. Iglesias,&nbsp;Ryohtaroh T. Ishikawa,&nbsp;Minwoo Jeon,&nbsp;Yusuke Kawabata,&nbsp;Martin Kolleck,&nbsp;Hugo Laguna,&nbsp;Julian Lomas,&nbsp;Antonio C. López Jiménez,&nbsp;Paula Manzano,&nbsp;Takuma Matsumoto,&nbsp;David Mayo Turrado,&nbsp;Thimo Meierdierks,&nbsp;Stefan Meining,&nbsp;Markus Monecke,&nbsp;José Miguel Morales-Fernández,&nbsp;Antonio Jesús Moreno Mantas,&nbsp;Alejandro Moreno Vacas,&nbsp;Marc Ferenc Müller,&nbsp;Reinhard Müller,&nbsp;Yoshihiro Naito,&nbsp;Eiji Nakai,&nbsp;Armonía Núñez Peral,&nbsp;Takayoshi Oba,&nbsp;Geoffrey Palo,&nbsp;Isabel Pérez-Grande,&nbsp;Javier Piqueras Carreño,&nbsp;Tobias Preis,&nbsp;Damien Przybylski,&nbsp;Carlos Quintero Noda,&nbsp;Sandeep Ramanath,&nbsp;Jose Luis Ramos Más,&nbsp;Nour Raouafi,&nbsp;María-Jesús Rivas-Martínez,&nbsp;Pedro Rodríguez Martínez,&nbsp;Manuel Rodríguez Valido,&nbsp;Basilio Ruiz Cobo,&nbsp;Antonio Sánchez Rodríguez,&nbsp;Mariano Sanchez Toledo,&nbsp;Antonio Sánchez Gómez,&nbsp;Esteban Sanchis Kilders,&nbsp;Kamal Sant,&nbsp;Pablo Santamarina Guerrero,&nbsp;Erich Schulze,&nbsp;Toshifumi Shimizu,&nbsp;Manuel Silva-López,&nbsp;Kunal Singh,&nbsp;Azaymi L. Siu-Tapia,&nbsp;Thomas Sonner,&nbsp;Jan Staub,&nbsp;Hanna Strecker,&nbsp;Angel Tobaruela,&nbsp;Ignacio Torralbo,&nbsp;Alexandra Tritschler,&nbsp;Toshihiro Tsuzuki,&nbsp;Fumihiro Uraguchi,&nbsp;Reiner Volkmer,&nbsp;Angelos Vourlidas,&nbsp;Dušan Vukadinović,&nbsp;Stephan Werner,&nbsp;Andreas Zerr","doi":"10.1007/s11207-025-02485-1","DOIUrl":"10.1007/s11207-025-02485-1","url":null,"abstract":"<div><p>In July 2024, <span>Sunrise</span> completed its third successful science flight. The <span>Sunrise iii</span> observatory had been upgraded significantly after the two previous successful flights in 2009 and 2013, to tackle the most recent science challenges concerning the solar atmosphere. Three completely new instruments focus on the small-scale physical processes and their complex interaction from the deepest observable layers in the photosphere up to chromospheric heights. Previously poorly explored spectral regions and lines are exploited to paint a three-dimensional picture of the solar atmosphere with unprecedented completeness and level of detail.</p><p>The full polarimetric information is captured by all three instruments to reveal the interaction between the magnetic fields and the hydrodynamic processes. Two slit-based spectropolarimeters, the <span>Sunrise</span> UV Spectropolarimeter and Imager (SUSI) and the <span>Sunrise</span> Chromospheric Infrared spectro-Polarimeter (SCIP), focus on the near-ultraviolet (309 – 417 nm) and the near-infrared (765 – 855 nm) regions respectively, and the imaging spectropolarimeter Tunable Magnetograph (<span>TuMag</span>) simultaneously obtains maps of the full field-of-view of <span>(46times 46)</span> Mm² in the photosphere and the chromosphere in the visible (525 and 517 nm). The instruments are operated in an orchestrated mode, benefiting from a new Image Stabilization and Light Distribution unit (<span>ISLiD</span>), with the Correlating Wavefront Sensor (CWS) providing the autofocus control and an image stability with a root-mean-square value smaller than 0.005”. A new gondola was constructed to significantly improve the telescope pointing stability, required to achieve uninterrupted observations over many hours.</p><p><span>Sunrise iii</span> was launched successfully on 10 July 2024, from the Esrange Space Center of the Swedish Space Corporation near Kiruna (Sweden). It reached the landing site between the Mackenzie River and the Great Bear Lake in Canada after a flight duration of 6.5 days. In this paper, we give an overview of the <span>Sunrise iii</span> observatory and its instruments.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02485-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170940","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":"Time Path of Turbulence and Multi-Fractality of Magnetic Field in the Evolution of an Active Region","authors":"Valentina Abramenko","doi":"10.1007/s11207-025-02484-2","DOIUrl":"10.1007/s11207-025-02484-2","url":null,"abstract":"<div><p>Magnetograms acquired with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) were used to calculate and analyze time variations of turbulence and multifractality in the photosphere during the development and flaring of a mature active region NOAA 13354 during its passage across the solar disk. Turbulence was explored with 2D magnetic power spectra from magnetograms, and multifractality was analyzed using the structure functions of magnetograms. Time variations of the magnetic power spectrum exponent <span>(alpha )</span> and of the multifractality exponent <span>(kappa )</span> demonstrate no pre-flare or post-flare abrupt peculiarities, instead, long periods of stability with smooth transitions into other conditions were observed. A conclusion was inferred that the turbulence and multifractality time path in the photospheric magnetic field does not follow the timing of single flares, however, it tends to correspond to the levels of the magneto-morphological complexity and flaring productivity of an AR. So, in the sense of self-organized criticality (SOC), the photosphere, being in the state of self-organization, evolves independently from the highly intermittent, SOC-state corona.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.4,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145170941","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":"Data Processing Pipeline of the SUTRI EUV Imager on the SATech-01 Satellite","authors":"Ziyao Hu,&nbsp;Kaifan Ji,&nbsp;Xianyong Bai,&nbsp;Xiao Yang,&nbsp;Yuanyong Deng,&nbsp;Wei Duan,&nbsp;Zhenyong Hou,&nbsp;Zihao Yang","doi":"10.1007/s11207-025-02483-3","DOIUrl":"10.1007/s11207-025-02483-3","url":null,"abstract":"<div><p>Solar observations in extreme ultraviolet (EUV) wavelengths are a crucial component of solar activity research and space weather forecasting. The Solar Upper Transition Region Imager (SUTRI) on the SATech-01 satellite is designed to take full-disk solar images in the Ne <span>vii</span> 46.5 nm spectral line (T = 0.5 MK). It was launched in 2022 and the science data were released on January 10, 2023. In this article, we describe the data preprocessing method employed to SUTRI data to eliminate inherent instrument effects and standardize the raw data to obtain scientific data. Alongside common data processing steps, our pipeline includes correcting for horizontal stripes from the CMOS imaging camera. As an experiment payload, SUTRI does not have an image stabilization system. Thus, a multi-step iterative algorithm has been developed to precisely align series of drifted images due to the limited pointing accuracy of the satellite platform. Our method may not be limited to SUTRI; it also serves as a reference for future solar EUV telescope data processing.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02483-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140126","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":"Structure and Dynamics of the Sun’s Interior Revealed by the Helioseismic and Magnetic Imager","authors":"Alexander G. Kosovichev,&nbsp;Sarbani Basu,&nbsp;Yuto Bekki,&nbsp;Juan Camilo Buitrago-Casas,&nbsp;Theodosios Chatzistergos,&nbsp;Ruizhu Chen,&nbsp;Jørgen Christensen-Dalsgaard,&nbsp;Alina Donea,&nbsp;Bernhard Fleck,&nbsp;Damien Fournier,&nbsp;Rafael A. García,&nbsp;Alexander V. Getling,&nbsp;Laurent Gizon,&nbsp;Douglas O. Gough,&nbsp;Shravan Hanasoge,&nbsp;Chris S. Hanson,&nbsp;Shea A. Hess Webber,&nbsp;J. Todd Hoeksema,&nbsp;Rachel Howe,&nbsp;Kiran Jain,&nbsp;Spiridon Kasapis,&nbsp;Samarth G. Kashyap,&nbsp;Irina N. Kitiashvili,&nbsp;Rudolf Komm,&nbsp;Sylvain G. Korzennik,&nbsp;Natalie A. Krivova,&nbsp;Jeffrey R. Kuhn,&nbsp;Zhi-Chao Liang,&nbsp;Charles Lindsey,&nbsp;Sushant S. Mahajan,&nbsp;Krishnendu Mandal,&nbsp;Prasad Mani,&nbsp;Juan Carlos Martinez Oliveros,&nbsp;Savita Mathur,&nbsp;M. Cristina Rabello Soares,&nbsp;S. Paul Rajaguru,&nbsp;Johann Reiter,&nbsp;Edward J. Rhodes Jr.,&nbsp;Jean-Pierre Rozelot,&nbsp;Philip H. Scherrer,&nbsp;Sami K. Solanki,&nbsp;John T. Stefan,&nbsp;Juri Toomre,&nbsp;Sushanta C. Tripathy,&nbsp;Lisa A. Upton,&nbsp;Junwei Zhao","doi":"10.1007/s11207-025-02480-6","DOIUrl":"10.1007/s11207-025-02480-6","url":null,"abstract":"<div><p>High-resolution helioseismology observations with the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) provide a unique three-dimensional view of the solar interior structure and dynamics, revealing a tremendous complexity of the physical processes inside the Sun. We present an overview of the results of the HMI helioseismology program and discuss their implications for modern theoretical models and simulations of the solar interior.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02480-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135280","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":"Linear Correlation Between Radial and Normal Component Fluctuations of the Interplanetary Magnetic Field","authors":"Munetoshi Tokumaru,&nbsp;Nishiki Nozaki,&nbsp;Ken’ichi Fujiki","doi":"10.1007/s11207-025-02475-3","DOIUrl":"10.1007/s11207-025-02475-3","url":null,"abstract":"<div><p>The interplanetary magnetic field (IMF), particularly its north–south component, acts as a key parameter for controlling the space weather effect of solar wind disturbances on the Earth; therefore, accurate understanding of the behavior of the IMF is important for improvement of space weather prediction. This study reports the relation between radial (<span>(B_{r})</span>) and normal (<span>(B_{n})</span>) components of IMF by analyzing in situ observations collected by inner- and outer-heliosphere spacecraft over multiple solar cycles. A quadratic relation between <span>(B_{r})</span> and <span>(B_{n})</span> with a 22-year periodicity which corresponds to the magnetic polarity cycle of the Sun was observed in IMF data of the inner-heliosphere spacecraft. In contrast, IMF data of the outer-heliosphere spacecraft did not show such a quadratic relation but exhibited a linear relation between <span>(B_{r})</span> and <span>(B_{n})</span> with a slope and correlation coefficient depending on the latitude: positive and negative slopes (correlation coefficients) were revealed from the IMF data for north and south latitudes, respectively, and those magnitudes increased with the latitude. Slopes and correlation coefficients of the linear relation depended on neither the radial distance nor the solar activity. The same linear relation between <span>(B_{r})</span> and <span>(B_{n})</span> was found for the IMF data of the inner-heliosphere spacecraft by sorting them into two groups in terms of the latitude. Therefore, quadratic relation was ascribed to the combined effect of the latitude variation of the inner-heliosphere spacecraft and the latitude dependence of the linear relation. Although the physical process to generate the linear relation remains an open question, some kind of MHD waves may be responsible for it.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02475-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140203","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":"Comparison of Polar Magnetic Fields Derived from MILOS and MERLIN Inversions with Hinode/SOT-SP Data","authors":"Masahito Kubo,&nbsp;Daikou Shiota,&nbsp;Yukio Katsukawa,&nbsp;Masumi Shimojo,&nbsp;David Orozco Suárez,&nbsp;Nariaki Nitta,&nbsp;Marc DeRosa,&nbsp;Rebecca Centeno,&nbsp;Haruhisa Iijima,&nbsp;Takuma Matsumoto,&nbsp;Satoshi Masuda","doi":"10.1007/s11207-025-02487-z","DOIUrl":"10.1007/s11207-025-02487-z","url":null,"abstract":"<div><p>The detailed investigation of the polar magnetic field and its time evolution is one of the major achievements of Hinode. Precise measurements of the polar magnetic field are essential for understanding the solar cycle, as they provide important constraints for identifying the source regions of the solar wind. The Spectropolarimeter (SP) of the Solar Optical Telescope (SOT) on board Hinode has been the instrument best suited to make such measurements. In this study, we compare the SOT-SP data for the polar regions, processed using two representative Milne-Eddington inversion codes, MILOS and MERLIN. These codes are applied to the same level-1 SOT-SP data, and the same disambiguation algorithm is used on the maps that go through the two inversions. We find that the radial magnetic-flux density (the magnetic-flux density with respect to the local vertical) provided by the MERLIN inversion tends to be approximately 7% – 10% larger than that obtained from the MILOS inversion. The slightly higher radial magnetic-flux density from MERLIN appears to be common to the polar magnetic fields observed at different phases of the solar cycle. When MILOS is run with the same scattered-light profile and the same magnetic filling factor that are derived with the MERLIN inversion, the radial magnetic-flux density derived from the two inversions is almost the same. We attribute the difference in the radial magnetic-flux density to different filling factors adopted by the two inversions, based on whether the scattered-light profiles are assumed to be the Stokes I profiles averaged over the neighboring pixels or over the entire field of view. The relationship between the radial magnetic-flux density and magnetic filling factor could be more complex in the polar (limb) observations due to the possible contributions of the transverse magnetic-field component to the estimation of the radial magnetic-flux density.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144125859","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":"Linear Analysis of Shear-Flow Instabilities in a Prominence-Corona Interface with Ambipolar Diffusion","authors":"Llorenç Melis,&nbsp;Roberto Soler","doi":"10.1007/s11207-025-02481-5","DOIUrl":"10.1007/s11207-025-02481-5","url":null,"abstract":"<div><p>Observations have shown the presence of the Kelvin–Helmholtz instability (KHi) in solar prominences. Effects due to partial ionization of the prominence plasma may influence the KHi onset. We study the triggering of the KHi in an interface model that consists of a partially ionized prominence region and a fully ionized coronal region, with a uniform magnetic field parallel to the interface. There is a longitudinal flow in the prominence region. The plasma is compressible and the role of ambipolar diffusion, which accounts for collisions between charges and neutrals, is taken into account in the prominence plasma. We derive the dispersion relation of linear perturbations on the interface and analyze some limit cases analytically. Numerical results are obtained for realistic prominence parameters. We find that compressibility and gas pressure are important in determining the unstable flow velocities, specially in the range of sub-Alfvénic flows that are consistent with the observations. The ambipolar diffusion has a generally destabilizing influence and reduces the threshold flow velocity for the KHi onset.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02481-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144117698","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":"Visible Emission Line Coronagraph (VELC) on Board Aditya-L1","authors":"Jagdev Singh,&nbsp;R. Ramesh,&nbsp;B. Raghavendra Prasad,&nbsp;V. Muthu Priyal,&nbsp;K. Sasikumar Raja,&nbsp;S. N. Venkata,&nbsp;P. U. Kamath,&nbsp;V. Natarajan,&nbsp;S. Pawankumar,&nbsp;V. U. Sanal Krishnan,&nbsp;P. Savarimuthu,&nbsp;Shalabh Mishra,&nbsp;Varun Kumar,&nbsp;Chavali Sumana,&nbsp;S. Bhavana Hegde,&nbsp;D. Utkarsha,&nbsp;Amit Kumar,&nbsp;S. Nagabhushana,&nbsp;S. Kathiravan,&nbsp;P. Vemareddy,&nbsp;C. Kathiravan,&nbsp;K. Nagaraju,&nbsp;Belur Ravindra,&nbsp;Wageesh Mishra","doi":"10.1007/s11207-025-02477-1","DOIUrl":"10.1007/s11207-025-02477-1","url":null,"abstract":"<div><p>Aditya-L1, India’s first dedicated mission to study the Sun and its atmosphere from the Sun-Earth Lagrangian L1 location was successfully launched on September 2, 2023. It carries seven payloads. The Visible Emission Line Coronagraph (VELC) is a major payload on Aditya-L1. VELC is designed to carry out imaging and spectroscopic observations (the latter in three emission lines of the corona), simultaneously. Images of the solar corona in the continuum at 5000 Å, with a field of view (FoV) from 1.05 <span>(mathrm{R}_{odot })</span> to 3 <span>(mathrm{R}_{odot })</span> can be obtained at variable intervals depending on the data volume that can be downloaded. Spectroscopic observations of the solar corona in three emission lines, namely 5303 Å Fe<span>xiv</span>, 7892 Å Fe<span>xi</span>, and 10,747 Å Fe<span>xiii</span> are possible simultaneously, with different exposure times and cadence. Four slits, each of width 50 <span>({ mu })</span>m, separated by 3.75 mm help to simultaneously obtain spectra at four positions in the solar corona in all the aforementioned lines. A Linear Scan Mechanism (LSM) makes it possible to scan the solar corona up to ± 1.5 <span>(mathrm{R}_{odot })</span>. The instrument has the facility to carry out spectropolarimetric observations at 10,747 Å also in the FoV range 1.05 – 1.5 <span>(mathrm{R}_{odot })</span>. Various components of the instrument were tested interferometrically on the optical bench before installation. The individual components were aligned and performance of the payload was checked in the laboratory using a laser source and tungsten lamp. Wavelength calibration of the instrument was verified using the Sun as a light source. All the detectors were calibrated for different parameters such as dark current and its variation with exposure time. Here, we discuss the various features of the VELC, alignment, calibration, performance, possible observations, initial data analysis, and results of initial tests conducted in-orbit.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100266","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":"Potential Field Source Surface and Non-linear Force-Free Field Extrapolation to Model Magnetic Field Structure for a Giant Solar Filament","authors":"Abbi S. Demissie,&nbsp;Tilaye Tadesse,&nbsp;Araya Asfaw,&nbsp;Tong Shi","doi":"10.1007/s11207-025-02474-4","DOIUrl":"10.1007/s11207-025-02474-4","url":null,"abstract":"<div><p>Solar filaments are intriguing structures suspended in the solar corona at heights up to 100 Mm above the chromosphere, but they are made of chromospheric material which is one hundred times cooler and denser than the coronal material. Studying filament magnetic field structures, magnetic energy and electric current density is crucial to know its stability, because unstable conditions can result in explosive events like flares and coronal mass ejections (CMEs). A few recent studies have been conducted to model large-scale filaments in the quiet Sun though the majority of studies focus on modeling small-scale active region filaments. This study is the first to use potential field source surface (PFSS) and non-linear force-free field (NLFFF) models in spherical geometry to study a giant filament (with length more than 800 Mm) along a polarity inversion line (PIL) in a weak-field region (with photospheric field region of ≈ 50 G). The two modeling methods are applied to data obtained from a giant filament observation on February 10, 2015 with preprocessing of photospheric full-disk vector magnetograms from the Helioseismic and Magnetic Imager (HMI) and Vector Spectromagnetograph (VSM) using optimization procedure to make the boundary data more consistent with the force-free principle. The large-scale magnetic configuration surrounding the filament is derived from the PFSS model, while the NLFFF extrapolation provides a detailed three-dimensional structure of the filament using both HMI and VSM data. Results from both instruments show good agreement. The NLFFF extrapolation based on HMI data yields higher total and free magnetic energy compared to VSM data. Moreover, the total surface electric current density is greater with VSM data, consistent with the magnetic field strength derived from both instruments.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 5","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144100267","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}