Solar Physics最新文献

{"title":"Magnetic Field-Constrained Ensemble Image Segmentation of Coronal Holes in Chromospheric Observations","authors":"Jaime A. Landeros,&nbsp;Michael S. Kirk,&nbsp;C. Nick Arge,&nbsp;Laura E. Boucheron,&nbsp;Jie Zhang,&nbsp;Vadim M. Uritsky,&nbsp;Jeremy A. Grajeda,&nbsp;Matthew Dupertuis","doi":"10.1007/s11207-024-02416-6","DOIUrl":"10.1007/s11207-024-02416-6","url":null,"abstract":"<div><p>Coronal holes (CHs) are large-scale, low-density regions in the solar atmosphere that may expel high-speed solar wind streams that incite hazardous, geomagnetic storms. Coronal and solar wind models can predict these high-speed streams, and the performance of the coronal model can be validated against segmented CH boundaries. We present a novel method named Sub-Transition Region Identification of Ensemble Coronal Holes (STRIDE-CH) to address prominent challenges in segmenting CHs using extreme-ultraviolet (EUV) imagery. Ground-based, chromospheric He <span>i</span> 10,830 Å line imagery and underlying Fe <span>i</span> photospheric magnetograms are revisited to disambiguate CHs from filaments and quiet Sun, overcome obscuration by coronal loops, and complement established methods in the community which use space-borne coronal EUV observations. Classical computer vision techniques are applied to constrain the radiative and magnetic properties of detected CHs, produce an ensemble of boundaries, and compile these boundaries in a confidence map that quantifies the likelihood of the CH presence throughout the solar disk. This method is a science-enabling one towards future studies of CH formation and variability from a mid-atmospheric perspective.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-024-02416-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110122","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":"Plasma-Analyzer Package for Aditya (PAPA) on Board the Indian Aditya-L1 Mission","authors":"R. Satheesh Thampi,&nbsp;J. K. Abhishek,&nbsp;Dersana Sasidharan,&nbsp;Ganesh Varma,&nbsp;Vijay Kumar Sen,&nbsp;Sabooj Ray,&nbsp;M. B. Dhanya,&nbsp;Ullekh Pandey,&nbsp;Shishir Kumar S. Chandra,&nbsp;J. B. Akash,&nbsp;A. N. Aneesh,&nbsp;Tincy M. Wilson,&nbsp;S. Naresh,&nbsp;Neha Naik,&nbsp;Mathin Chemukula Yadav,&nbsp;V. Venkataraman,&nbsp;Rosmy John,&nbsp;R. Manoj,&nbsp;Govind G. Nampoothiri,&nbsp;Pritesh Meshram,&nbsp;Maria George,&nbsp;Vinitha Ramdas,&nbsp;Ginju V. George,&nbsp;Anju M. Pillai,&nbsp;Arjun Dey,&nbsp;Surajit Das,&nbsp;G. Subha Varier,&nbsp;G. Sajitha,&nbsp;Sheeja Mathews,&nbsp;P. Pradeep Kumar,&nbsp;G. R. Nisha,&nbsp;Amarnath Nandi,&nbsp;B. Sundar,&nbsp;R. Sethunadh,&nbsp;A. Rajendra,&nbsp;H. Saleem,&nbsp;A. K. Abdul Samad","doi":"10.1007/s11207-024-02414-8","DOIUrl":"10.1007/s11207-024-02414-8","url":null,"abstract":"<div><p>Aditya-L1 is the first space-based solar observatory from India, which is studying the Sun and solar wind from the first Lagrangian point (L1) in a halo orbit. Among the seven payloads, four of them are remote sensing and three are in situ ones. The Plasma-Analyzer Package for Aditya (PAPA) is one among the in situ payloads for exploring the composition of the solar wind and its energy distribution (in the range from 0.01 to 3 keV for electrons and 0.01 to 25 keV for ions) continuously throughout the lifetime of the mission. PAPA has two sensors: the Solar-Wind Electron Energy Probe (SWEEP) indented to measure the solar-wind electron flux and the Solar-Wind Ion Composition AnalyzeR (SWICAR) indented to measure the ion flux and composition as a function of direction and energy as well as electrons. Thus, SWEEP measures only electron parameters, whereas SWICAR has two modes of operation – ion mode in which ion parameters are measured and electron mode in which electron parameters are measured. These two modes in SWICAR are mutually exclusive. The payload is unique and the technologies like the high-voltage (± 5 kV DC) programmable power supply and the dual-mode (electrons and ions) detection of particles using a single sensor (SWICAR) are notable first-time developments. Data from PAPA will provide detailed knowledge of the solar-wind conditions with high time resolution. SWICAR will also provide: (1) the elemental composition of solar-wind ions in the mass range of 1 – 60 amu, and (2) the differential energy flux and abundances of dominant ion species. The key parameters such as bulk speed, density, and kinetic temperature of the solar-wind electrons and dominant ion species can be regularly derived. From these, inferences can be made on the coronal temperatures, plasma sources of suprathermal ion populations, and the nature and dynamics of the solar-wind plasma, with the support of models. In this article, the scientific objectives as well as the design aspects of PAPA payload are discussed in detail along with the calibration and first on board observational results.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143110125","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":"Various Modifications to Debye-Hückel Interactions in Solar Equations of State","authors":"Regner Trampedach,&nbsp;Werner Däppen","doi":"10.1007/s11207-024-02415-7","DOIUrl":"10.1007/s11207-024-02415-7","url":null,"abstract":"<div><p>The first-order effect of Coulomb forces between the charged particles of a plasma is the well-known Debye-Hückel-term. This term represents a negative contribution to the pressure and energy of the gas, which at high densities could overwhelm the ideal gas contributions and make the gas implode into a black hole. However, this fate could be prevented by specific physical mechanisms. We investigate three different mechanisms and analyze their effects on the equation of state and solar models, as well as their physical justifications. We conclude that higher-order Coulomb terms, in combination with quantum diffraction of electrons, provide the needed convergence.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109714","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":"So Far, so Good — My First 82 Years","authors":"Jan Stenflo","doi":"10.1007/s11207-025-02430-2","DOIUrl":"10.1007/s11207-025-02430-2","url":null,"abstract":"<div><p>My romantic attraction to the stars started at the age of 11 under the dark Swedish skies. While it was clear from then on that I wanted to be an astronomer, a sequence of chance encounters led me to choose solar physics and embark on an unpredictable path across the globe, including work for my PhD in the USSR about the Sun’s magnetic field, followed by an experiment on a Soviet satellite to record scattering polarization on the Sun. On my first hike in the Rocky Mountains in 1971, I had a chance encounter with my future wife and married 4 months later in Sweden. In 1980, we moved to Switzerland for 43 years. Finally, our geographically scattered family reunited. All of us, sons and grandsons, are now settled in Colorado. My story tells how this unplanned path was intertwined with the search for answers about the nature of solar magnetism.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-025-02430-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143109713","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":"Editorial Appreciation","authors":"Iñigo Arregui,&nbsp;Cristina H. Mandrini,&nbsp;Lidia van Driel-Gesztelyi,&nbsp;Marco Velli,&nbsp;Frank Schulz","doi":"10.1007/s11207-025-02429-9","DOIUrl":"10.1007/s11207-025-02429-9","url":null,"abstract":"","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142995369","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":"Catastrophic Cooling Instability in Optically Thin Plasmas","authors":"Timothy Waters,&nbsp;Amanda Stricklan","doi":"10.1007/s11207-024-02417-5","DOIUrl":"10.1007/s11207-024-02417-5","url":null,"abstract":"<div><p>The solar corona is the prototypical example of a low-density environment heated to high temperatures by external sources. The plasma cools radiatively, and because it is optically thin to this radiation, it becomes possible to model the density, velocity, and temperature structure of the system by modifying the MHD equations to include an energy source term that approximates the local heating and cooling rates. The solutions can be highly inhomogeneous and even multiphase because the well-known linear instability associated with this source term, thermal instability, leads to a catastrophic heating and cooling of the plasma in the nonlinear regime. Here we show that there is a separate, much simpler linear instability accompanying this source term that can rival thermal instability in dynamical importance. The stability criterion is the isochoric one identified by Parker (1953), and we demonstrate that cooling functions derived from collisional ionization equilibrium are highly prone to violating this criterion. If catastrophic cooling instability can act locally in global simulations, then it is an alternative mechanism for forming condensations, and due to its nonequilibrium character, it may be relevant to explaining a host of phenomena associated with the production of cooler gas in hot, low density plasmas.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-024-02417-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976513","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":"Hydrogen Ionization Inside the Sun","authors":"Vladimir A. Baturin,&nbsp;Sergey V. Ayukov,&nbsp;Anna V. Oreshina,&nbsp;Alexey B. Gorshkov,&nbsp;Victor K. Gryaznov,&nbsp;Igor L. Iosilevskiy,&nbsp;Werner Däppen","doi":"10.1007/s11207-024-02413-9","DOIUrl":"10.1007/s11207-024-02413-9","url":null,"abstract":"<div><p>Hydrogen is the main chemical component of the solar plasma, and H-ionization determines basic properties of the first adiabatic exponent <span>({Gamma _{1}})</span>. Its ionization significantly differs from the ionization of other chemicals. Due to the large number concentration, H-ionization causes a pronounced lowering of <span>({Gamma _{1}})</span>, with a strongly asymmetric and extending across almost the entire solar convective zone. The excited states in the hydrogen atom are modeled using a partition function, which accounts for the internal degrees of freedom of the composite particle. A temperature-dependent partition function with an asymptotic cut-off tail is derived from the quantum mechanical solution for the hydrogen atom in the plasma. We present numerical simulations of hydrogen ionization, calculated using two partition function models: Planck-Larkin (PL) and Starostin-Roerich (SR). In the SR model, the hydrogen ionization shifts to higher temperatures than in the PL model. Different models for excited states of the hydrogen atom may change <span>({Gamma _{1}})</span> by as much as <span>(10^{-2})</span>. The <span>({Gamma _{1}})</span> profiles for pure hydrogen exhibit a “twisted rope” structure for the two models, significantly affecting the helium ionization and the position of the helium hump. This entanglement of H and He effect provides a valuable opportunity to investigate the role of excited states in the solar plasma.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939280","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":"Photometric Comparison of Metis and LASCO-C2 Polarized Brightness Images","authors":"Alberto M. Vásquez,&nbsp;Federico A. Nuevo,&nbsp;Aleksandr Burtovoi,&nbsp;Philippe Lamy,&nbsp;Marco Romoli,&nbsp;Hugo Gilardy,&nbsp;Richard A. Frazin,&nbsp;Nishtha Sachdeva,&nbsp;Ward B. Manchester IV,&nbsp;Lucia Abbo,&nbsp;Yara De Leo,&nbsp;Federica Frassati,&nbsp;Giovanna Jerse,&nbsp;Federico Landini,&nbsp;Giuliana Russano,&nbsp;Clementina Sasso,&nbsp;Roberto Susino,&nbsp;Michela Uslenghi","doi":"10.1007/s11207-024-02370-3","DOIUrl":"10.1007/s11207-024-02370-3","url":null,"abstract":"<div><p>The Metis coronagraph onboard Solar Orbiter and the LASCO-C2 coronagraph onboard SoHO both acquire white light polarized brightness (pB) images of the solar corona. When the Sun–Solar Orbiter distance is less than 0.85 AU, i.e., outside orbital segments around aphelia, the range of elongations covered by the fields-of-view of the two instruments overlap significantly, allowing a quantitative comparison of their images. We report on such a comparison during September 2022, with images taken during a superior conjunction of the two spacecraft with the Sun, as well as close to that event. In each comparison, the two instruments observed the corona from opposite viewpoints, within <span>(approx 1^{circ })</span> in both Carrington longitude and latitude, with Metis at a distance of about half an astronomical unit from the Sun. We find that the Metis measurements are systematically larger than those of LASCO-C2 throughout the corona, with the Metis-to-C2 ratio of pB exhibiting a median value of <span>(approx 1.6)</span>. The discrepancy is observed comparing essentially simultaneous observations, so it cannot be explained as an effect of coronal dynamics. Synthetic images of the solar corona computed from a stationary three-dimensional magneto-hydrodynamic model, replicating the geometry of the observations, are photometrically consistent. This rules out the small departure of the two instruments from observing from opposite viewpoints, or their different distance to the Sun, as the cause of their discrepant measurements. We conclude that the reported discrepancy has its root in the calibration methods of the two instruments, which should be further investigated.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939150","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":"Anticipating Solar Flares","authors":"Hugh Hudson","doi":"10.1007/s11207-024-02418-4","DOIUrl":"10.1007/s11207-024-02418-4","url":null,"abstract":"<div><p>Solar flares commonly have a “hot onset precursor event” (HOPE), detectable from soft X-ray observations. To detect this requires subtraction of pre-flare fluxes from the non-flaring Sun prior to the event, fitting an isothermal emission model to the flare excess fluxes by comparing the GOES passbands at 1 – 8 Å and 0.5 – 4 Å, and plotting the timewise evolution of the flare emission in a diagram of temperature vs. emission measure. The HOPE then appears as an initial “horizontal branch” in this diagram. It precedes the nonthermal impulsive phase of the flare and thus the flare peak in soft X-rays as well. We use this property to define a “flare anticipation index” (FAI), which can serve as an alert for observational programs aimed at solar flares based on near-real-time soft X-ray observations. This FAI gives lead times of a few minutes and produces very few false positive alerts, even for flare brightenings that are too weak to merit NOAA classification.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-024-02418-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939258","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":"Forecasting Shock-Associated Energetic Particle Intensities in the Inner Heliosphere: A Proof-of-Concept Capability for the PUNCH Mission","authors":"M. A. Dayeh,&nbsp;M. J. Starkey,&nbsp;H. A. Elliott,&nbsp;R. Attie,&nbsp;C. E. DeForest,&nbsp;R. Bučik,&nbsp;M. I. Desai","doi":"10.1007/s11207-024-02409-5","DOIUrl":"10.1007/s11207-024-02409-5","url":null,"abstract":"<div><p>Solar energetic particles (SEPs) associated with shocks driven by fast coronal mass ejections (CMEs) or shocks developed by corotating interaction regions (CIRs) often extend to high energies, and are thus key elements of space weather. The PUNCH mission, set to be launched in 2025, is equipped with a photometric instrument that enables 3D tracking of solar wind structures in the interplanetary space through polarized light. Tracking techniques are used to estimate speeds and speed gradients of solar structures, including speed jumps at fast shocks. We report on a strong and robust relation between the shock speed jump magnitude at CME and CIR shocks and the peak fluxes of associated energetic particles from the analysis of 59 CME-driven shocks and 74 CIRs observed by Wind/STEP between 1997 – 2023. We demonstrate that this relation, along with PUNCH anticipated observations of solar structures, can be used to forecast shock-associated particle events close to the Sun, thus advancing and providing a crucial input to forecasting of SEP fluxes in the heliosphere.</p></div>","PeriodicalId":777,"journal":{"name":"Solar Physics","volume":"300 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11207-024-02409-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142912940","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}