Article
Astronomy & Astrophysics
Pawan Kumar, Melinda Nagy, Alexandre Lemerle, Bidya Binay Karak, Kristof Petrovay
Summary: The polar precursor method is considered one of the most robust ways to predict the amplitude of an upcoming solar cycle, with the ability to make accurate predictions up to 4 years in advance. By combining observational data and model outputs, the correlation level of predictions can be further improved.
ASTROPHYSICAL JOURNAL
(2021)
Review
Astronomy & Astrophysics
Prantika Bhowmik, Jie Jiang, Lisa Upton, Alexandre Lemerle, Dibyendu Nandy
Summary: The dynamic activity of stars, such as the Sun, affects planetary space environments through various factors. Solar phenomena like flares and coronal mass ejections can cause hazardous space weather. The primary driver of solar activity is magnetic fields created by a mechanism called the magnetohydrodynamic dynamo. While the mechanism of solar cycles has been studied for a long time, predicting the strength of future sunspot cycles remains challenging. This review discusses observational constraints, recent physical insights, and advances in solar cycle predictions.
SPACE SCIENCE REVIEWS
(2023)
Article
Chemistry, Physical
Abbasriyaludeen Abdul Raheem, Chitra Kumar, Palanichamy Murugan, Chandrasekar Praveen
Summary: The study synthesized symmetrical and unsymmetrical molecules as nonfullerene acceptors with tetracyanobutadiene (TCBD) as a twisted end group. Structural correlation analysis revealed better acceptor properties for symmetrical molecules compared to unsymmetrical analogues, leading to higher power conversion efficiencies in binary solar cell configurations. The nonplanar TCBD auxiliary within a calamitic-type pi-framework was validated to realize alternative NFAs, with promising initial results for potential fine-tuning of molecular structures to form ideal acceptors for organic photovoltaics.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Astronomy & Astrophysics
R. L. Bailey, M. A. Reiss, C. N. Arge, C. Moestl, C. J. Henney, M. J. Owens, U. Amerstorfer, T. Amerstorfer, A. J. Weiss, J. Hinterreiter
Summary: Studying the ambient solar wind is crucial for space weather research, and accurately forecasting the flow of ambient solar wind is imperative for space weather awareness.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2021)
Article
Astronomy & Astrophysics
Gordon J. D. Petrie
Summary: This study provides the first systematic comparison between photospheric polar magnetic field data from the National Solar Observatory's Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph (SOLIS/VSM) and the Hinode Solar Optical Telescope Spectropolarimeter (SOT/SP). The results show that the vector-based polar fluxes from SOT/SP are significantly lower than the longitudinal-based fluxes from both telescopes.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Samuel J. Schonfeld, Carl J. Henney, Shaela Jones, Charles N. Arge
Summary: This study explores the use of observed polar coronal holes to constrain the flux distribution within the polar regions of global solar magnetic field maps. The findings show that modifications to the polar flux can improve predictions for coronal holes and solar wind, and that low-latitude magnetic fields have a significant impact on setting the boundaries of polar coronal holes.
ASTROPHYSICAL JOURNAL
(2022)
Review
Astronomy & Astrophysics
Thomas Wiegelmann, Takashi Sakurai
Summary: The structure and dynamics of the solar corona are dominated by the magnetic field, using force-free field assumption to simplify the model. Constructing a realistic 3D nonlinear force-free coronal magnetic field model requires sophisticated numerical computations and boundary conditions obtained from measurements of the magnetic field vector in the solar photosphere.
LIVING REVIEWS IN SOLAR PHYSICS
(2021)
Article
Astronomy & Astrophysics
Yan Xu, Dipankar Banerjee, Subhamoy Chatterjee, Werner Poetzi, Ziran Wang, Xindi Ruan, Ju Jing, Haimin Wang
Summary: Polar crown filaments (PCFs) are important features in studying solar polar fields and their cyclical variations. The rapid migration of PCFs towards the pole is a precursor for polarity reversal and the solar activity cycle. The migration speed of PCFs shows asymmetry between the northern and southern hemispheres and is not strongly correlated with maximum sunspot numbers.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
J. Javaraiah
Summary: The solar cycle usually has multiple peaks, known as Gnevyshev peaks. Understanding this property of solar cycles helps in understanding the solar dynamo mechanism. The analysis of sunspot data from 1874 to 2017 shows a correlation between the amplitude of the main peak and the value of the second highest peak during the maximum of a solar cycle. Using this relationship, we predict the value of the second maximum for Solar Cycle 25.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Environmental Sciences
Ian Hough, Ron Sarafian, Alexandra Shtein, Bin Zhou, Johanna Lepeule, Itai Kloog
Summary: The study developed a multi-stage ensemble model to estimate daily mean PM2.5 and PM10 concentrations in France from 2000 to 2019 at a 1 km spatial resolution. By training three base learners and generating ensemble predictions through a generalized additive model, the Gaussian Markov random field dominated the ensemble, showing high accuracy in cross-validation.
ATMOSPHERIC ENVIRONMENT
(2021)
Article
Astronomy & Astrophysics
Aditya Priyadarshi, Manjunath Hegde, Bibhuti Kumar Jha, Subhamoy Chatterjee, Sudip Mandal, Mayukh Chowdhury, Dipankar Banerjee
Summary: By digitizing the suncharts from the Kodaikanal Solar Observatory and analyzing cycle 19 and cycle 20 data, we found that the length and area of filaments increase with latitude and their poleward migration is dominated by a specific tilt sign. Our findings were cross verified with the KoSO digitized photographic plate database, showing good agreement. This work will enable researchers to effectively utilize the hand-drawn solar data and extract new scientific insights.
ASTROPHYSICAL JOURNAL
(2023)
Article
Multidisciplinary Sciences
Ryohko Ishikawa, Javier Trujillo Bueno, Tanausu del Pino Aleman, Takenori J. Okamoto, David E. McKenzie, Frederic Auchere, Ryouhei Kano, Donguk Song, Masaki Yoshida, Laurel A. Rachmeler, Ken Kobayashi, Hirohisa Hara, Masahito Kubo, Noriyuki Narukage, Taro Sakao, Toshifumi Shimizu, Yoshinori Suematsu, Christian Bethge, Bart De Pontieu, Alberto Sainz Dalda, Genevieve D. Vigil, Amy Winebarger, Ernest Alsina Ballester, Luca Belluzzi, Jiri Stepan, Andres Asensio Ramos, Mats Carlsson, Jorrit Leenaarts
Summary: Unprecedented spectropolarimetric observations of an active region plage and its surrounding enhanced network reveal the role of magnetic field in coupling different atmospheric layers and heating the plage chromosphere.
Article
Astronomy & Astrophysics
G. Livadiotis, D. J. McComas, E. J. Zirnstein
Summary: This study investigates the thermodynamics of plasma protons in the polar regions of the inner heliosheath (IHS) and its connection with solar activity. Based on the year of energetic neutral atom creation, the thermodynamic parameters of the plasma are characterized and the temperatures are statistically analyzed. Autocorrelation analysis is then performed between the IHS temperature and solar activity using sunspot number and fractional area of polar coronal holes as proxies. The findings demonstrate a high correlation between IHS proton temperatures and sunspot number, as well as a high negative correlation between proton plasma temperature and coronal hole fractional areas.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
I. Tahtinen, I. I. Virtanen, A. A. Pevtsov, K. Mursula
Summary: By studying the relationship between photospheric magnetic fields and ultraviolet radiation, we found that the percentage of bright pixels can explain the variability of 1600 angstrom emission. We developed a model to predict the size of the photospheric magnetic field and found a close correspondence between the magnetic field and bright and dark clusters.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Glyn A. Collinson, Li-Jen Chen, Lan K. Jian, John Dorelli
Summary: NASA's Psyche spacecraft will explore the magnetic fields and electromagnetic waves of asteroid (16) Psyche, and it is necessary to combine data from other missions to understand the environmental conditions and interactions.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
L. Rodriguez-Garcia, T. Nieves-Chinchilla, R. Gomez-Herrero, I. Zouganelis, A. Vourlidas, L. A. Balmaceda, M. Dumbovic, L. K. Jian, L. Mays, F. Carcaboso, L. F. G. dos Santos, J. Rodriguez-Pacheco
Summary: The main objective of this study is to investigate the radial and longitudinal evolution of the interplanetary counterpart (ICME) in the inner heliosphere and to examine the different magnetic flux-rope configurations observed on the solar disk and in situ at various locations.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
V. M. S. Carrasco, A. Munoz-Jaramillo, M. C. Gallego, J. M. Vaquero
Summary: Christoph Scheiner, one of the most outstanding astronomers in the history of sunspot observations, played a crucial role in determining the solar activity level of the first solar cycles of the telescopic era with his book Rosa Ursina. However, significant errors in the number of sunspot groups assigned to Scheiner's records have been detected. Reanalysis of his source documents reveals the clear shape of the solar cycle and a lower daily number of sunspot groups compared to existing databases. The study also compares solar minima in 2008-2009 and 2018-2019 with the most probable solar activity level in 1632.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Laura A. Balmaceda, Angelos Vourlidas, Guillermo Stenborg, Ryun-Young Kwon
Summary: We conducted a detailed multi-viewpoint analysis of extreme-ultraviolet observations to analyze the formation and three-dimensional evolution of two coronal mass ejections (CMEs) and their associated waves in the low corona. Our analysis revealed three stages in the early evolution of the CME, with the hyper-inflation stage potentially playing a crucial role in CME formation and having wide-ranging implications for solar eruption research.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Subhamoy Chatterjee, Andres Munoz-Jaramillo, Derek A. Lamb
Summary: Big-data labelling is critical for supervised machine learning in astronomy. This study shows that training convolutional neural networks (CNNs) on crudely labelled astronomical videos can improve data labelling quality and reduce the need for human intervention. The study also highlights the versatility of CNNs in simplifying the labelling task for complex dynamic events.
Article
Astronomy & Astrophysics
Kalpa Henadhira Arachchige, Ofer Cohen, Andres Munoz-Jaramillo, Anthony R. Yeates
Summary: This study introduces a synthetic magnetogram as an input for solar wind models and compares the results with observed magnetograms using a space weather modeling framework. By comparing extreme ultraviolet images and simulation data with in situ observations, the ability of dynamo models to be used as input for solar wind models can be quantified.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Lei Cheng, Ming Zhang, David Lario, Laura A. Balmaceda, Ryun Young Kwon, Christina Cohen
Summary: This paper presents a stochastic three-dimensional focused transport simulation of solar energetic particles (SEPs) produced by a data-driven coronal mass ejection (CME) shock. The model is applied to a SEP event observed by STEREO-A and Parker Solar Probe. The simulation results are well correlated with observations, suggesting that the SEP event could be explained by the acceleration of particles by a weak CME shock.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
N. Dresing, L. Rodriguez-Garcia, I. C. Jebaraj, A. Warmuth, S. Wallace, L. Balmaceda, T. Podladchikova, R. D. Strauss, A. Kouloumvakos, C. Palmroos, V. Krupar, J. Gieseler, Z. Xu, J. G. Mitchell, C. M. S. Cohen, G. A. de Nolfo, E. Palmerio, F. Carcaboso, E. K. J. Kilpua, D. Trotta, U. Auster, E. Asvestari, D. da Silva, W. Droge, T. Getachew, R. Gomez-Herrero, M. Grande, D. Heyner, M. Holmstroem, J. Huovelin, Y. Kartavykh, M. Laurenza, C. O. Lee, G. Mason, M. Maksimovic, J. Mieth, G. Murakami, P. Oleynik, M. Pinto, M. Pulupa, I. Richter, J. Rodriguez-Pacheco, B. Sanchez-Cano, F. Schuller, H. Ueno, R. Vainio, A. Vecchio, A. M. Veronig, N. Wijsen
Summary: On April 17, 2021, a complex and long-lasting solar eruption produced a widespread solar energetic particle event that was observed by five well-separated observers in the inner heliosphere. The event was the second of its kind in solar cycle 25 and produced relativistic electrons and protons. The aim of this study was to understand the reasons for the wide spread of elevated SEP intensities and identify the source regions of the observed particles.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
L. Rodriguez-Garcia, L. A. Balmaceda, R. Gomez-Herrero, A. Kouloumvakos, N. Dresing, D. Lario, I. Zouganelis, A. Fedeli, F. Espinosa Lara, I. Cernuda, G. C. Ho, R. F. Wimmer-Schweingruber, J. Rodriguez-Pacheco
Summary: This study aims to identify potential correlations between solar energetic electron (SEE) events measured by the MESSENGER mission and the properties of parent solar activity phenomena. Statistical analysis reveals an asymmetry in the connection angles (CAs) for SEE events with the highest peak intensities, and moderate to strong correlations are found between the electron peak intensity and the maximum speed of CME-driven shock, flare peak intensity, and CME speed at apex for well-connected events. The correlations become blurred when including poorly connected events.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Sabrina L. Savage, Amy R. Winebarger, Ken Kobayashi, P. S. Athiray, Dyana Beabout, Leon Golub, Robert W. Walsh, Brent Beabout, Stephen Bradshaw, Alexander R. Bruccoleri, Patrick R. Champey, Peter Cheimets, Jonathan Cirtain, Edward E. DeLuca, Giulio Del Zanna, Jaroslav Dudik, Anthony Guillory, Harlan Haight, Ralf K. Heilmann, Edward Hertz, William Hogue, Jeffery Kegley, Jeffery Kolodziejczak, Chad Madsen, Helen Mason, David E. McKenzie, Jagan Ranganathan, Katharine K. Reeves, Bryan Robertson, Mark L. Schattenburg, Jorg Scholvin, Richard Siler, Paola Testa, Genevieve D. Vigil, Harry P. Warren, Benjamin Watkinson, Bruce Weddendorf, Ernest Wright
Summary: The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket experiment was launched on July 30, 2021, to capture X-ray spectral images of coronal active regions. MaGIXS is the first instrument to provide spatially resolved soft X-ray spectra across a wide field of view. The paper presents details from the first MaGIXS flight, the captured observations, data processing techniques, and the first science results.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Ming Zhang, Lei Cheng, Ju Zhang, Pete Riley, Ryun Young Kwon, David Lario, Laura Balmaceda, Nikolai V. V. Pogorelov
Summary: In order to predict radiation hazards from solar energetic particles (SEPs), a data-driven physics-based particle transport model was developed to calculate the injection, acceleration, and propagation of SEPs. The model utilizes corona and heliospheric plasma and magnetic field configuration from a magnetohydrodynamic model, combined with observed CME shocks, to simulate the behavior of SEPs. The model was successfully applied to a CME event in 2011 and accurately reproduced observations from spacecraft at different locations.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
Giulio Del Zanna, Jenna Samra, Austin Monaghan, Chad Madsen, Paul Bryans, Edward DeLuca, Helen Mason, Ben Berkey, Alfred de Wijn, Yeimy J. Rivera
Summary: The AIR-Spec instrument allows exploration of the near-infrared wavelength range and has been used in two total solar eclipses. By comparing its data with other instruments, the study provides detailed diagnostics for temperature, electron density, and elemental abundances. The results show good agreement in electron density from different instruments and indicate different temperature distributions on the west and east limbs. The analysis confirms the photospheric abundance of sulfur and iron in both regions.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
F. A. Iglesias, C. Francile, J. Lazarte-Gelmetti, L. A. Balmaceda, H. Cremades, F. Cisterna
Summary: This study characterizes the daytime sky quality at the Carlos Ulrico Cesco station in El Leoncito National Park, San Juan, Argentina. Data from15 years of observations and meteorological stations from 2000 to 2020 are analyzed. The results confirm that El Leoncito is an excellent place for daytime astronomical observations.
Article
Astronomy & Astrophysics
Teresa Nieves-Chinchilla, Sanchita Pal, Tarik M. Salman, Fernando Carcaboso, Silvina E. Guidoni, Hebe Cremades, Ayris Narock, Laura A. Balmaceda, Benjamin J. Lynch, Nada Al-Haddad, Laura Rodriguez-Garcia, Thomas W. Narock, Luiz F. G. Dos Santos, Florian Regnault, Christina Kay, Reka M. Winslow, Erika Palmerio, Emma E. Davies, Camilla Scolini, Andreas J. Weiss, Nathalia Alzate, Mariana Jeunon, Roger Pujadas
Summary: This paper highlights the importance of advancing our understanding of the fundamental physics of heliospheric flux ropes, and urges for novel and necessary approaches to significantly improve the current state of flux rope research. It briefly discusses the current understanding of flux rope formation and evolution, and summarizes the strategies that have been employed to comprehend the dynamics of heliospheric structures. The challenges and recommendations presented are expected to enhance our in-depth knowledge of our nearest star, its dynamics, and its influence in the heliosphere.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2023)
Article
Astronomy & Astrophysics
Nariaki V. Nitta, Radoslav Bucik, Glenn M. Mason, George C. Ho, Christina M. S. Cohen, Raul Gomez-Herrero, Linghua Wang, Laura A. Balmaceda
Summary: A series of He-3-rich solar energetic particle (SEP) events were observed by Solar Orbiter in May 2021 at a radial distance of 0.95 AU. An isolated active region AR 12824 was likely the ultimate source of these SEP events. The period of the enhanced flux of He-3 was also a period of frequent type III bursts in the decametric-hectometric range, confirming their close relationship.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2023)
Article
Astronomy & Astrophysics
Abril Sahade, Angelos Vourlidas, Laura A. A. Balmaceda, Mariana Cecere
Summary: We study the low corona evolution of the Cartwheel coronal mass ejection (CME; 2008 April 9) using reconstruction and magnetohydrodynamic simulations. We find a pseudostreamer structure with a null point that may be responsible for the complex evolution of the magnetic flux rope (MFR) at the initial phase. By setting up a similar magnetic configuration in a numerical simulation, we reproduce the observed behavior and validate the importance of the pseudostreamer null point.
ASTROPHYSICAL JOURNAL
(2023)
