Results 31 to 40 of about 1,232 (254)

Solar cycle variation of magnetic flux emergence

The Astrophysical Journal, 1977
The number of X-ray bright points (XBP) has been measured from solar X-ray images obtained during two rocket flights in 1976. When compared with the data obtained during the Skylab mission (1973), the number is found to be higher by a factor of 2. As the probability of obtaining the result by chance is less than 1 in 5 million, it is concluded that the
J. M. Davis, L. Golub, A. S. Kreiger
openaire   +1 more source

The Eruption of a Magnetic Flux Rope Observed by Solar Orbiter and Parker Solar Probe

The Astrophysical Journal, 2023
Magnetic flux ropes are a key component of coronal mass ejections, forming the core of these eruptive phenomena. However, determining whether a flux rope is present prior to eruption onset and, if so, the rope’s handedness and the number of turns that ...
David M. Long, Lucie M. Green, Francesco Pecora, David H. Brooks, Hanna Strecker, David Orozco-Suárez, Laura A. Hayes, Emma E. Davies, Ute V. Amerstorfer, Marilena Mierla, David Lario, David Berghmans, Andrei N. Zhukov, Hannah T. Rüdisser   +13 more
doaj   +1 more source

Magnetic structures of an emerging flux region in the solar photosphere and chromosphere [PDF]

Astronomy and Astrophysics, 2010
Aims. We investigate the vector magnetic field and Doppler velocity in the photosphere and upper chromosphere of a young emerging flux region of the sun close to disk center. Methods. Spectropolarimetric scans of a young active region made using the second generation Tenerife Infrared Polarimeter (TIP II) on the German Vacuum Tower Telescope (VTT) are ...
Xu, Z., Lagg, A., Solanki, S.
openaire   +2 more sources

Exploring the Connection between Helioseismic Travel Time Anomalies and the Emergence of Large Active Regions during Solar Cycle 24

The Astrophysical Journal, 2023
We investigate deviations in the mean phase travel time of acoustic waves preceding the emergence of 46 large active regions observed by the Helioseismic and Magnetic Imager.
John T. Stefan, Alexander G. Kosovichev
doaj   +1 more source

Observations of solar small-scale magnetic flux-sheet emergence [PDF]

Astronomy & Astrophysics, 2019
Aims. Two types of flux emergence were recently discovered in numerical simulations: magnetic loops and magnetic sheet emergence. While magnetic loop emergence has been documented well in recent years using high-resolution full Stokes data from ground-based telescopes as well as satellites, magnetic sheet emergence is still an understudied process.
C. E. Fischer, J. M. Borrero, N. Bello González, A. J. Kaithakkal   +3 more
openaire   +2 more sources

Injection of Magnetic Energy and Magnetic Helicity into the Solar Atmosphere by an Emerging Magnetic Flux Tube [PDF]

The Astrophysical Journal, 2003
We present a detailed investigation of the dynamical behavior of emerging magnetic flux using three-dimensional MHD numerical simulation. A magnetic flux tube with a left-handed twist, initially placed below the photosphere, emerges into the solar atmosphere.
T. Magara, D. W. Longcope
openaire   +1 more source

Mechanistic Control of C─H Bond Activation and C─C Coupling in Light‐Driven Methane Conversion to C2+ Products over Multifunctional Photocatalysts

Advanced Functional Materials, EarlyView.
Methane photocatalytic activation under mild conditions remains a formidable challenge in the synthesis of solar fuels. In this review, we emphasize the growing importance of multifunctional materials and hybrid systems within a unified mechanistic framework that integrates selective C─H bond activation, formation and control of intermediates, C─C ...
Di Hu, Yuheng Jiang, Vitaly V. Ordomsky, Bastian Mei, Zhiyong Tang, Andrei Y. Khodakov   +5 more
wiley   +1 more source

Charge Generation and Recombination Pathways in All‐Polymer Bulk Heterojunction Solar Cells

Advanced Functional Materials, EarlyView.
Multimodal spectroscopy and device analysis reveal how field‐dependent charge generation, transport limitations, and non‐geminate recombination govern performance losses in all polymer solar cells. The results identify the key processes controlling charge extraction and recombination, providing insights for the design of more efficient all‐polymer ...
Shahidul Alam, Wejdan Althobaiti, Safakath Karuthedath, Christopher E. Petoukhoff, Amr Dahman, Khawla Alkhezaim, Oleksandr Matiash, José P. Jurado, Mariia Ferree, Ning Su, Jacob Blaskovits, Denis Andrienko, Vladimir Dyakonov, Andreas Sperlich, Vojtech Nádaždy, Tobin J. Marks, Antonio Facchetti, Frédéric Laquai   +17 more
wiley   +1 more source

Three-dimensional magnetic field structure of a flux-emerging region in the solar atmosphere [PDF]

Astronomy & Astrophysics, 2019
We analyze high-resolution spectropolarimetric observations of a flux-emerging region (FER) in order to understand its magnetic and kinematic structure. Our spectropolarimetric observations in the He I 10830 Å spectral region of a FER were recorded with GRIS at the 1.5 m aperture GREGOR telescope.
Yadav, Rahul, de la Cruz Rodríguez, Jaime, Díaz Baso, Carlos José, Prasad, Avijeet, Libbrecht, Tine, Robustini, Carolina, Asensio Ramos, Andrés   +6 more
openaire   +2 more sources

Opportunities of Semiconducting Oxide Nanostructures as Advanced Luminescent Materials in Photonics

Advanced Materials, EarlyView.
The review discusses the challenges of wide and ultrawide bandgap semiconducting oxides as a suitable material platform for photonics. They offer great versatility in terms of tuning microstructure, native defects, doping, anisotropy, and micro‐ and nano‐structuring. The review focuses on their light emission, light‐confinement in optical cavities, and
Ana Cremades, Pedro Hidalgo, David Maestre, Ruth Martínez‐Casado, Emilio Nogales, Beatriz Rodríguez, G. Cristian Vásquez, Bianchi Méndez   +7 more
wiley   +1 more source