Results 51 to 60 of about 600 (183)

Development and Cancellation of Long‐Duration Positive Ionospheric Storms: Both Changes of the F2‐Layer Peak Height and O/N2 Ratio Can Be Decisive

Space Weather, Volume 24, Issue 7, July 2026.
Abstract For decades, two competing hypotheses on the key drivers of mid‐latitude long‐duration positive ionospheric storms (LDPS) have been considered: (a) an increase of the F2‐layer peak height (hmF2) and (b) an increase in the atomic oxygen to molecular nitrogen density ratio (O/N2).
D. V. Kotov, M. O. Reznychenko, P. G. Richards, O. V. Bogomaz, L. P. Goncharenko, L. J. Paxton, M. Hernández‐Pajares, A. I. Reznychenko, D. P. Shkonda, V. V. Barabash, L. Ya. Emelyanov, I. F. Domnin, A. Ye. Miroshnikov, V. P. Burmaka, D. A. Dzyubanov, Yu. I. Podyachiy   +15 more
wiley   +1 more source

Mercury's Eccentric Orbit as a Driver of Significant “Seasonal” Change in Upstream Solar Wind Forcing

Geophysical Research Letters, Volume 53, Issue 12, 28 June 2026.
Abstract Mercury experiences the most intense and variable solar wind (SW) conditions in the solar system due to its close, eccentric orbit about the Sun. In addition to variation driven by coronal source and solar cycle, the SW arriving at Mercury varies periodically as the planet's heliocentric distance changes by over 50% per orbit.
Ryan M. Dewey, Caitriona Mary Jackman, Mathias Rojo, Lina Z. Hadid, Beatriz Sánchez‐Cano, Charles F. Bowers, Jim M. Raines, Susan T. Lepri, Stefano Livi, Jesse T. Coburn, Sae Aizawa, Yeimy J. Rivera, Weijie Sun, Jiutong Zhao, James A. Slavin, Daniel Heyner, Daragh M. Hollman, Alexander D. Shane   +17 more
wiley   +1 more source

Global Effect of New Active Regions on Coronal Holes and Their Wind Streams

The Astrophysical Journal
Solar wind prediction algorithms and simulations of coronal events often employ photospheric field maps that are assembled over a 27 day solar rotation. This has stimulated efforts to update and better synchronize the maps by applying flux transport and ...
Y.-M. Wang, K. J. Knizhnik, I. Ugarte-Urra, M. J. Weberg   +3 more
doaj   +1 more source

MHD waves in the solar north polar coronal hole

Astronomische Nachrichten, 2010
AbstractThe effects, hitherto not treated, of the temperature and the number density gradients, both in the parallel and the perpendicular direction to the magnetic field, of O VI ions, on the MHD wave propagation characteristics in the solar North Polar Coronal Hole are investigated.
Devlen, E., Pekunlu, E. R.
openaire   +3 more sources

Comparing Solar Structure Detection Methods in SDO/AIA Observations and the Application to Raw Uncalibrated Data

Journal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 3, June 2026.
Abstract Recent advances in solar physics increasingly rely on automated identification of coronal structures using machine learning. Yet most studies emphasize scientific performance without evaluating feasibility for onboard deployment to prioritize downlink observations.
P. Gonidakis, F. Carella, E. Dineva, H‐J. Jeong, P. Antunes, A. Podobas, S. Raptis, V. Toy‐Edens, M. Jin, S. Poedts, J. Magdalenic, G. Miloshevich   +11 more
wiley   +1 more source

Identifying and Predicting Coronal Mass Ejection Occurrence: Observational Checklists for Space Weather Forecasters

Space Weather, Volume 24, Issue 6, June 2026.
Abstract Ejections of magnetized plasma from the Sun, known as coronal mass ejections, can drive major geomagnetic activity if Earth‐directed, and are therefore monitored by space weather forecasters. The current focus being the forecast of the arrival time of a coronal mass ejection at Earth and the level of geomagnetic impact.
L. M. Green, A. W. James, N. Ngampoopun, S. L. Yardley, K. Waite, E. K. Mottram, J. Hernandez Camero, J. O'kane   +7 more
wiley   +1 more source

An Empirical Model of a Polar Coronal Hole at Solar Minimum

The Astrophysical Journal, 1999
We present a comprehensive and self-consistent empirical model for several plasma parameters in the extended solar corona above a polar coronal hole. The model is derived from observations with the SOHO Ultraviolet Coronagraph Spectrometer (UVCS/SOHO) during the period between 1996 November and 1997 April.
CRANMER S. R., KOHL J. L., NOCI G., ANTONUCCI E., TONDELLO G., HUBER M. C. E., STRACHAN L., PANASYUK A. V., GARDNER L. D., ROMOLI M., FINESCHI S., DOBRZYCKA D., RAYMOND J. C., NICOLOSI, PIERGIORGIO, SIEGMUND O. H. W., SPADARO D., BENNA C., CIARAVELLA A., GIORDANO S., HABBAL S., KAROVSKA M., LI X., MARTIN R., MICHELS J. G., MODIGLIANI A., NALETTO, GIAMPIERO, O'NEAL R. H., PERNECHELE C., POLETTO G., SMITH P. L., SULEIMAN R. M.   +30 more
openaire   +2 more sources

ST‐TFFM‐Observer: A Global Ionospheric TEC Prediction Model Based on Dynamic System Theory With Enhanced Time‐Frequency Dependence Modeling

Space Weather, Volume 24, Issue 6, June 2026.
Abstract ST‐Observer is a novel proposed spatiotemporal prediction model based on dynamic system theory, which has been proven to be superior to existing models in multiple spatiotemporal prediction tasks. However, its structural design results in weak time dependent modeling capabilities and a lack of frequency dependent modeling capabilities.
Liwei Sun, Haijun Liu, Huijun Le, Jing Yuan, Shijia Li, Xingyue Yao, Guoming Yuan   +6 more
wiley   +1 more source

On the Origin of the Sudden Heliospheric Open Magnetic Flux Enhancement During the 2014 Pole Reversal

The Astrophysical Journal
Coronal holes are recognized as the primary sources of heliospheric open magnetic flux (OMF). However, a noticeable gap exists between in situ measured OMF and that derived from remote-sensing observations of the Sun.
Stephan G. Heinemann, Mathew J. Owens, Manuela Temmer, James A. Turtle, Charles N. Arge, Carl J. Henney, Jens Pomoell, Eleanna Asvestari, Jon A. Linker, Cooper Downs, Ronald M. Caplan, Stefan J. Hofmeister, Camilla Scolini, Rui F. Pinto, Maria S. Madjarska   +14 more
doaj   +1 more source

Geoelectric Field Caused by Flux Transfer Events in an Ionosphere‐Coupled Vlasiator Simulation

Journal of Geophysical Research: Space Physics, Volume 131, Issue 6, June 2026.
Abstract We report on the relationship between flux transfer events (FTEs) at Earth's magnetopause and the geoelectric field that is induced near the FTEs' magnetic footpoints. We study this system using the global hybrid‐Vlasov code Vlasiator, which has recently been extended to model ionospheric physics.
K. Horaites, M. Alho, Y. Pfau‐Kempf, U. Ganse, A. Workayehu, J. Suni, F. Tesema, L. Juusola, G. Cozzani, S. Hoilijoki, I. Zaitsev, S. Kavosi, M. Palmroth   +12 more
wiley   +1 more source