Results 21 to 30 of about 17,672 (303)

Case study of the mesospheric and lower thermospheric effects of solar x-ray flares: Coupled ion-neutral modelling and comparison with EISCAT and riometer measurements [PDF]

, 2008
Two case studies of upper mesospheric and lower thermospheric (UMLT) high-latitude effects of solar X-ray flares are presented. Sodankylä Ion-neutral Chemistry Model (SIC) electron density profiles agree with D-region EISCAT and riometer ...
Beharrell, M.J., A. Seppälä, Verronen, P.T., Seppälä, A., Ulich, T., C.-F. Enell, Enell, C.-F., Honary, F., P. T. Verronen, J. P. Vierinen, T. Ulich, A. Kero, E. Turunen, M. J. Beharrell, Vierinen, J.P., Turunen, E., F. Honary, Kero, A.   +17 more
core   +1 more source

Statistical Study of the Correlation between Solar Energetic Particles and Properties of Active Regions

The Astrophysical Journal, 2023
The flux of energetic particles originating from the Sun fluctuates during the solar cycles. It depends on the number and properties of active regions (ARs) present in a single day and associated solar activities, such as solar flares and coronal mass ...
Russell D. Marroquin, Viacheslav Sadykov, Alexander Kosovichev, Irina N. Kitiashvili, Vincent Oria, Gelu M. Nita, Egor Illarionov, Patrick M. O’Keefe, Fraila Francis, Chun Jie Chong, Paul Kosovich, Aatiya Ali   +11 more
doaj   +1 more source

Magnetic local time (MLT) dependence of auroral peak emission height and morphology [PDF]

Annales Geophysicae, 2022
We investigate the bulk behaviour of auroral structures and peak emission height as a function of magnetic local time (MLT). These data are collected from the Fennoscandian Lapland and Svalbard latitudes from seven identical auroral all-sky cameras (ASC)
N. Partamies, N. Partamies, D. Whiter, K. Kauristie, S. Massetti   +4 more
doaj   +1 more source

Acceleration, Containment, and Emission of Very Low Energy Solar Flare Particles [PDF]

Symposium - International Astronomical Union, 1974
We present the first observations of protons down to 44 keV and electrons down to ≲ keV emitted in an impulsive solar particle event. The observations are from the Apollo 15 Subsatellite during a flare event which began on September 1, 1971. We obtain a lower limit estimate of the energy contained in ≳ MeV protons in the flare. The effects of adiabatic
R. P. Lin, R. E. McGuire, K. A. Anderson
openaire   +1 more source

The role of alpha particles in the emission of plasma waves inside solar ejecta [PDF]

Brazilian Journal of Physics, 2002
The enhancement of the resonant instability of right-hand polarized electromagnetic ion cyclotron waves by alpha particles for physical parameters corresponding to coronal mass ejections is studied. We focus on the effects of alpha thermal anisotropy and relative He++/H+ abundance on growth and absorption rates.
Dasso, S., Gratton, F. T., Farrugia, Charlie J.   +2 more
openaire   +6 more sources

Formation of the Injection Function of Solar Energetic Particles in Gradual Events

The Astrophysical Journal, 2023
We present a model for solar energetic particle injection into interplanetary space in gradual events, in which particle acceleration occurs in a limited region of the solar atmosphere.
Ivan Petukhov, Anastasia Petukhova, Stanislav Petukhov   +2 more
doaj   +1 more source

Simulation of the Solar Energetic Particle Event on 2020 May 29 Observed by Parker Solar Probe

The Astrophysical Journal, 2023
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 propagating through a data-driven model of coronal and heliospheric magnetic ...
Lei Cheng, Ming Zhang, David Lario, Laura A. Balmaceda, Ryun Young Kwon, Christina Cohen   +5 more
doaj   +1 more source

N-S Asymmetry and Solar Cycle Distribution of Superactive Regions from 1976 to 2017

Universe, 2022
There were 51 superactive regions (SARs) during solar cycles (SCs) 21–24. We divided the SARs into SARs1, which produced extreme space weather events including ≥X5.0 flares, ground level events (GLEs), and super geomagnetic storms (SGSs, Dst < −250 nT ...
Ming-Xian Zhao, Gui-Ming Le, Yong-Hua Liu   +2 more
doaj   +1 more source

Dayside and nightside reconnection rates inferred from IMAGE FUV and Super Dual Auroral Radar Network data [PDF]

, 2006
peer reviewedThe spectrographic imager at 121.8 nm ( SI12) of the far ultraviolet ( FUV) experiment onboard the IMAGE spacecraft produces global images of the Doppler- shifted Lyman alpha emission of the proton aurora.
Hubert, Benoît, Hubert, B., Cowley, S. W. H., Blockx, C., Milan, S. E., Gérard, Jean-Claude, Blockx, Caroline, Gérard, J.-c., Grocott, A.   +8 more
core   +1 more source

Three-dimensional reconstruction of multiple particle acceleration regions during a coronal mass ejection [PDF]

, 2020
Context. Some of the most prominent sources for particle acceleration in our Solar System are large eruptions of magnetised plasma from the Sun called coronal mass ejections (CMEs).
Pomoell, J., D. E. Morosan, Morosan, D. E., J. Pomoell, E. Palmerio, Vainio, R., Palmerio, E., M. Palmroth, R. Vainio, Kilpua, E. K. J., Palmroth, M., E. K. J. Kilpua   +11 more
core   +1 more source