Search Publications
Solar flare forecasting model supported with artificial neural network techniques
Li, R.; Wang, H. N.; Cui, Y. M. +2 more
Nowadays operational models for solar activity forecasting are still based on the statistical relationship between solar activity and solar magnetic field evolution. In order to set up this relationship, many parameters have been proposed to be the measures. Conventional measures are based on the sunspot group classification which provides limited…
Recent advances in observations and modeling of the solar ultraviolet and X-ray spectral irradiance
Woods, Thomas N.
There have been significant, recent advances in understanding the solar ultraviolet (UV) and X-ray spectral irradiance from several different satellite missions and from new efforts in modeling the variations of the solar spectral irradiance. The recent satellite missions with solar UV and X-ray spectral irradiance observations include the X-ray S…
Helioseismology and the solar cycle
Howe, Rachel
Helioseismic measurements stretching back for about three decades have clearly shown that the acoustic modes are sensitive to solar-cycle changes. 2006 marks the first full 11-year cycle of continuous observations from the Global Oscillation Network Group (GONG), and 10 years of observations with the Michelson Doppler Imager (MDI) aboard the SOHO …
Segmentation of extreme ultraviolet solar images via multichannel fuzzy clustering
Hochedez, Jean-François; Delouille, Véronique; Barra, Vincent
The study of the variability of the solar corona and the monitoring of its traditional regions (Coronal Holes, Quiet Sun and Active Regions) are of great importance in astrophysics as well as in view of the Space Weather and Space Climate applications. Here we propose a multichannel unsupervised spatially constrained fuzzy clustering algorithm tha…
Variations of the solar acoustic high-degree mode frequencies over solar cycle 23
Schou, J.; Rabello-Soares, M. C.; Korzennik, Sylvain G.
Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present variations of the solar acoustic mode frequencies caused by the solar activity cycle. High-degree (100 < ℓ < 900) solar acoustic modes were analyzed using global helioseismology analysis …
Comparing proton fluxes of central meridian SEP events with those predicted by SOLPENCO
Lario, D.; Aran, A.; Sanahuja, B.
We have developed an operational code, SOLPENCO, that can be used for space weather prediction schemes of solar energetic particle (SEP) events. SOLPENCO provides proton differential flux and cumulated fluence profiles from the onset of the event up to the arrival of the associated traveling interplanetary shock at the observer’s position (either …
Tilts and polarity separation in the sunspot groups and active regions at the ascending and descending phases of the cycle 23
Zharkova, V. V.; Zharkov, S. I.
The Solar Feature Catalogues for sunspots and active regions measured with SOHO/MDI instrument and Ca II K3 spectroheliograph of the Paris-Meudon Observatory are analyzed with the automated classification technique for sunspot groups and active region polarities. We report the first classification results for daily variations of tilt angles (norma…
Probing solar and stellar interior dynamics and dynamo
Kosovichev, Alexander G.
Solar and stellar activity is a result of complex interaction between magnetic field, turbulent convection and differential rotation in a star’s interior. Magnetic field is believed to be generated by a dynamo process in the convection zone. It emerges on the surface forming sunspots and starspots. Localization of the magnetic spots and their evol…
Multi-scale reconnections in a complex CME
Mandrini, C. H.; van Driel-Gesztelyi, L.; Culhane, J. L. +6 more
A series of three flares of GOES class M, M and C, and a CME were observed on 20 January 2004 occurring in close succession in NOAA 10540. Types II, III, and N radio bursts were associated. We use the combined observations from TRACE, EIT, Hα images from Kwasan Observatory, MDI magnetograms, GOES, and radio observations from Culgoora and Wind/ WAV…
The dynamics of the solar radiative zone
Turck-Chièze, Sylvaine; Talon, Suzanne
The picture of the solar radiative zone is evolving quickly. This review is separated in two parts. We first recall how the two powerful probes of the solar interior, namely the neutrinos and helioseismology have scrutinized the microscopic properties of the solar radiative plasma. Recent observations stimulate today complementary activities beyon…