Search Publications
Survey and Merging of Sunspot Catalogs
Clette, Frédéric; Lefevre, Laure
In view of the construction of new sunspot-based activity indices and proxies, we conducted a comprehensive survey of all existing catalogs providing detailed parameters of photospheric features over long time intervals. Although there are a fair number of such catalogs, a global evaluation showed that they suffer from multiple limitations: finite…
Variations in Abundance Enhancements in Impulsive Solar Energetic-Particle Events and Related CMEs and Flares
Reames, Donald V.; Kahler, Stephen W.; Cliver, Edward W.
We study event-to-event variations in the abundance enhancements of the elements He through Pb for Fe-rich impulsive solar energetic-particle (SEP) events, and their relationship with properties of associated coronal mass ejections (CMEs) and solar flares. Using a least-squares procedure we fit the power-law enhancement of element abundances as a …
Tracking Solar Active Region Outflow Plasma from Its Source to the Near-Earth Environment
Mandrini, C. H.; van Driel-Gesztelyi, L.; Culhane, J. L. +6 more
Seeking to establish whether active-region upflow material contributes to the slow solar wind, we examine in detail the plasma upflows from Active Region (AR) 10978, which crossed the Sun's disc in the interval 8 to 16 December 2007 during Carrington rotation (CR) 2064. In previous work, using data from the Hinode/EUV Imaging Spectrometer, upflow …
Identification of Interplanetary Coronal Mass Ejections at Ulysses Using Multiple Solar Wind Signatures
Richardson, I. G.
Previous studies have discussed the identification of interplanetary coronal mass ejections (ICMEs) near the Earth based on various solar wind signatures. In particular, methods have been developed of identifying regions of anomalously low solar wind proton temperatures (Tp) and plasma compositional anomalies relative to the composition…
Far- and Extreme-UV Solar Spectral Irradiance and Radiance from Simplified Atmospheric Physical Models
Fontenla, J. M.; Landi, E.; Snow, M. +1 more
This article describes an update of the physical models that we use to reconstruct the FUV and EUV irradiance spectra and the radiance spectra of the features that at any given point in time may cover the solar disk depending on the state of solar activity. The present update introduces important modifications to the chromosphere-corona transition…
Gauribidanur Low-Frequency Solar Spectrograph
Ramesh, R.; Kathiravan, C.; Kishore, P. +2 more
A new radio spectrograph, dedicated to observe the Sun, has been recently commissioned by the Indian Institute of Astrophysics (IIA) at the Gauribidanur Radio Observatory, about 100 km North of Bangalore. The instrument, called the Gauribidanur Low-frequency Solar Spectrograph (GLOSS), operates in the frequency range≈40 - 440 MHz. Radio emission i…
CME Expansion as the Driver of Metric Type II Shock Emission as Revealed by Self-consistent Analysis of High-Cadence EUV Images and Radio Spectrograms
Hillaris, A.; Preka-Papadema, P.; Moussas, X. +6 more
On 13 June 2010, an eruptive event occurred near the solar limb. It included a small filament eruption and the onset of a relatively narrow coronal mass ejection (CME) surrounded by an extreme ultraviolet (EUV) wave front recorded by the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) at high cadence. The ejection was accompa…
Applying an Automatic Image-Processing Method to Synoptic Observations
Tlatov, Andrey G.; Vasil'eva, Valeria V.; Makarova, Valentina V. +1 more
We used an automatic image-processing method to detect solar-activity features observed in white light at the Kislovodsk Solar Station. This technique was applied to automatically or semi-automatically detect sunspots and active regions. The results of this automated recognition were verified with statistical data available from other observatorie…
A New Sigmoid Catalog from Hinode and the Solar Dynamics Observatory: Statistical Properties and Evolutionary Histories
DeLuca, E. E.; Savcheva, A. S.; McKillop, S. C. +2 more
We present a new sigmoid catalog covering the duration of the Hinode mission and the Solar Dynamics Observatory (SDO) until the end of 2012. The catalog consists of 72 mostly long-lasting sigmoids. We collect and make available all X-ray and EUV data from Hinode, SDO, and the Solar TErrestrial RElations Observatory (STEREO), and we determine the s…
Coronal Holes in Solar Cycles 21 to 23
Tlatov, A.; Tavastsherna, K.; Vasil'eva, V.
We present identifications of coronal holes (CHs) from observations in the He I 10 830 Å line made at Kitt Peak Observatory (from 1975 to 2003) and in the EUV 195 Å wavelength with SOHO/EIT (from 1996 to 2012). To determine whether a feature is a CH we have developed semi-automatic techniques for delineating CH borders on synoptic charts and for s…