Search Publications
Observable Effects of Interplanetary Coronal Mass Ejections on Ground Level Neutron Monitor Count Rates
Rodríguez-Pacheco, J.; Hidalgo, M. A.; Blanco, J. J. +3 more
In this work, non-recurrent Forbush decreases (FDs) triggered by the passage of shock-driving interplanetary coronal mass ejections (ICMEs) have been analyzed. Fifty-nine ICMEs have been studied, but only 25 % of them were associated to a FD. We find that shock-driving magnetic clouds (MCs) produce deeper FDs than shock-driving ejecta. This fact c…
Solar Intranetwork Magnetic Elements: Flux Distributions
Wang, Jingxiu; Jin, Chunlan; Zhou, Guiping
The current study aims at quantifying the flux distributions of solar intranetwork (IN) magnetic field based on the data taken in four quiet and two enhanced network areas with the Narrow-band Filter Imager of the Solar Optical Telescope on board the Hinode satellite. More than 14000 IN elements and 3000 NT elements were visually identified. They …
Properties of the 15 February 2011 Flare Seismic Sources
Green, L. M.; Zharkova, V. V.; Matthews, S. A. +1 more
The first near-side X-class flare of Solar Cycle 24 occurred in February 2011 (SOL2011-02-05T01:55) and produced a very strong seismic response in the photosphere. One sunquake was reported by Kosovichev (Astrophys. J. Lett.734, L15, 2011), followed by the discovery of a second sunquake by Zharkov, Green, Matthews et al. (Astrophys. J. Lett.741, L…
Magnetic Flux of EUV Arcade and Dimming Regions as a Relevant Parameter for Early Diagnostics of Solar Eruptions - Sources of Non-recurrent Geomagnetic Storms and Forbush Decreases
Grechnev, V. V.; Chertok, I. M.; Belov, A. V. +1 more
This study aims at the early diagnostics of the geoeffectiveness of coronal mass ejections (CMEs) from quantitative parameters of the accompanying EUV dimming and arcade events. We study events of the 23th solar cycle, in which major non-recurrent geomagnetic storms (GMS) with Dst<−100 nT are sufficiently reliably identified with their solar so…
Quiet Sun Explosive Events: Jets, Splashes, and Eruptions
Innes, D. E.; Teriaca, L.
Explosive events appear as broad non-Gaussian wings in the line profiles of small transition-region phenomena. Images from the Solar Dynamics Observatory (SDO) give a first view of the plasma dynamics at the sites of explosive events seen simultaneously in O VI spectra of a region of quiet Sun, taken with the ultraviolet spectrometer Solar Ultravi…
Modeling Total Solar Irradiance with San Fernando Observatory Ground-Based Photometry: Comparison with ACRIM, PMOD, and RMIB Composites
Chapman, G. A.; Preminger, D. G.; Cookson, A. M.
We model total solar irradiance (TSI) using photometric irradiance indices from the San Fernando Observatory (SFO), and compare our model with measurements compiled from different space-based radiometers. Space-based measurements of TSI have been obtained recently from ACRIM-3 on board the ACRIMSAT. These data have been combined with other data se…
Dynamics of Coronal Bright Points as Seen by Sun Watcher Using Active Pixel System Detector and Image Processing (SWAP), Atmospheric Imaging Assembly (AIA), and Helioseismic and Magnetic Imager (HMI)
Banerjee, D.; Krishna Prasad, S.; Ravindra, B. +2 more
The Sun Watcher using Active Pixel system detector and Image Processing (SWAP) onboard the PRoject for OnBoard Autonomy-2 (PROBA2) spacecraft provides images of the solar corona in EUV channel centered at 174 Å. These data, together with the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Ob…
A Multi-wavelength Analysis of Active Regions and Sunspots by Comparison of Automatic Detection Algorithms
Verbeeck, C.; Delouille, V.; Colak, T. +4 more
Since the Solar Dynamics Observatory (SDO) began recording ≈ 1 TB of data per day, there has been an increased need to automatically extract features and events for further analysis. Here we compare the overall detection performance, correlations between extracted properties, and usability for feature tracking of four solar feature-detection algor…
Using Statistical Multivariable Models to Understand the Relationship Between Interplanetary Coronal Mass Ejecta and Magnetic Flux Ropes
Riley, P.; Richardson, I. G.
In-situ measurements of interplanetary coronal mass ejections (ICMEs) display a wide range of properties. A distinct subset, "magnetic clouds" (MCs), are readily identifiable by a smooth rotation in an enhanced magnetic field, together with an unusually low solar wind proton temperature. In this study, we analyze Ulysses spacecraft measurements to…
Photometric Calibration of the LASCO-C2 Coronagraph over 14 Years (1996 - 2009)
Llebaria, A.; Lamy, P.; Gardès, B.
We present a photometric calibration of the SOHO/LASCO-C2 coronagraph based on the analysis of all stars down to magnitude V=8 that transited its field of view during the past 14 years of operation (1996 - 2009), extending the previous work of Llebaria, Lamy, and Danjard (Icarus182, 281, 2006). The pre-processing of the images incorporates the mos…