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Automated Detection Of Eit Waves And Dimmings
Berghmans, David; Podladchikova, Olena
Studies of the onset of Earth-directed coronal mass ejections (CMEs) rely on solar disk observations where CME structures are difficult to disentangle because of the diversity and transient character of the phenomena involved. Dimmings and coronal waves are among the best evidence of the large-scale reorganization of coronal magnetic fields associ…
Multifractal Analysis Of Solar Magnetograms
Abramenko, Valentyna I.
As solar observational techniques improve, fine small-scale structures observed on the solar surface become more pronounced. Complex filigree structures of solar granulation, sunspots, photospheric magnetic and velocity fields cannot be described adequately by a single parameter (e.g., filling factor, fractal dimension, or power-law index). Method…
Nine Years Of Euv Bright Points
McIntosh, Scott W.; Gurman, Joseph B.
We discuss early results derived from an algorithm that automates the detection, cataloging, and analysis of extreme-ultraviolet (EUV) "bright points" (BP) from 9 years of data acquired by the Extreme-ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO). The algorithm relies upon the computation of a map of "intensi…
Large-Scale Activity in the Bastille Day 2000 Solar Event
Grechnev, V. V.; Chertok, I. M.
We have analyzed dimmings, i.e., regions of temporarily reduced brightness, and manifestations of a coronal wave in the famous event of 14 July 2000 using images produced with the EUV telescope SOHO/EIT. Our analysis was inspired by a paper by Andrews (2001, Solar Phys. 204, 181 (Paper I)), in which this event was studied using running-difference …
Statistical Properties Of Sunspots In 1996 2004: I. Detection, North South Asymmetry And Area Distribution
Zharkova, V. V.; Zharkov, S.; Ipson, S. S.
The first statistical results in sunspot distributions in 1996-2004 obtained from the Solar Feature Catalogues (SFC) are presented. A novel robust technique is developed for automated identification of sunspots on SOHO/MDI white-light (WL) full-disk solar images. The technique applies image standardization procedures for elimination of the limb da…
Automated Boundary-extraction And Region-growing Techniques Applied To Solar Magnetograms
Gallagher, Peter T.; McAteer, R. T. James; Ireland, Jack +1 more
We present an automated approach to active region extraction from full-disc MDI longitudinal magnetograms. This uses a region-growing technique in conjunction with boundary-extraction to define a number of enclosed contours as belonging to separate regions of magnetic significance on the solar disc. This provides an objective definition of active …
Solar Feature Catalogues In Egso
Zharkova, V. V.; Aboudarham, J.; Zharkov, S. +3 more
The Solar Feature Catalogues (SFCs) are created from digitized solar images using automated pattern recognition techniques developed in the European Grid of Solar Observation (EGSO) project. The techniques were applied for detection of sunspots, active regions and filaments in the automatically standardized full-disk solar images in CaII K1, CaII …
Independent Global Modes of Solar Magnetic Field Fluctuations
Lawrence, J. K.; Cadavid, A. C.; Ruzmaikin, A. +1 more
Observed solar, interplanetary and geomagnetic time series contain quasi periodicities on scales of 1-2.5 years. The further discovery of 1.3 year fluctuations in helioseismic observations suggests that a variety of signals may be related to the underlying dynamo in the Sun. We use independent component analysis to study the temporal and spatial v…
Magnetic Clouds Observed at 1 Au During the Period 2000-2003
Nieves-Chinchilla, T.; Hidalgo, M. A.; Sequeiros, J.
In this work we have performed a systematic study of all the magnetic clouds identified in the time interval 2000-2003. The study shows that the non force-free model of Hidalgo is a good approximation to the magnetic topology of the MCs in the interplanetary medium. This conclusion is reached based on the good fits obtained with the model for most…
High-Spatial-Resolution Imaging Combining High-Order Adaptive Optics, Frame Selection, and Speckle Masking Reconstruction
Xu, Yan; Cao, Wenda; Yang, Guo +5 more
We present, for the first time, high-spatial-resolution observations combining high-order adaptive optics (AO), frame selection, and post-facto image correction via speckle masking. The data analysis is based on observations of solar active region NOAA 10486 taken with the Dunn Solar Telescope (DST) at the Sacramento Peak Observatory (SPO) of the …