Search Publications
Temporal and Periodic Variation of the MCMESI for the Last Two Solar Cycles; Comparison with the Number of Different Class X-ray Solar Flares
Kilcik, Ali; Chowdhury, Partha; Sarp, Volkan +4 more
In this study we compared the temporal and periodic variations of the Maximum CME Speed Index (MCMESI) and the the number of different class (C, M, and X) solar X-ray flares for the last two solar cycles (Solar Cycles 23 and 24). To obtain the correlation between the MCMESI and solar flare numbers the cross-correlation analysis was applied to mont…
Correlations of Sunspot Physical Characteristics during Solar Cycle 23
Valio, Adriana; Spagiari, Eduardo; Marengoni, Mauricio +1 more
The behavior of sunspots is governed by the magnetic dynamo acting deep within the convection zone of the Sun. Therefore, knowledge of sunspot physical characteristics and how they evolve in time during a solar cycle can help to improve our understanding of the solar magnetic behavior. This work analyzes the physical characteristics of sunspots du…
A Catalog of Bipolar Active Regions Violating the Hale Polarity Law, 1989 - 2018
Zhukova, Anastasiya; Sokoloff, Dmitry; Abramenko, Valentina +1 more
There is no list of bipolar active regions (ARs) with reverse polarity (anti-Hale regions), although statistical investigations of such ARs (bearing the imprint of deep subphotospheric processes) are important for understanding solar-cycle mechanisms. We studied 8606 ARs from 1 January 1989 to 31 December 2018 to detect anti-Hale regions and to co…
Data-Driven Classification of Coronal Hole and Streamer Belt Solar Wind
Macneil, Allan R.; Owens, Mathew; Bloch, Téo +2 more
We present two new solar wind origin classification schemes developed independently using unsupervised machine learning. The first scheme aims to classify solar wind into three types: coronal-hole wind, streamer-belt wind, and `unclassified' which does not fit into either of the previous two categories. The second scheme independently derives thre…
Investigation of the Middle Corona with SWAP and a Data-Driven Non-Potential Coronal Magnetic Field Model
West, Matthew J.; Meyer, Karen A.; Upton, Lisa A. +2 more
The large field-of-view of the Sun Watcher using Active Pixel System detector and Image Processing (SWAP) instrument onboard the PRoject for Onboard Autonomy 2 (PROBA2) spacecraft provides a unique opportunity to study extended coronal structures observed in the EUV in conjunction with global coronal magnetic field simulations. A global non-potent…
Estimate of Plasma Temperatures Across a CME-Driven Shock from a Comparison Between EUV and Radio Data
Frassati, Federica; Mancuso, Salvatore; Bemporad, Alessandro
In this work, we analyze the evolution of an EUV wave front associated with a solar eruption that occurred on 30 October 2014, with the aim of investigating, through differential emission measure (DEM) analysis, the physical properties of the plasma compressed and heated by the accompanying shock wave. The EUV wave was observed by the Atmospheric …
New Homogeneous Dataset of Solar EUV Synoptic Maps from SOHO/EIT and SDO/AIA
Asikainen, T.; Mursula, K.; Hamada, A.
Synoptic maps of solar EUV intensities have been constructed for many decades in order to display the distribution of the different EUV emissions across the solar surface, with each map representing one Carrington rotation (i.e. one rotation of the Sun). This article presents a new solar EUV synoptic map dataset based on full-disk images from the …
Three-Dimensional Reconstructions of Coronal Wave Surfaces Using a New Mask-Fitting Method
Feng, Li; Lu, Lei; Gan, Weiqun +5 more
Coronal waves are large-scale disturbances often driven by coronal mass ejections (CMEs). We investigate a spectacular wave event on 7 March 2012, which is associated with an X5.4 flare (SOL2012-03-07). By using a running center-median (RCM) filtering method for the detection of temporal variations in extreme ultraviolet (EUV) images, we enhance t…
The Solar Event of 14 - 15 July 2012 and Its Geoeffectiveness
Gil, Agnieszka; Modzelewska, Renata; Moskwa, Szczepan +5 more
During Solar Cycle 24, which started at the end of 2008, the Sun was calm, and there were not many spectacular geoeffective events. In this article, we analyze the geomagnetic storm that happened on 15 July 2012 during the 602nd anniversary of the Polish Battle of Grunwald, thus we propose this event to be called the "Battle of Grunwald Day Storm"…
Temporal and Spatial Scales in Coronal Rain Revealed by UV Imaging and Spectroscopic Observations
Toriumi, Shin; Antolin, Patrick; Katsukawa, Yukio +1 more
Coronal rain corresponds to cool and dense clumps in the corona accreting towards the solar surface; it is often observed above solar active regions. These clumps are generally thought to be produced by a thermal instability in the corona and their lifetime is limited by the time they take to reach the chromosphere. Although the rain usually fragm…