Search Publications
> 25 MeV Proton Events Observed by the High Energy Telescopes on the STEREO A and B Spacecraft and/or at Earth During the First ∼ Seven Years of the STEREO Mission
Christian, E. R.; Leske, R. A.; Labrador, A. W. +7 more
Using observations from the High Energy Telescopes (HETs) on the STEREO A and B spacecraft and similar observations from near-Earth spacecraft, we summarize the properties of more than 200 individual > 25 MeV solar proton events, some detected by multiple spacecraft, that occurred from the beginning of the STEREO mission in October 2006 to Dece…
Multi-Scale Gaussian Normalization for Solar Image Processing
Morgan, Huw; Druckmüller, Miloslav
Extreme ultra-violet images of the corona contain information over a wide range of spatial scales, and different structures such as active regions, quiet Sun, and filament channels contain information at very different brightness regimes. Processing of these images is important to reveal information, often hidden within the data, without introduci…
A Multi-Observatory Inter-Comparison of Line-of-Sight Synoptic Solar Magnetograms
Liu, Y.; Riley, P.; Hoeksema, T. +7 more
The observed photospheric magnetic field is a crucial parameter for understanding a range of fundamental solar and heliospheric phenomena. Synoptic maps, in particular, which are derived from the observed line-of-sight photospheric magnetic field and built up over a period of 27 days, are the main driver for global numerical models of the solar co…
Three-Dimensional Evolution of Flux-Rope CMEs and Its Relation to the Local Orientation of the Heliospheric Current Sheet
Kilpua, E. K. J.; Vourlidas, A.; Isavnin, A.
Flux ropes ejected from the Sun may change their geometrical orientation during their evolution, which directly affects their geoeffectiveness. Therefore, it is crucial to understand how solar flux ropes evolve in the heliosphere to improve our space-weather forecasting tools. We present a follow-up study of the concepts described by Isavnin, Vour…
Coronal Mass Ejections and Non-recurrent Forbush Decreases
Gopalswamy, N.; Mavromichalaki, H.; Papaioannou, A. +7 more
Coronal mass ejections (CMEs) and their interplanetary counterparts (interplanetary coronal mass ejections, ICMEs) are responsible for large solar energetic particle events and severe geomagnetic storms. They can modulate the intensity of Galactic cosmic rays, resulting in non-recurrent Forbush decreases (FDs). We investigate the connection betwee…
Comparative Study of MHD Modeling of the Background Solar Wind
Temmer, M.; Veronig, A. M.; Riley, P. +4 more
Knowledge about the background solar wind plays a crucial role in the framework of space-weather forecasting. In-situ measurements of the background solar wind are only available for a few points in the heliosphere where spacecraft are located, therefore we have to rely on heliospheric models to derive the distribution of solar-wind parameters in …
Coronal Magnetic Field Evolution from 1996 to 2012: Continuous Non-potential Simulations
Yeates, A. R.
Coupled flux transport and magneto-frictional simulations are extended to simulate the continuous magnetic-field evolution in the global solar corona for over 15 years, from the start of Solar Cycle 23 in 1996. By simplifying the dynamics, our model follows the build-up and transport of electric currents and free magnetic energy in the corona, off…
Abundance Enhancements in Impulsive Solar Energetic-Particle Events with Associated Coronal Mass Ejections
Reames, Donald V.; Kahler, Stephen W.; Cliver, Edward W.
We study the abundances of the elements He through Pb in Fe-rich impulsive solar energetic-particle (SEP) events with measurable abundances of ions with atomic number Z>2 observed on the Wind spacecraft, and their relationship with coronal mass ejections (CMEs) observed by the Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar …
Solar Sources of Interplanetary Coronal Mass Ejections During the Solar Cycle 23/24 Minimum
Mierla, M.; Zhukov, A. N.; Rodriguez, L. +3 more
We examine solar sources for 20 interplanetary coronal mass ejections (ICMEs) observed in 2009 in the near-Earth solar wind. We performed a detailed analysis of coronagraph and extreme ultraviolet (EUV) observations from the Solar Terrestrial Relations Observatory (STEREO) and Solar and Heliospheric Observatory (SOHO). Our study shows that the cor…
Statistical Analysis of Large-Scale EUV Waves Observed by STEREO/EUVI
Temmer, M.; Veronig, A. M.; Vršnak, B. +3 more
We statistically analyzed the kinematical evolution and wave pulse characteristics of 60 strong large-scale EUV wave events that occurred during January 2007 to February 2011 with the STEREO twin spacecraft. For the start velocity, the arithmetic mean is 312±115 km s−1 (within a range of 100 - 630 km s−1). For the mean (linea…