Search Publications
Solar Energetic Particle Events with Protons Above 500 MeV Between 1995 and 2015 Measured with SOHO/EPHIN
Dresing, N.; Heber, B.; Kühl, P. +1 more
The Sun is an effective particle accelerator that produces solar energetic particle (SEP) events, during which particles of up to several GeVs can be observed. These events, when they are observed at Earth with the neutron monitor network, are called ground-level enhancements (GLEs). Although these events with their high-energy component have been…
Origin and Ion Charge State Evolution of Solar Wind Transients during 4 - 7 August 2011
Slemzin, V.; Goryaev, F.; Pagano, P. +5 more
We present a study of the complex event consisting of several solar wind transients detected by the Advanced Composition Explorer (ACE) on 4 - 7 August 2011, which caused a geomagnetic storm with Dst =−110 nT. The supposed coronal sources, three flares and coronal mass ejections (CMEs), occurred on 2 - 4 August 2011 in active region (AR) 11261. To…
A Statistical Analysis of the Solar Phenomena Associated with Global EUV Waves
Long, D. M.; Carley, E. P.; Pérez-Suárez, D. +2 more
Solar eruptions are the most spectacular events in our solar system and are associated with many different signatures of energy release including solar flares, coronal mass ejections, global waves, radio emission and accelerated particles. Here, we apply the Coronal Pulse Identification and Tracking Algorithm (CorPITA) to the high-cadence synoptic…
A Relationship Between the Solar Rotation and Activity Analysed by Tracing Sunspot Groups
Ruždjak, Domagoj; Brajša, Roman; Skokić, Ivica +2 more
The sunspot position published in the data bases of the Greenwich Photoheliographic Results (GPR), the US Air Force Solar Optical Observing Network and National Oceanic and Atmospheric Administration (USAF/NOAA), and of the Debrecen Photoheliographic Data (DPD) in the period 1874 to 2016 were used to calculate yearly values of the solar differenti…
Understanding Problem Forecasts of ISEST Campaign Flare-CME Events
Nitta, Nariaki; Webb, David
The goal of the International Study of Earth-affecting Solar Transients (ISEST) project as part of the Variability of the Sun and Its Terrestrial Impact (VarSITI) program is to understand the origin, evolution, and propagation of solar transients through the space between the Sun and Earth, and to improve our prediction capability for space weathe…
A Helioseismic Perspective on the Depth of the Minimum Between Solar Cycles 23 and 24
Broomhall, A. -M.
The minimum in the solar-activity cycle observed between Cycles 23 and 24 is generally regarded as being unusually deep and long. This minimum is being followed by a cycle with one of the smallest amplitudes in recent history. We perform an in-depth analysis of this minimum with helioseismology. We use Global Oscillation Network Group (GONG) data …
Observations and Modelling of the Pre-flare Period of the 29 March 2014 X1 Flare
Long, D. M.; Harra, L. K.; Matthews, S. A. +3 more
On 29 March 2014, NOAA Active Region (AR) 12017 produced an X1 flare that was simultaneously observed by an unprecedented number of observatories. We have investigated the pre-flare period of this flare from 14:00 UT until 19:00 UT using joint observations made by the Interface Region Imaging Spectrometer (IRIS) and the Hinode Extreme Ultraviolet …
Variation in Coronal Activity from Solar Cycle 24 Minimum to Maximum Using Three-Dimensional Reconstructions of the Coronal Electron Density from STEREO/COR1
Thompson, William T.; Davila, Joseph M.; Wang, Tongjiang +2 more
Three-dimensional electron density distributions in the solar corona are reconstructed for 100 Carrington rotations (CR 2054 - 2153) during 2007/03 - 2014/08 using the spherically symmetric method from polarized white-light observations with the inner coronagraph (COR1) onboard the twin Solar Terrestrial Relations Observatory (STEREO). These three…
Interplanetary Coronal Mass Ejections Resulting from Earth-Directed CMEs Using SOHO and ACE Combined Data During Solar Cycle 23
Paouris, Evangelos; Mavromichalaki, Helen
In this work a total of 266 interplanetary coronal mass ejections observed by the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph (SOHO/LASCO) and then studied by in situ observations from Advanced Composition Explorer (ACE) spacecraft, are presented in a new catalog for the time interval 1996 - 2009 covering Solar Cyc…
The Relation Between Magnetic Fields and X-ray Emission for Solar Microflares and Active Regions
Kirichenko, A. S.; Bogachev, S. A.
We present the result of a comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we used the monochromatic MgXII Imaging Spectroheliometer (MISH), the Full-disk EUV Telescope (FET), and the Sol…