Search Publications
Oscillations in the 45 - 5000 MHz Radio Spectrum of the 18 April 2014 Flare
Monstein, Christian; Rybák, Ján; Karlický, Marian
Using a new type of oscillation map, made from the radio spectra by the wavelet technique, we study the 18 April 2014 M7.3 flare (SOL2014-04-18T13:03:00L245C017). We find a quasi-periodic character of this flare with periods in the range 65 - 115 seconds. At the very beginning of this flare, in connection with the drifting pulsation structure (pla…
Intermittency of the Solar Magnetic Field and Solar Magnetic Activity Cycle
Obridko, V. N.; Sokoloff, D. D.; Shibalova, A. S.
Small-scale solar magnetic fields demonstrate features of fractal intermittent behavior, which requires quantification. For this purpose we investigate how the observational estimate of the solar magnetic flux density B depends on resolution D in order to obtain the scaling lnBD=−k lnD +a in a reasonably wide range. The quantity k demon…
Measurement of Solar Neutrons on 05 March 2012, Using a Fiber-Type Neutron Monitor Onboard the Attached Payload to the ISS
Masuda, S.; Muraki, Y.; Kawano, H. +3 more
The solar neutron detector Space Environment Data Acquisition Equipment - Attached Payload (SEDA-FIB) onboard the International Space Station (ISS) detected several events from the solar direction associated with three large solar flares observed on 05 (X1.1), 07 (X5.4), and 09 (M6.3) March 2012. In this study, we focus on the interesting event of…
Temporal Variations in Solar Irradiance Since 1947
Tebabal, A.; Damtie, B.; Nigussie, M. +1 more
The study of variations in total solar irradiance (TSI) and spectral irradiance is important for understanding how the Sun affects the Earth's climate. A data-driven approach is used in this article to analyze and model the temporal variation of the TSI and Mg II index back to 1947. In both cases, observed data in the time interval of the satellit…
Validation of the CME Geomagnetic Forecast Alerts Under the COMESEP Alert System
Dumbović, Mateja; Vršnak, Bojan; Rao, Yamini K. +3 more
Under the European Union 7th Framework Programme (EU FP7) project Coronal Mass Ejections and Solar Energetic Particles (COMESEP, http://comesep.aeronomy.be), an automated space weather alert system has been developed to forecast solar energetic particles (SEP) and coronal mass ejection (CME) risk levels at Earth. The COMESEP alert system uses the …
Formation of Radio Type II Bursts During a Multiple Coronal Mass Ejection Event
Valtonen, Eino; Pohjolainen, Silja; Al-Hamadani, Firas
We study the solar event on 27 September 2001 that consisted of three consecutive coronal mass ejections (CMEs) originating from the same active region, which were associated with several periods of radio type II burst emission at decameter-hectometer (DH) wavelengths. Our analysis shows that the first radio burst originated from a low-density env…
Investigation on M-class Flare-Associated Coronal Mass Ejections with and Without DH Type II Radio Bursts
Shanmugaraju, A.; Selvarani, G.; Lawrance, M. Bendict +1 more
We perform a statistical analysis on 157 M-class soft X-ray flares observed during 1997 - 2014 with and without deca-hectometric (DH) type II radio bursts aiming at the reasons for the non-occurrence of DH type II bursts in certain events. All the selected events are associated with halo Coronal Mass Ejections (CMEs) detected by the Solar and Heli…
Multi-label Learning for Detection of CME-Associated Phenomena
Yang, Y. H.; Xie, Z. X.; Peng, B. +2 more
Coronal mass ejections (CMEs) are considered as one of the driving sources of space weather. They are usually associated with many physical phenomena, e.g. flares, coronal dimmings, and sigmoids. To detect these phenomena, traditional supervised-learning methods assumed that at most one event occurred in a CME; therefore each CME instance is assoc…
Long- and Mid-Term Variations of the Soft X-ray Flare Type in Solar Cycles
Chertok, I. M.; Belov, A. V.
Using data from the Geostationary Operational Environmental Satellites (GOES) spacecraft in the 1 - 8 Å wavelength range for Solar Cycles 23, 24, and part of Cycles 21 and 22, we compare mean temporal parameters (rise and decay times, and duration) and the proportion of impulsive short-duration events (SDE) and gradual long-duration events (LDE) a…
A Long-Term Decrease of the Mid-Size Segmentation Lengths Observed in the He II (30.4 nm) Solar EUV Emission
Didkovsky, Leonid; Wieman, Seth; Korogodina, Elena
Power spectra of segmentation-cell length (a dominant length scale of EUV emission in the transition region) from full-disk He II extreme ultraviolet (EUV) images observed by the Extreme ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Ob…