Search Publications
Wave-like Formation of Hot Loop Arcades
Shestov, S.; Kuzin, S.; Zimovets, I. +2 more
We present observations of hot arcades made with the Mg XII spectroheliograph onboard the CORONAS-F mission, which provides monochromatic images of hot plasma in the Mg XII 8.42 Å resonance line. The arcades were observed to form above the polarity inversion line between active regions NOAA 09847 and 09848 at four successive episodes: at 09:18, 14…
Kinematics of ICMEs/Shocks: Blast Wave Reconstruction Using Type-II Emissions
Aguilar-Rodriguez, E.; Corona-Romero, P.; Gonzalez-Esparza, J. A. +2 more
We present a physical methodology for reconstructing the trajectory of interplanetary shocks using Type-II radio emission data. This technique calculates the shock trajectory assuming that the disturbance propagates as a blast wave in the interplanetary medium. We applied this blast-wave reconstruction (BWR) technique to analyze eight fast Earth-d…
Mid-Term Quasi-Periodicities and Solar Cycle Variation of the White-Light Corona from 18.5 Years (1996.0 - 2014.5) of LASCO Observations
Llebaria, A.; Lamy, P.; Barlyaeva, T.
We report on the analysis of the temporal evolution of the solar corona based on 18.5 years (1996.0 - 2014.5) of white-light observations with the SOHO/LASCO-C2 coronagraph. This evolution is quantified by generating spatially integrated values of the K-corona radiance, first globally, then in latitudinal sectors. The analysis considers time serie…
Fine and Superfine Structure of the Decameter-Hectometer Type II Burst on 7 June 2011
Panchenko, M.; Poedts, S.; Konovalenko, A. A. +4 more
The characteristics of a type II burst with a herringbone structure observed both with ground-based radio telescopes (UTR-2 and URAN-2) and space-borne spectrometers (STEREO-A and B) are discussed. The burst was recorded on 7 June 2011 in the frequency band 3 - 33 MHz. It was characterized by extremely rich fine structure. Statistical analysis of …
Dynamics of Microwave Sources Associated with the Neutral Line and the Magnetic-Field Parameters of Sunspots as a Factor in Predicting Large Flares
Abramov-Maximov, V. E.; Borovik, V. N.; Opeikina, L. V. +1 more
We studied the evolution of five active regions (ARs) where strong X-class flares occurred in 2011 - 2012 (NOAA ARs 11158, 11166, 11263, 11283 and 11520). Our study focuses on the pre-flare phase of these ARs (during a few days before the flare) to reveal features in the microwave radiation and magnetic-field characteristics of the ARs that indica…
Ensemble Modeling of Successive Halo CMEs: A Case Study
Arge, C. N.; Odstrcil, D.; Pizzo, V. +3 more
The Wang-Sheeley-Arge (WSA)-Enlil cone modeling system is used for making routine arrival-time forecasts of Earth-directed halo coronal mass ejections (CMEs), since they typically produce the most geoeffective events. A major objective of this work is to better understand the sensitivity of the WSA-Enlil modeling results to input model parameters …
The Properties of the Tilts of Bipolar Solar Regions
Tlatov, A.; Illarionov, E.; Sokoloff, D.
We investigate various properties associated with the tilt of isolated magnetic bipoles in magnetograms taken at the solar surface. We show that bipoles can be divided into two groups that have tilts of opposite signs, and reveal similar properties with respect to bipole area, flux, and bipolar moment. Detailed comparison of these physical quantit…
Update of the Photometric Calibration of the LASCO-C2 Coronagraph Using Stars
Howard, R. A.; Colaninno, R. C.
We present an update to the photometric calibration of the LASCO-C2 coronagraph onboard the SOHO spacecraft. We obtained the new calibration using data from the beginning of the mission in 1996 until 2013. We re-examined the LASCO-C2 photometric calibration by comparing the past three calibrations and the present calibration with the goal of valid…
Calibration of Hinode/XRT for Coalignment
McKenzie, David E.; Yoshimura, Keiji
We present coalignment calibration procedures for the X-ray Telescope (XRT) onboard the Hinode satellite. We performed not only an XRT stand-alone calibration, but also cross calibration using data from the Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). Several new me…
Empirical Relationship Between CME Parameters and Geo-effectiveness of Halo CMEs in the Rising Phase of Solar Cycle 24 (2011 - 2013)
Moon, Y. -J.; Shanmugaraju, A.; Umapathy, S. +2 more
We analyzed the physical characteristics of 40 halo coronal mass ejections (CMEs) and their geo-effective parameters observed during the period 2011 to 2013 in the rising phase of Solar Cycle 24. Out of all halo CMEs observed by SOHO/LASCO, we selected 40 halo CMEs and investigated their geomagnetic effects. In particular, we estimated the CME dir…