Search Publications
Interplanetary and Geomagnetic Consequences of Interacting CMEs of 13 - 14 June 2012
Srivastava, Nandita; Mishra, Wageesh; Chakrabarty, D.
We report on the kinematics of two interacting CMEs observed on 13 and 14 June 2012. The two CMEs originated from the same active region NOAA 11504. After their launches which were separated by several hours, they were observed to interact at a distance of 100 R⊙ from the Sun. The interaction led to a moderate geomagnetic storm at the E…
High-Speed Solar Wind Streams and Geomagnetic Storms During Solar Cycle 24
Mavromichalaki, H.; Gerontidou, M.; Daglis, T.
An updated catalog is created of 303 well-defined high-speed solar wind streams that occurred in the time period 2009 - 2016. These streams are identified from solar and interplanetary measurements obtained from the OMNIWeb database as well as from the Solar and Heliospheric Observatory (SOHO) database. This time interval covers the deep minimum o…
Evolution of CME Mass in the Corona
Vourlidas, Angelos; Howard, Russell A.
The idea that coronal mass ejections (CMEs) pile up mass in their transport through the corona and heliosphere is widely accepted. However, it has not been shown that this is the case. We perform an initial study of the volume electron density of the fronts of 13 three-part CMEs with well-defined frontal boundaries observed with the Solar and Heli…
Statistical Analysis of Solar Events Associated with Storm Sudden Commencements over One Year of Solar Maximum During Cycle 23: Propagation from the Sun to the Earth and Effects
Pick, M.; Pitout, F.; Bocchialini, K. +9 more
Taking the 32 storm sudden commencements (SSCs) listed by the International Service of Geomagnetic Indices (ISGI) of the Observatory de l'Ebre during 2002 (solar activity maximum in Cycle 23) as a starting point, we performed a multi-criterion analysis based on observations (propagation time, velocity comparisons, sense of the magnetic field rotat…
Single ICMEs and Complex Transient Structures in the Solar Wind in 2010 - 2011
Zhukov, A. N.; Slemzin, V.; Goryaev, F. +3 more
We analyze the statistics, solar sources, and properties of interplanetary coronal mass ejections (ICMEs) in the solar wind. The total number of coronal mass ejections (CMEs) registered in the Coordinated Data Analysis Workshops catalog (CDAW) during the first eight years of Cycle 24 was 61% larger than in the same period of Cycle 23, but the numb…
An Anisotropic Cosmic-Ray Enhancement Event on 07-June-2015: A Possible Origin
Usoskin, Ilya G.; Gil, Agnieszka; Mishev, Alexander +3 more
A usual event, called anisotropic cosmic-ray enhancement (ACRE), was observed as a small increase (≤5 % ) in the count rates of polar neutron monitors during 12 - 19 UT on 07 June 2015. The enhancement was highly anisotropic, as detected only by neutron monitors with asymptotic directions in the southwest quadrant in geocentric solar ecliptic (GSE…
Physical Processes Involved in the EUV "Surge" Event of 9 May 2012
Démoulin, Pascal; Mandrini, Cristina H.; López Fuentes, Marcelo +4 more
We study an extreme ultraviolet (EUV) confined ejection observed on 9 May 2012 in Active Region (AR) NOAA 11476. For the analysis we use observations in multiple wavelengths (EUV, X-rays, Hα , and magnetograms) from a variety of ground- and space-based instruments. The magnetic configuration showed two rotating bipoles within the following polarit…
Onboard Automated CME Detection Algorithm for the Visible Emission Line Coronagraph on ADITYA-L1
Pant, Vaibhav; Banerjee, Dipankar; Sankarasubramanian, K. +3 more
ADITYA-L1 is India's first space mission to study the Sun from the Lagrange 1 position. The Visible Emission Line Coronagraph (VELC) is one of seven payloads on the ADITYA-L1 mission, which is scheduled to be launched around 2020. One of the primary objectives of the VELC is to study the dynamics of coronal mass ejections (CMEs) in the inner coron…
The 2015 Summer Solstice Storm: One of the Major Geomagnetic Storms of Solar Cycle 24 Observed at Ground Level
Augusto, C. R. A.; Navia, C. E.; de Oliveira, M. N. +8 more
We report on the 22 - 23 June 2015 geomagnetic storm that occurred at the summer solstice. There have been fewer intense geomagnetic storms during the current solar cycle, Solar Cycle 24, than in the previous cycle. This situation changed after mid-June 2015, when one of the largest solar active regions (AR 12371) of Solar Cycle 24 that was locate…
Estimate of the Upper Limit on Hot Plasma Differential Emission Measure (DEM) in Non-Flaring Active Regions and Nanoflare Frequency Based on the Mg XII Spectroheliograph Data from CORONAS-F/SPIRIT
Reva, Anton; Ulyanov, Artem; Kirichenko, Alexey +2 more
Nanoflare-heating theory predicts steady hot-plasma emission in non-flaring active regions. It is hard to find this emission with conventional non-monochromatic imagers (such as the Atmospheric Imaging Assembly or the X-Ray Telescope), because their images contain a cool-temperature background. In this work, we search for hot plasma in non-flaring…