Search Publications
Solar jets observed with the Interface Region Imaging Spectrograph (IRIS)
Schmieder, Brigitte; Joshi, Reetika; Chandra, Ramesh
Solar jets are impulsive, collimated plasma ejections that are triggered by magnetic reconnection. They are observed for many decades in various temperatures and wavelengths, therefore their kinematic characteristics, such as velocity and recurrence, have been extensively studied. Nevertheless, the high spatial resolution of the Interface Region I…
Uncovering the process that transports magnetic helicity to coronal mass ejection flux ropes
Pal, Sanchita
Magnetic helicity, an intrinsic property of eruptive helical flux ropes (FRs) forming coronal mass ejections (CMEs), plays an important role in determining CME geoeffectiveness. In the solar atmosphere and heliosphere, helicity remains conserved in a closed volume. Considering this fact as a basis of our study, we perform a quantitative comparison…
Over-expansion of coronal mass ejections modelled using 3D MHD EUHFORIA simulations
Poedts, Stefaan; Scolini, Camilla; Schmieder, Brigitte +5 more
Coronal mass ejections (CMEs) are large scale eruptions observed close to the Sun. They are travelling through the heliosphere and possibly interacting with the Earth environment creating interruptions or even damaging new technology instruments. Most of the time their physical conditions (velocity, density, pressure) are only measured in situ at …
Investigation of the negative ionospheric response of the 8 September 2017 geomagnetic storm over the European sector
Oikonomou, Christina; Haralambous, Haris; Paul, Ashik +4 more
In this study, we investigate the negative ionospheric response over the European sector during two storms that took place on 8 September 2017, primarily, by exploiting observations over ten European locations. The spatial and temporal variations of TEC, foF2 and hmF2 ionospheric characteristics are examined with the aim to explain the physical me…
Gaia astrometric and photometric study of open clusters Dolidze 18 & Ruprecht 70
Tadross, A. L.; Hendy, Y. H.
Here, we conducted a photometric and astrometric study of two open stellar clusters Dolidze 18 and Ruprecht 70, which have not been photometrically studied before. The most important thing for using Gaia (DR2) database lies in the positions, parallax, and proper motions, which make us split cluster members from the field ones and get precise astro…
Flux emergence and generation of flare-productive active regions
Toriumi, Shin
Solar flares and coronal mass ejections are among the most prominent manifestations of the magnetic activity of the Sun. The strongest events of them tend to occur in active regions (ARs) that are large, complex, and dynamically evolving. However, it is not clear what the key observational features of such ARs are, and how these features are produ…
The transport of galactic cosmic rays in heliosphere: The HELMOD model compared with other commonly employed solar modulation models
Gervasi, M.; Rancoita, P. G.; Boschini, M. J. +2 more
HELMOD model allows one to describe how solar modulation affects the propagation of galactic cosmic rays (GCRs) through the heliosphere by solving the Parker transport equation. HELMOD provides modulated spectra for protons and nuclei during high and low solar activity periods, in the inner and outer heliosphere, at Earth location and outside the …
Dielectric characterization and polarimetric analysis of lunar north polar crater Hermite-A using Chandrayaan-1 Mini-SAR, Lunar Reconnaissance Orbiter (LRO) Mini-RF, and Chandrayaan-2 DFSAR data
Chauhan, Prakash; Singh, Awinash; Sharma, Aanchal +5 more
Studies of the lunar surface from Synthetic Aperture Radar (SAR) data have played a prominent role in the exploration of the lunar surface in recent times. This study uses data from SAR sensors from three Moon missions: Chandrayaan-1 Mini-SAR, Lunar Reconnaissance Orbiter (LRO) Mini-RF and Chandrayaan-2 Dual Frequency Synthetic Aperture Radar (DFS…
Solar and interplanetary events that drove two CIR-related geomagnetic storms of 1 June 2013 and 7 October 2015, and their ionospheric responses at the American and African equatorial ionization Anomaly regions
Akala, A. O.; Amaechi, P. O.; Simi, K. G. +3 more
This study investigates the sequence of solar and interplanetary events that drove the 1 June 2013 and October 2015 geomagnetic storms and how the American (68°-78oE) and African (32°-42oE) Equatorial Ionization Anomaly (EIA) regions responded to them. We constructed the EIA structures by using Total Electron Content (TEC) an…
Ionospheric total electron content anomaly possibly associated with the April 4, 2010 Mw7.2 Baja California earthquake
Zhou, Chen; Liu, Jing; Wang, Wenbin +2 more
Identifying ionospheric disturbances potentially related to an earthquake is a challenging work. Based on the ionospheric total electron content (TEC) data from the madrigal database at the Haystack Observatory, Massachusetts Institute of Technology, a new decomposition and nonlinear fitting method has been developed and applied in this work to ex…