Search Publications
A detailed comparison of techniques used to model drift in numerical cosmic ray modulation models
Ferreira, S. E. S.; Engelbrecht, N. Eugene; Mohlolo, S. T.
Drifts have long been known to play a significant role in the transport and modulation of galactic cosmic rays (GCRs), occurring due to gradients in, as well as the curvature of, the heliospheric magnetic field (HMF). GCRs also drift along the wavy current sheet, a structure separating regions of opposite HMF polarity. Furthermore, the influence o…
Complex network view to solar flare asymmetric activity
Taran, Somayeh; Khodakarami, Edris; Safari, Hossein
Asymmetric behavior of the solar hemispheres is an essential aspect of the activity. This paper uses a complex network approach to study the solar flare asymmetric activity in two hemispheres. We construct a network based on the locations and flare flux (GOES flux classification) from 2008 December to 2019 December for 4033 and 4725 flares on the …
Enthalpy-based modeling of tomographically reconstructed quiet-Sun coronal loops
Mandrini, C. H.; Vásquez, A. M.; Mac Cormack, C. +2 more
The structure of the solar corona is made of magnetic flux tubes or loops. Due to the lack of contrast with their environment, observing and studying coronal loops in the quiet Sun is extremely difficult. In this work we use a differential emission measure tomographic (DEMT) technique to reconstruct, from a series of EUV images covering an entire …
Theoretical studies of low and high frequency electrostatic solitary waves in the magnetopause associated with asymmetric magnetic reconnection
Bharuthram, R.; Rufai, O. R.; Maharaj, S. K.
In a comprehensive analysis of Cluster data, Graham et al. (2015) have reported the existence of slow and fast electrostatic solitary waves (ESWs) associated with asymmetric magnetic reconnection arising from the merger of the magnetic fields, and mixing, of the hot tenuous magnetospheric plasma and the cooler dense magnetosheath plasma. Their ana…
Detection of the third innermost radiation belt on LEO CORONAS-Photon satellite around 2009 solar minimum
Phillips, Kenneth J. H.; Sylwester, Janusz; Dudnik, Oleksiy V. +2 more
We analyze variations of high energy charged particle populations filling various magnetospheric regions under, inside and outside of the Van Allen inner and outer electron radiation belts in May 2009. The study is based on the experimental data obtained from the STEP-F and the SphinX instruments placed close to each other aboard the low-Earth cir…
A study of the characteristic properties of SEP events observed by SOHO ERNE during solar cycle 24
Biji, M. S.; Prince, P. R.
Properties and association of Solar Energetic Particle (SEP) events with their solar sources during the 24th solar cycle were examined. SEPs observed by SOHO ERNE were used. SEP properties include solar release time, peak proton flux and total fluence in different energy channels. Solar release times of SEP events were found out using Velocity Dis…
Machine learning for effective spacecraft operation: Operating INTEGRAL through dynamic radiation environments
Finn, Timothy; Southworth, Richard; Donati, Alessandro +8 more
INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) is an astronomical observatory of the European Space Agency, responsible for many significant scientific discoveries in the last few decades. It orbits Earth since 2002 in a highly elliptical orbit, passing through the Van Allen belts - areas with high-energy ionized particles that can dam…
The 6.7 keV thermal emission lines in the stellar flare spectra of two chromospherically active Binaries: Algol and GT Mus
Eze, Ambrose Chukwudi; Esaenwi, Sudum; Madu, Fidelis Okey
Chromospherically active binaries' (CABs) are late-type evolved stars with strong chromosphere/coronae and high flare activity levels. Starspot evolution in these CABs and binaries reveals strong stellar and chromospheric activities. In binaries, the tidal interaction via the internal dynamo motion, during rapid rotation of the component stars gen…
Episodic and declining fluvial processes in Noctis Fossae, Syria Planum Province, Mars
Chavan, Anil; Sarkar, Subham; Bhandari, Subhash
The Noachian surfaces across Mars bear abundant evidence for aqueous processes; however, the transformation of the planet from warm and wet to the present-day cold and dry is unclear. A key question is whether these processes continued by the same or different magnitudes in the Hesperian and Amazonian times. The equatorial region of Mars has exten…
Plasma vortices driven by magnetic torsion generated by electric currents in non-magnetic planetary wakes
Flandes, Alberto; Durand-Manterola, Héctor Javier
In non-collisional magnetised astrophysical plasmas, vortices can form as it is the case of the Venus plasma wake where Lundin et al. (2013) identified a large vortex through the integration of data of many orbits from the Venus Express (VEX) spacecraft. On the one hand, our purpose is to develop a theoretical foundation in order to explain the oc…