Search Publications
Latitudinal distribution of solar coronal active regions
Chargeishvili, B. B.; Maghradze, D. A.; Japaridze, D. R. +3 more
We studied the cyclic evolution of the latitudinal distribution of solar coronal active regions based on daily images from SOHO EIT for the period 1995-2017. Fully automated software was used, which included the following steps: initial preparation of images in the data series, normalization of histograms and correction of limb brightening, segmen…
Insights from multi-wavelength observations during high and low states of non-magnetic CVs
Szkody, Paula
Close binaries containing a white dwarf accreting from a disk that receives material from a late stellar companion show an interesting variety of behaviors that depend on their accretion rates and the changes in this rate. The highest accretion rates are evident during the bright states of novalikes, as well as the superoutbursts of the shortest p…
Chirality and magnetic configuration associated with two-ribbon solar flares: AR 10930 versus AR 11158
Chen, P. F.; Li, Bo; Yan, Yihua +2 more
The structural property of the magnetic field in flare-bearing solar active regions (ARs) is one of the key aspects for understanding and forecasting solar flares. In this paper, we make a comparative analysis on the chirality and magnetic configurations associated with two X-class two-ribbon flares happening in AR 10930 and AR 11158. The photosph…
Automated crater detection algorithms from a machine learning perspective in the convolutional neural network era
DeLatte, D. M.; Crites, S. T.; Guttenberg, N. +1 more
Convolutional Neural Networks (CNN) offer promising opportunities to automatically glean scientifically relevant information directly from annotated images, without needing to handcraft features for detection. Crater counting started with hand counting hundreds, thousands, or even millions of craters in order to determine the age of geological uni…
Numerical integration of stochastic differential equations: A parallel cosmic ray modulation implementation on Africa's fastest computer
Moeketsi, D. M.; Engelbrecht, N. E.; Strauss, R. D. +2 more
Three-dimensional studies of the transport and modulation of cosmic ray particles in turbulent astrospheres require large-scale simulations using specialized scientific codes. Essentially, a multi-dimensional Fokker-Planck type equation (a parabolic diffusion equation) must be integrated numerically. One such approach is to convert the relevant tr…
First solar observations with ALMA
Loukitcheva, Maria
The Atacama Large Millimeter-Submillimeter Array (ALMA) has opened a new window for studying the Sun via high-resolution high-sensitivity imaging at millimeter wavelengths. In this contribution I review the capabilities of the instrument for solar observing and describe the extensive effort taken to bring the possibility of solar observing with AL…
LISA Pathfinder mission extension: A feasibility analysis
Rasotto, Mirco; Renk, Florian; Dei Tos, Diogene A. +1 more
A proposed mission extension for LISA Pathfinder involved redirecting the probe to the Sun-Earth gravitational saddle point. Realistic models for both space and ground segments were used to carry out a number of analyses for trajectory design, orbit determination, and navigation cost. In this work, we present the methods that allow assessing the f…
The dynamic chromosphere: Pushing the boundaries of observations and models
Pereira, Tiago M. D.
The interface between the bright solar surface and the million-degree corona continues to hold the key to many unsolved problems in solar physics. Advances in instrumentation now allow us to observe the dynamic structures of the solar chromosphere down to less than 0.″1 with cadences of just a few seconds and in multiple pola…
Solar irradiance, climatic indicators and climate change - An empirical analysis
Singh, A. K.; Bhargawa, Asheesh
Since the Sun is the main source of energy for our planet therefore even a slight change in its output energy can make a huge difference in the climatic conditions of the terrestrial environment. The rate of energy coming from the Sun (solar irradiance) might affect our climate directly by changing the rate of solar heating of the Earth and the at…
Data-driven modelling of the Van Allen Belts: The 5DRBM model for trapped electrons
Kretschmar, Peter; Ness, Jan-Uwe; Kuulkers, Erik +10 more
The magnetosphere sustained by the rotation of the Earth's liquid iron core traps charged particles, mostly electrons and protons, into structures referred to as the Van Allen Belts. These radiation belts, in which the density of charged energetic particles can be very destructive for sensitive instrumentation, have to be crossed on every orbit of…