97 citations · 302 across the 28 of their papers we have counts for
28 papers
Velocity-field estimation techniques for on-disk solar coronal bright fronts (CBFs) and shock-wave propagation
Oleg Stepanyuk, Kamen Kozarev
Coronal mass ejections (CMEs) are large expulsions of plasma and magnetic fields from the solar corona into the heliosphere. Coronal shock waves are driven by CMEs, and accurate So…
Long-Baseline VLF Observations of Solar Flares from Antarctica
Kamen Kozarev, Peter Petkov, Ivaylo Nachev +4
We present long-baseline Very Low Frequency (VLF) observations of solar flare-induced ionospheric disturbances obtained at the Bulgarian Polar Astronomical Observatory (St. Kliment…
The SKA as a Probe of Heliospheric Turbulence and Radio-wave Propagation Effects
Nicolina Chrysaphi, Eduard P. Kontar, Hamish A. S. Reid +3
Density turbulence in the heliosphere can impact traversing radio photons originating from anywhere in the universe, leading to distortions of both the spectroscopic and imaging pr…
Role of SKA in Advancing Remote Measurements of Magnetic Fields of Solar Coronal Mass Ejections
Devojyoti Kansabanik, Surajit Mondal, Shaheda Begum Shaik +13
Coronal Mass Ejections (CMEs) are large expulsions of magnetized plasma from the Sun into interplanetary space and are the primary drivers of extreme space weather variations. The…
Review of Machine Learning Models for Solar Energetic Particle Prediction
Spiridon Kasapis, Pouya Hosseinzadeh, Kathryn Whitman +73
Solar energetic particle (SEP) events have attracted increasing attention due to their significant radiation hazards for aviation, spacecraft electronics, and human missions beyond…
A network for solar optical observations in Bulgaria
Rositsa Miteva, Pencho Markishki, Werner Pötzi +6
The report presents a new initiative for the development of a network of ground-based stations for solar observations in the optical range. Three separate locations in Bulgaria hav…
New Bulgarian-Austrian project 'Joint observations and investigations of solar chromospheric and coronal activity'
Rositsa Miteva, Werner Pötzi, Astrid Veronig +9
We present the bilateral collaboration between Bulgarian and Austrian solar and space weather researchers on the topic of chromospheric and coronal activity. This new project will…
Segmentation and Tracking of Eruptive Solar Phenomena with Convolutional Neural Networks
Oleg Stepanyuk, Kamen Kozarev
Solar eruptive events are complex phenomena, which most often include coronal mass ejections (CME), CME-driven compressive and shock waves, flares, and filament eruptions. CMEs are…
Multi-Instrument Observations and Tracking of a Coronal Mass Ejection Front From Low to Middle Corona
Oleg Stepanyuk, Kamen Kozarev
The shape and dynamics of coronal mass ejections (CMEs) vary significantly based on the instrument and wavelength used. This has led to significant debate about the proper definiti…
Source location and evolution of a multi-lane type II radio burst
P. Zucca, P. Zhang, K. Kozarev +8
Shocks in the solar corona can accelerate electrons that in turn generate radio emission known as type II radio bursts. The characteristics and morphology of these radio bursts in…
Modeling Metric Gyrosynchrotron Radio Emission From the Quiet Solar Corona
Kamen Kozarev, Mohamed Nedal
The radio emission of the quiet Sun in the metric and decametric bands has not been well studied historically due to limitations of existing instruments. It is nominally dominated…
Characterization of the Early Dynamics of Solar Coronal Bright Fronts
Mohamed Nedal, Kamen Kozarev, Rositsa Miteva +2
We present a comprehensive characterization of 26 CME-driven compressive waves known as Coronal Bright Fronts (CBFs) observed in the low solar corona between 2010 and 2017. These C…
Coronal Diagnostics of Solar Type-III Radio Bursts Using LOFAR and PSP Observations
Mohamed Nedal, Kamen Kozarev, Peijin Zhang +1
This study aims to investigate the ambiguous source and the underlying physical processes of the solar type III radio bursts that occurred on April 3, 2019, through the utilization…
Forecasting Solar Energetic Proton Integral Fluxes with Bi-Directional Long Short-Term Memory Neural Networks
Mohamed Nedal, Kamen Kozarev, Nestor Arsenov +1
Solar energetic particles are mainly protons and originate from the Sun during solar flares or coronal shock waves. Forecasting the Solar Energetic Protons (SEP) flux is critical f…
Assessing the spectral characteristics of band splitting type II radio bursts observed by CALLISTO spectrometers
F. N. Minta, S. Nozawa, K. Kozarev +2
Metric type II radio bursts are usually early indicators of CME-driven shocks and other space weather phenomena in the solar corona. This paper presents a detailed investigation of…
RFI Flagging in Solar and Space Weather Low Frequency Radio Observations
Peijin Zhang, André R. Offringa, Pietro Zucca +2
Radio spectroscopy provides a unique inspection perspective for solar and space weather research, which can reveal the plasma and energetic electron information in the solar corona…
Solar radio bursts observations by Egypt- Alexandria CALLISTO spectrometer: First results
F. N. Minta, S. Nozawa, K. Kozarev +2
The newly installed CALLISTO spectrometer, hosted by the Department of Space Environment, Institute of Basic and Applied Sciences- EJUST, commenced operation on August 14, 2021. Th…
Multi-Scale Image Preprocessing and Feature Tracking for Remote CME Characterization
Oleg Stepanyuk, Kamen Kozarev, Mohamed Nedal
Coronal Mass Ejections (CMEs) influence the interplanetary environment over vast distances in the solar system by injecting huge clouds of fast solar plasma and energetic particles…
Imaging of the Quiet Sun in the Frequency Range of 20-80 MHz
PeiJin Zhang, Pietro Zucca, Kamen Kozarev +7
Radio emission of the quiet Sun is considered to be due to thermal bremsstrahlung emission of the hot solar atmosphere. The properties of the quiet Sun in the microwave band have b…
A Multi-Event Study of Early-Stage SEP Acceleration by CME-Driven Shocks -- Sun to 1 AU
Kamen Kozarev, Mohamed Nedal, Rositsa Miteva +2
The solar corona below 10 solar radii is an important region for early acceleration and transport of solar energetic particles (SEPs) by coronal mass ejection-driven shock waves. T…
Comprehensive Characterization of Solar Eruptions With Remote and In-Situ Observations, and Modeling: The Major Solar Events on 4 November 2015
Iver H. Cairns, Kamen A. Kozarev, Nariaki V. Nitta +12
Solar energetic particles (SEPs) are an important product of solar activity. They are connected to solar active regions and flares, coronal mass ejections (CMEs), EUV waves, shocks…
Early-Stage SEP Acceleration by CME-Driven Shocks with Realistic Seed Spectra: I. Low corona
Kamen Kozarev, Maher A. Dayeh, Ashraf Farahat
An outstanding problem in heliospheric physics is understanding the acceleration of solar energetic particles (SEP) in coronal mass ejections (CMEs) and flares. A fundamental quest…
Solar Imaging using Low Frequency Arrays
C. Lonsdale, L. Benkevitch, I. Cairns +8
Low frequency imaging radio arrays such as MWA, LWA and LOFAR have been recently commissioned, and significantly more advanced and flexible arrays are planned for the near term. Th…
The Coronal Analysis of SHocks and Waves (CASHeW) Framework
K. Kozarev, A. Davey, A. Kendrick +2
Coronal Bright Fronts (CBF) are large-scale wavelike disturbances in the solar corona, related to solar eruptions. They are observed in extreme ultraviolet (EUV) light as transient…