Article
Astronomy & Astrophysics
G. Qin, S. -S. Wu
Summary: Forbush decreases (Fds) in galactic cosmic ray intensity are related to interplanetary coronal mass ejections (ICMEs), with particles being partially blocked in the sheath-MC structure due to enhanced magnetic focusing effect. Simulation results conform to the main characteristics of Fd observations, suggesting that both magnetic turbulence and background magnetic field in the sheath-MC structure are important for reproducing the observed two-step Fd.
ASTROPHYSICAL JOURNAL
(2021)
Article
Geosciences, Multidisciplinary
Jingnan Guo, Xiaolei Li, Jian Zhang, Mikhail I. Dobynde, Yuming Wang, Zigong Xu, Thomas Berger, Jordanka Semkova, Robert F. Wimmer-Schweingruber, Donald M. Hassler, Cary Zeitlin, Bent Ehresmann, Daniel Matthiae, Bin Zhuang
Summary: On 28 October 2021, solar eruptions caused intense and long-lasting enhancements in solar energetic particle (SEP) flux observed by spacecraft across the heliosphere. The arrival of SEPs at Earth resulted in the 73rd ground level enhancement (GLE) event recorded by ground-based neutron monitors. Notably, this study presents the first GLE event detected on the surfaces of Earth, Moon, and Mars, using particle and radiation detectors. By analyzing data from near-Earth spacecraft, the event-integrated proton spectrum is determined, and particle transport models are employed to predict radiation levels on the lunar and martian surfaces. Additionally, previous GLE event doses on the Moon and Mars are modeled and compared with the current event, contributing to our understanding of potential radiation risks for future human exploration of these celestial bodies.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Engineering, Aerospace
R. D. Strauss, Nigussie M. Giday, Ephrem B. Seba, Daniel A. Chekole, Gemechu F. Garuma, Bereket H. Kassa, Teshome Dugassa, C. Diedericks
Summary: We discuss a newly established neutron monitor station in Ethiopia, which can detect individual neutrons and calculate waiting time distribution. A new quantity called the correlation ratio is proposed as a proxy for the spectral index of atmospheric particles incident on the monitor. The ENTOTO mini-neutron monitor measurements are expected to contribute to the understanding of cosmic ray acceleration and transport.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
R. D. Strauss, C. van der Merwe, C. Diedericks, H. Kruger, H. G. Kruger, K. D. Moloto, S. Lotz, G. M. Mosotho
Summary: Neutron monitors have been the primary instruments for monitoring cosmic ray flux for over 70 years, and it is crucial to continue such measurements to maintain the long-term time series. With the growing interest in space weather effects, particularly radiation risks from solar energetic particles and galactic cosmic rays, expanding the neutron monitor network for near-real-time measurements is vital. This paper discusses a new electronics system retrofitted to the SANAE neutron monitor in Antarctica, presenting initial results with high temporal resolution and discussing data analysis techniques. The successful upgrades suggest the system can revitalize the neutron monitor network and possibly reactivate decommissioned instruments.
ADVANCES IN SPACE RESEARCH
(2021)
Article
Astronomy & Astrophysics
Stavros Dimitrakoudis, David K. Milling, Andy Kale, Ian R. Mann
Summary: The study assesses the optimum spacing for magnetometer stations to monitor and assess the risk of geomagnetically induced currents (GICs) in the power grid. It analyzes the response of geomagnetic disturbances (GMD) to two storm-time substorms using data from two magnetometer arrays. The findings suggest that a network with station separations of around 200 km is appropriate for monitoring both small and large scale geomagnetic disturbances and driving GICs in the electric power grid.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2022)
Article
Engineering, Aerospace
E. Echer, W. D. Gonzalez
Summary: This study analyzed the relationship between Dst* and solar wind parameters in the main phase of single-step geomagnetic storms. The peak values of Bzp and E-yp had a higher correlation with Dst* than their difference values (DBz and DEy). The findings suggest that Eyp and Delta E-y values can serve as interplanetary criteria for assessing moderate and intense storms.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Astronomy & Astrophysics
I. Briki, M. Mazouz, L. Ghedira
Summary: We report measurements of the angular distributions of low momentum atmospheric muons at 38 m above sea level for zenith angles between -60 and 60 degrees in the south-north direction. The muon detection was performed using two NaI(Tl) scintillation detectors mounted in coincidence. The integrated and differential muon flux were determined by analyzing the deposited energy spectra in the scintillators backed up by a Geant4 simulation of the experimental setup. The results are consistent with the cosn(0) distribution and fill the gap in the geomagnetic cutoff rigidity interval 8 GV < Pc < 14 GV where no similar measurements were performed before. We found that n = 1.88 - 0.12 P mu c in the domain of muon momentum cutoff P mu c < 1 GeV/c. These measurements are useful for muon studies requiring accurate integrated flux.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Engineering, Aerospace
Daniel Gecasek, Pavol Bobik, Jan Genci, Jan Villim, Martin Vasko
Summary: This article presents COR, a tool for simulating cosmic ray trajectories in the magnetosphere. The tool offers extensive functionalities and the capability to conduct simulations on scalable systems. The code has been validated and compared with other available codes.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Environmental Sciences
Tommaso Alberti, Paola De Michelis, Lucia Santarelli, Davide Faranda, Giuseppe Consolini, Maria Federica Marcucci
Summary: Using a dynamical systems approach, this study examines the persistence and predictability of geomagnetic perturbations at different latitudes and levels of geomagnetic activity. The analysis of the measured magnetic field data reveals that the instantaneous dimension of the horizontal strength of the magnetic field increases during disturbed periods, indicating external driving. During quiet times, the fluctuation of the instantaneous dimension values around the state-space dimension suggests a more stochastic and less predictable nature of the system.
Article
Geochemistry & Geophysics
D. Wagner, R. Neuhaeuser, R. Arlt
Summary: Observations of aurorae can be used to gather information about Earth's magnetic field in historic times and fill gaps in solar activity observations. A Bayesian approach to reconstruct the auroral oval allows estimation of magnetic pole positions and the Kp index, with high accuracy demonstrated in modern geomagnetic storms.
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
(2022)
Article
Engineering, Aerospace
R. A. Caballero-Lopez, R. Manzano
Summary: In this study, the spectrum of solar cosmic rays flux during ground-level enhancements was analyzed using lead-free and standard neutron monitors in the South Pole station. The effects of anisotropy were significantly reduced by using data from both monitors. The results showed a clear relationship between the spectral index behavior and the observed increases in both monitors. The method was also shown to be capable of calculating the solar cosmic ray spectrum at any required stage of the event.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Multidisciplinary Sciences
Oksana Mandrikova, Bogdana Mandrikova
Summary: Cosmic rays have played a significant role in the development of fundamental physics, providing valuable information about solar activity and processes in near-Earth space. Analyzing cosmic ray variations helps in timely diagnosis of anomalies and is crucial in the study of space weather.
Article
Astronomy & Astrophysics
Bei Zhu, Ying D. Liu, Ryun-Young Kwon, Meng Jin, L. C. Lee, Xiaojun Xu
Summary: The solar eruption on September 10, 2017, led to a ground-level enhancement (GLE) event, with magnetic connectivities showing that the shock propagate through the heliospheric current sheet, resulting in efficient particle acceleration. This process provides a potential mechanism for the production of GLE events.
ASTROPHYSICAL JOURNAL
(2021)
Article
Physics, Multidisciplinary
Zhang Yun-Feng, Jia Huan-Yu, Wang Hui
Summary: This paper analyzes the proton flux peak energy spectrum of the recent GLE event and finds that the energy spectrum index in the lower energy range given by satellites is smaller than that in the higher energy range given by neutron monitors, implying a re-acceleration mechanism for solar high energy particles.
ACTA PHYSICA SINICA
(2021)
Article
Astronomy & Astrophysics
R. E. Ugwoke, A. A. Ubachukwu, J. O. Urama, O. Okike, J. A. Alhassan, A. E. Chukwude
Summary: We used PCA to study five GLEs of CR events, and found that it is a useful tool for analyzing the multivariate data involved. The results showed that the method can distinguish between NMs that observed Forbush decreases and those that observed GLEs at the same time. Additionally, NMs with identical signal counts and similar correlation factors had similar CR counts.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Geochemistry & Geophysics
V. L. Petrov, A. V. Bogomolov, V. V. Bogomolov, V. V. Kalegaev, M. I. Panasyuk, S. I. Svertilov, A. A. Kosenko
GEOMAGNETISM AND AERONOMY
(2020)
Editorial Material
Astronomy & Astrophysics
O. P. Verkhoglyadova, C. D. Bussy-Virat, A. Caspi, D. R. Jackson, V. Kalegaev, J. Klenzing, J. Nieves-Chinchilla, A. Vourlidas
Summary: The gaps in space weather observations that could be addressed by small satellites have been identified in this study. Potential improvements in solar inputs, space radiation control, energy budget estimation of the upper Earth's atmosphere, and satellite drag modeling are briefly discussed. Key observables, instruments, and observation strategies for small satellites are recommended, along with a proposal for tracking optimization.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2021)
Article
Astronomy & Astrophysics
Mikhail Panasyuk, Elena Zhukova, Vladimir V. Kalegaev, Helmi Malova, Victor Y. Popov, Natalia A. Vlasova, Lev M. Zelenyi
Summary: Accelerating oxygen ions in the perturbed Earth's magnetotail is considered as a possible source of energetic heavy ions in the ring current. The simulations show that the acceleration processes depend on particle charges and characteristic time scales of induced electric field variations, with maximum energies gained correlating with charge values. The Earth's magnetotail can efficiently accelerate heavy ions to energies around several MeV during magnetic substorms, contributing to the population of the ring current and radiation belts.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Biographical-Item
Physics, Multidisciplinary
Yu Yu Balega, E. E. Boos, L. M. Zelenyi, V. V. Kalegaev, L. A. Kuzmichev, L. I. Miroshnichenko, A. A. Petrukovich, A. A. Petrukhin, V. V. Radchenko, V. I. Savrin, S. I. Svertilov, Yu I. Stozhkov
Article
Engineering, Aerospace
N. A. Vlasova, V. I. Tulupov, V. V. Kalegaev
Summary: The paper presents a comparative analysis of solar proton fluxes and interplanetary medium parameters during two solar events in 2011 and 2014, showing the determining role of interplanetary magnetic field structure in shaping the features of particle flux time profiles in the given events.
Article
Astronomy & Astrophysics
V. A. Sadovnichy, M. I. Panasyuk, S. I. Svertilov, V. M. Lipunov, V. V. Bogomolov, A. V. Bogomolov, E. S. Gorbovskoy, A. F. Iyudin, V. V. Kalegaev, V. G. Kornilov, I. H. Park, V. L. Petrov, N. N. Vedenkin, I. V. Yashin
Summary: This paper presents a catalogue of gamma-ray bursts detected by the instruments onboard the Lomonosov space observatory, providing experience in multi-wavelength and multi-messenger observations of GRBs. Detailed light curves and energy spectra of the detected GRBs are presented, along with discussions on prompt, early, and afterglow optical observations of several GRBs.
Article
Engineering, Aerospace
M. Prokhorov, V. V. Bogomolov, A. Bogomolov, A. F. Iyudin, V. V. Kalegaev, I. N. Myagkova, V. Osedlo, S. Svertilov
Summary: The study proposes the use of the normalized range method to analyze the fast variability of electron fluxes in near-Earth space. By analyzing the SiriusSat experiment data, it is found that there is excessive flux variability in the gap region east of the South Atlantic anomaly.
Article
Engineering, Aerospace
A. R. Ivanova, V. V. Kalegaev
Summary: The dynamics of the boundaries of the auroral oval during a magnetic storm were studied using the Meteor M2 satellite, with a focus on the influence of the magnetosphere and interplanetary medium. The study found that the oval's dynamics were influenced by solar wind pressure, interplanetary magnetic field, and geomagnetic activity.
Article
Environmental Sciences
Pavel Klimov, Vladimir Kalegaev, Ksenia Sigaeva, Alexandra Ivanova, Grigory Antonyuk, Viktor Benghin, Ivan Zolotarev
Summary: The Tracking Ultraviolet Set-up (TUS) on board the Lomonosov satellite measured the pulsations of UV intensity in the auroral region. A total of 64 pulsation events were recorded during two measurement periods, and a high-intensity, long-duration, continuous auroral activity (HILDCAA) was detected during both periods. Simultaneous measurements by Lomonosov and Meteor-M2 satellites in low Earth orbit showed enhanced fluxes of energetic electrons in the Earth's outer radiation belt.
Article
Astronomy & Astrophysics
H. Wu, T. Chen, V. Kalegaev, S. Ye
Summary: This study examines the phenomenon of electron flux dropout in the outer radiation belt. By analyzing data from multiple satellites, it is found that electron flux dropout can occur at both MeV and keV energy levels, and different mechanisms are responsible for the depletion in each energy range.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
H. Wu, T. Chen, V. Kalegaev, S. Ye
Summary: This study investigates the phenomenon of electron flux dropout in the outer radiation belt and reveals the different behaviors of electron flux at different energy levels. These findings are crucial for understanding the evolutionary process and mechanisms of the radiation belt.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Geochemistry & Geophysics
N. A. Vlasova, V. V. Kalegaev, I. S. Nazarkov
Summary: The study presented the results of how the dynamics of relativistic electron fluxes in Earth's outer radiation belt are dependent on the intensity of geomagnetic storms. It was found that during strong magnetic storms with |Dst|(max) similar to >= 120 nT, global changes in the magnetospheric magnetic field have a dominant influence on the dynamics of relativistic electrons, leading to adiabatic variations in their fluxes.
GEOMAGNETISM AND AERONOMY
(2021)
Article
Geochemistry & Geophysics
I. N. Myagkova, V. R. Shirokii, V. V. Kalegaev, O. G. Barinov, S. A. Dolenko
Summary: The study examines the potential use of artificial neural networks, specifically classical multilayer perceptrons, with coupling functions to forecast time series of the Dst geomagnetic index. The analysis is based on parameters of the solar wind and interplanetary magnetic field measured at the libration point L1 on the ACE spacecraft. It is found that the largest improvement in forecast quality comes from the Bs and vBs functions, along with the simultaneous use of multiple coupling functions.
GEOMAGNETISM AND AERONOMY
(2021)
Article
Physics, Multidisciplinary
V. V. Bogomolov, A. V. Bogomolov, Yu. N. Dement'ev, V. E. Eremeev, Yu. K. Zaiko, V. V. Kalegaev, P. A. Klimov, V. I. Osedlo, M. I. Panasyuk, V. L. Petrov, O. Yu. Peretjat'ko, M. V. Podzolko, S. I. Svertilov
MOSCOW UNIVERSITY PHYSICS BULLETIN
(2020)
Article
Geochemistry & Geophysics
N. A. Vlasova, V. V. Kalegaev, I. S. Nazarkov, A. Prost
GEOMAGNETISM AND AERONOMY
(2020)
