Article
Engineering, Aerospace
R. N. Boroyev, M. S. Vasiliev
Summary: The relationship between auroral activity indices (AE, Kp, SME) and interplanetary medium parameters during the main phase of magnetic storms is investigated. A total of 142 magnetic storms driven by Sheath (41), CIR (61), and ICME (40) events from 1990 to 2020 are selected. The study reveals that the correlation coefficient between the average values of the SME index and the solar wind electric field for Sheath events is close to those for CIR and ICME events. Moreover, during the main phase of Sheath-induced magnetic storms, the correlation coefficient between Kpaver&Eswaver is higher than the correlation coefficient between AEaver&Eswaver. It is also observed that average values of solar wind dynamic pressure and IMF rB fluctuations are correlated across all types of solar wind.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
A. M. El-Taher, A. A. Thabet
Summary: The study revealed long-term periodicities in the frequency range 8-16 yr for Kp, Ap, and aa indices, while Dst index showed this periodicity during the period 1980-2018. Additionally, prominent periodicities were found in the frequency bands of 2-4 yr and 4-8 yr for all geomagnetic indices.
ADVANCES IN SPACE RESEARCH
(2021)
Article
Astronomy & Astrophysics
Pablo S. Moya, Bea Zenteno-Quinteros, Ivan Gallo-Mendez, Victor A. Pinto
Summary: The interactions between plasma particles and electromagnetic waves are crucial in space environments. The characteristics of these interactions depend on the composition of the plasma. The presence of heavy ions significantly affects the dispersion properties of kinetic Alfven waves and should be considered in modeling plasma phenomena in the inner magnetosphere.
ASTROPHYSICAL JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Run Shi, Jun Liang, Binbin Ni
Summary: The study found that with decreasing perpendicular wavelength and increasing hot electron temperature, the coupling of kinetic Alfven waves to electron acoustic waves becomes more important; electron acoustic waves exhibit strong Landau damping outside the transition region, with nonlinear dissipation becoming significant inside the transition region.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
A. J. Hull, P. A. Damiano, C. C. Chaston, J. R. Johnson, G. D. Reeves
Summary: This study investigates the properties of traveling kinetic Alfven waves (KAWs) and their role in energizing electrons in the inner magnetosphere during a geomagnetic storm. The results demonstrate the crucial importance of cold electrons for reproducing observed distributions.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Jiwon Choi, Dong-Hun Lee
Summary: Standing poloidal Alfven waves are excited by wave-particle interaction in the magnetosphere, with ultralow frequency radial oscillations. Through magnetohydrodynamic simulations, it has been shown that the long-lasting poloidal waves depend on the local Alfven frequency gradient being negligible. Two necessary conditions for the existence of persistent poloidal modes have been derived, which are consistent with statistical observations.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Oleksiy V. Arkhypov, Maxim L. Khodachenko
Summary: By studying surface stellar activity features, we have discovered the existence of drifting lanes (DLs) and found a correlation between their drift rates and stellar effective temperatures. The presence of these DLs suggests that Alfven waves are an important factor in triggering surface magnetic fields in stars, and provides a unique way of probing the magnetic field strength in stellar tachoclines.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Jouni Takalo
Summary: The study reveals a gap, known as the Gnevyshev gap (GG), in the time series of sunspot group areas between ascending and descending phases of the solar cycle, more pronounced in even-numbered cycles. This gap has an impact on geomagnetic disturbances indices, showing significant declines during and after the GG, especially for even cycles.
Article
Geosciences, Multidisciplinary
Olga S. Mikhailova, Ekaterina E. Smotrova, Pavel N. Mager
Summary: The resonant generation of ultra-low frequency waves by energetic electrons in the magnetosphere has been observed for the first time. The study reveals the interaction mechanism between energetic electrons and the wave.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Engineering, Marine
Vamshikrishna Domala, Tae-wan Kim
Summary: This study explores the use of Empirical Model Decomposition (EMD) and Hodrick Prescot (HP) filter in predicting significant wave height. The Long Short-Term Memory (LSTM) technique, commonly used for sequence predictions in Natural Language Processing (NLP), is adapted for time series forecasting. The EMD and HP filter are used to extract components and trends from the original wave data, which are then fed into the LSTM model for prediction.
Article
Mathematics
Mengni Li, Pin Yu
Summary: This paper studies the rigidity aspect of the scattering problem for Alfven waves in magnetized plasmas, and proves that the waves must vanish under certain conditions. The proof is based on a careful study of the null structure and a family of weighted energy estimates.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2021)
Article
Astronomy & Astrophysics
Lei Dai, Yimin Han, Chi Wang, Shuo Yao, Walter Gonzalez, Suping Duan, Benoit Lavraud, Yong Ren, Zhenyuan Guo
Summary: This study provides in situ observational evidence for magnetopause reconnection induced by interplanetary Alfven waves. The intensified southward magnetic field caused by these waves leads to detectable signatures of magnetic reconnection at the magnetopause, followed by an increase in auroral electrojet indices. The results offer insights on the temporal patterns of solar wind magnetosphere-ionosphere coupling, especially during the descending phase of the solar cycle.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Danila Kostarev, Pavel N. Mager, Dmitri Y. Klimushkin
Summary: This article proposes a mechanism for generating the parallel electric field by an Alfven wave in a single framework without using hybrid models, which helps to better understand the physics of the process. Also, the proposed mechanism describes well the acceleration of electrons to the observed energies.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Physics, Multidisciplinary
Sayanee Jana, Manoranjan Khan
Summary: The study investigates the dynamical behavior of weakly nonlinear Alfven waves in positive ion-negative ion magnetized plasmas. It shows that the dynamics of the nonlinear wave is governed by a higher-order dispersion modified derivative nonlinear Schrodinger equation (DNLSE) due to the inertial effect of both ions. Both analytical and numerical solutions predict the existence of solitary wave structures in positive ion-negative ion plasmas under experimental parameters.
Article
Astronomy & Astrophysics
Daniel Iong, Yang Chen, Gabor Toth, Shasha Zou, Tuija Pulkkinen, Jiaen Ren, Enrico Camporeale, Tamas Gombosi
Summary: In this study, gradient boosting machines (GBMs) were developed to forecast the SYM-H index multiple hours ahead using different combinations of solar wind and interplanetary magnetic field (IMF) parameters, derived parameters, and past SYM-H values. By quantifying the contributions from each input using Shapley Additive Explanation values, the predictions were found to be consistent with physical understanding and provided insight into the complex relationship between solar wind and Earth's ring current. GBMs were compared with neural networks, showing a statistically significant improvement in root mean squared error over the best published black-box neural network schemes and the Burton equation.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2022)
Article
Astronomy & Astrophysics
A. D. Vira, B. A. Larsen, R. M. Skoug, P. A. Fernandes
Summary: Space instruments heavily rely on modeling to predict and understand instrument response, with the Bayesian approach providing a framework to incorporate prior knowledge and propagate uncertainty. The empirical Bayes model presented in the study allows for good prediction of instrument performance and exploration of certain parameters during the mission.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
A. J. Boyd, H. E. Spence, G. D. Reeves, H. O. Funsten, R. M. Skoug, B. A. Larsen, J. B. Blake, J. F. Fennell, S. G. Claudepierre, D. N. Baker, S. G. Kanekal, A. N. Jaynes
Summary: This paper introduces a new data product that combines pitch angle resolved electron flux measurements from the RBSP ECT suite on the Van Allen Probes, providing researchers with a consistent cross-calibrated data set to explore particle dynamics in the inner magnetosphere. The data set includes flux spectra spanning a wide range of energies from 15 eV up to 20 MeV.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
Brett A. McCuen, Mark B. Moldwin, Mark Engebretson
Summary: Research has identified transient-large-amplitude (TLA) geomagnetic disturbances as not directly driving geomagnetically induced currents (GIC), but potentially related to larger geomagnetic disturbances. TLA events are more likely to occur within 30 minutes after a substorm onset or during nighttime magnetic perturbation events. The characteristics of TLA events suggest that localized ionospheric source currents may play a key role in generating extreme geomagnetic impulses and GICs.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Mark J. Engebretson, Lidiya Y. Ahmed, Viacheslav A. Pilipenko, Erik S. Steinmetz, Mark B. Moldwin, Martin G. Connors, David H. Boteler, James M. Weygand, Shane Coyle, Shin Ohtani, Jesper Gjerloev, Christopher T. Russell
Summary: Superposed epoch analyses were conducted on large nighttime magnetic perturbation events observed in Arctic Canada in 2015 and 2017. The study found that only the IMF Bz component showed consistent temporal variations before MPEs, and most of the MPEs did not coincide with large-scale peaks in ionospheric electrojets. More disturbed values of various parameters appeared post-midnight than pre-midnight.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Ephrem B. Seba, Melessew Nigussie, Nigussie M. Giday, Mark B. Moldwin
Summary: The study explores the relationship between upward propagating gravity waves and ionospheric irregularities using data from TIMED and Swarm satellites. Results indicate that gravity wave characteristics and ionospheric irregularities play a role in the global nighttime equatorial plasma density variations and longitudinal shifts.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2021)
Article
Astronomy & Astrophysics
Yining Shi, Mark B. Moldwin
Summary: This paper presents a statistical study of magnetic field vector residuals between Swarm observations and two Earth magnetic field models, showing that the residuals increase with higher geomagnetic activity levels, and the CHAOS-7 model has lower residuals compared to the IGRF-13 model. Asymmetries in magnetic field residuals are observed between the northern and southern hemispheres, with the northern hemisphere having more frequent occurrence of large residuals across all local times.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
James M. Weygand, Mark J. Engebretson, Viacheslav A. Pilipenko, Erik S. Steinmetz, Mark B. Moldwin, Martin G. Connors, Yukitoshi Nishimura, Larry R. Lyons, Christopher T. Russell, Shin-Ichi Ohtani, Jesper Gjerloev
Summary: The study found that most MPEs occur near midnight and predominantly within the westward electrojet. Premidnight MPEs are mainly associated with the Harang current system, while postmidnight MPEs are more likely to occur in either the downward region 1 or upward region 2 current system.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
V. Pierrard, E. Botek, J. -f. Ripoll, S. A. Thaller, M. B. Moldwin, M. Ruohoniemi, G. Reeves
Summary: The plasmapause serves as the boundary of the plasmasphere and undergoes sudden changes in plasma density, affecting different regions of the magnetosphere due to various circulating waves. By comparing measurement data and models, it is found that the position of the plasmapause is directly linked to the radiation belt boundaries. During geomagnetic storms, the plasmapause moves equatorward in relation to the equatorward edge motion of the auroral oval.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2021)
Article
Geochemistry & Geophysics
Ephrem Beshir Seba, Melessew Nigussie, Mark B. Moldwin
Summary: This study analyzes the influence of thermospheric winds on the variability of ionospheric plasma density irregularities during solar maximum periods. The results show that the plasma density irregularities are strongest during post-midnight hours in the African - American longitude sector, and this is associated with an enhancement in eastward zonal wind after midnight. We also observe a westward shift in the occurrence of plasma irregularities. The reversal of zonal wind from westward to eastward during post-sunset hours is found to be important for the generation and variability of plasma irregularities.
JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS
(2022)
Article
Astronomy & Astrophysics
Alex Paul Hoffmann, Mark B. Moldwin
Summary: This study proposes a signal processing algorithm that uses density-based cluster analysis and compressive sensing to remove spacecraft magnetic noise. The algorithm does not require prior knowledge of the noise signals and has been validated through simulations and experiments.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Mark J. Engebretson, Laura E. Simms, Viacheslav A. Pilipenko, Lilia Bouayed, Mark B. Moldwin, James M. Weygand, Michael D. Hartinger, Zhonghua Xu, C. Robert Clauer, Shane Coyle, Anna N. Willer, Mervyn P. Freeman, Andy J. Gerrard
Summary: This study investigated impulsive geomagnetic disturbances (GMDs) at high latitude station pairs in both the northern and southern hemispheres. The analysis revealed that GMDs were larger in the winter hemisphere and were dependent on the sign of the interplanetary magnetic field (IMF) component By. Most events occurred simultaneously, regardless of the sign of By as long as |By| <= 2 |Bz|. Prior to most events, IMF Bz was negative. Supplementing the data with IMF data from other solar wind missions improved the consistency of IMF orientations.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Brett A. McCuen, Mark B. Moldwin, Erik S. Steinmetz, Mark J. Engebretson
Summary: We developed an automated algorithm to identify high-frequency geomagnetic disturbances in ground magnetometer data and classify the events by their sources. The algorithm searches for and identifies changes in the surface magnetic field, dB/dt, with specified amplitude and timescale. We manually classified the events by their sources and used a support vector machine classification algorithm to further classify the remaining events. The automated algorithm enables systematic identification and analysis of space weather related dB/dt events and automated detection of magnetometer noise intervals in magnetic field databases.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Alex Paul Hoffmann, Mark B. Moldwin, Brady P. Strabel, Lauro V. Ojeda
Summary: In the traditional method, magnetometers are placed on a deployable boom to measure stray magnetic fields generated by spacecraft electrical subsystems. However, this is not feasible on low-cost platforms. To overcome this problem, we propose using the Quad-Mag CubeSat magnetometer with an improved UBSS noise removal algorithm. We demonstrate in the lab that UBSS reduces noise signals, enabling high-fidelity magnetic field measurements from a CubeSat without a boom.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Geosciences, Multidisciplinary
Brady P. Strabel, Leonardo H. Regoli, Mark B. Moldwin, Lauro V. Ojeda, Yining Shi, Jacob D. Thoma, Isaac S. Narrett, Bret Bronner, Matthew Pellioni
Summary: This paper presents a CubeSat magnetometer board (Quad-Mag) equipped with four PNI RM3100 magnetometers. By oversampling with multiple sensors, the Quad-Mag achieves a low noise floor and enables accurate magnetic field measurements under optimal conditions.
GEOSCIENTIFIC INSTRUMENTATION METHODS AND DATA SYSTEMS
(2022)
Article
Geosciences, Multidisciplinary
Mark B. Moldwin, Edward Wilcox, Eftyhia Zesta, Todd M. Bonalsky
Summary: This article presents the results of a destructive single-event effect susceptibility radiation test of the PNI RM3100 magnetometer sensor and concludes that it is highly suitable for various space environments.
GEOSCIENTIFIC INSTRUMENTATION METHODS AND DATA SYSTEMS
(2022)
