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
Physics, Mathematical
Tarek Saanouni, Radhia Ghanmi
Summary: This work develops a local theory of inhomogeneous coupled Schrodinger equations and proves the existence of a local energy solution in the sub-critical regime. The methods used include Lorentz spaces and weighted Lebesgue spaces to handle the effects of the inhomogeneous term.
JOURNAL OF MATHEMATICAL PHYSICS
(2023)
Article
Astronomy & Astrophysics
S. A. Belov, S. Vasheghani Farahani, N. E. Molevich
Summary: The aim of this study is to investigate the effects of thermal misbalance on the behavior of Alfven waves in solar active regions. The study provides a description of the non-linear forces associated with Alfven waves in non-ideal conditions and their influence on the boundary of thin magnetic structures in thermally active plasmas. The results show that the effects of thermal misbalance are stronger for shear Alfven waves compared to torsional Alfven waves.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Physics, Mathematical
Tarek Saanouni, Radhia Ghanmi
Summary: This study examines an inhomogeneous Schrodinger coupled system in the mass-super-critical and energy-sub-critical regimes. It shows a sharp dichotomy in the focusing sign, utilizing variational methods, a Gagliardo-Nirenberg-type inequality, and a new approach of Dodson and Murphy. In the defocusing sign, it proves the scattering of global solutions in the energy space using a classical Morawetz estimate.
JOURNAL OF MATHEMATICAL PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
M. O. Archer, D. J. Southwood, M. D. Hartinger, L. Rastatter, K. Nykyri
Summary: Ultra-low frequency (ULF) wave observations often rely on plasma-magnetic field correlations, but assumptions behind this result may not be valid in the magnetosphere. Standing waves and inhomogeneities can lead to anomalous correlations, affecting the interpretation of observations.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Physics, Multidisciplinary
Kuldeep Singh, Gursirat Singh, N. S. Saini
Summary: This paper investigates the formation and dynamics of periodic and solitary kinetic Alfven waves in nonthermal electron-positron-ion plasma. The KdV equation is derived using the reductive perturbation technique, and the Sagdeev potential and Hirota bilinear methods are applied to examine the wave dynamics. The study reveals that the plasma beta, positron density, propagation angle, and nonthermality of electrons and positrons have a significant influence on the behavior of the waves.
CHINESE JOURNAL OF PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
C. Z. Xiao, Y. G. Chen, J. F. Myatt, Q. Wang, Y. Chen, Z. J. Liu, C. Y. Zheng, X. T. He
Summary: The theory of absolute stimulated Brillouin side scattering in inhomogeneous flowing plasma is presented and numerically verified. The results show good agreement between theoretical and numerical thresholds under certain conditions, correcting an old threshold. The research also discusses the possibility of finding such instability in current experiments.
Article
Astronomy & Astrophysics
L. B. De Toni, R. Gaelzer, L. F. Ziebell
Summary: In this work, the characteristics of the group velocity of obliquely propagating Alfven waves in a dusty plasma are investigated. The dispersion relation is derived using kinetic theory and the group velocities are numerically calculated for compressional and shear Alfven waves. The results show that the group velocity of compressional Alfven waves is greatly influenced by the wave-vector direction, while shear Alfven waves propagate mainly along the magnetic field. Changes in dust parameters can significantly alter the waves' characteristics.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. S. Leonovich, Q. G. Zong, D. A. Kozlov, A. A. Vlasov
Summary: The paper proposes a new method (phase portraits) to determine the type of Alfven waves observed onboard a spacecraft. By plotting the radial dependence of the phase shift between the transverse components of the wavefield, the transverse structure of the observed Alfven wave can be determined. Phase portraits are constructed for most types of ULF monochromatic Alfven waves observed in the Earth's magnetosphere.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
G. J. Kramer, C. Z. Cheng
Summary: This study investigates the effect of plasma shaping on the continuous spectrum, frequency gaps, and number of eigenmodes. The results show that plasma shaping impacts the coupling between Alfven and slow magnetosonic waves through geodesic magnetic curvature and plasma pressure. Ideal magnetohydrodynamic simulations reveal a large number of potential eigenmodes, with the number of eigenmodes correlated to the maximum geodesic curvature. The formation of a low amplitude and dense discrete spectrum of possible eigenmodes is hypothesized, which can be further explored experimentally.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Multidisciplinary Sciences
D. B. Graham, Yu. V. Khotyaintsev, M. Andre, A. Vaivads, A. Divin, J. F. Drake, C. Norgren, O. Le Contel, P. -A. Lindqvist, A. C. Rager, D. J. Gershman, C. T. Russell, J. L. Burch, K. -J. Hwang, K. Dokgo
Summary: The waves contribute to anomalous diffusion but do not contribute to the reconnection electric field. However, they do produce an anomalous electron drift and diffusion across the current layer associated with magnetic reconnection, which modifies the reconnection process.
NATURE COMMUNICATIONS
(2022)
Article
Astronomy & Astrophysics
K. C. Barik, S. Singh, G. S. Lakhina
Summary: A theoretical model discusses the resonant instability of kinetic Alfven waves (KAWs) driven by ion beam and how non-Maxwellian kappa-electrons impede the growth of KAWs. The model also examines the effects of other plasma parameters on wave excitation and can generate waves with frequencies relevant to auroral ionospheric altitudes. Predictions from the model are applicable to planetary environments with ion beams and non-Maxwellian kappa-electrons.
ASTROPHYSICAL JOURNAL
(2021)
Article
Physics, Multidisciplinary
Chitrita Dasgupta, Sarit Maitra, Gadadhar Banerjee
Summary: This study develops a nonlinear theory for dust acoustic waves in a strongly coupled inhomogeneous collisionless dusty plasma. By employing a reductive perturbation technique, a variable coefficient KdV-Burgers equation is derived from the generalized hydrodynamic set of partial differential equations. An analytic expression for the solution is obtained using the generalized expansion method, which describes monotonic kink-type shock waves. The effects of nonthermal ions, dust-dust correlation, and ion temperature on wave propagation are also investigated.
WAVES IN RANDOM AND COMPLEX MEDIA
(2022)
Article
Physics, Fluids & Plasmas
I. Y. Dodin
Summary: This paper presents a quasilinear theory (QLT) for a classical plasma interacting with inhomogeneous turbulence. The theory is applicable to various Hamiltonians and includes relativistic, electromagnetic, and gravitational effects. It provides a framework to study the interaction between the plasma and turbulence, background fields, and ponderomotive effects.
JOURNAL OF PLASMA PHYSICS
(2022)
Article
Astronomy & Astrophysics
Anna Tkachenko, Vladimir Krasnoselskikh, Andrii Voshchepynets
Summary: This paper describes a theoretical model of harmonic emissions of type III solar radio bursts. The model considers nonlinear coupling of Langmuir waves in the solar wind plasma and proposes two mechanisms for generating harmonic emissions in quasihomogeneous and inhomogeneous plasma. The results suggest that harmonic emissions from quasihomogeneous plasma are more intense.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
D. J. McComas, T. Sharma, E. R. Christian, C. M. S. Cohen, M. I. Desai, M. E. Hill, L. Y. Khoo, W. H. Matthaeus, D. G. Mitchell, F. Pecora, J. S. Rankin, N. A. Schwadron, J. R. Szalay, M. M. Shen, C. R. Braga, P. S. Mostafavi, S. D. Bale
Summary: We report the first direct measurements of the particle and field environments of a coronal mass ejection (CME) leg very close to the Sun using observations from Parker Solar Probe (PSP). The observations showed a complete dropout in low-energy solar energetic ions, while the magnetic field and solar wind plasma did not show significant changes at the boundaries of the dropout. The CME leg was found to be significantly different from the assumed magnetic and plasma structure of CMEs near the Sun and observed in interplanetary CMEs farther out in the solar wind.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
S. Lotz, A. E. Nel, R. T. Wicks, O. W. Roberts, N. E. Engelbrecht, R. D. Strauss, G. J. J. Botha, E. P. Kontar, A. Pitna, S. D. Bale
Summary: In this study, the radial dependence of the inertial and dissipation range indices, as well as the spectral break separating the inertial and dissipation range in power density spectra of interplanetary magnetic field fluctuations, was examined using Parker Solar Probe data. The results showed that the inertial scale power-law index had a very weak radial dependence, possibly becoming steeper closer to the Sun. The dissipation range power-law index, however, had a clear dependence on radial distance, decreasing as the distance to the Sun decreased.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
C. Phillips, R. Bandyopadhyay, D. J. McComas, S. D. Bale
Summary: Several studies have shown that intermittent structures in the near-Earth environment are important for energy dissipation and particle energization. Recent data from the Parker Solar Probe (PSP) suggest that proton heating is concentrated near coherent structures in the near-Sun environment. This study explores whether electrons exhibit similar behavior and finds that electron temperature is enhanced near strong discontinuities, supporting the inhomogeneous heating of electrons near intermittent structures.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Nour E. Raouafi, G. Stenborg, D. B. Seaton, H. Wang, J. Wang, C. E. DeForest, S. D. Bale, J. F. Drake, V. M. Uritsky, J. T. Karpen, C. R. DeVore, A. C. Sterling, T. S. Horbury, L. K. Harra, S. Bourouaine, J. C. Kasper, P. Kumar, T. D. Phan, M. Velli
Summary: We present EUV solar observations providing evidence for omnipresent jetting activity driven by small-scale magnetic reconnection at the base of the solar corona. This discovery highlights the importance of small-scale magnetic reconnection in solar and stellar atmospheres in understanding phenomena such as coronal heating and solar wind acceleration. The observed switchback solar wind phenomenon might be linked to the magnetic activity at the base of the corona.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Zesen Huang, Nikos Sioulas, Chen Shi, Marco Velli, Trevor Bowen, Nooshin Davis, B. D. G. Chandran, Lorenzo Matteini, Ning Kang, Xiaofei Shi, Jia Huang, Stuart D. Bale, J. C. Kasper, Davin E. Larson, Roberto Livi, P. L. Whittlesey, Ali Rahmati, Kristoff Paulson, M. Stevens, A. W. Case, Thierry Dudok de Wit, David M. M. Malaspina, J. W. Bonnell, Keith Goetz, Peter R. R. Harvey, Robert J. J. MacDowall
Summary: The trace magnetic power spectrum in the solar wind follows a double power law, with lower frequencies showing flatter spectral exponents close to -1. The origin of the 1/f range is still debated. This study examines 109 magnetically incompressible solar wind intervals to understand the statistics and radial evolution of the low-frequency power spectral exponents.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Jana Safrankova, Zdenek Nemecek, Frantisek Nemec, Daniel Verscharen, Timothy S. Horbury, Stuart D. Bale, Lubomir Prech
Summary: We conduct a comprehensive statistical study on the evolution of compressive and noncompressive magnetic field fluctuations in the inner heliosphere. Using data from Parker Solar Probe and Solar Orbiter at different distances from the Sun, we analyze solar wind power spectra of magnetic field fluctuations in the inertial and kinetic frequency ranges. Our findings reveal that the spectrum in the inertial range becomes steeper as the distance from the Sun increases, while in the kinetic range, the spectral indices increase with distance and remain approximately constant towards 1 au. The radial profiles of spectral slopes, fluctuation amplitudes, spectral breaks, and their relationships undergo rapid changes near 0.4 au.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Jia Huang, J. C. Kasper, Davin E. Larson, Michael D. McManus, P. Whittlesey, Roberto Livi, Ali Rahmati, Orlando Romeo, K. G. Klein, Weijie Sun, Bart van der Holst, Zhenguang Huang, Lan K. Jian, Adam Szabo, J. L. Verniero, C. H. K. Chen, B. Lavraud, Mingzhe Liu, Samuel T. Badman, Tatiana Niembro, Kristoff Paulson, M. Stevens, A. W. Case, Marc Pulupa, Stuart D. Bale, J. S. Halekas
Summary: The study found that the slow solar wind from the streamer belt forms a high plasma beta equatorial plasma sheet known as the heliospheric plasma sheet (HPS). Parker Solar Probe observations revealed that the heliospheric current sheet (HCS) crossings near the Sun can either be full or partial current sheet (PCS) crossings, which have different characteristics. The PCS solar wind differs from the HPS solar wind in terms of pressure balance, stability, and abundance of helium and alpha-proton differential speed. It is suggested that the PCS solar wind originates from coronal loops deep inside the streamer belt and further investigations are valuable for understanding the heating and acceleration of slow solar wind.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
David M. M. Malaspina, Alexandru Toma, Jamey R. R. Szalay, Marc Pulupa, Petr Pokorny, Stuart D. D. Bale, Keith Goetz
Summary: A database of in situ dust impact detections made by the Parker Solar Probe spacecraft is created to study interplanetary dust dynamics in the inner heliosphere. A standardized dust detection methodology is established and tested. Individual impact detections are included in the database, and corrections are made for effects related to plasma waves and finite detection window duration. The corrections suggest that most dust impacts on Parker Solar Probe are random, and the true dust impact rate may be approximately 50% greater than the uncorrected data, especially near perihelion.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
Wen Liu, Jinsong Zhao, Tieyan Wang, Xiangcheng Dong, Justin C. Kasper, Stuart D. Bale, Chen Shi, Dejin Wu
Summary: This study examines the radial distribution of ion-scale waves observed by the Parker Solar Probe and finds a significant enhancement in wave occurrence rate in the near-Sun solar wind compared to beyond 0.3 au. The decrease in wave occurrence rate with radial distance is not only due to sampling effect but also related to the physics of wave excitation, such as the enhanced ion beam instability. The study also identifies the wave mode nature of left-handed and right-handed polarized waves as the Alfven ion cyclotron mode wave and the fast magnetosonic whistler mode wave, respectively.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Oksana Kruparova, Vratislav Krupar, Adam Szabo, Marc Pulupa, Stuart D. Bale
Summary: In this study, we conducted a comprehensive analysis of electron density in the solar wind using quasi-thermal noise spectroscopy. We derived a power-law model for electron density as a function of radial distance and discussed its potential applications in localizing interplanetary solar radio bursts and calibrating particle instruments on the Parker Solar Probe.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Nikos Sioulas, Marco Velli, Zesen Huang, Chen Shi, Trevor A. A. Bowen, B. D. G. Chandran, Ioannis Liodis, Nooshin Davis, Stuart D. D. Bale, T. S. Horbury, Thierry Dudok de Wit, Davin Larson, Michael L. L. Stevens, Justin Kasper, Christopher J. J. Owen, Anthony Case, Marc Pulupa, David M. M. Malaspina, Roberto Livi, Keith Goetz, Peter R. R. Harvey, Robert J. J. MacDowall, John W. W. Bonnell
Summary: In this study, a merged data set from Parker Solar Probe (PSP) and Solar Orbiter (SO) was analyzed to investigate the radial evolution of power and spectral index anisotropy in the wavevector space of solar wind turbulence. The results show that the anisotropic signatures of turbulence display a distinct radial evolution when considering fast and slow wind streams. The findings provide strong observational constraints for anisotropic theories of MHD turbulence in the solar wind.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Immanuel Christopher Jebaraj, Vladimir Krasnoselskikh, Marc Pulupa, Jasmina Magdalenic, Stuart D. Bale
Summary: This research report presents the first detailed observations of type III fundamental-harmonic pairs in hectokilometric wavelengths, observed by the Parker Solar Probe. The report provides a statistical analysis of the spectral characteristics, polarization measurements, and other characteristics of the fundamental-harmonic pairs, drawing conclusions based on the observations.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Geosciences, Multidisciplinary
H. George, D. M. Malaspina, K. Goodrich, Y. Ma, R. Ramstad, D. Conner, S. D. Bale, S. Curry
Summary: The occurrence of Venusian lightning has been debated for decades. Previous whistler wave observations suggested a high occurrence rate, but optical and spacecraft detections have not found lightning. Our study presents observations from Parker Solar Probe that eliminate lightning as a possible source for whistler waves near Venus. This indicates that the whistler-based lightning occurrence rates on Venus may be overestimated.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
Vladimir Krasnoselskikh, Arnaud Zaslavsky, Anton Artemyev, Clara Froment, Thierry Dudok de Wit, Nour E. Raouafi, Oleksiy V. Agapitov, Stuart D. Bale, Jaye L. Verniero
Summary: The exploration of the inner heliosphere by the Parker Solar Probe has revealed the presence of switchbacks in the highly structured solar wind, which may be generated by interchange reconnection (IR). Although IR does not significantly contribute to the heating and acceleration of the solar wind, it affects the way the solar wind is connected to its sources and can lead to a new energy balance.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
F. S. Mozer, O. Agapitov, S. D. Bale, R. Livi, O. Romeo, K. Sauer, I. Y. Vasko, J. Verniero
Summary: This letter describes a new phenomenon observed on the Parker Solar Probe, which is the recurring plasma density enhancements. These enhancements have a similar Delta n/n of 10% and occur at a repetition rate of about 5 Hz. The steady-state existence of these enhancements suggests a balance between their pressure gradient and the electric field. The measurements of the electric field and density fluctuations provide strong evidence for their accuracy. These plasma density enhancements are accompanied by low-frequency electromagnetic waves and may play an important role in plasma heating, scattering, and acceleration.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
