Article
Astronomy & Astrophysics
L. Adhikari, G. P. Zank, L-L Zhao, D. Telloni, T. S. Horbury, H. O'Brien, V Evans, V Angelini, C. J. Owen, P. Louarn, A. Fedorov
Summary: The study examines the evolution of anisotropic turbulence in the solar wind utilizing SolO measurements and the NI MHD turbulence model, finding that the ratio of energy components and fluctuations increase with the angle between the solar wind speed and magnetic field before decreasing again. Additionally, it is observed that solar wind turbulence is a combination of dominant 2D components and minority slab components as a function of heliocentric distance, with theoretical and observed results showing excellent agreement.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
D. Perrone, S. Perri, R. Bruno, D. Stansby, R. D'Amicis, V. K. Jagarlamudi, R. Laker, S. Toledo-Redondo, J. E. Stawarz, D. Telloni, R. De Marco, C. J. Owen, J. M. Raines, A. Settino, B. Lavraud, M. Maksimovic, A. Vaivads, T. D. Phan, N. Fargette, P. Louarn, I. Zouganelis
Summary: This study investigates the radial evolution of solar wind plasma from coronal holes using measurements from Solar Orbiter and Parker Solar Probe. The observations reveal the radial trends of proton density, magnetic field, and proton temperature, as well as the characteristics of turbulence and coherent structures at different radial distances. This work provides valuable insights into the turbulent nature of solar wind plasma and its evolution from the Sun to the Earth.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
R. Bandyopadhyay, W. H. Matthaeus, D. J. McComas, R. Chhiber, A. Usmanov, J. Huang, R. Livi, D. E. Larson, J. C. Kasper, A. W. Case, M. Stevens, P. Whittlesey, O. M. Romeo, S. D. Bale, J. W. Bonnell, T. Dudok de Wit, K. Goetz, P. R. Harvey, R. J. MacDowall, D. M. Malaspina, M. Pulupa
Summary: This study examines the sub-Alfvenic solar wind samples encountered by the Parker Solar Probe near the Sun, investigating the turbulence, anisotropy, intermittency, and directional switchback properties and comparing them to neighboring super-Alfvenic periods.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Mathematics, Interdisciplinary Applications
Giuseppe Consolini, Paola De Michelis, Viorel-Puiu Paun
Summary: This study investigates the scaling characteristics of both the magnetic field and the plasma velocity in solar wind turbulence using a novel approach called joint multifractal analysis. The differences in joint multifractal characteristics between the magnetic and velocity field fluctuations in fast and slow solar wind streams are identified.
FRACTAL AND FRACTIONAL
(2023)
Article
Astronomy & Astrophysics
P. Louarn, A. Fedorov, L. Prech, C. J. Owen, R. Bruno, S. Livi, B. Lavraud, A. P. Rouillard, V Genot, N. Andre, G. Fruit, V Reville, R. Kieokaew, I Plotnikov, E. Penou, A. Barthe, D. Khataria, M. Berthomier, R. D'Amicis, L. Sorriso-Valvo, F. Allegrini, J. Raines, D. Verscharen, V Fortunato, G. Mele, T. S. Horbury, H. O'brien, V Evans, V Angelini, M. Maksimovic, J. C. Kasper, S. D. Bale
Summary: This study focuses on analyzing the kinetic properties of the proton population in the Alfvenic slow solar wind, and the possible link with propagating magnetic structures. The research shows a remarkable correlation between magnetic and velocity components, and documents the variability of the proton VDFs shape in relation to the propagation of magnetic structures.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
L. Adhikari, G. P. Zank, D. Telloni, L-L Zhao
Summary: This study presents the first theoretical modeling of joint Parker Solar Probe (PSP)-Metis/Solar Orbiter (SolO) quadrature observations. The results show that the observed solar wind speed and density are consistent with the theoretical predictions, and the slow solar wind is found to be highly Alfvenic. The study also demonstrates the similarity between theoretical and PSP measurements in terms of slab fluctuations and turbulence pressure.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Yu Khotyaintsev, D. B. Graham, A. Vaivads, K. Steinvall, N. J. T. Edberg, A. Eriksson, E. P. G. Johansson, L. Sorriso-Valvo, M. Maksimovic, S. D. Bale, T. Chust, V Krasnoselskikh, M. Kretzschmar, E. Lorfevre, D. Plettemeier, J. Soucek, M. Steller, S. Stverak, P. Travnicek, A. Vecchio, T. S. Horbury, H. O'Brien, V Evans, V Angelini, E. Lorfevre
Summary: The study aims to demonstrate the relationship between solar wind platform waves and plasma density fluctuations using measurements from Solar Orbiter, thus expanding the application of plasma measurement methods and providing new insights into solar wind physics.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Tommaso Alberti, Simone Benella, Giuseppe Consolini, Mirko Stumpo, Roberto Benzi
Summary: The Parker Solar Probe mission presents a unique opportunity to study the characteristics of the solar wind. Recent research has revealed changes in the magnetic and velocity field fluctuations when moving away from the Sun, likely due to the effects of magnetic field fluctuations and plasma thermal expansion.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Rohit Chhiber, William H. Matthaeus, Arcadi Usmanov, Riddhi Bandyopadhyay, Melvyn L. Goldstein
Summary: Motivated by theoretical, numerical, and observational evidence, this study explores the possibility that the critical transition between sub-Alfvenic flow and super-Alfvenic flow in the solar atmosphere takes place within fragmented subvolumes. The initial observations could not provide enough evidence to distinguish between this possibility and a folded surface separating simply connected regions. However, future observations may help differentiate between the two possibilities. A global magnetohydrodynamic model coupled with a turbulence transport model is used to generate possible realizations of this critical zone.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
D. B. Graham, Yu Khotyaintsev, A. Vaivads, N. J. T. Edberg, A. Eriksson, E. P. G. Johansson, L. Sorriso-Valvo, M. Maksimovic, J. Soucek, D. Pisa, S. D. Bale, T. Chust, M. Kretzschmar, V Krasnoselskikh, E. Lorfevre, D. Plettemeier, M. Steller, S. Stverak, P. Travnicek, A. Vecchio, T. S. Horbury, H. O'Brien, V Evans, V Angelini
Summary: This study investigates electrostatic Langmuir and ion-acoustic waves in the solar wind, exploring their relationship with current structures. Results show that ion-acoustic waves are frequently observed in the solar wind, often associated with regions of enhanced currents, but not directly at current structures.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Richa N. Jain, R. K. Choudhary, Anil Bhardwaj, Umang Parikh, Bijoy K. Dai, M. Roopa
Summary: Radio signals from India's Mars Orbiter Mission were used to study turbulence in the solar plasma, and the corresponding turbulence power spectrum was obtained. These findings are important for understanding the mechanisms of solar wind acceleration and coronal heating.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Sakshee Sakshee, Riddhi Bandyopadhyay, Supratik Banerjee
Summary: This study found that there is a similar spectral-index anisotropy in switchback and non-switchback intervals, consistent with critical balance, but power anisotropy is more enhanced in the non-switchback samples, possibly due to the 'less developed' turbulence in the non-switchback periods.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
C. H. K. Chen, B. D. G. Chandran, L. D. Woodham, S. Jones, J. C. Perez, S. Bourouaine, T. A. Bowen, K. G. Klein, M. Moncuquet, J. C. Kasper, S. D. Bale
Summary: PSP's fourth solar encounter revealed differences in turbulence properties between inbound and outbound regions, likely due to proximity to the heliospheric current sheet. Turbulence in the streamer belt wind near the HCS showed characteristics similar to slow wind at 1 au, suggesting it as prototypical slow solar wind. Furthermore, measured Alvenic turbulence energy fluxes in the streamer belt were significantly lower than model predictions, indicating the need for additional mechanisms to explain solar wind acceleration in this region.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Physics, Multidisciplinary
J. C. Kasper, K. G. Klein, E. Lichko, Jia Huang, C. H. K. Chen, S. T. Badman, J. Bonnell, P. L. Whittlesey, R. Livi, D. Larson, M. Pulupa, A. Rahmati, D. Stansby, K. E. Korreck, M. Stevens, A. W. Case, S. D. Bale, M. Maksimovic, M. Moncuquet, K. Goetz, J. S. Halekas, D. Malaspina, Nour E. Raouafi, A. Szabo, R. MacDowall, Marco Velli, Thierry Dudok de Wit, G. P. Zank
Summary: The high temperatures and strong magnetic fields of the solar corona form streams of solar wind that expand through the Solar System, with magnetic pressure dominating both ion and electron pressure. The sub-Alfvenic nature of the flow suggests suppressed magnetic reconnection at the base of the pseudostreamer, as evidenced by unusually low densities in the region.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
L. Sorriso-Valvo, R. Marino, R. Foldes, E. Leveque, R. D'Amicis, R. Bruno, D. Telloni, E. Yordanova
Summary: This study estimates the energy transfer rate of turbulent cascade in the expanding solar wind by using a linear scaling of the mixed third-order moment of the magnetohydrodynamic (MHD) fluctuations. Data from the Helios 2 spacecraft and direct numerical simulations with the FLAME code were used for interpretation. The results show that the turbulence energy transfer rate decays approximately as a power law of the distance and corresponds to the observed radial temperature profile in the fast wind case.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
T. Getachew, D. J. McComas, C. J. Joyce, E. Palmerio, E. R. Christian, C. M. S. Cohen, M. Desai, J. Giacalone, M. E. Hill, W. H. Matthaeus, R. L. McNutt, D. G. Mitchell, J. G. Mitchell, J. S. Rankin, E. C. Roelof, N. A. Schwadron, J. R. Szalay, G. P. Zank, L-L Zhao, B. J. Lynch, T. D. Phan, S. D. Bale, P. L. Whittlesey, J. C. Kasper
Summary: In this paper, we examine a low-energy solar energetic particle event observed on September 30, 2020. The event shows interesting time profile and ion composition, indicating particle anisotropies and velocity dispersion. Our analysis suggests that this event may be associated with a slow streamer blowout coronal mass ejection.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Oreste Pezzi, Pasquale Blasi, William H. Matthaeus
Summary: This paper discusses the energization of relativistic charged particles in three-dimensional incompressible MHD turbulence and the diffusive properties of their motion. The results show that turbulent plasma motion induces a random electric field, leading to stochastic acceleration of test particles in a simulated box, developing a second-order Fermi process. Some particles are trapped in large-scale structures and experience exponential acceleration if certain conditions are met.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Nikos Sioulas, Marco Velli, Rohit Chhiber, Loukas Vlahos, William H. Matthaeus, Riddhi Bandyopadhyay, Manuel E. Cuesta, Chen Shi, Trevor A. Bowen, Ramiz A. Qudsi, Michael L. Stevens, Stuart D. Bale
Summary: This study uses data from the Parker Solar Probe to investigate the statistical properties of coherent structures in the inner heliosphere. The results show a correlation between magnetic field intermittency and observable consequences such as plasma heating and turbulence dissipation. Proton heating is found to occur in magnetic structures characterized by a partial variance of increments (PVI) value of 1 or higher. The study also reveals that coherent structures are not evenly distributed and tend to form clusters. Smaller scale structures with a PVI value between 1 and 6 play a major role in magnetic energy dissipation.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
M. Desai, D. G. Mitchell, D. J. McComas, J. F. Drake, T. Phan, J. R. Szalay, E. C. Roelof, J. Giacalone, M. E. Hill, E. R. Christian, N. A. Schwadron, R. L. McNutt, M. E. Wiedenbeck, C. Joyce, C. M. S. Cohen, A. J. Davis, S. M. Krimigis, R. A. Leske, W. H. Matthaeus, O. Malandraki, R. A. Mewaldt, A. Labrador, E. C. Stone, S. D. Bale, J. Verniero, A. Rahmati, P. Whittlesey, R. Livi, D. Larson, M. Pulupa, R. J. MacDowall, J. T. Niehof, J. C. Kasper, T. S. Horbury
Summary: We present observations of suprathermal H, He, O, and Fe ions associated with crossings of the heliospheric current sheet (HCS) at distances less than 0.1 AU from the Sun. Our key findings include the variations in heavy-ion intensities during crossings, the absence of velocity dispersion in ion arrival times, the pitch-angle distributions of He ions, the steepening of the He, O, and Fe spectra, and the increase of maximum energies with the ion's charge-to-mass ratio. These observations challenge current mechanisms and models for the production and transport of energetic ions.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Francesco Pecora, William H. Matthaeus, Leonardo Primavera, Antonella Greco, Rohit Chhiber, Riddhi Bandyopadhyay, Sergio Servidio
Summary: The subject of switchbacks in the magnetic field has drawn significant interest in the space physics community since the launch of the Parker Solar Probe (PSP) in 2018. This study analyzes the frequency of switchbacks per unit distance for the first eight orbits of PSP, observing a sharp decrease in occurrence rate near the Sun and a gentle increase outward. The analysis accounts for variations in magnetic field cadences and local averages, confirming the robustness of the findings.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Manuel Enrique Cuesta, Tulasi N. Parashar, Rohit Chhiber, William H. Matthaeus
Summary: This article examines the evolution of intermittency from near-Sun plasma to radial distances as large as 10 au. Statistical analysis of magnetic-field vector components reveals that regions with lower Reynolds numbers have lower kurtosis, indicating less intermittent behavior. Additionally, the refined similarity hypothesis is applied to calculate intermittency parameters and fractal scaling in the inertial range.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2022)
Article
Astronomy & Astrophysics
Rohit Chhiber, William H. Matthaeus, Arcadi Usmanov, Riddhi Bandyopadhyay, Melvyn L. Goldstein
Summary: Motivated by theoretical, numerical, and observational evidence, this study explores the possibility that the critical transition between sub-Alfvenic flow and super-Alfvenic flow in the solar atmosphere takes place within fragmented subvolumes. The initial observations could not provide enough evidence to distinguish between this possibility and a folded surface separating simply connected regions. However, future observations may help differentiate between the two possibilities. A global magnetohydrodynamic model coupled with a turbulence transport model is used to generate possible realizations of this critical zone.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Nikos Sioulas, Zesen Huang, Marco Velli, Rohit Chhiber, Manuel E. Cuesta, Chen Shi, William H. Matthaeus, Riddhi Bandyopadhyay, Loukas Vlahos, Trevor A. Bowen, Ramiz A. Qudsi, Stuart D. Bale, Christopher J. Owen, P. Louarn, A. Fedorov, Milan Maksimovic, Michael L. Stevens, Anthony Case, Justin Kasper, Davin Larson, Marc Pulupa, Roberto Livi
Summary: Parker Solar Probe and SolO data were used to investigate magnetic field intermittency in the solar wind. Small-scale intermittency was observed to strengthen radially, while no clear trend was observed at larger scales. Lower-order moment-based methods were considered more appropriate for examining the evolution of coherent structures. Intermittency was found to be related to plasma parameters and the angle between the magnetic field and solar wind flow.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
A. P. Snodin, T. Jitsuk, D. Ruffolo, W. H. Matthaeus
Summary: This study tests the generality of an improved theory by applying it to a noisy reduced magnetohydrodynamic (NRMHD) turbulence model and comparing perpendicular diffusion coefficients with other theories and test particle simulations. The results show that the improved theory matches simulations within a factor of 2, demonstrating its accuracy and effectiveness in understanding energetic particle transport in turbulent magnetic fields.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Manuel Enrique Cuesta, Rohit Chhiber, Sohom Roy, Joshua Goodwill, Francesco Pecora, Jake Jarosik, William H. Matthaeus, Tulasi N. Parashar, Riddhi Bandyopadhyay
Summary: This study examines the radial evolution of correlation lengths perpendicular and parallel to the magnetic-field direction in solar wind data. An anisotropy is observed in the inner heliosphere, which decreases with increasing heliocentric distance and eventually becomes isotropic within 1 au. Results from ACE and WIND support the reversal of the anisotropy. This study provides insights into the radial evolution of turbulent fluctuations in the heliosphere.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
Yanwen Wang, Rohit Chhiber, Subash Adhikari, Yan Yang, Riddhi Bandyopadhyay, Michael A. Shay, Sean Oughton, William H. Matthaeus, Manuel E. Cuesta
Summary: This article investigates the accurate evaluation of cascade rates in various systems, taking into account the limitations of available data and turbulence symmetry. By examining the increment form of the von Karman-Howarth equation, the accuracy and feasibility of third-order laws are effectively assessed. The conditions for obtaining correct and accurate dissipation rates from these laws are studied using simulation results.
ASTROPHYSICAL JOURNAL
(2022)
Article
Physics, Fluids & Plasmas
Riddhi Bandyopadhyay, Ramiz A. Qudsi, S. Peter Gary, William H. Matthaeus, Tulasi N. Parashar, Bennett A. Maruca, Vadim Roytershteyn, Alexandros Chasapis, Barbara L. Giles, Daniel J. Gershman, Craig J. Pollock, Christopher T. Russell, Robert J. Strangeway, Roy B. Torbert, Thomas E. Moore, James L. Burch
Summary: Previous studies have shown that a narrower range of proton temperature anisotropy values is observed as proton beta increases. This study further explores the relationship between instability growth rates and turbulence time scales in turbulent plasmas, and finds that in regions of extreme temperature anisotropy, the instability growth rates are comparable or faster than the turbulence time scales.
PHYSICS OF PLASMAS
(2022)
Article
Astronomy & Astrophysics
Haley DeWeese, Bennett A. Maruca, Ramiz A. Qudsi, Alexandros Chasapis, Mark Pultrone, Elliot Johnson, Sarah K. Vines, Michael A. Shay, William H. Matthaeus, Roman G. Gomez, Stephen A. Fuselier, Barbara L. Giles, Daniel J. Gershman, Christopher T. Russell, Robert J. Strangeway, James L. Burch, Roy B. Torbert
Summary: This study investigates the instability-driven limits on the anisotropy of alpha particles in Earth's magnetosheath using data from the Magnetic Multiscale Mission. The range of temperature anisotropy narrows as plasma beta increases, indicating the presence of kinetic microinstabilities. The data distribution aligns well with the contours of constant growth rate for various instabilities.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Francesco Pecora, Sergio Servidio, Leonardo Primavera, Antonella Greco, Yan Yang, William H. Matthaeus
Summary: Exploration of plasma dynamics in space, including turbulence, is entering a new era of multisatellite constellation measurements that will determine fundamental properties with unprecedented precision. Familiar but imprecise approximations will need to be abandoned and replaced with more-advanced approaches. HelioSwarm, a nine-spacecraft constellation, along with numerical simulations, is used to study turbulence and compute multidimensional spectra and turbulent energy flux, providing crucial information on the nature of astrophysical turbulence.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Physics, Fluids & Plasmas
Sohom Roy, R. Chhiber, S. Dasso, M. E. Ruiz, W. H. Matthaeus
Summary: This article investigates plasma turbulence in the solar wind and empirically demonstrates the applicability of the similarity decay hypothesis to the two-point correlation functions in this turbulence. The results indicate that this approach is useful for space turbulence data analysis and global and subgrid-scale dynamical modeling.