Article
Astronomy & Astrophysics
A. Fedorov, P. Louarn, C. J. Owen, T. S. Horbury, L. Prech, T. Durovcova, A. Barthe, A. P. Rouillard, J. C. Kasper, S. D. Bale, R. Bruno, H. O'Brien, V Evans, V Angelini, D. Larson, R. Livi, B. Lavraud, N. Andre, V Genot, E. Penou, G. Mele, V Fortunato
Summary: Researchers discovered that fluctuations in the solar wind and the phenomenon of rapid polarity reversals may have the same origin, possibly due to solar wind velocity shearing causing magnetic field lines to bend and produce flux ropes. These results provide further explanation for solar wind phenomena near the Sun.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
T. A. Howson, I. De Moortel, D. I. Pontin
Summary: The study shows that the magnetic Kelvin-Helmholtz instability can trigger magnetic reconnection and enhance the dissipation rate of energy stored in the magnetic field in the solar corona. Magnetic reconnection tends to occur along the boundaries of Kelvin-Helmholtz vortices, and the rate decreases with a reduction in the growth rate of KHI.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. Froment, V Krasnoselskikh, T. Dudok de Wit, O. Agapitov, N. Fargette, B. Lavraud, A. Larosa, M. Kretzschmar, V. K. Jagarlamudi, M. Velli, D. Malaspina, P. L. Whittlesey, S. D. Bale, A. W. Case, K. Goetz, J. C. Kasper, K. E. Korreck, D. E. Larson, R. J. MacDowall, F. S. Mozer, M. Pulupa, C. Revillet, M. L. Stevens
Summary: The Parker Solar Probe's first encounters with the Sun revealed direct evidence for magnetic reconnection occurring at the boundaries of three switchbacks. The analysis showed that during magnetic reconnection, ion velocity and magnetic fields exhibit distinct changes.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
G. H. H. Suen, C. J. Owen, D. Verscharen, T. S. Horbury, P. Louarn, R. De Marco
Summary: This study analyzed data collected by the Solar Orbiter spacecraft and identified three instances of magnetic reconnection occurring at the trailing edge of magnetic switchbacks. The results suggest that magnetic reconnection may contribute to the erosion of switchbacks and explain the relative rarity of switchback observations at 1 au.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
B. Popescu Braileanu, V. S. Lukin, E. Khomenko
Summary: We present the results of high-resolution simulations on the magnetized Rayleigh Taylor instability (RTI) at the interface between a solar prominence and the corona. The simulations demonstrate the conversion of gravitational energy into magnetic energy through the generation and amplification of magnetic structures by RTI. Significant impact of flow decoupling, ionization, and recombination reactions on the structure formation in magnetized RTI is also found.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Xiaoyan Xie, Zhixing Mei, Chengcai Shen, Qiangwei Cai, Jing Ye, Katharine K. Reeves, Ilia I. Roussev, Jun Lin
Summary: In this study, magnetohydrodynamics numerical experiments were conducted to investigate the dynamic behaviour of the current sheet between coronal mass ejection and solar flare. The research found that the CS exhibits oscillations and plasmoid motions, providing insights into the evolution of solar activities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
L. D. Woodham, T. S. Horbury, L. Matteini, T. Woolley, R. Laker, S. D. Bale, G. Nicolaou, J. E. Stawarz, D. Stansby, H. Hietala, D. E. Larson, R. Livi, J. L. Verniero, M. McManus, J. C. Kasper, K. E. Korreck, N. Raouafi, M. Moncuquet, M. P. Pulupa
Summary: The study shows that patches of switchbacks in the solar wind are highlighted by transverse deflections in the flow and magnetic field away from the radial direction. These deflections are correlated with enhancements in parallel proton temperature, while perpendicular proton temperature remains relatively constant. Patches sometimes exhibit small enhancements in proton and electron density.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. J. Owen, A. C. Foster, R. Bruno, S. Livi, P. Louarn, M. Berthomier, A. Fedorov, C. Anekallu, D. Kataria, C. W. Kelly, G. R. Lewis, G. Watson, L. Bercic, D. Stansby, G. Suen, D. Verscharen, V Fortunato, G. Nicolaou, R. T. Wicks, I. J. Rae, B. Lavraud, T. S. Horbury, H. O'Brien, V Evans, V Angelini
Summary: This study re-examines the existing model of the structure of reconnection layers in solar wind events, proposing the existence of multiple distinct layers around bifurcated current sheets. Evidence from a case study using Solar Orbiter data supports this concept, but further detailed examination is needed for full confirmation.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Sanchita Pal, Emilia Kilpua, Simon Good, Jens Pomoell, Daniel J. Price
Summary: This study investigates the relationship between twist profiles in magnetic cloud flux ropes at 1 AU and the amount of erosion they undergo in interplanetary space. The results show that the first magnetic cloud experiences more erosion than the second one, leading to a larger reduction in magnetic flux between the Sun and 1 AU.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Simon Opie, Daniel Verscharen, Christopher H. K. Chen, Christopher J. Owen, Philip A. Isenberg
Summary: By analyzing the solar wind observations from the Solar Orbiter mission, the interplay between background turbulent fluctuations and kinetic instabilities is investigated. It is found that the non-equilibrium conditions causing micro-instabilities are accompanied by increased variability in the magnetic field. The competition between turbulence and instabilities is shown to significantly regulate the proton-scale energetics of the solar wind.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
E. Husidic, M. Lazar, H. Fichtner, K. Scherer, S. Poedts
Summary: The present paper aims to improve the evaluation of the main transport coefficients in nonequilibrium plasmas by considering the implicit realistic characterization of particle velocity distributions. In the presence of suprathermal electrons, the transport coefficients are found to be systematically and markedly enhanced due to the additional kinetic energy contributed by these populations. The results highlight the importance of accurately modeling suprathermal populations with the Kappa distribution in contrast to other modified interpretations that underestimate their effects.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
V Zharkova, Q. Xia
Summary: This research explores variations of electron pitch-angle distributions during spacecraft crossing of reconnecting current sheets with magnetic islands. Results show that energy gains and PADs of particles depend on magnetic field topology, spacecraft crossing paths, and guiding field strength. The study helps explain a variety of PAD features observed in the solar wind and the Earth's magnetosphere.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. J. Owen, D. O. Kataria, L. Bercic, T. S. Horbury, M. Berthomier, D. Verscharen, R. Bruno, S. Livi, P. Louarn, C. Anekallu, C. W. Kelly, G. R. Lewis, G. Watson, V Fortunato, G. Mele, G. Nicolaou, R. T. Wicks, H. O'Brien, V Evans, V Angelini
Summary: Small-scale kinetic processes like turbulence, plasma instabilities, and magnetic reconnection are crucial for dissipating energy and shaping the large-scale evolution of the solar wind. The limitations on measurement frequencies of particle instruments have hindered the understanding of solar wind kinetic physics. The new measurement scheme discussed in this paper offers a way to obtain detailed electron velocity distribution functions in real-time, providing a new tool for studying the kinetic processes of the solar wind.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Zhi Li, Mao Zhang
Summary: Magnetic holes are commonly found in Earth's magnetosphere plasma system. Understanding their formation mechanisms and their impact on the background plasma is crucial for gaining insight into energy conversion in near-earth space environments. This study provides clear evidence that a kinetic-scale magnetic hole occurs in the separatrix region of asymmetry reconnection at the Earth's magnetopause, suggesting a broader connection between magnetic holes and reconnection. High-resolution measurements show that electrons along the separatrix region are trapped and significantly thermalized by the magnetic hole. Observations indicate that a separatrix region with significant shear flow can create favorable conditions for stable magnetic holes, which can continuously generate high-energy electrons.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
J. S. Halekas, P. L. Whittlesey, D. E. Larson, D. McGinnis, S. D. Bale, M. Berthomier, A. W. Case, B. D. G. Chandran, J. C. Kasper, K. G. Klein, K. E. Korreck, R. Livi, R. J. MacDowall, M. Maksimovic, D. M. Malaspina, L. Matteini, M. P. Pulupa, M. L. Stevens
Summary: The analysis of Parker Solar Probe's observations near the Sun revealed trends in electron heat flux related to plasma beta values. In high beta regions, while the heat flux decreases, the suprathermal electron flux remains stable or even increases.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
V Agapitov, J. F. Drake, M. Swisdak, S. D. Bale, T. S. Horbury, J. C. Kasper, R. J. MacDowall, F. S. Mozer, T. D. Phan, M. Pulupa, E. Raouafi, M. Velli
Summary: A major discovery of Parker Solar Probe is the presence of localized increases in solar wind speed and associated deflections of the magnetic field. This phenomenon is believed to be caused by magnetic reconnection and flux rope ejection. The study examines the role of flux rope merging in controlling the structure of these deflections through observations, analysis, and simulations. The results reveal the importance of merging in reducing the wrapping magnetic field and elongating the deflections. The findings are consistent with recent statistical analysis from PSP.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
H. Arnold, J. F. Drake, M. Swisdak, F. Guo, J. T. Dahlin, Q. Zhang
Summary: This study explores the formation, development, and impact of slow shocks in the upstream regions of reconnecting current layers. It investigates their potential role in producing the hot thermal component of electrons in solar flares.
ASTROPHYSICAL JOURNAL
(2022)
Article
Physics, Multidisciplinary
Peiyun Shi, Prabhakar Srivastav, M. Hasan Barbhuiya, Paul A. Cassak, Earl E. Scime, M. Swisdak
Summary: Non-Maxwellian electron velocity distribution functions containing a warm bulk population and a cold beam were measured directly during electron-only reconnection in a laboratory plasma. The experimental results are consistent with recent observations in the magnetosheath and provide further insight.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
P. S. Pyakurel, M. A. Shay, J. F. Drake, T. D. Phan, P. A. Cassak, J. L. Verniero
Summary: Observations in Earth's turbulent magnetosheath downstream of a quasiparallel bow shock reveal a prevalence of electron-scale current sheets favorable for electron-only reconnection where ions are not coupled to the reconnecting magnetic fields. In small-scale turbulence, magnetic structures associated with intense current sheets are limited in all dimensions. The 2D and 3D kinetic particle-in-cell simulations investigate electron-only reconnection, showing a new form of 3D electron-only reconnection with higher reconnection rates.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
S. J. Naus, J. Qiu, C. R. DeVore, S. K. Antiochos, J. T. Dahlias, J. F. Drake, M. Swisdak
Summary: We analyzed the structure and evolution of ribbons from the M7.3 flare and found that the ribbon width is highly intermittent and closely related to nonthermal hard X-ray emissions. Our results suggest a strong connection between the production of nonthermal electrons and the locally enhanced perpendicular extent of flare ribbon fronts.
ASTROPHYSICAL JOURNAL
(2022)
Article
Physics, Multidisciplinary
E. Boella, K. Schoeffler, N. Shukla, M. E. Innocenti, G. Lapenta, R. Fonseca, L. O. Silva
Summary: This study investigates the head-on collision between electrostatic shocks using multi-dimensional particle-in-cell simulations. It is found that a strong magnetic field develops after the interaction, leading to a significant drop in shock velocities. This transverse magnetic field is generated by the Weibel instability driven by pressure anisotropies due to longitudinal electron heating during the shock approach.
NEW JOURNAL OF PHYSICS
(2022)
Article
Physics, Fluids & Plasmas
Peiyun Shi, Prabhakar Srivastav, M. Hasan Barbhuiya, Paul A. Cassak, Earl E. Scime, M. Swisdak, Cuyler Beatty, Tyler Gilbert, Regis John, Matthew Lazo, Ripudaman Singh Nirwan, Mitchell Paul, Ethan E. Scime, Katey Stevenson, Thomas Steinberger
Summary: In this study, electron heating and acceleration during electron-only reconnection were investigated using the PHAse Space MApping (PHASMA) facility. The results showed that electron heating is localized around the separatrix, and the electron temperature increases continuously along the separatrix with distance from the X-line. Non-Maxwellian electron velocity distribution functions (EVDFs) consisting of a warm bulk population and a cold beam were directly measured, revealing the signature of electron acceleration caused by electron-only reconnection. The laboratory measurements agreed well with the theoretical simulations, and provided insights beyond the magnetosheath observations.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Fluids & Plasmas
M. Oka, T. D. Phan, M. Oieroset, D. L. Turner, J. F. Drake, X. Li, S. A. Fuselier, D. J. Gershman, B. L. Giles, R. E. Ergun, R. B. Torbert, H. Y. Wei, R. J. Strangeway, C. T. Russell, J. L. Burch
Summary: This study shows that electrons in Earth's magnetotail are energized by the locally averaged electric field magnitude, suggesting the importance of reconnection-driven turbulence. However, the non-thermal power-law component can be small even with a large electric field and significant heating of the bulk population.
PHYSICS OF PLASMAS
(2022)
Article
Astronomy & Astrophysics
Stefan Eriksson, Marc Swisdak, James M. Weygand, Alfred Mallet, David L. Newman, Giovanni Lapenta, Lynn B. Wilson, Drew L. Turner, Bjorn Larsen
Summary: Wind spacecraft measurements were used to analyze magnetic reconnection exhausts in the ecliptic plane of the solar wind at 1 au. The study found an exponential decay in the distribution of current sheet widths, and a linear increase in the distribution of magnetic field rotation angles. The orientations of wide exhausts were consistent with a dominant Parker-spiral magnetic field, while narrow exhausts were isotropic. These findings suggest that CS bifurcation and turbulence play a role in aligning the exhaust directions with the large-scale heliospheric current sheet.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
M. Hasan Barbhuiya, P. A. Cassak, M. A. Shay, Vadim Roytershteyn, M. Swisdak, Amir Caspi, Andrei Runov, Haoming Liang
Summary: This article presents a theory of electron ring velocity space distributions and validates it using 2.5-dimensional PIC simulations. The study finds that the ring distributions are caused by a plateau in the reconnected magnetic field profile and the predicted temperature matches the observed values. This research may provide an explanation for the generation of high temperature plasma in super-hot solar flares.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Multidisciplinary Sciences
S. D. Bale, J. F. Drake, M. D. McManus, M. I. Desai, S. T. Badman, D. E. Larson, M. Swisdak, T. S. Horbury, N. E. Raouafi, T. Phan, M. Velli, D. J. McComas, C. M. S. Cohen, D. Mitchell, O. Panasenco, J. C. Kasper
Summary: The fast solar wind that fills the heliosphere originates from coronal holes on the Sun and is believed to be accelerated by magnetic reconnection mechanisms such as wave heating and interchange reconnection. Measurements from the Parker Solar Probe provide strong evidence for the interchange reconnection mechanism, showing imprints of supergranulation structure in the solar wind and the presence of magnetic switchbacks and bursty wind streams. Computer simulations support these observations and suggest that the reconnection is collisionless and drives the fast wind through both plasma pressure and radial Alfvenic flow bursts.
Article
Astronomy & Astrophysics
B. Lavraud, M. Opher, K. Dialynas, D. L. Turner, S. Eriksson, E. Provornikova, M. Z. Kornbleuth, P. Mostafavi, A. Fedorov, J. D. Richardson, S. A. Fuselier, J. Drake, M. Swisdak, M. Eubanks, T. Y. Chen, H. Kucharek, P. Kollmann, M. Blanc, N. Andre, V. Genot, R. F. Wimmer-Schweingruber, S. Barabash, P. Brandt, R. McNutt
Summary: We emphasize the significance of magnetic reconnection at the heliopause, both as a crucial process driving the interaction between the solar and interstellar media and as a defining element of the heliopause itself. We discuss the key observations that have contributed to the ongoing debates regarding the definition, location, and shape of the heliopause. Furthermore, we highlight the need for appropriate measurements in order to differentiate between the current interpretations of plasma and magnetic field structures near the heliopause, particularly due to the lack of data from Voyager 1 and 2, and propose certain requirements for thermal plasma measurements on a future Interstellar Probe.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2023)
Article
Astronomy & Astrophysics
Hanqing Ma, J. F. Drake, M. Swisdak
Summary: This study investigates the scattering of electron heat flux by self-generated oblique electromagnetic waves using two-dimensional particle-in-cell simulations. The results show that oblique whistler waves and filamentary-like Weibel instabilities inhibit the heat flux and drive the electron velocity distributions toward isotropy. The scattering rate is mainly controlled by the average speed of the heat flux compared with the electron Alfven speed.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
M. Swisdak, J. Giacalone, J. F. Drake, M. Opher, G. P. Zank, B. Zieger
Summary: We compare hybrid and particle-in-cell simulations of the solar wind termination shock and find excellent agreement in downstream variations. The quasi-perpendicular shock accelerates interstellar pickup ions to a maximum energy, with higher fluxes and maximal energies observed in the particle-in-cell simulation.
ASTROPHYSICAL JOURNAL
(2023)
Article
Physics, Fluids & Plasmas
W. L. Zhang, T. Grismayer, K. M. Schoeffler, R. A. Fonseca, L. O. Silva
Summary: The study shows that when a mixed plasma is irradiated by a weakly relativistic laser pulse, distinct signals at harmonics of the plasma frequency in the harmonic spectrum are observed. These signals are attributed to the inverse two-plasmon decay of the counterpropagating plasma waves. This phenomenon can even be observed at a very low density level of the plasma.
