Article
Astronomy & Astrophysics
J. P. Eastwood, J. E. Stawarz, T. D. Phan, R. Laker, S. Robertson, L-L Zhao, G. P. Zank, B. Lavraud, M. A. Shay, V Evans, V Angelini, H. O'Brien, T. S. Horbury
Summary: This study presents new observations of a flux rope confined to a bifurcated current sheet in the solar wind, providing new insights into the hierarchy of scales on which flux ropes can form. Comparative data from Wind extend the spatial scale over which reconnection signatures have been found at solar wind current sheets. The local orientations of the current sheet at Solar Orbiter and Wind are found to be rotated relative to each other, indicating potential implications for patchy vs. continuous reconnection scenarios.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
N. Fargette, B. Lavraud, A. Rouillard, J. P. Eastwood, S. D. Bale, T. Phan, M. Oieroset, J. S. Halekas, J. Kasper, M. Berthomier, A. W. Case, K. E. Korreck, D. E. Larson, P. Louarn, D. Malaspina, M. Pulupa, M. L. Stevens, P. L. Whittlesey, R. J. MacDowall, K. Goetz, P. R. Harvey, T. Dudok de Wit, J. W. Bonnell
Summary: The study reports magnetic structures observed by the Parker Solar Probe in the solar wind, showing a strong peak in magnetic field magnitude with an embedded central current sheet. The structures are likely a result of initially distinct flux tubes interacting during solar wind propagation, based on the general properties analyzed in the study.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
K. Steinvall, Yu Khotyaintsev, G. Cozzani, A. Vaivads, E. Yordanova, A. Eriksson, N. J. T. Edberg, M. Maksimovic, S. D. Bale, T. Chust, V Krasnoselskikh, M. Kretzschmar, E. Lorfevre, D. Plettemeier, J. Soucek, M. Steller, S. Stverak, A. Vecchio, T. S. Horbury, H. O'Brien, V Evans, A. Fedorov, P. Louarn, V Genot, N. Andre, B. Lavraud, A. P. Rouillard, C. J. Owen
Summary: This paper assesses the quality of the low-frequency DC electric field measured by the Radio and Plasma Waves instrument on Solar Orbiter and investigates the possibility of using this data to estimate solar wind speed. Using the deHoffmann-Teller analysis, a simple model was developed to estimate solar wind speed based on electric and magnetic field measurements. The results suggest that the observed variations in the electric field are closely related to variations in the magnetic field, with potential for improving the estimation of solar wind speed.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Geosciences, Multidisciplinary
T. D. Phan, J. L. Verniero, D. Larson, B. Lavraud, J. F. Drake, M. Oieroset, J. P. Eastwood, S. D. Bale, R. Livi, J. S. Halekas, P. L. Whittlesey, A. Rahmati, D. Stansby, M. Pulupa, R. J. MacDowall, P. A. Szabo, A. Koval, M. Desai, S. A. Fuselier, M. Velli, M. Hesse, P. S. Pyakurel, K. Maheshwari, J. C. Kasper, J. M. Stevens, A. W. Case, N. E. Raouafi
Summary: This article reports the observation of reconnection exhausts in the Heliospheric Current Sheet (HCS) by the Parker Solar Probe at close proximity to the Sun. These exhausts accelerated protons and increased their energy, while also causing the leakage of separatrix field lines.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
M. Hubbert, Y. Qi, C. T. Russell, J. L. Burch, B. L. Giles, T. E. Moore
Summary: This report examines tail current sheets supported only by electron currents in Earth's magnetotail. Three of these current sheets are interpreted in terms of the time-evolution of reconnection onset, showing evidence of parallel electron heating, perpendicular ion heating, and current sheet expansion. The data suggests that electron-only reconnection can act as a precursor to electron-ion reconnection, but also that it is more than merely a precursor to ion reconnection.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
Zilu Zhou, Xiaojun Xu, Pingbing Zuo, Yi Wang, Qi Xu, Yudong Ye, Jing Wang, Ming Wang, Qing Chang, Xing Wang, Lei Luo
Summary: This study examines plasma heating at thin current sheets in the solar wind using data from the WIND spacecraft from 2004 to 2019. The results show significant plasma heating at current sheets in both slow and fast wind, with a more significant increase in proton temperature in the fast wind.
ASTROPHYSICAL JOURNAL LETTERS
(2022)
Article
Astronomy & Astrophysics
A. B. Lotekar, I. Y. Vasko, T. Phan, S. D. Bale, T. A. Bowen, J. Halekas, A. Artemyev, Yu Khotyaintsev, F. S. Mozer
Summary: This study presents statistical analysis of proton kinetic-scale current sheets observed by the Parker Solar Probe. The analysis reveals the range and typical values for the thickness and current density of these current sheets, as well as their asymmetry and relationship with scale and magnetic shear angles. The findings suggest that these proton kinetic-scale current sheets are produced by turbulence cascade and are not suppressed by the diamagnetic mechanism.
ASTROPHYSICAL JOURNAL
(2022)
Review
Astronomy & Astrophysics
O. Pezzi, F. Pecora, J. le Roux, N. E. Engelbrecht, A. Greco, S. Servidio, H. Malova, O. Khabarova, O. Malandraki, R. Bruno, W. H. Matthaeus, G. Li, L. M. Zelenyi, R. A. Kislov, V. N. Obridko, V. D. Kuznetsov
Summary: Our understanding of processes in the heliosphere began with reduced dimensionality models, but non-planar structures play a crucial role in explaining phenomena like particle acceleration and energy dissipation; This review focuses on the theoretical paradigms and differences between 2D and 3D views of current sheets, magnetic islands, and flux ropes; The complex nature of magnetic reconnection and particle acceleration in a turbulent environment is highlighted through numerical simulations and in-situ observations.
SPACE SCIENCE REVIEWS
(2021)
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, Fluids & Plasmas
C. Granier, D. Borgogno, L. Comisso, D. Grasso, E. Tassi, R. Numata
Summary: The marginal stability conditions for the formation of plasmoids in a purely collisionless and strong guide field situation are investigated in this study. It is found that plasmoids can be obtained from current sheets with a smaller aspect ratio in the marginal stability current layers.
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
Chengcai Shen, John C. Raymond, Nicholas A. Murphy
Summary: Nonequilibrium ionization (NEI) is crucial for astrophysical plasma diagnostics. The study combines fast NEI calculations with magnetohydrodynamic (MHD) simulations to analyze the ionization properties of a Petschek-type magnetic reconnection current sheet during solar eruptions. The results reveal under-ionized features in shocked reconnection outflows and thermal halo regions outside the shocks and demonstrate the strong dependence of departure from equilibrium ionization on plasma density. The study also shows the potential reversal between under-ionized and over-ionized states at the lower tip of reconnection current sheets, which can significantly affect multiple SDO/AIA band ratios along the reconnection current sheet.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Kan Liou, Chin-Chun Wu
Summary: This statistical study analyzed 1197 heliospheric current sheet (HCS) events associated with sector boundaries observed by the Wind spacecraft between 1995 and 2020. The average properties of the HCS events were characterized by their width, longitude, latitudinal angle, occurrence rate, solar cycle variations, plasma and field properties, proton temperature increase, and temperature anisotropy. The results suggest that the HCS is relatively stable and persistent at 1 astronomical unit on a large scale, while it is likely controlled by the dynamics of the current system on a small scale.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Nikos Sioulas, Heinz Isliker, Loukas Vlahos
Summary: In this article, the physics of charged particle energization inside a strongly turbulent plasma are studied. It is found that the synergistic effects of energization at reconnecting current sheets and nonreconnecting current sheets play a key role in the heating, power-law high energy tail formation, escape time, and acceleration time of electrons and ions. The systematic acceleration of particles at reconnecting current sheets leads to the formation of power-law tails in energy distributions, while the stochastic energization through interaction with nonreconnecting current sheets accounts for the heating in the solar corona and during solar flares. The combination of these two acceleration mechanisms influences the steady-state energy distribution and transport properties of particles in position and energy space.
ASTRONOMY & ASTROPHYSICS
(2022)
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)