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.
Review
Physics, Multidisciplinary
Quanming Lu, Huishan Fu, Rongsheng Wang, San Lu
Summary: Magnetic reconnection is the physical mechanism for explosive phenomena in the solar atmosphere and planetary magnetospheres, where plasma is usually collisionless. In the standard model of collisionless magnetic reconnection, the diffusion region consists of two substructures: an electron diffusion region embedded in an ion diffusion region. Observations from spacecraft and kinetic simulations have provided opportunities to study collisionless magnetic reconnection beyond the standard model.
Article
Astronomy & Astrophysics
Muni Zhou, Zhuo Liu, Nuno F. Loureiro
Summary: We investigated the spectral properties of electromagnetic fluctuations in weakly collisional, low-beta plasmas at sub-ion scale turbulence. Our numerical results strongly support the description of turbulence as a critically balanced Kolmogorov-like cascade of kinetic Alfven wave fluctuations, considering intermittency effects. The measured universal index of the energy spectra excludes the role of tearing mediation in determining the spectra.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Shu-Di Yang, Liang Wang, Chuanfei Dong
Summary: This article reports the first fully kinetic simulations of collisionless reconnection in a three-species dusty plasma with negatively charged dust grains, discovering the double Hall pattern and analyzing the reconnection rate. This study is significant for explaining observations of planetary magnetospheres and astrophysical objects, as well as for laboratory studies of dusty plasmas.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Review
Astronomy & Astrophysics
H. Ji, J. Yoo, W. Fox, M. Yamada, M. Argall, J. Egedal, Y. -h. Liu, R. Wilder, S. Eriksson, W. Daughton, K. Bergstedt, S. Bose, J. Burch, R. Torbert, J. Ng, L. -j. Chen
Summary: A concise review is given on the past two decades' results from laboratory experiments on collisionless magnetic reconnection in direct relation with space measurements, especially by the Magnetospheric Multiscale (MMS) mission. The physics foundation of fast reconnection in collisionless plasmas has been largely established, and future opportunities based on multiscale experiments and space missions are discussed.
SPACE SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
H. Gurram, J. Egedal, W. Daughton
Summary: This study found that shear Alfven waves (SAWs) can efficiently transport wave energy during magnetic reconnection in the magnetotail, greatly enhancing the energy input for the Aurora Borealis compared to previous estimates.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Physics, Fluids & Plasmas
C. Granier, E. Tassi, D. Borgogno, D. Grasso
Summary: This study derives and analyzes the dispersion relation for the growth rate of collisionless tearing modes driven by electron inertia in a strong guide field regime, taking into account equilibrium electron temperature anisotropy. The derived dispersion relation does not show an enhancement of the growth rate as the ratio between perpendicular and parallel equilibrium electron temperatures increases, indicating a significant difference compared to cases with absent or moderate guide field. In the strong guide field regime, the tearing mode is found to become weakly damped as the ratio Theta (e) increases, showing good quantitative agreement with numerical simulations.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Multidisciplinary
Alain Ghizzo, Daniele Del Sarto, Homam Betar
Summary: In this study, we conducted high-resolution kinetic simulations of interpenetrating plasma beams. We found that this configuration is unstable to Weibel-type and two-stream instabilities, which linearly induce a growth of magnetic and electrostatic energy, respectively, at the expense of kinetic energy. We also discovered the possibility of a reversal of energy flow associated with these beam-plasma instabilities with the excitation of secondary propagating oblique modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Alain Ghizzo, Daniele Del Sarto, Homan Betar
Summary: We perform simulations to study the interpenetrating plasma beams, which are susceptible to Weibel-type and two-stream instabilities. We find that the energy flow associated with beam-plasma instabilities can be reversed when secondary propagating oblique modes are excited. This reversal is caused by the reinforcement of the filamentation process in the phase space.
PHYSICAL REVIEW LETTERS
(2023)
Article
Astronomy & Astrophysics
Yukang Shu, San Lu, Quanming Lu, Weixing Ding, Shui Wang
Summary: Collisionless magnetic reconnection is common in space plasma environments, with the reconnection site being unstable and generating reconnection fronts. Energy conversion mainly occurs at the reconnection fronts, while the reconnection rate only represents the energy conversion at the reconnection site.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Aohua Mao, Zhibin Wang
Summary: Plasmas with low-temperature ions are commonly observed in solar-terrestrial space and fusion plasmas. This study focuses on the effects of multiple ion temperatures on magnetic reconnection, finding that changes in colder ion density and warmer/colder ion ratio can significantly impact reconnection rates and dynamics.
Article
Geosciences, Multidisciplinary
Z. H. Zhong, M. Zhou, D. B. Graham, Yu. V. Khotyaintsev, Y. F. Wu, O. Le Contel, H. M. Li, X. Tao, R. X. Tang, X. H. Deng
Summary: This paper investigates the whistler-mode waves within an electron-scale current sheet and measures their dispersion relation for the first time. The study shows that the drifting electron component along the magnetic field critically modifies the dispersion relation and demonstrates that these whistler waves propagate into the diffusion region from outside rather than being locally excited.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Dario Borgogno, Daniela Grasso, Beatrice Achilli, Massimiliano Rome, Luca Comisso
Summary: In collisionless plasmas, the formation of plasmoids driven by magnetic reconnection is analyzed. It is found that the coexistence of plasmoid formation and Kelvin-Helmholtz instability is present due to the strong velocity shears. Depending on the local values of the magnetic and velocity fields, the current density layers experience plasmoid or KH instability. The competition among these instabilities affects the evolution of current sheets and the difference in energy cascade between magnetic and kinetic spectra.
ASTROPHYSICAL JOURNAL
(2022)
Article
Physics, Fluids & Plasmas
Chang Liu, Dylan P. Brennan, Andrey Lvovskiy, Carlos Paz-Soldan, Eric D. Fredrickson, Amitava Bhattacharjee
Summary: This paper investigates a new type of compressional Alfven eigenmodes observed in magnetic fusion experiments, which can be driven by runaway electrons, possibly explaining kinetic instabilities observed in DIII-D disruption experiments. By calculating parameters such as spatial structure, frequencies, and mode growth rates, a better understanding of the excitation mechanism of CAEs can be obtained.
Article
Physics, Fluids & Plasmas
R. A. Tinguely, P. G. Puglia, N. Fil, S. Dowson, M. Porkolab, A. Dvornova, A. Fasoli, M. Fitzgerald, V Guillemot, G. T. A. Huysmans, M. Maslov, S. Sharapov, D. Testa
Summary: This study presents a detailed investigation on the coupling between plasma antennas and the Alfven Eigenmode Active Diagnostic in JET. Stable Alfven Eigenmodes at different frequencies and modes are observed under various plasma conditions, with different behaviors for low and high frequency modes. The results provide insights for optimizing plasma-antenna coupling in future JET experiments.
