Article
Astronomy & Astrophysics
K. Bora, R. Bhattacharyya, P. K. Smolarkiewicz
Summary: This study extends the computational model EULAG-MHD by incorporating Hall magnetohydrodynamics (HMHD) to explore fast magnetic reconnection at the ion inertial length scale. The results show that magnetic reconnections onset significantly earlier in HMHD simulations, leading to the development of magnetic flux ropes and tubes in three-dimensional evolution.
ASTROPHYSICAL JOURNAL
(2021)
Article
Geosciences, Multidisciplinary
Qianyun Xu, Meng Zhou, Wenqing Ma, Jiansen He, Shiyong Huang, Zhihong Zhong, Ye Pang, Xiaohua Deng
Summary: This paper investigates the electron acceleration mechanism in strong turbulence in the Earth's magnetosheath based on novel observations. The study finds that electrons are magnetized in turbulent fields for the majority of the time and primarily accelerated by the parallel electric field within coherent structures. The acceleration rate increases as the spatial scale reduces, with the most intense acceleration occurring over about one ion inertial length.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Computer Science, Interdisciplinary Applications
Hongtao Liu, Xiaofeng Cai, Yong Cao, Giovanni Lapenta
Summary: This paper introduces a novel kinetic scheme called ECSL for the Vlasov-Ampere system, which retains the efficiency of explicit schemes while maintaining energy conservation and unconditional stability properties. The ECSL method includes a conservative Semi-Lagrangian scheme and a novel field solver, ensuring conservation of total energy and mass on a fully discrete level. The ECSL scheme provides reliable solutions even with insufficient spatial and temporal resolution, making it a promising tool for multiscale and lengthy simulations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Mechanics
Arindam Mistri, Debkumar Chakraborty, Samiran Ghosh
Summary: This study investigates the excitation of nonlinear electrostatic ion cyclotron waves caused by a moving charged obstacle in collisionless plasmas. In the weakly nonlinear and dispersive limit, it is found that the excitations can be described by a forced Ostrovsky-type model equation. The exact analytical solution predicts the periodic solution of the nonlinear equation for a specific form of the obstacle. The computational results show the generation of coherent nonlinear structures, such as bipolar, sawtooth, and multi-harmonic, of the electric field at the transcritical speed of the obstacle along with the wave packets, which agree well with astrophysical observations in auroral plasmas.
Article
Physics, Fluids & Plasmas
Josselin Garnier, Kilian Baudin, Adrien Fusaro, Antonio Picozzi
Summary: The study explores the long-term behavior of a modulationally unstable conservative nonintegrable system, revealing the self-organization process into a large-scale incoherent localized structure with hidden coherent soliton states. The analysis provides a theoretical approach for the coupled description of coherent soliton component and incoherent structure.
Article
Geosciences, Multidisciplinary
J. Suni, M. Palmroth, L. Turc, M. Battarbee, A. Johlander, V Tarvus, M. Alho, M. Bussov, M. Dubart, U. Ganse, M. Grandin, K. Horaites, T. Manglayev, K. Papadakis, Y. Pfau-Kempf, H. Zhou
Summary: The Earth's magnetosheath is formed by compressed and slowed down solar wind plasma at the Earth's bow shock. Magnetosheath jets are pulses of enhanced dynamic pressure in the magnetosheath. Research indicates that up to 75% of magnetosheath jets are caused by foreshock compressive structures impacting the bow shock, and these jets penetrate deeper into the magnetosheath than the remaining 25% of jets whose origins are unclear.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Optics
Zehong Liang, Jingyi Shi, Quanfeng Wei, Ziyu Wang, You Wu, Junjie Jiang, Lingling Shui, Dongmei Deng
Summary: This paper introduces a novel class of inseparable coherent structures through theory and experiment. These structures vanish in a completely coherent environment but can be maintained in a coexistent state of extreme incoherence and full coherence. The analysis reveals an interesting association between the magnitude and the phase of the coherent structure, displaying both synergy and opposition. The work uncovers the inner mechanism of inseparable coherent structures and expands the horizon for optical twist.
Article
Physics, Multidisciplinary
H. Peng, T. W. Huang, K. Jiang, R. Li, C. N. Wu, M. Y. Yu, C. Riconda, S. Weber, C. T. Zhou, S. C. Ruan
Summary: This study proposes a method to achieve coherent Cherenkov radiation using superluminal plasma wake. Through simulations and theoretical modeling, it is shown that this radiation has ultra-short duration, high intensity, and excellent directionality. Furthermore, the central frequency of the radiation can be easily tuned over a wide range.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Fluids & Plasmas
Olivier Doche, Sedat Tardu, Jonathan Schillings, Amandine Capogna
Summary: This investigation uses direct numerical simulations to study the response of wall turbulences in channel flow to uniform streamwise and spanwise magnetic fields. It is found that spanwise magnetic field leads to flow relaminarization at lower Stuart numbers compared to the streamwise magnetic field. A detailed analysis of the turbulence structure is needed to fully understand this phenomenon.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Astronomy & Astrophysics
Macy Huston, Jason Wright
Summary: This study investigates the impact of light reflection from Dyson spheres on stars, finding that it causes the stars to expand and cool. The observational consequences of this effect are significant only when the spheres have very high temperatures and/or high specular reflectivity.
ASTROPHYSICAL JOURNAL
(2022)
Article
Computer Science, Interdisciplinary Applications
Chang Yang, Michel Mehrenberger
Summary: This paper introduces a highly accurate monotonicity-preserving Semi-Lagrangian scheme for Vlasov-Poisson simulations, which uses a limiter to avoid accuracy loss and clipping near extrema while maintaining monotonicity. The scheme preserves the monotonicity of the solution for locally monotonic data, while maintaining good properties and high accuracy similar to the unlimited scheme. Numerical tests show that the limited scheme is more diffusive compared to cubic splines, but has better L-1 conservation, making it advantageous for problems with sharp gradients.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Ashish Chauniyal, Rebecca Janisch
Summary: Gamma/gamma interfaces play a crucial role in driving plastic deformation in lamellar TiAl alloys. The presence of different variants of gamma/gamma twin interfaces, such as coherent and semicoherent interfaces, results in variations in deformation behavior. It has been found that the coherency state of the gamma/gamma interfaces leads to preferential nucleation and affects the strength of the lamellar microstructure. These findings contribute to the future design of alloy microstructures based on interface types and coherency states.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Multidisciplinary Sciences
Junjie Liu, Valentin V. Laguta, Katherine Inzani, Weichuan Huang, Sujit Das, Ruchira Chatterjee, Evan Sheridan, Sinead M. Griffin, Arzhang Ardavan, Ramamoorthy Ramesh
Summary: Magnetoelectrics, materials that exhibit coupling between magnetic and electric degrees of freedom, provide a rich environment for studying the fundamental materials physics of spin-charge coupling and offer opportunities for future information technology paradigms. Results show that spins of ferric ions can be preferentially aligned perpendicular to the ferroelectric polar axis and manipulated using an electric field, with coherent control of spin superpositions achieved by applying electric field pulses during time-resolved EPR measurements. These findings suggest a new pathway towards spin manipulation for quantum and classical spintronics.
Article
Computer Science, Interdisciplinary Applications
Zhuoning Li, Zhenli Xu, Zhiguo Yang
Summary: In this paper, we present an efficient and accurate energy-conserving implicit particle-in-cell (PIC) algorithm for simulating complex plasma systems with multiple physical scales.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Xiaofeng Cai, Jing-Mei Qiu, Yang Yang
Summary: The paper introduces a new method called ELDG, which incorporates a modified adjoint problem and integration of PDE over a space-time region partitioned by time-dependent linear functions. By introducing a new flux term to account for errors in characteristics approximation, the ELDG method combines the advantages of SL DG and classical Eulerian RK DG methods. The use of linear functions for characteristics approximation in the EL DG framework simplifies shapes of upstream cells and reduces time step constraints.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
J. Dargent, N. Aunai, B. Lavraud, S. Toledo-Redondo, F. Califano
GEOPHYSICAL RESEARCH LETTERS
(2020)
Article
Physics, Multidisciplinary
Francesco Pegoraro, Sergei V. Bulanov
Article
Physics, Fluids & Plasmas
P. J. Morrison, T. Andreussi, F. Pegoraro
JOURNAL OF PLASMA PHYSICS
(2020)
Review
Physics, Multidisciplinary
Francesco Pegoraro, Pierluigi Veltri
RIVISTA DEL NUOVO CIMENTO
(2020)
Editorial Material
Physics, Fluids & Plasmas
F. Califano, G. Manfredi, F. Valentini
JOURNAL OF PLASMA PHYSICS
(2020)
Article
Astronomy & Astrophysics
S. Fadanelli, B. Lavraud, F. Califano, G. Cozzani, F. Finelli, M. Sisti
Summary: The energization and de-energization of a plasma result from the complex interplay between multiple electromagnetic and thermodynamic effects. The relationships between local energy transfers and correlations between different terms are crucial in understanding the overall energy gain or loss in the system, with higher conversion rates occurring mostly at the smallest local plasma scales.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Manuela Sisti, Francesco Finelli, Giorgio Pedrazzi, Matteo Faganello, Francesco Califano, Francesca Delli Ponti
Summary: This study investigates the impact of kinetic turbulence in magnetized space plasmas on the formation of coherent current structures and magnetic reconnection. Automatic techniques are proposed to detect reconnection events, showing that the use of unsupervised machine learning methods is competitive in performance compared to other threshold-based methods using standard reconnection proxies.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Richard E. Denton, Roy B. Torbert, Hiroshi Hasegawa, Kevin J. Genestreti, Roberto Manuzzo, Gerard Belmont, Laurence Rezeau, Francesco Califano, Rumi Nakamura, Jan Egedal, Olivier Le Contel, James L. Burch, Daniel J. Gershman, Ivan Dors, Matthew R. Argall, Christopher T. Russell, Robert J. Strangeway, Barbara L. Giles
Summary: Two methods, Spatio-Temporal Difference (STD) and polynomial reconstruction, are demonstrated for determining the two-dimensional magnetic structure velocity in a magnetic reconnection event observed by the Magnetospheric Multiscale (MMS) spacecraft. Both methods utilize magnetic field measurements, with the reconstruction technique also incorporating current density measurements from particle instruments. There is general agreement between the results of these methods and previously published velocity determinations, but both are susceptible to contamination by magnetometer calibration errors.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Eugenio Ferrato, Vittorio Giannetti, Francesco Califano, Tommaso Andreussi
Summary: This paper characterizes the HT5k Hall thruster in different operating conditions and proposes a 0D-hybrid model for atmospheric propellant fed Hall thruster discharges. The calibrated model comparison against experimental data shows a mean absolute error of 3.7% in thrust and 7.6% in discharge power.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Astronomy & Astrophysics
L. Bucciantini, P. Henri, G. Wattieaux, F. Califano, X. Vallieres, O. Randriamboarison
Summary: Mutual impedance (MI) experiments are plasma diagnostic techniques used for determining plasma density and electron temperature. This study investigates the impact of large antenna emission amplitudes on the diagnostic performance of MI instruments, relaxing the assumption of linear plasma perturbations. The results show that the identification of plasma density and electron temperature remains robust even for large amplitude emissions.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Multidisciplinary Sciences
Giuseppina Nigro, Francesco Pegoraro, Francesco Valentini
Summary: The workshop aimed to promote exchange and collaboration between experimentalists, theoreticians, and numerical plasma modelers from different fields working on plasma physics, reviewing main achievements of the past fifty years and discussing future developments.
RENDICONTI LINCEI-SCIENZE FISICHE E NATURALI
(2021)
Article
Astronomy & Astrophysics
A. Hu, M. Sisti, F. Finelli, F. Califano, J. Dargent, M. Faganello, E. Camporeale, J. Teunissen
ASTROPHYSICAL JOURNAL
(2020)
Article
Multidisciplinary Sciences
Francesco Pegoraro, Sergei Bulanov
RENDICONTI LINCEI-SCIENZE FISICHE E NATURALI
(2020)
Article
Astronomy & Astrophysics
Roberto Manuzzo, Francesco Califano, Gerard Belmont, Laurence Rezeau
ANNALES GEOPHYSICAE
(2020)
Article
Astronomy & Astrophysics
S. Bulanov, P. Sasorov, F. Pegoraro, H. Kadlecova, S. S. Bulanov, T. Zh Esirkepov, N. N. Rosanov, G. Korn