Self-generated turbulence by plasmas and magnetic field collective interaction in 3D large temporal-spatial turbulent magnetic reconnection: I. The Basic Feature

2020 ◽  
Author(s):  
Bojing Zhu ◽  
Hui Yan ◽  
Huihong Cheng ◽  
Ying Zhong ◽  
Yunfei Du ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Plasma Turbulence ◽  
Math Model ◽  
Collective Interaction ◽  
Magnetic Fluctuation ◽  
Fully Coupled ◽  
Appl Math

<p>The role of turbulence is one of key issues for understanding the magnetic and plasma energy conversion, plasma heating and high energy particles acceleration in large temporal-spatial scale turbulent magnetic reconnection (LTSTMR; observed current sheet thickness to characteristic electron length, Larmor radius for low-beta and electron inertial length for high-beta, ratios on the order of ten to the power of ten or higher; observed evolution time to electron cyclotron time ratios on the order of ten to the power of ten or higher) . Solar atmosphere activities (e.g., limbs, flares, coronal mass ejections, solar winds and so on), which are the most important phenomenon in the solar and Sun-Earth space systems, are typical LTSTMRs.</p><p>Here we used our newly developed RHPIC-LBM algorithm[*]  to perform the role of  turbulence in the magnetic fluctuation-induced self-generating-organization  (MF-ISGO), the turbulence in the plasma turbulence-induced self-feeding-sustaining (PT-ISFS), and the interaction of turbulence between MF-ISGO and PT-ISFS in the continuous kinetic-dynamic-hydro fully coupled LTSTMR. </p><p>First, we find that the self-generated turbulence by magnetic field and plasma motion collective interaction include two fully coupled processes of 1) fluid vortex induced magnetic reconnection (MR) and 2) MR induced fluid vortex. The Biermann battery effect and  alpha-effect can not only generate magnetic fields, but can server them to trigger MR, the Spitzer resistance and turbulence resistance (beta-effect)  can not only generate magnetic eddies, but can server  them to trigger fluid turbulence.  </p><p>Then, we find that these interaction leads to vortex splitting and phase separating instabilities, and there are four species instabilities coexist in the evolution process. 1) Vortex separation interface instabilities. 2)Magnetic fluctuation-induced self-generating-organization instabilities. 3) Plasma turbulence-induced self-feeding-sustaining instabilities. 4) Vortex shedding instabilities.</p><p>Finally, the nuanced details of the magnetic topological structure and the topological characterization of flow structures in plasma of the simulated 3D LTSTMR are also presented.</p><p>The characterization of turbulence anisotropy and the turbulence acceleration of the LTSTMR are presented in Part II and Part III of this three-paper series study.</p><p>*Techniques and algorithms for RHPIC-LBM have been developed in previous studies (e.g.,Zhu2020a, Zhu2020b)</p><p>References</p><p>Zhu, B. J., Yan, H., Zhong, Y., et al. 2020a, Appl Math Model, 78, 932, doi: 10.1016/j.apm.2019.09.043</p><p>Zhu, B. J., Yan, H., Zhong, Y., et al. 2020b, Appl Math Model, 78, 968,doi: 10.1016/j.apm.2019.05.027</p>

scholarly journals Experimental Characterization of Geometric Aspects of the Behavior of Magnetic Shape Memory Materials and Theoretical Interpretation

2019 ◽  
Vol 4 (3) ◽  
pp. 121-126
Author(s):  
Juan Manuel Hernandez ◽  
P. Mullner ◽  
P. Linquist ◽  
J. Carreraa
Keyword(s):  
Magnetic Field ◽  
Geometric Analysis ◽  
Martensite Phase ◽  
Rotating Magnetic Field ◽  
Small Samples ◽  
Elastic Behavior ◽  
Theoretical Interpretation ◽  
Magnetic Shape Memory

Small samples of a Ni-Mn-Ga single crystal of three different geometries were subjected to bending by applying a rotating magnetic field. The magneto-mechanical behavior of the sample in cantilever was analyzed and special attention was given to elongations and curvature along the deformation process. A sequence of 3000 images was made using a high-resolution camera and the data was analyzed using a code in Matlab. Furthermore, the geometric analysis showed that, when the magnetic field is equal to cero, the sample do not recover its original shape totally and the presence of a pseudo-elastic behavior was observed. Analysis and interpretation of the data allows the presentation of some hypotheses concerning to the crystalline structure and the role of dislocations, represented by a dislocation density, in the martensite phase of these materials. These hypotheses are discussed more formally in the second part of this paper. Some experiments are proposed that would give the opportunity to a wider theoretical knowledge of MSMM.

scholarly journals The role of magnetic handedness in magnetic cloud propagation

2010 ◽  
Vol 28 (5) ◽  
pp. 1075-1100 ◽  
Author(s):  
U. Taubenschuss ◽  
N. V. Erkaev ◽  
H. K. Biernat ◽  
C. J. Farrugia ◽  
C. Möstl ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Interplanetary Magnetic Field ◽  
Equatorial Plane ◽  
Magnetic Clouds ◽  
Geometrical Parameters ◽  
Meridional Plane ◽  
Mhd Simulations

Abstract. We investigate the propagation of magnetic clouds (MCs) through the inner heliosphere using 2.5-D ideal magnetohydrodynamic (MHD) simulations. A numerical solution is obtained on a spherical grid, either in a meridional plane or in an equatorial plane, by using a Roe-type approximate Riemann solver in the frame of a finite volume approach. The structured background solar wind is simulated for a solar activity minimum phase. In the frame of MC propagation, special emphasis is placed on the role of the initial magnetic handedness of the MC's force-free magnetic field because this parameter strongly influences the efficiency of magnetic reconnection between the MC's magnetic field and the interplanetary magnetic field. Magnetic clouds with an axis oriented perpendicular to the equatorial plane develop into an elliptic shape, and the ellipse drifts into azimuthal direction. A new feature seen in our simulations is an additional tilt of the ellipse with respect to the direction of propagation as a direct consequence of magnetic reconnection. During propagation in a meridional plane, the initial circular cross section develops a concave-outward shape. Depending on the initial handedness, the cloud's magnetic field may reconnect along its backside flanks to the ambient interplanetary magnetic field (IMF), thereby losing magnetic flux to the IMF. Such a process in combination with a structured ambient solar wind has never been analyzed in detail before. Furthermore, we address the topics of force-free magnetic field conservation and the development of equatorward flows ahead of a concave-outward shaped MC. Detailed profiles are presented for the radial evolution of magnetoplasma and geometrical parameters. The principal features seen in our MHD simulations are in good agreement with in-situ measurements performed by spacecraft. The 2.5-D studies presented here may serve as a basis under more simple geometrical conditions to understand more complicated effects seen in 3-D simulations.

Identifying and Quantifying the Role of Magnetic Reconnection in Space Plasma Turbulence

2020 ◽  
Author(s):  
Jeffersson Andres Agudelo Rueda ◽  
Daniel Verscharen ◽  
Robert Wicks ◽  
Christopher Owen ◽  
Georgios Nicolaou ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Reconnection ◽  
Space Plasma ◽  
Plasma Turbulence ◽  
Close Link ◽  
Particle In Cell ◽  
Open Questions ◽  
Strong Current ◽  
Characteristic Features

<p>One of the outstanding open questions in space plasma physics is the heating problem in the solar corona and the solar wind. In-situ measurements, as well as MHD and kinetic simulations, suggest a relation between the turbulent nature of plasma and the onset of magnetic reconnection as a channel of energy dissipation, particle acceleration and a heating mechanism. It has also been proven that non-linear interactions between counter propagating Alfvén waves drives plasma towards a turbulent state. On the other hand, the interactions between particles and waves becomes stronger at scales near the ion(electron) gyroradious ρi (ρe ), and so turbulence can enhance conditions for reconnection and increase the number of reconnection sites. Therefore, there is a close link between turbulence and reconnection. We use fully kinetic particle in cell (PIC) simulations, able to resolve the kinetic phenomena, to study the onset of reconnection in a 3D simulation box with parameters similar to the solar wind under Alfvénic turbulence. We identify in our simulations characteristic features of reconnection sites as steep gradients of the magnetic field strength alongside with the formation of strong current sheets and inflow-outflow patterns of plasma particles near the diffusion regions. These results will be used to quantify the role reconnection in plasma turbulence.</p>

Structure functions analysis of sub-ion scale turbulent fluctuations and dissipation range in a magnetized plasma

2021 ◽  
Author(s):  
Giuseppe Arrò ◽  
Francesco Califano ◽  
Giovanni Lapenta
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Plasma Turbulence ◽  
Structure Functions ◽  
Magnetized Plasma ◽  
Small Scale ◽  
Turbulent Fluctuations ◽  
The Magnetic Field ◽  
Turbulent Cascade ◽  
Dissipation Range

<p>Turbulence in collisionless magnetized plasmas is a complex multi-scale process involving many decades of scales ranging from large magnetohydrodynamic (MHD) scales down to small ion and electron kinetic scales, associated with different physical regimes. It is well know that the MHD turbulent cascade is driven by the nonlinear interaction of low-frequency Alfvén waves but, on the other hand, the properties of plasma turbulence at sub-ion scales are not yet fully understood. In addition to a great variety of relatively high frequency modes such as kinetic Alfvén waves and whistler waves, magnetic reconnection has been suggested to be a key element in the development of kinetic scale turbulence because it allows for energy to be transferred from large scales directly into sub-ion scales through currents sheets disruption. In this context, an unusual reconnection mechanism driven exclusively by the electrons (with ions being demagnetized), called "electron-only reconnection", has been recently observed for the first time in the Earth’s magnetosheath and its role in plasma turbulence is still a matter of great debate. <br><br>Using 2D-3V hybrid Vlasov-Maxwell (HVM) simulations of freely decaying plasma turbulence, we investigate and compare the properties of the turbulence associated with standard ion-coupled reconnection and of the turbulence associated with electron-only reconnection [Califano et al., 2018]. By analyzing the structure functions of the turbulent magnetic field and ion fluid velocity fluctuations, we find that the turbulence associated with electron-only reconnection shows the same statistical features as the turbulence associated with standard ion-coupled reconnection and no peculiar signature related to electron-only reconnection is found in the turbulence statistics. This result suggests that the properties of the turbulent cascade in a magnetized plasma are independent of the specific mechanism associated with magnetic reconnection but depend only on the coupling between the magnetic field and the different particle species present in the system. Finally, the properties of the magnetic field dissipation range are discussed as well and we claim that its formation, and thus the dissipation of magnetic energy, is driven only by the small scale electron dynamics since ions are demagnetized in this range [Arró et al., 2020].<br><br>This work has received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 776262 (AIDA, www.aida-space.eu).<br><br>References:<br><br>G. Arró, F. Califano, and G. Lapenta. Statistical properties of turbulent fluctuations associated with electron-only magnetic reconnection. , 642:A45, Oct. 2020. doi: 10.1051/0004-6361/202038696.<br><br>F. Califano, S. S. Cerri, M. Faganello, D. Laveder, M. Sisti, and M. W. Kunz. Electron-only magnetic reconnection in plasma turbulence. arXiv e-prints, art. arXiv:1810.03957, Oct. 2018.</p>

Flux tubes and energetic particles in Parker Solar Probe orbit 5: magnetic helicity - PVI method and ISOIS observations

2021 ◽  
Author(s):  
Francesco Pecora ◽  
Sergio Servidio ◽  
Antonella Greco ◽  
Stuart D. Bale ◽  
David J. McComas ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Energetic Particle ◽  
Plasma Turbulence ◽  
Small Scale ◽  
Flux Tubes ◽  
Particle Measurements ◽  
The Magnetic Field

<p>Plasma turbulence can be viewed as a magnetic landscape populated by large- and small-scale coherent structures, consisting notionally of magnetic flux tubes and their boundaries. Such structures exist over a wide range of scales and exhibit diverse morphology and plasma properties.  Moreover, interactions of particles with turbulence may involve temporary trapping in, as well as exclusion from, certain regions of space, generally controlled by the topology and connectivity of the magnetic field.  In some cases, such as SEP "dropouts'' the influence of the magnetic structure is dramatic; in other cases, it is more subtle, as in edge effects in SEP confinement. With Parker Solar Probe now closer to the sun than any previous mission, novel opportunities are available for examination of the relationship between magnetic flux structures and energetic particle populations. </p><p>We present a method that is able to characterize both the large- and small-scale structures of the turbulent solar wind, based on the combined use of a filtered magnetic helicity (H<sub>m</sub>) and the partial variance of increments (PVI). The synergistic combination with energetic particle measurements suggests whether these populations are either trapped within or excluded from the helical structure.</p><p>This simple, single-spacecraft technique exploits the natural tendency of flux tubes to assume a cylindrical symmetry of the magnetic field about a central axis. Moreover, large helical magnetic tubes might be separated by small-scale magnetic reconnection events (current sheets) and present magnetic discontinuity with the ambient solar wind. The method was first validated via direct numerical simulations of plasma turbulence and then applied to data from the Parker Solar Probe (PSP) mission. In particular, ISOIS energetic particle (EP) measurements along with FIELDS magnetic field measurements and SWEAP plasma moments, are enabling characterization of observations of EPs closer to their sources than ever before.<br> <br>This novel analysis, combining H<sub>m </sub>and PVI methods, reveals that a large number of flux tubes populate the solar wind and continuously merge in contact regions where magnetic reconnection and particle acceleration may occur. Moreover, the detection of boundaries, correlated with high-energy particle measurements, gives more insights into the nature of such helical structures as "excluding barriers'' suggesting a strong link between particle properties and fields topology. This research is partially supported by the Parker Solar Probe project. </p>

Modelling plasma turbulence observed by Parker Solar Probe during its first two orbits with hybrid-kinetic simulations

2020 ◽  
Author(s):  
Luca Franci ◽  
Alice Giroul ◽  
David Burgess ◽  
Emanuele Papini ◽  
Christopher Chen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Hybrid Approach ◽  
Theoretical Models ◽  
Plasma Turbulence ◽  
Quantitative Agreement ◽  
Particle Interactions ◽  
Physical Conditions ◽  
New Findings ◽  
Turbulent Cascade

<p>We employ 2D and 3D high-resolution hybrid kinetic simulations of plasma turbulence to explore the physical conditions encountered by the Parker Solar Probe (PSP) spacecraft during its first two orbits, modelling the turbulent cascade self-consistently from large fluid scales down to kinetic scales. <br>By varying key parameters (e.g., the ion and electron plasma beta, the level of fluctuations with respect to the ambient magnetic field, the injection scale), we explore different plasma conditions. We identify a new kinetic-scale regime with respect to what has previously been found in both hybrid simulations and spacecraft observations of the solar wind and of the near-Earth environment, characterized among other things by a steeper magnetic field spectrum. Our simulations reproduce PSP observations and thus offer the opportunity to investigate the physical mechanism(s) behind such change in the turbulent cascade properties. We discuss our results in the framework of theoretical models of the nonlinear interaction of dispersive wave modes, field-particle interactions, and magnetic reconnection in low-beta plasmas.<br>We also analyse intermittency, magnetic compressibility, polarization of wave-like fluctuations, and statistics of magnetic reconnection events by means of iterative filters, a new method for the analysis of nonlinear nonstationary signals.<br>Together with our previous numerical results in quantitative agreement with MMS observations in the Earth’s magnetosheath, our new findings confirm the ability of the hybrid approach to model in-situ observations, which is fundamental for interpreting observational results and for planning future spacecraft missions.</p>

scholarly journals The Coupling Use of Weak Magnetic Field and Fe0/H2O2 Process for Bisphenol a Abatement: Influence of Reaction Conditions and Mechanisms

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1724
Author(s):  
Liping Liang ◽  
Fenfen Xi ◽  
Liubiao Cheng ◽  
Weishou Tan ◽  
Qiang Tang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Bisphenol A ◽  
Weak Magnetic Field ◽  
Heterogeneous Fenton ◽  
Reaction Conditions ◽  
Bpa Removal ◽  
Ph Range ◽  
Background Ions

The coupling use of the heterogeneous Fenton-like process (zero-valent iron (Fe0)/H2O2) and weak magnetic field (MWF) for bisphenol A (BPA) abatement was systematically investigated in this study. Though both the Fe0/H2O2 and WMF-Fe0/H2O2 processes are sensitive to pH, WMF remarkably enhanced BPA removal under the pH range of 3.0–6.0 by 0.5–9.5 times. The characterization of Fe0 confirmed the role of WMF in promoting the corrosion of Fe0. Radicals, rather than Fe intermediates, were responsible for BPA degradation. Due to the presence of Cl– as the background ions and its reactivity towards HO•, reactive chlorine species (RCS, i.e., Cl• and Cl2•−) were produced and considerably contributed to BPA degradation. In addition, ~37% and 54% of degraded BPA was ascribed to RCS in the presence of 2 and 100 mM of Cl−, respectively. However, 1.9 mg/L of ClO3− was detected in the presence of 2 mM of Cl− in the WMF- Fe0/H2O2 process. HCO3− could diminish ClO3− generation significantly through transforming RCS. The concentration of ClO3− decreased by 74% and 82% with dosing 1 and 10 mM HCO3−, respectively. The results of this study suggest that the WMF-Fe0/H2O2 process is a promising approach for BPA removal.

scholarly journals Statistical properties of turbulent fluctuations associated with electron-only magnetic reconnection

2020 ◽  
Vol 642 ◽  
pp. A45
Author(s):  
G. Arró ◽  
F. Califano ◽  
G. Lapenta
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Fluid Velocity ◽  
Turbulent Energy ◽  
Plasma Turbulence ◽  
Statistical Properties ◽  
Energy Cascade ◽  
Magnetized Plasma ◽  
Field Energy ◽  
Turbulent Fluctuations

Context. Recent satellite measurements in the turbulent magnetosheath of Earth have given evidence of an unusual reconnection mechanism that is driven exclusively by electrons. This newly observed process was called electron-only reconnection, and its interplay with plasma turbulence is a matter of great debate. Aims. By using 2D-3V hybrid Vlasov–Maxwell simulations of freely decaying plasma turbulence, we study the role of electron-only reconnection in the development of plasma turbulence. In particular, we search for possible differences with respect to the turbulence associated with standard ion-coupled reconnection. Methods. We analyzed the structure functions of the turbulent magnetic field and ion fluid velocity fluctuations to characterize the structure and the intermittency properties of the turbulent energy cascade. Results. We find that the statistical properties of turbulent fluctuations associated with electron-only reconnection are consistent with those of turbulent fluctuations associated with standard ion-coupled reconnection, and no peculiar signature related to electron-only reconnection is found in the turbulence statistics. This result suggests that the turbulent energy cascade in a collisionless magnetized plasma does not depend on the specific mechanism associated with magnetic reconnection. The properties of the dissipation range are discussed as well, and we claim that only electrons contribute to the dissipation of magnetic field energy at sub-ion scales.

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