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

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

10.5194/egusphere-egu21-9050 ◽

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

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 Alfv&#233;n 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 Alfv&#233;n 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&#8217;s magnetosheath and its role in plasma turbulence is still a matter of great debate. 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 [Arr&#243; et al., 2020]. 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). References: G. Arr&#243;, 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. 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.

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Turbulence changes from magnetic fields in a stationary plasma

Journal of Plasma Physics ◽

10.1017/s0022377810000711 ◽

2010 ◽

Vol 77 (4) ◽

pp. 537-545 ◽

Cited By ~ 3

Author(s):

A. B. ALEXANDER ◽

C. T. RAYNOR ◽

D. L. WIGGINS ◽

M. K. ROBINSON ◽

C. C. AKPOVO ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Fields ◽

Field Strength ◽

Magnetic Field Strength ◽

Axial Magnetic Field ◽

Turbulent Energy ◽

Dominant Mode ◽

Dc Glow Discharge ◽

Turbulent Fluctuations ◽

Stationary Plasma

AbstractWhen the krypton plasma in a DC glow discharge tube is exposed to an axial magnetic field, the turbulent energy and the characteristic dominant mode in the turbulent fluctuations are systematically and unexpectedly reduced with increasing magnetic field strength. When the index measuring the rate of transfer of energy through fluctuation scales is monitored, a lambda-like dependence on turbulent energy is routinely observed in all magnetic fields. From this, a critical turbulent energy is identified, which also decreases with increasing magnetic field strength.

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Magnetic field annihilation and charged particle acceleration in ultra-relativistic laser plasmas

High Power Laser Science and Engineering ◽

10.1017/hpl.2020.45 ◽

2021 ◽

Vol 9 ◽

Author(s):

Yan-Jun Gu ◽

Sergei V. Bulanov

Keyword(s):

Magnetic Field ◽

Magnetic Reconnection ◽

Laser Plasma ◽

Large Scale ◽

Rapid Development ◽

Collisionless Plasma ◽

Basic Mechanism ◽

Field Energy ◽

Plasma Interactions ◽

Magnetic Field Energy

Abstract Magnetic reconnection driven by laser plasma interactions attracts great interests in the recent decades. Motivated by the rapid development of the laser technology, the ultra strong magnetic field generated by the laser-plasma accelerated electrons provides unique environment to investigate the relativistic magnetic field annihilation and reconnection. It opens a new way for understanding relativistic regimes of fast magnetic field dissipation particularly in space plasmas, where the large scale magnetic field energy is converted to the energy of the nonthermal charged particles. Here we review the recent results in relativistic magnetic reconnection based on the laser and collisionless plasma interactions. The basic mechanism and the theoretical model are discussed. Several proposed experimental setups for relativistic reconnection research are presented.

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Tearing instability inside a 2D current sheet with a normal magnetic field

10.5194/egusphere-egu21-13282 ◽

2021 ◽

Author(s):

Chen Shi ◽

Anton Artemyev ◽

Marco Velli ◽

Anna Tenerani

Keyword(s):

Magnetic Field ◽

Magnetic Reconnection ◽

Current Sheet ◽

Normal Component ◽

Field Energy ◽

Tearing Mode ◽

Magnetic Field Energy ◽

Tearing Instability ◽

The Magnetic Field ◽

Normal Magnetic Field

Magnetic reconnection converts the magnetic field energy into thermal and kinetic energies of the plasma. This process usually happens at extremely fast speed and is therefore believed to be a fundamental mechanism to explain various explosive phenomena such as coronal mass ejections and planetary magnetospheric storms. How magnetic reconnection is triggered from the large magnetohydrodynamic (MHD) scales remains an open question, with some theoretical and numerical studies showing the tearing instability to be involved. Observations in the Earth&#8217;s magnetotail and near the magnetopause show that a finite normal magnetic field is usually present inside the reconnecting current sheet. Besides, such a normal field may also exist in the solar corona. However, how this normal magnetic field modifies the tearing instability is not thoroughly studied. Here we discuss the linear tearing instability inside a two-dimensional current sheet with a normal component of magnetic field where the magnetic tension force is balanced by ion flows parallel and anti-parallel to the magnetic field. We solve the dispersion relation of the tearing mode with wave vector parallel to the reconnecting magnetic field. Our results confirm that the finite normal magnetic field stabilizes the tearing mode and makes the mode oscillatory instead of purely growing.

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Avalanches of Magnetic Reconnection

International Astronomical Union Colloquium ◽

10.1017/s025292110002889x ◽

1993 ◽

Vol 141 ◽

pp. 112-114

Author(s):

Edward T. Lu

Keyword(s):

Magnetic Field ◽

Magnetic Reconnection ◽

Energy Release ◽

Power Law ◽

Magnetic Energy ◽

Magnetized Plasma ◽

Release Process ◽

3 Dimensional ◽

Convective Motions ◽

The Magnetic Field

AbstractActive region coronal magnetic fields are expected to be in a twisted tangled state due to photospheric convective motions. These motions can drive the magnetic field to a statistically steady state where energy is released impulsively (Lu and Hamilton 1991). These relaxation events in the magnetic field can be interpreted as avalanches of many small reconnection events. We argue that the frequency distribution of these magnetic reconnection avalanches must be a power law. Furthermore, we calculate the expected distributions in a simple model of magnetic energy release events in a 3-dimensional complex magnetized plasma, and compare these to the distributions of solar flares. These distributions are found to match the observed power law distributions of solar flare energies, peak fluxes, and durations. This model implies that the energy-release process is fundamentally the same for flares of all sizes. Observational predictions of this model are discussed.

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The inherently three-dimensional nature of magnetized plasma turbulence

Journal of Plasma Physics ◽

10.1017/s0022377814001056 ◽

2014 ◽

Vol 81 (2) ◽

Cited By ~ 20

Author(s):

Gregory G. Howes

Keyword(s):

Three Dimensional ◽

Turbulent Energy ◽

Plasma Turbulence ◽

Alfven Waves ◽

Magnetized Plasma ◽

Alfvén Waves ◽

Mathematical Form ◽

Two Dimensional ◽

Nonlinear Properties ◽

Azimuthal Asymmetries

It is often asserted or implicitly assumed, without justification, that the results of two-dimensional investigations of plasma turbulence are applicable to the three-dimensional plasma environments of interest. A projection method is applied to derive two scalar equations that govern the nonlinear evolution of the Alfvénic and pseudo-Alfvénic components of ideal incompressible magnetohydrodynamic (MHD) plasma turbulence. The mathematical form of these equations makes clear the inherently three-dimensional nature of plasma turbulence, enabling an analysis of the nonlinear properties of two-dimensional limits often used to study plasma turbulence. In the anisotropic limit, k⊥ ≫ k∥, that naturally arises in magnetized plasma systems, the perpendicular 2D limit retains the dominant nonlinearities that are mediated only by the Alfvénic fluctuations but lacks the wave physics associated with the linear term that is necessary to capture the anisotropic cascade of turbulent energy. In the in-plane 2D limit, the nonlinear energy transfer is controlled instead by the pseudo-Alfvén waves, with the Alfvén waves relegated to a passive role. In the oblique 2D limit, an unavoidable azimuthal dependence connecting the wavevector components will likely cause artificial azimuthal asymmetries in the resulting turbulent dynamics. Therefore, none of these 2D limits is sufficient to capture fully the rich three-dimensional nonlinear dynamics critical to the evolution of plasma turbulence.

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

10.5194/egusphere-egu21-9911 ◽

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

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. &#160;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. &#160;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.&#160;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 (Hm) 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.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. &#160; This novel analysis, combining Hm 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.&#160;

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

10.5194/egusphere-egu2020-18202 ◽

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

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. 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. 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. Together with our previous numerical results in quantitative agreement with MMS observations in the Earth&#8217;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.

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

10.5194/egusphere-egu2020-7950 ◽

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

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.Here we&#160;used our newly developed RHPIC-LBM algorithm[*] &#160;to perform the role of&#160;&#160;turbulence in the magnetic fluctuation-induced self-generating-organization&#160; (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.&#160;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.&#160;The Biermann battery effect and&#160;&#160;alpha-effect can not only generate magnetic fields, but can server them to trigger MR, the Spitzer resistance and turbulence resistance (beta-effect)&#160;&#160;can not only generate magnetic eddies, but can server&#160;&#160;them to trigger fluid turbulence.&#160;&#160;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.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.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.*Techniques and algorithms for RHPIC-LBM have been developed in previous studies (e.g.,Zhu2020a, Zhu2020b)ReferencesZhu, B. J., Yan, H., Zhong, Y., et al. 2020a, Appl Math Model, 78, 932, doi: 10.1016/j.apm.2019.09.043Zhu, B. J., Yan, H., Zhong, Y., et al. 2020b, Appl Math Model, 78, 968,doi: 10.1016/j.apm.2019.05.027

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Intermittency and Scaling in Cascading Random Transport

Fractals ◽

10.1142/s0218348x98000146 ◽

1998 ◽

Vol 06 (02) ◽

pp. 121-126

Author(s):

Hideki Takayasu ◽

Yasuo Terasawa

Keyword(s):

Transport Model ◽

Asymptotic Relation ◽

Turbulent Energy ◽

Statistical Properties ◽

Energy Cascade ◽

Wave Number ◽

Scaling Relation

We analyze statistical properties of a directed random transport model which can be viewed as a simplest model for turbulent energy cascade in wave number space. A new scaling relation consistent with the known intermittency properties is derived as an asymptotic relation.

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