Formation of a quasi-one-dimensional current sheet in the laboratory experiment and in the Earth’s magnetotail

Yushkov, E. V.; Frank, A. G.; Artemyev, А. V.; Petrukovich, A. A.; Vasko, I. Y.

doi:10.1134/s1063780x15010055

Cited by 10 publications

(4 citation statements)

References 101 publications

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“…In this case, shock waves should be observed (in hot magnetotail plasma the proton thermal velocity is usually larger than Alfvén velocity, and thus, fast magnetosonic velocity is about the thermal velocity v T i ), while such waves were never found in the tail (see discussion in Hoshino et al , []). Thus, we can assume that e v T i n e is the maximum possible contribution of protons to the total current density when almost all proton population is represented by transient particles (see additional discussion of validity of this assumption for various plasma systems in Yushkov et al , []). In this case, the potential contribution of Speiser protons to the current density can be measured by the ratio of observed current density j y (given by the curlometer technique) and the value of e v T i n e .…”

Section: Data Set and Main Equationsmentioning

confidence: 99%

Statistics of intense dawn‐dusk currents in the Earth's magnetotail

et al. 2015

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We consider Cluster observations of events with an intense current density (>5 nA/m2) in the magnetotail current sheet. We use measurements by Cluster mission in the central magnetotail (X <− 16 RE, |Y|<10 RE, and |Bx|<10 nT) in the 2003 season when the spacecraft separation was about ∼300 km. For this season, when Cluster can probe very small scale currents, we collect the statistics of observations of strong current densities jy (in GSM coordinate system) and compare curlometer data with plasma parameters. The most intense currents are observed under disturbed conditions (plasma flow vx>300 km/s). We introduce the parameter vD/vTi (where vD=jy/ene, ne is an electron density, and vTi is a proton thermal velocity) and show that cases with vD/vTi∼1 correspond to the most intense currents observed in the vicinity of the reconnection regions. The comparison of electron and proton velocities demonstrates that electron often carry almost the entire current measured by a curlometer technique. The strong electron temperature anisotropy Te∥/Te⊥>1.2 corresponds to large magnitudes of By component of the magnetic field. We conclude that intense current sheets are often characterized by significant (more than 30%) contribution of electron curvature currents to the cross‐tail current. The comparison of observations and models shows that the electron anisotropy level is likely controlled by competition of two processes: the electron scattering on fluctuations generated by fire‐hose instability and the acceleration in sheared magnetic field configurations. We also suggest that current sheets embedded into the strong plasma flows (vx/vTi>0.1) can be balanced by ion flow anisotropy.

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Section: Data Set and Main Equationsmentioning

confidence: 99%

Statistics of intense dawn‐dusk currents in the Earth's magnetotail

et al. 2015

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“…In this section we describe the results of the comparison of the laboratory experiments on CS formation near the X-line region and Cluster observations in the Earth's magnetotail in [7,90]. We consider one particular series of laboratory experiments carried out with the device CS-3D at the Institute of General Physics in Moscow [28,33].…”

Section: Laboratory Experimentsmentioning

confidence: 99%

Formation of sub-ion scale filamentary force-free structures in the vicinity of reconnection region

Zelenyǐ

Frank

Artemyev

et al. 2016

Plasma Phys. Control. Fusion

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In this paper we review the results of spacecraft observations of current sheets (CSs) of sub-ion spatial scales in the Earth's magnetotail as well as experiments with these structures in laboratory devices. We demonstrate that such sub-ion CSs having a thickness less than the ion gyroradius are usually formed in the vicinity of the magnetic reconnection region and are supported by strong electron currents flowing along magnetic field lines. The magnetic field configuration of sub-ion CSs is close to the force-free configuration, with a strong shear magnetic field component in the CS central region. Spacecraft observations suggest that parallel electron currents are generated by electron beams (pronounced enhancement of the phase space density for electrons with small pitch angles and energies ∼1-3 keV). We discuss several models describing such force-free sub-ion CSs.

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“…In this paper, we aim to combine such an experiment carried out on the CS-3D plasma device (Bogdanov et al 2000, Frank et al 2008, Frank 2010 and THEMIS spacecraft observations (Angelopoulos 2008) to investigate the formation of inverse currents around the plasma flow front. Previous comparisons of CS-3D experiments with spacecraft observations of the magnetotail current sheet can be found in Artemyev et al (2013), Yushkov et al (2015), Frank et al (2016. The paper is structured as follows: description of spacecraft and laboratory datasets (section 2), analysis of plasma jet characteristics measured in the magnetotail (section 3) and in the laboratory (section 4), and comparison of these characteristics (section 5).…”

Section: Introductionmentioning

confidence: 99%

Currents in reconnection plasma jets: comparative study of laboratory experiments and spacecraft observations

Frank

Artemyev

et al. 2023

Plasma Phys. Control. Fusion

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The magnetic reconnection is a universal plasma process that has been observed in various space plasma systems and well reproduced in laboratory simulations. During reconnection, magnetic field energy is transformed into energy of fast plasma flows that propagate away from the reconnection site. The leading front of these flows is the primary interface where energies exchange between flows and ambient plasmas. One of the most investigated front is the so-called {\it dipolarization front} in the Earth's magnetotail. This study is devoted to a thorough comparison of the current system associated with dipolarization fronts and fronts of fast plasma flows in laboratory experiments. We show that in both systems the plasma flow front is characterized by inverse currents, which deform the magnetic field configuration of the front. Laboratory experiments further show that such inverse currents may contribute to the plasma flow breaking; we also discuss its implications on the magnetotail plasma, where a similar mechanism for plasma flow breaking is likely operating.

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Formation of a quasi-one-dimensional current sheet in the laboratory experiment and in the Earth’s magnetotail

Cited by 10 publications

References 101 publications

Statistics of intense dawn‐dusk currents in the Earth's magnetotail

Statistics of intense dawn‐dusk currents in the Earth's magnetotail

Formation of sub-ion scale filamentary force-free structures in the vicinity of reconnection region

Currents in reconnection plasma jets: comparative study of laboratory experiments and spacecraft observations

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