Instabilities of collisionless current sheets revisited: The role of anisotropic heating

Muñoz, Patricio A.; Kilian, Patrick; Büchner, Jörg

doi:10.1063/1.4901033

Cited by 11 publications

(11 citation statements)

References 98 publications

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“…The heating is along y, which will be considered the parallel direction in the following (and x or z, the perpendicular, colder directions). The Weibel instability has already been observed in antiparallel magnetic reconnection in previous investigations using similar parameters and geometry [78][79][80] . It has also been more frequently detected in relativistic pair plasmas, because in them the space available for its growth inside the CS is larger (see Ref.…”

Section: Acknowledgmentssupporting

confidence: 69%

“…The latter is, perhaps, due to the anisotropic heating of the background plasma population, different from the current carriers. Note that low resolution PiC simulations, with low order shape functions, without current smoothing, too small number of particle per cells or not resolving well enough the smallest electron length scales might not display accurately the structure of the off-diagonal terms of the electron pressure or electron inertia, due to the enhanced effective collisionality or numerical heating effects 80,96 .…”

Section: Acknowledgmentsmentioning

confidence: 99%

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Turbulent transport in 2D collisionless guide field reconnection

2017

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Transport in hot and dilute, i.e., collisionless, astrophysical and space plasmas is called "anomalous". This transport is due to the interaction between the particles and the self-generated turbulence by their collective interactions. The anomalous transport has very different and not well known properties compared to the transport due to binary collisions, dominant in colder and denser plasmas. Because of its relevance for astrophysical and space plasmas, we explore the excitation of turbulence in current sheets prone to componentor guide-field reconnection, a process not well understood yet. This configuration is typical for stellar coronae, and it is created in the laboratory for which a 2.5D geometry applies. In our analysis, in addition to the immediate vicinity of the X-line, we also include regions outside and near the separatrices. We analyze the anomalous transport properties by using 2.5D Particle-in-Cell code simulations. We split off the mean slow variation (in contrast to the fast turbulent fluctuations) of the macroscopic observables and determine the main transport terms of the generalized Ohm's law. We verify our findings by comparing with the independently determined slowing-down rate of the macroscopic currents (due to a net momentum transfer from particles to waves) and with the transport terms obtained by the first order correlations of the turbulent fluctuations. We find that the turbulence is most intense in the "low density" separatrix region of guide-field reconnection. It is excited by streaming instabilities, is mainly electrostatic and "patchy" in space, and so is the associated anomalous transport. Parts of the energy exchange between turbulence and particles are reversible and quasi-periodic. The remaining irreversible anomalous resistivity can be parametrized by an effective collision rate ranging from the local ion-cyclotron to the lower-hybrid frequency. The contributions to the parallel and the perpendicular (to the magnetic field) components of the slowly varying DC-electric fields, balanced by the turbulence, are similar. This anomalous electric field is, however, smaller than the contributions of the off-diagonal pressure and electron inertia terms of the Ohm's law. This result can now be verified by in-situ measurements of the turbulence, in and around the magnetic reconnection regions of the Earth's magnetosphere by the multi-spacecraft mission MMS and in laboratory experiments like MRX and VINETA-II. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in P.A. Muñoz, J. Büchner and P. Kilian, Physics of Plasmas 24, 022104 (2017), and may be found at http://dx.

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Section: Acknowledgmentssupporting

confidence: 69%

Section: Acknowledgmentsmentioning

confidence: 99%

Turbulent transport in 2D collisionless guide field reconnection

2017

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“…[ and other ones, useful under some specific conditions. By default, we use the second order shape function TSC to reduce the intrinsic PiC shot noise and the associated numerical heating without affecting the computational performance too much [52,53,41]. Once the sources of the electromagnetic fields in Eqs.…”

Section: Particle Mover (Pic Part)mentioning

confidence: 99%

A new hybrid code (CHIEF) implementing the inertial electron fluid equation without approximation

Muñoz

Jain

Kilian

et al. 2018

Computer Physics Communications

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We present a new hybrid algorithm implemented in the code CHIEF ( Code Hybrid with Inertial Electron Fluid) for simulations of electron–ion plasmas. The algorithm treats the ions kinetically, modeled by the Particle-in-Cell (PiC) method, and electrons as an inertial fluid, modeled by electron fluid equations without any of the approximations used in most of the other hybrid codes with an inertial electron fluid. This kind of code is appropriate to model a large variety of quasineutral plasma phenomena where the electron inertia and/or ion kinetic effects are relevant. We present here the governing equations of the model, how these are discretized and implemented numerically, as well as six test problems to validate our numerical approach. Our chosen test problems, where the electron inertia and ion kinetic effects play the essential role, are: 0) Excitation of parallel eigenmodes to check numerical convergence and stability, 1) parallel (to a background magnetic field) propagating electromagnetic waves, 2) perpendicular propagating electrostatic waves (ion Bernstein modes), 3) ion beam right-hand instability (resonant and non-resonant), 4) ion Landau damping, 5) ion firehose instability, and 6) 2D oblique ion firehose instability. Our results reproduce successfully the predictions of linear and non-linear theory for all these problems, validating our code. All properties of this hybrid code make it ideal to study multi-scale phenomena between electron and ion scales such as collisionless shocks, magnetic reconnection and kinetic plasma turbulence in the dissipation range above the electron scales

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“…We employ on average 64 particles per cell per species. The charge distribution of each finite-size particle is represented by third-order cubic splines [79], which improve energy conservation and reduce the relative amount of particle noise compared to lower-order splines [80,81]. At each step, we also apply a second-order compensated binomial filter [79] on the electric current and on the electromagnetic fields felt by the particles.…”

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confidence: 99%

Fully Kinetic Simulation of 3D Kinetic Alfvén Turbulence

et al. 2018

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We present results from a three-dimensional particle-in-cell simulation of plasma turbulence, resembling the plasma conditions found at kinetic scales of the solar wind. The spectral properties of the turbulence in the subion range are consistent with theoretical expectations for kinetic Alfvén waves. Furthermore, we calculate the local anisotropy, defined by the relation k_{∥}(k_{⊥}), where k_{∥} is a characteristic wave number along the local mean magnetic field at perpendicular scale l_{⊥}∼1/k_{⊥}. The subion range anisotropy is scale dependent with k_{∥}

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Instabilities of collisionless current sheets revisited: The role of anisotropic heating

Cited by 11 publications

References 98 publications

Turbulent transport in 2D collisionless guide field reconnection

Turbulent transport in 2D collisionless guide field reconnection

A new hybrid code (CHIEF) implementing the inertial electron fluid equation without approximation

Fully Kinetic Simulation of 3D Kinetic Alfvén Turbulence

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