Anomalous resistivity in non‐Maxwellian plasmas

Petkaki, P.

doi:10.1029/2003ja010092

Cited by 40 publications

(37 citation statements)

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“…It represents that the impact is small, which may be caused by the deviation of the electron distribution from the Maxwellian one after the onset of the unstable waves. The difference for these two distributions in exciting the instability is the lower threshold of drift velocity for kappa-type one [18]. On the other hand, the more unstable waves are excited in a multi dimensional simulations, which may play an important role in heating and accelerating electrons in some stage [20,27].…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…(1) in [18]). It represents that the impact is small, which may be caused by the deviation of the electron distribution from the Maxwellian one after the onset of the unstable waves.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…Considering that the energetic particles in tenuous and collisionless space plasmas are better fitted by kappa-type distributions [18,[24][25][26], we substituted the initial kappa-type ones into our simulations with E 0 = 0.0025 V m −1 , obtained that the averaged peak anomalous resistivity is respectively (1.50, 1.62, 1.72)×10 5 Ω m, and the the corresponding peak time is almost the same for the index κ = 3, 4, ∞ (Maxwellian distribution, see eq. (1) in [18]).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…(2) is integrated forward in time, with initial unstable waves originated in a white noise electric field applied at t = 0 [18]. In our simulations, the ion to electron mass ratio is m p /m e = 1836, n i = n e = 2 × 10 5 m −3 [3], T e = T i = 100 eV [19], where n i is the ion number density, T i is the ion temperature.…”

Section: Basic Equation and Simulation Methodsmentioning

confidence: 99%

“…The time step is Δt = 0.003w −1 pe . The space, velocity space, and time numbers of grid points are carefully selected to ensure the numeric stability and accuracy of the integration algorithm [17,18]. The initial ion and electron populations are respectively drift-like Maxwellian distribution functions,…”

Section: Basic Equation and Simulation Methodsmentioning

confidence: 99%

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Nonlinear dependence of anomalous resistivity on the reconnecting electric field in the Earth’s magnetotail

Zhang

2012

Chin. Sci. Bull.

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Based upon the observational data of the fast magnetic reconnection in the nearly collisionless magnetotail and the particle in cell (PIC) simulations on the electron acceleration in the reconnecting current sheet with guide magnetic field, we self consistently solved one dimension Vlasov equation with the magnetotail parameters and realistic mass ratio to explore the relationship between the anomalous resistivity and the induced electric field. As compared with theoretic formula for the current driven ion-acoustic and Buneman anomalous resistivity, the anomalous resistivity may result from the ion acoustic instability for small reconnecting electric field and the Buneman instability for large reconnecting electric field. The discrepancy between the theoretic results and numerical simulations may be caused by the high frequency instability that results from the deviation of electron distribution from Maxwellian one. These results are consistent with the early experimental results and favorable for the fast reconnection to take place. In a collissioness coronal and the Earth's magnetotail plasma, anomalous resistivity caused by kinetic-scale wave-particle interactions is usually assumed to trigger fast magnetic reconnection, which was widely accepted as the main mechanism that converts free magnetic energy into heating and accelerating electrons and produces magnetospheric substorms [1][2][3][4]. The energetic electrons up to ∼300 keV were measured in a rare crossing of the diffusion region of reconnecting current sheet (RCS) by the Wind spacecraft [5]. Egedal et al.[6], after analyzing in-situ measurements of electron distribution functions inside the magnetotail RCS respectively from Wind and Cluster, found that the relative energy gain of the superthermal electrons is the same and nearly independent of their initial energy, while the electrons with the thermal energy are less accelerated. Hence, they concluded that the super thermal electrons are accelerated by reconnecting parallel electric field in vicinity of the reconnection region. For other acceleration mechanisms, such as Fermi acceleration of electrons in contracting magnetic islands and stochastic acceleration, the *Corresponding author (email: wuguiping@seu.edu.cn) relative energy gain of the electrons is a function of their initial energy. Therefore, these direct observational signatures suggest that the electrons are accelerated to relativistic energy by reconnecting electric field inside the diffusion region. On the other hand, the role of the electron dynamics inside the diffusive region of RCS is very important to understand the collissionless magnetic reconnection [7]. The 2D and 3D particle-in-cell (PIC) simulations was widely used to trace the typical electron trajectories [8,9]. It is found that, with the guiding magnetic field or external driven reconnection in RCS, the electrons can only be accelerated by the electric field in the X-type region and then spread out along the separatrices. In the O-type region, no obvious electron accelerati...

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Section: Conclusion and Discussionmentioning

confidence: 99%

“…(1) in [18]). It represents that the impact is small, which may be caused by the deviation of the electron distribution from the Maxwellian one after the onset of the unstable waves.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Basic Equation and Simulation Methodsmentioning

confidence: 99%

Section: Basic Equation and Simulation Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Nonlinear dependence of anomalous resistivity on the reconnecting electric field in the Earth’s magnetotail

Zhang

2012

Chin. Sci. Bull.

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First observation of the anomalous electric field in the topside ionosphere by ionospheric modification over EISCAT

Kosch

Vickers

Ogawa

et al. 2014

Geophysical Research Letters

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We have developed an active ground-based technique to estimate the steady state field-aligned anomalous electric field (E*) in the topside ionosphere, up to~600 km, using the European Incoherent Scatter (EISCAT) ionospheric modification facility and UHF incoherent scatter radar. When pumping the ionosphere with high-power high-frequency radio waves, the F region electron temperature is significantly raised, increasing the plasma pressure gradient in the topside ionosphere, resulting in ion upflow along the magnetic field line. We estimate E* using a modified ion momentum equation and the Mass Spectrometer Incoherent Scatter model. From an experiment on 23 October 2013, E* points downward with an average amplitude of 1.6 μV/m, becoming weaker at higher altitudes. The mechanism for anomalous resistivity is thought to be low-frequency ion acoustic waves generated by the pump-induced flux of suprathermal electrons. These high-energy electrons are produced near the pump wave reflection altitude by plasma resonance and also result in observed artificially induced optical emissions.

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Vlasov Code Simulation of Anomalous Resistivity

Büchner

Elkina

2005

Space Sci Rev

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One of the outstanding open questions in space physics is that of the resistivity of collisionless plasmas, where binary collisions are inefficient and collective wave-particle interactions determine transport and dissipation. In order to obtain macroscopic transport coefficients one has to solve kinetic equations together with the Maxwell equations for the interacting electromagnetic fields, an essentially nonlinear problem. For weak turbulence the quasi-linear and other weakly nonlinear theories provide predictions for the saturated field fluctuations and the so called anomalous resistivity, the normal mode of current dissipation in collisionless space plasmas. Unfortunately, no generic anomalous resistivity expression is found yet, which could be used for a macroscopic Ohm's law description like the Spitzer -Braginski one for the case of binary collisions. We shortly review the main results obtained for the anomalous resistivity caused by ion sound turbulence in the framework of weak turbulence theories and by Particle-In-Cell (PIC) simulations. Since PIC simulations are noisy, introducing artificial numerical collisions, we review the possibilities of a direct integration of Vlasov's kinetic equation. Indeed, the implementation of highly accurate numerical schemes on modern parallel-processor computers stimulates the revival of Vlasov-code simulations. We discuss the state of the art of this simulation approach to determine the anomalous resistivity and give an outlook toward future work toward the solution of the still open question of a whether there is a generic expression for anomalous resistivity eligible for a macroscopic Ohm's description of collisionless plasmas.

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Anomalous resistivity in non‐Maxwellian plasmas

Cited by 40 publications

References 46 publications

Nonlinear dependence of anomalous resistivity on the reconnecting electric field in the Earth’s magnetotail

Nonlinear dependence of anomalous resistivity on the reconnecting electric field in the Earth’s magnetotail

First observation of the anomalous electric field in the topside ionosphere by ionospheric modification over EISCAT

Vlasov Code Simulation of Anomalous Resistivity

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