Nonlinear Dependence of Anomalous Ion‐Acoustic Resistivity on Electron Drift Velocity

Petkaki, P.; Freeman, M. P.

doi:10.1086/590654

Cited by 38 publications

(47 citation statements)

References 31 publications

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“…However, these assumptions are theoretical, and can not be directly inferred from observations of the solar corona (Watt et al 2002;Petkaki & Freeman 2008). Therefore, for the study of electrostatic waves, the only force acting on the plasma is that of an electric field, and the 1D electrostatic Vlasov equation is written as (Petkaki & Freeman 2008) …”

Section: Basic Equation and Simulation Methodsmentioning

confidence: 99%

Electron acceleration in the turbulent reconnecting current sheets in solar flares

Huang

2009

A&A

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Context. We investigate the nonlinear evolution of the electron distribution in the presence of the strong inductive electric field in the reconnecting current sheets (RCS) of solar flares. Aims. We aim to study the characteristics of nonthermal electron-beam plasma instability and its influence on electron acceleration in RCS. Methods. Including the external inductive field, the one-dimensional Vlasov simulation is performed with a realistic mass ratio for the first time. Results. Our principal findings are as follows: 1) the Buneman instability can be quickly excited on the timescale of 10 −7 s for the typical parameters of solar flares. After saturation, the beam-plasma instabilities are excited due to the non-Maxwellian electron distribution; 2) the final velocity of the electrons trapped by these waves is of the same order as the phase speed of the waves, while the untrapped electrons continue to be accelerated; 3) the inferred anomalous resistance of the current sheet and the energy conversion rate are basically of the same order as those previously estimated, e.g., "the analysis of Martens". Conclusions. The Buneman instability is excited on the timescale of 10 −7 s and the wave-particle resonant interaction limits the low-energy electrons to be further accelerated in RCS.

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Section: Basic Equation and Simulation Methodsmentioning

confidence: 99%

Electron acceleration in the turbulent reconnecting current sheets in solar flares

Huang

2009

A&A

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“…As stated in [12] that the anomalous resistivity during the nonlinear phase is highly variable in time, and sensitive to the initial noise fields, we numerically solved eqs. (2)- (5) for nine different induced electric fields, and used an ensemble of 10 Vlasov simulations for each set of initial conditions, which differ only in the initial electric field noise as that in [12].…”

Section: Anomalous Resistivitymentioning

confidence: 99%

“…(2)- (5) for nine different induced electric fields, and used an ensemble of 10 Vlasov simulations for each set of initial conditions, which differ only in the initial electric field noise as that in [12]. The time evolution of the ensemble Vlasov simulations for E 0 =0.00025 V m −1 , 0.0025 V m −1 are plotted in Figure 3, where thin lines mark each η of the 10 initial noise fields and thick line denote mean η.…”

Section: Anomalous Resistivitymentioning

confidence: 99%

“…Recently, one dimension (1D) Vlasov simulations with parameters appropriate to the magnetopause and low-latitude boundary layer highlight the importance of the anomalous resistivity produced by the ion acoustic instability [11]. Petkaki and Freeman inferred non-linear dependance of anomalous resistivity on the bulk drift velocity of electrons [12]. We performed 1D Vlasov simulations, including the external inductive field with a realistic mass ratio and parameters appropriate to solar coronal for the first time, investigated the nonlinear dependance of the anomalous resistivity on the induced electric field and bulk drift velocity, and found that the excited electrostatic waves have the characteristics of the Buneman instability, i.e.…”

mentioning

confidence: 99%

“…We performed 1D Vlasov simulations, including the external inductive field with a realistic mass ratio and parameters appropriate to solar coronal for the first time, investigated the nonlinear dependance of the anomalous resistivity on the induced electric field and bulk drift velocity, and found that the excited electrostatic waves have the characteristics of the Buneman instability, i.e. propagating in opposite directions with the growth rate of the order of the ion plasma frequency, and decreasing the wave vector at the maximum growth rate with increase of the bulk drift velocity of electrons [10][11][12].…”

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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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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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Nonlinear Dependence of Anomalous Ion‐Acoustic Resistivity on Electron Drift Velocity

Cited by 38 publications

References 31 publications

Electron acceleration in the turbulent reconnecting current sheets in solar flares

Electron acceleration in the turbulent reconnecting current sheets in solar flares

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

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