Ion thermal effects on E-region instabilities: 2D kinetic simulations

Oppenheim, M. M.; Dimant, Y. S.

doi:10.1016/j.jastp.2004.07.007

Cited by 42 publications

(69 citation statements)

References 81 publications

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“…Note that this level of fluctuations is higher than it would be expected heuristically (Dimant and Milikh, 2003), δn e /n 0 ∼ /ν in 4%. A similar effect has been observed in previous 2-D fully-PIC or hybrid simulations Oppenheim and Dimant, 2004). A possible explanation is that the constraint to the two dimensions does not allow the turbulent energy to leak out in the parallel to B 0 direction where the instability is highly damped.…”

Section: Runsupporting

confidence: 83%

“…The effect of wave-front tilting has been observed in previous simulations with PIC ions (e.g. Janhunen, 1994;Oppenheim and Dimant, 2004;Oppenheim et al, 2008). Dimant and Oppenheim (2004) attributed this effect to the additional instability driving mechanism of the ion-thermal nature.…”

Section: Runmentioning

confidence: 61%

“…For this purpose we chose parameters the same as for fully PIC simulations performed by Oppenheim and Dimant (2004), but left the plasma density and the driving field as in Run 2. The electron mass in Run 3 was artificially increased by a factor of 44 which affects the parameter 0 , Eq.…”

Section: Runmentioning

confidence: 99%

“…Nonlinear simulations of the FB instability are based on the two-fluid (Newman and Ott, 1981), particlein-cell (PIC) (Machida and Goertz, 1988;Schlegel and Thiemann, 1994;Janhunen, 1994;Oppenheim and Dimant, 2004;Oppenheim et al, 2008), or hybrid Dyrud et al, 2006) -semifluid, semi-PIC -codes. Note that for the FB instability, the kinetic effect of ion Landau damping is crucial because it gives the short-wavelength restriction on linearly unstable spectral domain.…”

Section: Introductionmentioning

confidence: 99%

“…Even properly rescaled, such computational results not fully model the actual physical situation. Furthermore, numerical studies of wave activity have been mostly limited to 2-D cases: either in the plane parallel to the magnetic field (Machida and Goertz, 1988;Schlegel and Thiemann, 1994) or in the perpendicular plane (Newman and Ott, 1981;Janhunen, 1994;Oppenheim and Dimant, 2004;Dyrud et al, 2006;Oppenheim et al, 2008). The latter simulations are more relevant to the actual situation because they correctly take into account the dominant electron nonlinearity associated with the fluid-model term ∝δE×∇δn e , where δE and δn e are the turbulent electric field and electron density perturbations, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Modeling of the Farley-Buneman instability in the E-region ionosphere: a new hybrid approach

2008

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Abstract.A novel approach to nonlinear simulations of the Farley-Buneman (FB) instability in the E-region ionosphere is developed. The mathematical model includes a fluid description of electrons and a simplified kinetic description of ions based on a kinetic equation with the Bhatnagar-GrossCrook (BGK) collision term. This hybrid model takes into account all major factors crucial for development and nonlinear stabilization of the instability (collisional drag forces, ion inertia and Landau damping, dominant electron nonlinearity, etc.). At the same time, these simulations are free of noises caused by the finite number of particles and may require less computer resources than particle-in-cell (PIC) or hybridsemi-fluid semi-PIC -simulations. First results of 2-D simulations are presented which agree reasonably well with those of previous 2-D PIC simulations. One of the potentially useful applications of the novel computational approach is modeling of the FB instability not far from its threshold.

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Section: Runsupporting

confidence: 83%

Section: Runmentioning

confidence: 61%

Section: Runmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling of the Farley-Buneman instability in the E-region ionosphere: a new hybrid approach

2008

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First 3‐D simulations of meteor plasma dynamics and turbulence

Oppenheim

Dimant

2015

Geophysical Research Letters

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Millions of small but detectable meteors hit the Earth's atmosphere every second, creating trails of hot plasma that turbulently diffuse into the background atmosphere. For over 60 years, radars have detected meteor plasmas and used these signals to infer characteristics of the meteoroid population and upper atmosphere, but, despite the importance of meteor radar measurements, the complex processes by which these plasmas evolve have never been thoroughly explained or modeled. In this paper, we present the first fully 3‐D simulations of meteor evolution, showing meteor plasmas developing instabilities, becoming turbulent, and inhomogeneously diffusing into the background ionosphere. These instabilities explain the characteristics and strength of many radar observations, in particular the high‐resolution nonspecular echoes made by large radars. The simulations reveal how meteors create strong electric fields that dig out deep plasma channels along the Earth's magnetic fields. They also allow researchers to explore the impacts of the intense winds and wind shears, commonly found at these altitudes, on meteor plasma evolution. This study will allow the development of more sophisticated models of meteor radar signals, enabling the extraction of detailed information about the properties of meteoroid particles and the atmosphere.

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Photoelectron‐induced waves: A likely source of 150 km radar echoes and enhanced electron modes

Oppenheim

Dimant

2016

Geophysical Research Letters

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VHF radars near the geomagnetic equator receive coherent reflections from plasma density irregularities between 130 and 160 km in altitude during the daytime. Though researchers first discovered these 150 km echoes over 50 years ago and use them to monitor vertical plasma drifts, the underlying mechanism that creates them remains a mystery. This paper uses large‐scale kinetic simulations to show that photoelectrons can drive electron waves, which then enhance ion density irregularities that radars could observe as 150 km echoes. This model explains why 150 km echoes exist only during the day and why they appear at their lowest altitudes near noon. It predicts the spectral structure observed by Chau (2004) and suggests observations that can further evaluate this mechanism. It also shows the types and strength of electron modes that photoelectron‐wave interactions generate in a magnetized plasma.

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Ion thermal effects on E-region instabilities: 2D kinetic simulations

Cited by 42 publications

References 81 publications

Modeling of the Farley-Buneman instability in the E-region ionosphere: a new hybrid approach

Modeling of the Farley-Buneman instability in the E-region ionosphere: a new hybrid approach

First 3‐D simulations of meteor plasma dynamics and turbulence

Photoelectron‐induced waves: A likely source of 150 km radar echoes and enhanced electron modes

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