Comparative study of forward and backward test-kinetic simulation approaches

Voitcu, Gabriel; Echim, Marius; Marchand, R.

doi:10.1016/j.cpc.2012.07.005

Cited by 6 publications

(2 citation statements)

References 19 publications

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“…The background magnetic field is assumed to be dipolar with equatorial strength at the Earth's surface of    with 64 points (particles with initial velocities larger than E c are excluded from the sample). To confirm that this resolution is sufficient (Voitcu et al, 2012), we limited the range in velocities to focus on the resonance region of the first subpacket, and doubled the number of gyrophase grid points. Apart from some finer features associated with the phase mixing of lower and higher density regions, there was no noticeable difference.…”

Section: Backward-in-time Test Particle Simulationmentioning

confidence: 99%

Measurability of the Nonlinear Response of Electron Distribution Function to Chorus Emissions in the Earth's Radiation Belt

et al. 2021

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We conduct test particle simulations to study the perturbations in a hot electron velocity distribution caused by a rising chorus element propagating parallel to the ambient magnetic field in the Earth's outer radiation belt. The wavefield is constructed from the nonlinear growth theory of chorus emissions of Omura (2021, https://doi.org/10.1186/s40623-021-01380%2Dw), with additional considerations about saturation and propagation of the transverse resonant current being applied to model the subpacket structure. Using Liouville's theorem, we trace electrons back in time to reconstruct the evolution of electron velocity distribution at the magnetic equator. The electromagnetic hole created by nonlinear trapping and transport effects appears as a depression in the velocity distribution, aligned with the resonance velocity curve. We analyze the decrease of particle flux in this depression and estimate the energy resolution, pitch angle resolution, time resolution and geometric factor of particle analyzers needed to observe the perturbation. We conclude that particle detectors on current or recently operating spacecraft are always lacking in at least one of these parameters, which explains the missing direct observations of sharp phase space density depressions during chorus‐electron nonlinear resonant interaction. However, with a dedicated experiment and appropriate measurement strategy, such observations are within the possibilities of the current technology. Similarity of the simulated density perturbation and a step function mathematical model is used to draw an analogy between the backward wave oscillator regime of chorus generation and the nonlinear growth theory.

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Section: Backward-in-time Test Particle Simulationmentioning

confidence: 99%

Measurability of the Nonlinear Response of Electron Distribution Function to Chorus Emissions in the Earth's Radiation Belt

et al. 2021

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“…Crescent-like VDFs were observed for ions in the Earth's magnetotail, close to the neutral sheet and plasma sheet boundary layer (e.g. Nakamura et al, 1991Nakamura et al, , 1992Wilber et al, 2004), as well as in the magnetosheath, close to the magnetopause (e.g. Marcucci et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Crescent-shaped electron velocity distribution functions formed at the edges of plasma jets interacting with a tangential discontinuity

Voitcu

Echim

2018

Ann. Geophys.

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In this paper we discuss numerical simulations that illustrate a physical mechanism leading to the formation of crescent-shaped electron velocity distribution functions at the edges of a high-speed plasma jet impacting on a thin, steep and impenetrable tangential discontinuity with no magnetic shear. We use three-dimensional particle-in-cell simulations to compute the velocity distribution function of electrons in different areas of the plasma jet and at different phases of the interaction with the discontinuity. The simulation set-up corresponds to an idealized, yet relevant, magnetic configuration likely to be observed at the frontside magnetopause under the northward interplanetary magnetic field. The combined effect of the gradient-B drift and the remote sensing of large Larmor radius electrons leads to the formation of crescent-shaped electron velocity distribution functions. We provide examples of such distributions "measured" by a virtual satellite launched into the simulation domain.

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Transport and entry of plasma clouds/jets across transverse magnetic discontinuities: Three‐dimensional electromagnetic particle‐in‐cell simulations

Voitcu

Echim

2016

JGR Space Physics

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In this paper we use three‐dimensional electromagnetic particle‐in‐cell simulations to investigate the interaction of a small Larmor radius plasma cloud/jet with a transverse nonuniform magnetic field typical to a tangential discontinuity in a parallel geometry. The simulation setup corresponds to an idealized, yet relevant, magnetospheric configuration likely to be observed at the magnetopause during northward orientation of the interplanetary magnetic field. The numerical simulations are adapted to study the kinetic effects and their role on the transport and entry of localized plasma jets similar to those identified inside the Earth's magnetosheath propagating toward the magnetopause. The simulations reveal the formation of a perpendicular polarization electric field inside the main bulk of the plasma cloud that enables its forward transport and entry across the transverse magnetic field. The jet is able to penetrate the transition region when the height of the magnetic barrier does not exceed a certain critical threshold. Otherwise, the forward transport along the injection direction is stopped before full penetration of the magnetopause. Moreover, the jet is pushed back and simultaneously deflected in the perpendicular plane to the magnetic field. Our simulations evidence physical processes advocated previously by the theoretical model of impulsive penetration and revealed in laboratory experiments.

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Comparative study of forward and backward test-kinetic simulation approaches

Cited by 6 publications

References 19 publications

Measurability of the Nonlinear Response of Electron Distribution Function to Chorus Emissions in the Earth's Radiation Belt

Measurability of the Nonlinear Response of Electron Distribution Function to Chorus Emissions in the Earth's Radiation Belt

Crescent-shaped electron velocity distribution functions formed at the edges of plasma jets interacting with a tangential discontinuity

Transport and entry of plasma clouds/jets across transverse magnetic discontinuities: Three‐dimensional electromagnetic particle‐in‐cell simulations

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