scholarly journals Resonant Whistler‐Electron Interactions: MMS Observations Versus Test‐Particle Simulation

2020 ◽  
Vol 125 (10) ◽  
Author(s):  
E. Behar ◽  
F. Sahraoui ◽  
L. Berčič
Keyword(s):  
Test Particle ◽  
Particle Simulation ◽  
Versus Test ◽  
Electron Interactions

scholarly journals Ion Dynamics in the Meso-scale 3-D Kelvin–Helmholtz Instability: Perspectives From Test Particle Simulations

2021 ◽  
Vol 8 ◽  
Author(s):  
Xuanye Ma ◽  
Peter Delamere ◽  
Katariina Nykyri ◽  
Brandon Burkholder ◽  
Stefan Eriksson ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Reconnection ◽  
Test Particle ◽  
Acoustic Waves ◽  
Particle Simulation ◽  
Three Dimensions ◽  
Small Scale ◽  
Physical Processes ◽  
Length Scales ◽  
Ion Species

Over three decades of in-situ observations illustrate that the Kelvin–Helmholtz (KH) instability driven by the sheared flow between the magnetosheath and magnetospheric plasma often occurs on the magnetopause of Earth and other planets under various interplanetary magnetic field (IMF) conditions. It has been well demonstrated that the KH instability plays an important role for energy, momentum, and mass transport during the solar-wind-magnetosphere coupling process. Particularly, the KH instability is an important mechanism to trigger secondary small scale (i.e., often kinetic-scale) physical processes, such as magnetic reconnection, kinetic Alfvén waves, ion-acoustic waves, and turbulence, providing the bridge for the coupling of cross scale physical processes. From the simulation perspective, to fully investigate the role of the KH instability on the cross-scale process requires a numerical modeling that can describe the physical scales from a few Earth radii to a few ion (even electron) inertial lengths in three dimensions, which is often computationally expensive. Thus, different simulation methods are required to explore physical processes on different length scales, and cross validate the physical processes which occur on the overlapping length scales. Test particle simulation provides such a bridge to connect the MHD scale to the kinetic scale. This study applies different test particle approaches and cross validates the different results against one another to investigate the behavior of different ion species (i.e., H+ and O+), which include particle distributions, mixing and heating. It shows that the ion transport rate is about 1025 particles/s, and mixing diffusion coefficient is about 1010 m2 s−1 regardless of the ion species. Magnetic field lines change their topology via the magnetic reconnection process driven by the three-dimensional KH instability, connecting two flux tubes with different temperature, which eventually causes anisotropic temperature in the newly reconnected flux.

scholarly journals Test particle simulation of non-ambipolar ion diffusion in tokamaks

2000 ◽  
Vol 40 (9) ◽  
pp. 1587-1596 ◽  
Author(s):  
T.P Kiviniemi ◽  
J.A Heikkinen ◽  
A.G Peeters
Keyword(s):  
Test Particle ◽  
Particle Simulation ◽  
Ion Diffusion

scholarly journals Simulating radial diffusion of energetic (MeV) electrons through a model of fluctuating electric and magnetic fields

2006 ◽  
Vol 24 (10) ◽  
pp. 2583-2598 ◽  
Author(s):  
T. Sarris ◽  
X. Li ◽  
M. Temerin
Keyword(s):  
Magnetic Fields ◽  
Test Particle ◽  
Diffusion Coefficients ◽  
Radial Diffusion ◽  
Particle Simulation ◽  
Quiet Time ◽  
Earth’S Magnetosphere ◽  
Electric And Magnetic Fields ◽  
Earth's Magnetosphere ◽  
Diffusion Rates

Abstract. In the present work, a test particle simulation is performed in a model of analytic Ultra Low Frequency, ULF, perturbations in the electric and magnetic fields of the Earth's magnetosphere. The goal of this work is to examine if the radial transport of energetic particles in quiet-time ULF magnetospheric perturbations of various azimuthal mode numbers can be described as a diffusive process and be approximated by theoretically derived radial diffusion coefficients. In the model realistic compressional electromagnetic field perturbations are constructed by a superposition of a large number of propagating electric and consistent magnetic pulses. The diffusion rates of the electrons under the effect of the fluctuating fields are calculated numerically through the test-particle simulation as a function of the radial coordinate L in a dipolar magnetosphere; these calculations are then compared to the symmetric, electromagnetic radial diffusion coefficients for compressional, poloidal perturbations in the Earth's magnetosphere. In the model the amplitude of the perturbation fields can be adjusted to represent realistic states of magnetospheric activity. Similarly, the azimuthal modulation of the fields can be adjusted to represent different azimuthal modes of fluctuations and the contribution to radial diffusion from each mode can be quantified. Two simulations of quiet-time magnetospheric variability are performed: in the first simulation, diffusion due to poloidal perturbations of mode number m=1 is calculated; in the second, the diffusion rates from multiple-mode (m=0 to m=8) perturbations are calculated. The numerical calculations of the diffusion coefficients derived from the particle orbits are found to agree with the corresponding theoretical estimates of the diffusion coefficient within a factor of two.

scholarly journals Three-dimensional test particle simulation of the 17-18 March 2013 CME shock-driven storm

2015 ◽  
Vol 42 (14) ◽  
pp. 5679-5685 ◽  
Author(s):  
Zhao Li ◽  
Mary Hudson ◽  
Brian Kress ◽  
Jan Paral
Keyword(s):  
Test Particle ◽  
Three Dimensional ◽  
Particle Simulation
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