scholarly journals Pitch-Angle Anisotropy Controls Particle Acceleration and Cooling in Radiative Relativistic Plasma Turbulence

2021 ◽  
Vol 127 (25) ◽  
Author(s):  
Luca Comisso ◽  
Lorenzo Sironi
Keyword(s):  
Particle Acceleration ◽  
Pitch Angle ◽  
Plasma Turbulence ◽  
Relativistic Plasma

scholarly journals First-principles Demonstration of Diffusive-advective Particle Acceleration in Kinetic Simulations of Relativistic Plasma Turbulence

2020 ◽  
Vol 893 (1) ◽  
pp. L7 ◽  
Author(s):  
Kai Wong ◽  
Vladimir Zhdankin ◽  
Dmitri A. Uzdensky ◽  
Gregory R. Werner ◽  
Mitchell C. Begelman
Keyword(s):  
Particle Acceleration ◽  
First Principles ◽  
Plasma Turbulence ◽  
Relativistic Plasma

scholarly journals System-size Convergence of Nonthermal Particle Acceleration in Relativistic Plasma Turbulence

2018 ◽  
Vol 867 (1) ◽  
pp. L18 ◽  
Author(s):  
Vladimir Zhdankin ◽  
Dmitri A. Uzdensky ◽  
Gregory R. Werner ◽  
Mitchell C. Begelman
Keyword(s):  
Particle Acceleration ◽  
System Size ◽  
Plasma Turbulence ◽  
Relativistic Plasma

MMS observations of explosive filamentary current within two adjacent ion scale flux ropes

2021 ◽  
Author(s):  
Yuchen Xiao ◽  
Shutao Yao ◽  
Ruilong Guo ◽  
Quanqi Shi ◽  
Anmin Tian ◽  
...  
Keyword(s):  
Particle Acceleration ◽  
Energy Dissipation ◽  
Magnetic Reconnection ◽  
Temporal Resolution ◽  
Pitch Angle ◽  
Angle Distribution ◽  
Pitch Angle Distribution ◽  
The Past ◽  
Flux Ropes ◽  
Spatio Temporal

<p>Flux ropes have attracted extensive attention due to their importance in studying instantaneous magnetic reconnection over the past years. Recently, with the improvement of high spatio-temporal resolution measurements, kinetic-scale flux ropes have been detected. However, their generation and energy energization are still unclear. In this study, electron-scale filamentary currents within two adjacent ion scale flux ropes are observed using MMS data. We find that:</p><p>1. Intense and explosive filamentary currents in parallel and perpendicular directions are found inside the flux ropes.</p><p>2. The electron pitch angle distribution appears "X" like shape, and could be caused by the electron acceleration.</p><p>3. The filamentary current appears in the center of the "X" distribution.</p><p>The filamentary currents are important and are considered to be the evidence of secondary reconnection [Wang et al., 2020]. The observations in our study are important to reveal the particle acceleration and energy dissipation in magnetic reconnection.</p>

Different Types of Plasma Turbulence in the Process of Solar Particle Acceleration

2006 ◽  
Author(s):  
Jorge Pérez-Peraza ◽  
Leonty I. Miroshnichenko ◽  
Eduard V. Vashenyuk ◽  
Yuri V. Balabin ◽  
Apolonio Gallegos-Cruz
Keyword(s):  
Particle Acceleration ◽  
Plasma Turbulence ◽  
Solar Particle ◽  
Different Types

Plasma turbulence generated during particle acceleration in magnetic islands

2021 ◽  
Author(s):  
Valentina Zharkova ◽  
Qian Xia
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Current Sheet ◽  
Plasma Turbulence ◽  
Lower Hybrid ◽  
Diffusion Region ◽  
Magnetic Islands ◽  
Langmuir Waves ◽  
Kink Instability ◽  
Hybrid Waves

<div> <div> <div> <p>We investigate plasma turbulence generated during particle acceleration in magnetic islands within 3D Harris-type reconnecting current sheets (RCSs),using the particle-in-cell approach.  RCSs with a strong guiding magnetic field  ar shown to lead to separation of electrons and ions into the opposite sides from the current sheet mid-plane that significantly reduces kink instability along the guiding field direction. Particles with the same charge also have asymmetric trajectories forming two distinct populations of beams: ‘transit’ particles, which pass through RCS from one edge to another, become strongly energised and form nearly unidirectional beams; and ‘bounced’ particles, which are reflected from the diffusion region and move back to the same side they entered the current sheet, gaining much less energy and forming more dispersive spatial distributions. Thes transit and bounced particles form the ‘bump-on-tail’ velocity distributions that naturally generate plasma turbulence. Using the wavelet analysis of electric and magnetic field fluctuations in the frequency domain, we identified some characteristic waves produced by particle beams. In particular, we found thre are Langmuir waves near X-nullpoints produced by two electron beam instabilities, while the presence of anisotropic temperature variations inside magnetic islands lead to whistler waves. The lower-hybrid waves are generated inside the magnetic islands, owing to the two-stream instabilities of the ions. While the high-frequency fluctuations, upper hybrid waves, or electron Bernstein waves, pile up near X-nullpoints. The results can be beneficial for understanding in-situ observations with modern space missions of energetic particles in the heliosphere.</p> </div> </div> </div>

Fully kinetic PIC simulations of particle acceleration and non-Maxwellian distribution functions due to current sheets in solar wind turbulence

2021 ◽  
Author(s):  
Patricio A. Munoz ◽  
Jörg Büchner ◽  
Neeraj Jain
Keyword(s):  
Solar Wind ◽  
Particle Acceleration ◽  
Current Sheet ◽  
Plasma Turbulence ◽  
Distribution Functions ◽  
Heat Fluxes ◽  
Magnetic Islands ◽  
Ion Distribution ◽  
Current Sheets ◽  
Particle In Cell

<p>Turbulence is ubiquitous in solar system plasmas like those of the solar wind and Earth's magnetosheath. Current sheets can be formed out of this turbulence, and eventually magnetic reconnection can take place in them, a process that converts magnetic into particle kinetic energy. This interplay between turbulence and current sheet formation has been extensively analyzed with MHD and hybrid-kinetic models. Those models cover all the range between large Alfvénic scales down to ion-kinetic scales. The consequences of current sheet formation in plasma turbulence that includes electron dynamics has, however, received comparatively less attention. For this sake we carry out 2.5D fully kinetic Particle-in-Cell simulations of kinetic plasma turbulence including both ion and electron spectral ranges. In order to further assess the electron kinetic effects, we also compare our results with hybrid-kinetic simulations including electron inertia in the generalized Ohm's law. We analyze and discuss the electron and ion energization processes in the current sheets and magnetic islands formed in the turbulence. We focus on the electron and ion distribution functions formed in and around those current sheets and their stability properties that are relevant for the micro-instabilities feeding back into the turbulence cascade. We also compare pitch angle distributions and non-Maxwellian features such as heat fluxes with recent in-situ solar wind observations, which demonstrated local particle acceleration processes in reconnecting solar wind current sheets [Khabarova et al., ApJ, 2020].</p>

scholarly journals Particle acceleration with anomalous pitch angle scattering in 3D separator reconnection

2020 ◽  
Vol 635 ◽  
pp. A63
Author(s):  
A. Borissov ◽  
T. Neukirch ◽  
E. P. Kontar ◽  
J. Threlfall ◽  
C. E. Parnell
Keyword(s):  
Particle Acceleration ◽  
Magnetic Reconnection ◽  
Test Particle ◽  
Pitch Angle ◽  
High Energy ◽  
Energy Spectra ◽  
Mhd Simulation ◽  
Mhd Simulations ◽  
Angle Scattering ◽  
Particle Orbits

Context. Understanding how the release of stored magnetic energy contributes to the generation of non-thermal high energy particles during solar flares is an important open problem in solar physics. There is a general consensus that magnetic reconnection plays a fundamental role in the energy release and conversion processes taking place during flares. A common approach for investigating how reconnection contributes to particle acceleration is to use test particle calculations in electromagnetic fields derived from numerical magnetohydrodynamic (MHD) simulations of reconnecting magnetic fields. These MHD simulations use anomalous resistivities that are orders of magnitude larger than the Spitzer resistivity that is based on Coulomb collisions. The processes leading to such an enhanced resistivity should also affect the test particles, for example, through pitch angle scattering. This study explores the effect of such a link between the level of resistivity and its impact on particle orbits and builds on a previous study using a 2D MHD simulation of magnetic reconnection. Aims. This paper aims to extend the previous investigation to a 3D magnetic reconnection configuration and to study the effect on test particle orbits. Methods. We carried out orbit calculations using a 3D MHD simulation of reconnection in a magnetic field with a magnetic separator. The orbit calculations use the relativistic guiding centre approximation but, crucially, they also include pitch angle scattering using stochastic differential equations. The effects of varying the resistivity and the models for pitch angle scattering on particle orbit trajectories, final positions, energy spectra, final pitch angle distribution, and orbit duration are all studied in detail. Results. Pitch angle scattering widens highly collimated beams of unscattered orbit trajectories, allowing orbits to access previously unaccessible field lines; this causes final positions to spread along other topological structures which could not be accessed without scattering. Scattered orbit energy spectra are found to be predominantly affected by the level of anomalous resistivity, with the pitch angle scattering model only playing a role in specific, isolated cases. This is in contrast to the study involving a 2D MHD simulation of magnetic reconnection, where pitch angle scattering had a more noticeable effect on the energy spectra. Pitch scattering effects are found to play a crucial role in determining the pitch angle and orbit duration distributions.

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