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

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

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 Scaling of magnetic dissipation and particle acceleration in ABC fields

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Qiang Chen ◽  
Krzysztof Nalewajko ◽  
Bhupendra Mishra
Keyword(s):  
Particle Acceleration ◽  
Magnetic Energy ◽  
Electric Energy ◽  
System Size ◽  
High Energy ◽  
Particle Energy ◽  
Growth Time ◽  
Two Dimensional ◽  
Energy Fraction ◽  
High Energy Part

Using particle-in-cell numerical simulations with electron–positron pair plasma, we study how the efficiencies of magnetic dissipation and particle acceleration scale with the initial coherence length $\lambda _0$ in relation to the system size $L$ of the two-dimensional ‘Arnold–Beltrami–Childress’ (ABC) magnetic field configurations. Topological constraints on the distribution of magnetic helicity in two-dimensional systems, identified earlier in relativistic force-free simulations, that prevent the high- $(L/\lambda _0)$ configurations from reaching the Taylor state, limit the magnetic dissipation efficiency to about $\epsilon _{\textrm {diss}} \simeq 60\,\%$ . We find that the peak growth time scale of the electric energy $\tau _{E,{\textrm {peak}}}$ scales with the characteristic value of initial Alfvén velocity $\beta _{A,{\textrm {ini}}}$ like $\tau _{E,\textrm {peak}} \propto (\lambda _0/L)\beta _{A,{\textrm {ini}}}^{-3}$ . The particle energy change is decomposed into non-thermal and thermal parts, with non-thermal energy gain dominant only for high initial magnetisation. The most robust description of the non-thermal high-energy part of the particle distribution is that the power-law index is a linear function of the initial magnetic energy fraction.

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