PLASMA PHYSICS: Connecting Again with Magnetic Reconnection

AbstractThe Particle-In-Cell (PIC) method has been developed by Oscar Buneman, Charles Birdsall, Roger W. Hockney, and John Dawson in the 1950s and, with the advances of computing power, has been further developed for several fields such as astrophysical, magnetospheric as well as solar plasmas and recently also for atmospheric and laser-plasma physics. Currently more than 15 semi-public PIC codes are available which we discuss in this review. Its applications have grown extensively with increasing computing power available on high performance computing facilities around the world. These systems allow the study of various topics of astrophysical plasmas, such as magnetic reconnection, pulsars and black hole magnetosphere, non-relativistic and relativistic shocks, relativistic jets, and laser-plasma physics. We review a plethora of astrophysical phenomena such as relativistic jets, instabilities, magnetic reconnection, pulsars, as well as PIC simulations of laser-plasma physics (until 2021) emphasizing the physics involved in the simulations. Finally, we give an outlook of the future simulations of jets associated to neutron stars, black holes and their merging and discuss the future of PIC simulations in the light of petascale and exascale computing.

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ViDA: a Vlasov–DArwin solver for plasma physics at electron scales

Journal of Plasma Physics ◽

10.1017/s0022377819000631 ◽

2019 ◽

Vol 85 (5) ◽

Cited By ~ 3

Author(s):

Oreste Pezzi ◽

Giulia Cozzani ◽

Francesco Califano ◽

Francesco Valentini ◽

Massimiliano Guarrasi ◽

...

Keyword(s):

Plasma Physics ◽

Magnetic Reconnection ◽

Spatial Scales ◽

Collisionless Plasma ◽

Low Noise ◽

Numerical Code ◽

Small Scale ◽

Diffusion Region ◽

Plasma Dynamics ◽

Algorithm Efficiency

We present a Vlasov–DArwin numerical code (ViDA) specifically designed to address plasma physics problems, where small-scale high accuracy is requested even during the nonlinear regime to guarantee a clean description of the plasma dynamics at fine spatial scales. The algorithm provides a low-noise description of proton and electron kinetic dynamics, by splitting in time the multi-advection Vlasov equation in phase space. Maxwell equations for the electric and magnetic fields are reorganized according to the Darwin approximation to remove light waves. Several numerical tests show that ViDA successfully reproduces the propagation of linear and nonlinear waves and captures the physics of magnetic reconnection. We also discuss preliminary tests of the parallelization algorithm efficiency, performed at CINECA on the Marconi-KNL cluster. ViDA will allow the running of Eulerian simulations of a non-relativistic fully kinetic collisionless plasma and it is expected to provide relevant insights into important problems of plasma astrophysics such as, for instance, the development of the turbulent cascade at electron scales and the structure and dynamics of electron-scale magnetic reconnection, such as the electron diffusion region.

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Filamentary Currents in Turbulent Magnetic Reconnection

10.5194/egusphere-egu2020-12754 ◽

2020 ◽

Author(s):

Meng Zhou ◽

Xiaohua Deng ◽

Zhihong Zhong ◽

Ye Pang

Keyword(s):

Plasma Physics ◽

Magnetic Reconnection ◽

Current Sheet ◽

Coherent Structures ◽

High Speed ◽

Large Scale ◽

Magnetic Energy ◽

Normal Direction ◽

Neutral Sheet ◽

Current Filaments

<p>Magnetic reconnection and turbulence are the two most important energy conversion phenomena in plasma physics. Magnetic reconnection and turbulence are often intertwined. For example, reconnection occurs in thin current layers formed during cascades of turbulence, while reconnection in large-scale current sheet also evolves into turbulence. How energy is dissipated and how particles are accelerated in turbulent magnetic reconnection are outstanding questions in magnetic reconnection and turbulence. Here we report MMS observations of filamentary currents in turbulent outflows in the Earth's magnetotail. We found sub-ion-scale filamentary currents in high-speed outflows that evolved into turbulent states. The normal direction of these current filaments is mainly along the X<sub>GSM</sub> direction, which is distinct from the neutral sheet. Some filamentary currents were reconnecting, thereby further dissipating the magnetic energy far from the X line. We notice that turbulent reconnection is more efficient in energizing electrons than laminar reconnection. Coherent structures composed of these filaments may be important in accelerating particles during turbulent reconnection. &#160;</p>

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Paradigm transition in cosmic plasma physics, magnetic reconnection and the generation of field-aligned current

Magnetospheric Current Systems - Geophysical Monograph Series ◽

10.1029/gm118p0011 ◽

2000 ◽

pp. 11-19 ◽

Cited By ~ 5

Author(s):

Yan Song ◽

Robert L. Lysak

Keyword(s):

Plasma Physics ◽

Magnetic Reconnection ◽

Cosmic Plasma ◽

Field Aligned Current

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Plasma physics of magnetic island coalescence during magnetic reconnection

Journal of Geophysical Research Space Physics ◽

10.1002/2013ja019483 ◽

2014 ◽

Vol 119 (8) ◽

pp. 6177-6189 ◽

Cited By ~ 18

Author(s):

Meng Zhou ◽

Ye Pang ◽

Xiaohua Deng ◽

Shiyong Huang ◽

Xiangsheng Lai

Keyword(s):

Plasma Physics ◽

Magnetic Reconnection ◽

Magnetic Island ◽

Island Coalescence

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A large rotating structure around AB Doradus A at VLBI scale

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009785 ◽

2019 ◽

Vol 15 (S354) ◽

pp. 189-194

Author(s):

J. B. Climent ◽

J. C. Guirado ◽

R. Azulay ◽

J. M. Marcaide

Keyword(s):

Magnetic Reconnection ◽

Main Sequence ◽

Complex Structure ◽

Main Sequence Star ◽

Polar Cap ◽

Vlbi Observations ◽

Rotating Structure ◽

Source Structure ◽

Expected Position

AbstractWe report the results of three VLBI observations of the pre-main-sequence star AB Doradus A at 8.4 GHz. With almost three years between consecutive observations, we found a complex structure at the expected position of this star for all epochs. Maps at epochs 2007 and 2010 show a double core-halo morphology while the 2013 map reveals three emission peaks with separations between 5 and 18 stellar radii. Furthermore, all maps show a clear variation of the source structure within the observing time. We consider a number of hypothesis in order to explain such observations, mainly: magnetic reconnection in loops on the polar cap, a more general loop scenario and a close companion to AB Dor A.

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