scholarly journals Laboratory study of astrophysical collisionless shock at SG-II laser facility

2018 ◽  
Vol 6 ◽  
Author(s):  
Dawei Yuan ◽  
Huigang Wei ◽  
Guiyun Liang ◽  
Feilu Wang ◽  
Yutong Li ◽  
...  
Keyword(s):  
Nuclear Reactions ◽  
High Energy ◽  
Laboratory Astrophysics ◽  
Observation Data ◽  
Collisionless Shock ◽  
Astrophysical Plasmas ◽  
High Energy Cosmic Rays ◽  
Physical Conditions ◽  
Laser Facility ◽  
Astrophysical Observation

Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-II laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.

scholarly journals Generating high-yield positrons and relativistic collisionless shocks by 10 PW laser

2017 ◽  
Vol 35 (2) ◽  
pp. 234-240 ◽  
Author(s):  
J. Jiao ◽  
B. Zhang ◽  
J. Yu ◽  
Z. Zhang ◽  
Y. Yan ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Quantum Electrodynamics ◽  
Positron Beam ◽  
High Energy ◽  
High Yield ◽  
Formation Condition ◽  
Lead Target ◽  
Collisionless Shock ◽  
High Energy Cosmic Rays ◽  
Electron Positron

AbstractRelativistic collisionless shock charged particle acceleration is considered as a possible origin of high-energy cosmic rays. However, it is hard to explore the nature of relativistic collisionless shock due to its low occurring frequency and remote detecting distance. Recently, there are some works attempt to solve this problem by generating relativistic collisionless shock in laboratory conditions. In laboratory, the scheme of generation of relativistic collisionless shock is that two electron–positron pair plasmas knock each other. However, in laboratory, the appropriate pair plasmas have been not generated. The 10 PW laser pulse maybe generates the pair plasmas that satisfy the formation condition of relativistic collisionless shock due to its ultrahigh intensity and energy. In this paper, we study the positron production by ultraintense laser high Z target interaction using numerical simulations, which consider quantum electrodynamics effect. The simulation results show that the forward positron beam up to 1013/kJ can be generated by 10 PW laser pulse interacting with lead target. The estimation of relativistic collisionless shock formation shows that the positron yield satisfies formation condition and the positron divergence needs to be controlled. Our results indicate that the generation of relativistic collisionless shock by 10 PW laser facilities in laboratory is possible.

scholarly journals Symmetry Breaking and Invariant Mass Approach to the Spiral Structure of Galaxies

1981 ◽  
Vol 94 ◽  
pp. 171-172
Author(s):  
K. O. Thielheim
Keyword(s):  
Black Holes ◽  
Cosmic Rays ◽  
Central Region ◽  
Recent Progress ◽  
Spiral Galaxies ◽  
Spiral Structure ◽  
High Energy ◽  
High Energy Cosmic Rays ◽  
Physical Conditions ◽  
The Galaxy

The physical conditions in the centre of spiral galaxies as our own galaxy still are not very well known. They offer themselves to more or less exotic speculations, some of which involve the possible existence of black holes and mechanisms for the production of high energy cosmic rays. In view of such argumentations I feel it worthwhile to look in more detail into recent progress obtained in the understanding of the dynamics of the central region of spiral galaxies which turns out to be intimately related to the galaxy as a whole, especially its spiral structure.

scholarly journals PROSPECTS OF HIGH ENERGY LABORATORY ASTROPHYSICS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 312-318 ◽  
Author(s):  
JOHNNY S. T. NG ◽  
PISIN CHEN
Keyword(s):  
High Energy ◽  
Cosmic Acceleration ◽  
Laboratory Astrophysics ◽  
Terrestrial Environment ◽  
Plasma Dynamics ◽  
High Energy Cosmic Rays ◽  
Air Fluorescence ◽  
Underlying Mechanisms ◽  
Observational Techniques ◽  
First Time

Ultra high energy cosmic rays (UHECR) have been observed but their sources and production mechanisms are yet to be understood. We envision a laboratory astrophysics program that will contribute to the understanding of cosmic accelerators with efforts to: 1) test and calibrate UHECR observational techniques, and 2) elucidate the underlying physics of cosmic acceleration through laboratory experiments and computer simulations. Innovative experiments belonging to the first category have already been done at the SLAC FFTB. Results on air fluorescence yields from the FLASH experiment are reviewed. Proposed future accelerator facilities can provided unprecedented high-energy-densities in a regime relevant to cosmic acceleration studies and accessible in a terrestrial environment for the first time. We review recent simulation studies of non-linear plasma dynamics that could give rise to cosmic acceleration, and discuss prospects for experimental investigation of the underlying mechanisms.

scholarly journals Turbulent hydrodynamics experiments in high energy density plasmas: scientific case and preliminary results of the TurboHEDP project

2018 ◽  
Vol 6 ◽  
Author(s):  
A. Casner ◽  
G. Rigon ◽  
B. Albertazzi ◽  
Th. Michel ◽  
T. Pikuz ◽  
...  
Keyword(s):  
Energy Density ◽  
High Energy ◽  
Laboratory Astrophysics ◽  
High Energy Density ◽  
Compressible Turbulence ◽  
Stepping Stones ◽  
Preliminary Results ◽  
Laser Facility ◽  
Numerical Tools ◽  
Phase Scaling

The physics of compressible turbulence in high energy density (HED) plasmas is an unchartered experimental area. Simulations of compressible and radiative flows relevant for astrophysics rely mainly on subscale parameters. Therefore, we plan to perform turbulent hydrodynamics experiments in HED plasmas (TurboHEDP) in order to improve our understanding of such important phenomena for interest in both communities: laser plasma physics and astrophysics. We will focus on the physics of supernovae remnants which are complex structures subject to fluid instabilities such as the Rayleigh–Taylor and Kelvin–Helmholtz instabilities. The advent of megajoule laser facilities, like the National Ignition Facility and the Laser Megajoule, creates novel opportunities in laboratory astrophysics, as it provides unique platforms to study turbulent mixing flows in HED plasmas. Indeed, the physics requires accelerating targets over larger distances and longer time periods than previously achieved. In a preparatory phase, scaling from experiments at lower laser energies is used to guarantee the performance of future MJ experiments. This subscale experiments allow us to develop experimental skills and numerical tools in this new field of research, and are stepping stones to achieve our objectives on larger laser facilities. We review first in this paper recent advances in high energy density experiments devoted to laboratory astrophysics. Then we describe the necessary steps forward to commission an experimental platform devoted to turbulent hydrodynamics on a megajoule laser facility. Recent novel experimental results acquired on LULI2000, as well as supporting radiative hydrodynamics simulations, are presented. Together with the development of LiF detectors as transformative X-ray diagnostics, these preliminary results are promising on the way to achieve micrometric spatial resolution in turbulent HED physics experiments in the near future.

High-energy Nd:glass laser facility for collisionless laboratory astrophysics

2012 ◽  
Vol 7 (03) ◽  
pp. P03010-P03010 ◽  
Author(s):  
C Niemann ◽  
C G Constantin ◽  
D B Schaeffer ◽  
A Tauschwitz ◽  
T Weiland ◽  
...  
Keyword(s):  
High Energy ◽  
Laboratory Astrophysics ◽  
Laser Facility ◽  
Nd:Glass Laser

scholarly journals PHYSICAL CONDITIONS IN NEARBY ACTIVE GALAXIES CORRELATED WITH ULTRA-HIGH-ENERGY COSMIC RAYS DETECTED BY THE PIERRE AUGER OBSERVATORY

2010 ◽  
Vol 25 (14) ◽  
pp. 2917-2932 ◽  
Author(s):  
SERGEY GUREEV ◽  
SERGEY TROITSKY
Keyword(s):  
Nearest Neighbors ◽  
High Energy ◽  
Active Galaxies ◽  
Pierre Auger Observatory ◽  
Ultra High Energy ◽  
Galactic Magnetic Field ◽  
Intermediate Mass ◽  
Correlated Sources ◽  
High Energy Cosmic Rays ◽  
Physical Conditions

We analyze the active-galaxy correlation reported in 2007 by the Pierre Auger Collaboration. The signal diminishes if the correlation-function approach (counting all "source–event" pairs and not only "nearest neighbors") is used, suggesting that the correlation may reveal individual sources and not their population. We analyze available data on physical conditions in these individual correlated sources and conclude that acceleration of protons to the observed energies is hardly possible in any of these galaxies, while heavier nuclei would be deflected by the Galactic magnetic field thus spoiling the correlation. Our results question the Auger interpretation of the reported anisotropy signal but do not contradict to its explanation with intermediate-mass nuclei accelerated in Cen A.

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