Spatiotemporal evolution of a thin plasma foil with Kappa distribution

AbstractThe one-dimensional behavior of a thin plasma foil heated by laser is studied, emphasizing on the fully kinetic effects associated with initial energetic electrons using a relativistic kinetic 1D3V Particle-In-Cell code. For this purpose, the generalized Lorentzian (Kappa) function inclusive the high energy tail is employed for initial electron distribution. The presence of the initially high-energy electrons leads to a different ion energy spectrum than the initially Maxwellian distribution. It is shown for the smaller Kappa parameter k where the high energy tail of the electron distribution function becomes more significant, the electron cooling rate increases. Moreover, the spatiotemporal evolution of electric field is strongly affected by the initial super-thermal electrons.

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Electrostatic heat flux instabilities

Journal of Plasma Physics ◽

10.1017/s0022377800021358 ◽

1978 ◽

Vol 20 (1) ◽

pp. 47-60 ◽

Cited By ~ 24

Author(s):

S. Peter Gary

Keyword(s):

Heat Flux ◽

Distribution Function ◽

Electron Beam ◽

Electron Distribution ◽

Electron Distribution Function ◽

High Energy ◽

Electrostatic Waves ◽

High Energy Tail ◽

Ion Acoustic ◽

Ion Cyclotron

The linear Vlasov dispersion relation for electrostatic waves in a homogeneous plasma is studied for instabilities driven by an electron heat flux. A two Maxwellian model of the electron distribution function gives rise to three unstable modes: the electron beam, ion-acoustic and ion cyclotron heat flux instabilities. At large Te/Ti the ion-acoustic instability has the lowest threshold; at small Te/Ti the electron beam instability is dominant; and at intermediate values of Te/Ti the ion cyclotron mode is the first to go unstable. The presence of a high energy tail on the electron distribution function raises the value of the dimensionless heat flux qe/(nemev3e) at the ion-acoustic threshold, but increasing atomic number of the ions decreases this value.

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The Influence of Deviations from the Maxwellian Electron Distribution on the Population densities in a low Temperature Monatomic Plasma

Zeitschrift für Naturforschung A ◽

10.1515/zna-1975-0411 ◽

1975 ◽

Vol 30 (4) ◽

pp. 451-460

Author(s):

H. A. Claaßen

Keyword(s):

Low Temperature ◽

Electron Energy ◽

Electron Distribution ◽

Electron Distribution Function ◽

High Energy ◽

Resonance Level ◽

Population Densities ◽

High Energy Tail ◽

Energy States ◽

Bound Electron

Abstract A selfconsistent solution with respect to both free and bound electron energy states is presented for a low temperature monatomic plasma. The deviations from a Maxwellian electron distribution under the action of unbalanced resonance transitions of the plasma atoms are incorporated in analytical form using a recursion formula, which links the high energy tail of the electron distribution function to its low energy part. The unbalance of the resonance level may be due to diffusion processes and/or radiation escape, which reflect the influence of the plasma boundaries. The population densities of the bound electron energy states are numerically determined by an iteration procedure. The calculations were performed for a cesium plasma both without and with consideration of resonance level diffusion and ambipolar diffusion. As is to be expected, the effect of a disturbance of the electron distribution on the population densities increases with decreasing electron density and increasing electron temperature.

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Kinetic beaming in radiative relativistic magnetic reconnection: a mechanism for rapid gamma-ray flares in jets

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2346 ◽

2020 ◽

Vol 498 (1) ◽

pp. 799-820 ◽

Cited By ~ 1

Author(s):

J M Mehlhaff ◽

G R Werner ◽

D A Uzdensky ◽

M C Begelman

Keyword(s):

Magnetic Reconnection ◽

Gamma Ray ◽

Critical Role ◽

High Energy ◽

Particle In Cell ◽

Pair Plasma ◽

Spectrum Radio ◽

Inverse Compton ◽

Emission Models ◽

The One

ABSTRACT Rapid gamma-ray flares pose an astrophysical puzzle, requiring mechanisms both to accelerate energetic particles and to produce fast observed variability. These dual requirements may be satisfied by collisionless relativistic magnetic reconnection. On the one hand, relativistic reconnection can energize gamma-ray emitting electrons. On the other hand, as previous kinetic simulations have shown, the reconnection acceleration mechanism preferentially focuses high energy particles – and their emitted photons – into beams, which may create rapid blips in flux as they cross a telescope’s line of sight. Using a series of 2D pair-plasma particle-in-cell simulations, we explicitly demonstrate the critical role played by radiative (specifically inverse Compton) cooling in mediating the observable signatures of this ‘kinetic beaming’ effect. Only in our efficiently cooled simulations do we measure kinetic beaming beyond one light crossing time of the reconnection layer. We find a correlation between the cooling strength and the photon energy range across which persistent kinetic beaming occurs: stronger cooling coincides with a wider range of beamed photon energies. We also apply our results to rapid gamma-ray flares in flat-spectrum radio quasars, suggesting that a paradigm of radiatively efficient kinetic beaming constrains relevant emission models. In particular, beaming-produced variability may be more easily realized in two-zone (e.g. spine-sheath) set-ups, with Compton seed photons originating in the jet itself, rather than in one-zone external Compton scenarios.

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High-resolution spectral imaging of SNR W44 and IC443 at 22 GHz with the Sardinia Radio Telescope

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317005221 ◽

2017 ◽

Vol 12 (S331) ◽

pp. 190-193

Author(s):

S. Loru ◽

A. Pellizzoni ◽

E. Egron ◽

N. Iacolina ◽

S. Righini ◽

...

Keyword(s):

High Resolution ◽

Radio Telescope ◽

High Frequency ◽

Electron Distribution ◽

Ad Hoc ◽

Imaging Techniques ◽

High Energy ◽

Spatially Resolved ◽

High Energy Tail ◽

Science Activities

AbstractIn the framework of the Astronomical Validation and Early Science activities of the Sardinia Radio Telescope (SRT, www.srt.inaf.it), we performed 22 GHz imaging observations of SNR W44 and IC443. Thanks to the single-dish imaging performances of SRT and innovative ad hoc imaging techniques, we obtained maps that provide a detailed view of the structure of the remnants. We are planning to exploit the high-frequency radio data of SNRs to better characterize the spatially-resolved spectra and search for possible spectral steepening or breaks in selected SNR regions, assessing the high-energy tail of the region-dependent electron distribution.

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Nonlinear dust acoustic waves in a mixed nonthermal high energy-tail electron distribution

Physics of Plasmas ◽

10.1063/1.2952002 ◽

2008 ◽

Vol 15 (7) ◽

pp. 073706 ◽

Cited By ~ 21

Author(s):

Smain Younsi ◽

Mouloud Tribeche

Keyword(s):

Acoustic Waves ◽

Electron Distribution ◽

High Energy ◽

Dust Acoustic Waves ◽

High Energy Tail ◽

Dust Acoustic

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Forward directed ion acceleration in a LWFA with ionization-induced injection

Journal of Plasma Physics ◽

10.1017/s0022377811000602 ◽

2012 ◽

Vol 78 (4) ◽

pp. 327-331 ◽

Cited By ~ 6

Author(s):

N. LEMOS ◽

J. L. MARTINS ◽

J. M. DIAS ◽

K. A. MARSH ◽

A. PAK ◽

...

Keyword(s):

Forward Direction ◽

High Energy ◽

Plasma Boundary ◽

Time Varying ◽

Azimuthal Magnetic Field ◽

Energetic Ions ◽

Ion Energy ◽

Particle In Cell ◽

High Energy Electrons ◽

Vacuum Interface

AbstractIn this work we present an experimental study where energetic ions were produced in an underdense 2.5 × 1019 cm−3 plasma created by a 50 fs Ti:Sapphire laser with 5 TWs of power. The plasma comprises 95% He and 5% N2 gases. Ionization-induced trapping of nitrogen K-shell electrons in the laser-induced wakefield generates an electron beam with a mean energy of 40 MeV and ~1 nC of charge. Some of the helium ions at the wake–vacuum interface are accelerated with a measured minimum ion energy of He1+ ions of 1.2 MeV and He2+ ions of 4 MeV. The physics of the interaction is studied with 2D particle-in-cell simulations. These reveal the formation of an ion filament on the axis of the plasma due to space charge attraction of the wakefield-accelerated high-charge electron bunch. Some of these high-energy electrons escape the plasma to form a sheath at the plasma–vacuum boundary that accelerates some of the ions in the filament in the forward direction. Electrons with energy less than the sheath potential cannot escape and return to the plasma boundary in a vortex-like motion. This in turn produces a time-varying azimuthal magnetic field, which generates a longitudinal electric field at the interface that further accelerates and collimates the ions.

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Fast magnetic energy dissipation in relativistic plasma induced by high order laser modes

High Power Laser Science and Engineering ◽

10.1017/hpl.2016.16 ◽

2016 ◽

Vol 4 ◽

Cited By ~ 7

Author(s):

Y. J. Gu ◽

Q. Yu ◽

O. Klimo ◽

T. Zh. Esirkepov ◽

S. V. Bulanov ◽

...

Keyword(s):

Magnetic Field ◽

Electric Field ◽

Magnetic Energy ◽

Collisionless Plasma ◽

High Energy ◽

Field Energy ◽

Displacement Current ◽

Particle In Cell ◽

Magnetic Field Energy ◽

High Energy Electrons

Fast magnetic field annihilation in a collisionless plasma is induced by using TEM(1,0) laser pulse. The magnetic quadrupole structure formation, expansion and annihilation stages are demonstrated with 2.5-dimensional particle-in-cell simulations. The magnetic field energy is converted to the electric field and accelerate the particles inside the annihilation plane. A bunch of high energy electrons moving backwards is detected in the current sheet. The strong displacement current is the dominant contribution which induces the longitudinal inductive electric field.

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