Electrostatic heat flux instabilities

1978 ◽  
Vol 20 (1) ◽  
pp. 47-60 ◽  
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.

scholarly journals Spatiotemporal evolution of a thin plasma foil with Kappa distribution

2014 ◽  
Vol 32 (4) ◽  
pp. 523-529 ◽  
Author(s):  
H. Mehdian ◽  
A. Kargarian ◽  
K. Hajisharifi
Keyword(s):  
Electron Distribution ◽  
Electron Distribution Function ◽  
High Energy ◽  
Spatiotemporal Evolution ◽  
Particle In Cell ◽  
High Energy Electrons ◽  
High Energy Tail ◽  
Kinetic Effects ◽  
The One ◽  
Thin Plasma

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.

scholarly journals Fokker-Planck simulations of ultrashort-pulse laser-plasma interactions

1992 ◽  
Vol 10 (3) ◽  
pp. 461-471 ◽  
Author(s):  
L. Drska ◽  
J. Limpouch ◽  
R. Liska
Keyword(s):  
Heat Flux ◽  
Distribution Function ◽  
Laser Radiation ◽  
Electric Field ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
Laser Pulses ◽  
Ultrashort Laser Pulses ◽  
Ultrashort Pulse Laser ◽  
The Impact

The interaction of ultrashort laser pulses with a fully ionized plasma is investigated in the plane geometry by means of numerical simulation. The impact of the space oscillations in the amplitude of the laser electric field on the shape of the electron distribution function, on laser beam absorption, and on electron heat transport is demonstrated. Oscillations in the absorption rate of laser radiation with the minima coincident to the maxima of the laser electric field lead to a further decrease in the absorption of laser radiation. Heat flux in the direction of increasing temperature in the underdense region is caused by the modification of the electron distribution function and by the density gradient. A limitation of heat flux to the overdense plasma isobserved with the flux limiter in range 0.03–0.08, growing moderately with the intensity 1014–1016 W/cm2 of the incident 1.2-ps laser pulse.

Effect of a highly energetic electron beam on the electron distribution function in a hot dense plasma. Application to an argon plasma

2000 ◽  
Vol 63 (3) ◽  
pp. 255-267 ◽  
Author(s):  
P. FAUCHER ◽  
N. PEYRAUD-CUENCA ◽  
F. B. ROSMEJ
Keyword(s):  
Distribution Function ◽  
Electron Beam ◽  
Boltzmann Equation ◽  
Energy Range ◽  
Electron Distribution ◽  
Dense Plasma ◽  
Electron Distribution Function ◽  
Energetic Electron ◽  
Argon Plasma ◽  
Excitation Threshold

The influence of a highly energetic electron beam on the electron distribution function (e.d.f.) in a hot dense plasma is investigated by solving the Boltzmann equation analytically. A plateau is obtained in the tail of the e.d.f. over an energy range between the excitation threshold and an energy value half that of the monoenergetic electrons. The importance of this plateau is discussed for a dense He-like argon plasma.

scholarly journals Heat Flux in a Non-Maxwellian Solar Coronal Plasma

1989 ◽  
Vol 104 (2) ◽  
pp. 289-292
Author(s):  
N.N. Ljepojevic ◽  
P. MacNeice
Keyword(s):  
Heat Flux ◽  
Distribution Function ◽  
High Velocity ◽  
Coronal Loop ◽  
Numerical Scheme ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
Planck Equation ◽  
Fourier Law ◽  
Velocity Form

AbstractWe determine the electron distribution function within a hot coronal loop using a hybrid numerical scheme which couples the Spitzer-Härm method at low velocities with the solution to the high velocity form of the Landau-Fokker-Planck equation. From this we calculate the heat flux throughout the loop and compare it with the classical fourier law of Spitzer and Härm(1953).

Resonantly unstable off-angle hydromagnetic waves

1967 ◽  
Vol 1 (1) ◽  
pp. 81-104 ◽  
Author(s):  
C. F. Kennel ◽  
H. V. Wong
Keyword(s):  
Magnetic Field ◽  
High Energy ◽  
Electrostatic Waves ◽  
High Energy Tail ◽  
Electrons And Ions ◽  
Ion Cyclotron ◽  
Cold Component ◽  
Hydromagnetic Waves ◽  
The Magnetic Field ◽  
Uniform Plasma

We consider semi-quantitatively the cyclotron resonance instability of ion cyclotron and magnetosonic waves propagating at an angle to the magnetic field in an infinite uniform plasma. The velocity distributions of electrons and ions consist of a dense cold component and a diffuse high-energy tail. If the high-energy protons are sufficiently intense and their pitch angle distributions sufficiently anisotropic, instability occurs for those waves propagating parallel to the magnetic field. If the spectrum of resonant protons is sufficiently hard, a reasonably large cone of propagating angles about the magnetic field can be unstable. Observed fluxes of trapped protons in the magnetosphere should destabilise the ion cyclotron wave at a lower intensity threshold than for at least one class of electrostatic waves.

Electron distribution function in an electron-beam plasma

1995 ◽  
Vol 51 (4) ◽  
pp. 3498-3503 ◽  
Author(s):  
V. S. Malinovsky ◽  
A. E. Belikov ◽  
O. V. Kuznetsov ◽  
R. G. Sharafutdinov
Keyword(s):  
Distribution Function ◽  
Electron Beam ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
Beam Plasma ◽  
Electron Beam Plasma
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