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

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.

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.

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.

A Useful Simple Recursion Formula to Account for Inelastic Collision Effects on the Electron Distribution in a Plasma

1973 ◽  
Vol 28 (12) ◽  
pp. 1875-1884 ◽  
Author(s):  
H. A. Claaßen
Keyword(s):  
Low Temperature ◽  
Analytical Solution ◽  
Ground State ◽  
Electron Distribution ◽  
Energy Levels ◽  
Recursion Formula ◽  
High Energy ◽  
Inelastic Electron ◽  
High Energy Tail ◽  
Simple Recursion

The competitive effects of inelastic electron-atom collisions and electron-electron interactions on a sufficiently isotropic electron distribution is considered for a low temperature monatomic plasma. It is presupposed that unbalanced collisional transitions between ground state and resonance level of the plasma atoms are the dominant disturbance effect on the electron distribution. The unbalance is assumed to be due to resonance radiation escape and excitation diffusion. An analytical solution, which permits the calculation of the electron distribution even well above the ionization energy of the atomic ground state, is presented. In particular, it is demonstrated that due to the rapid decrease of the Coulomb cross section with increasing electron energy, the solution for the high energy tail of the electron distribution can be related to its form at lower energies by a simple recursion formula. The latter enables an easy computation of the ionization coefficients even for the lowest atomic energy levels. The analytical solution and its high energy approximation are numerically evaluated for the example of a low temperature -low pressure cesium plasma.

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

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.

Solitons and freak waves in a mixed nonextensive high energy-tail electron distribution

2014 ◽  
Vol 21 (6) ◽  
pp. 062101 ◽  
Author(s):  
Omar Bouzit ◽  
Leila Ait Gougam ◽  
Mouloud Tribeche
Keyword(s):  
Electron Distribution ◽  
High Energy ◽  
Freak Waves ◽  
High Energy Tail

scholarly journals The electron energy distribution during HF pumping, a picture painted with all colors

2005 ◽  
Vol 23 (5) ◽  
pp. 1747-1754 ◽  
Author(s):  
B. Gustavsson ◽  
T. Sergienko ◽  
M. J. Kosch ◽  
M. T. Rietveld ◽  
B. U. E. Brändström ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Electron Temperature ◽  
Electron Energy ◽  
Optical Emission ◽  
Electron Excitation ◽  
High Energy ◽  
Electron Energy Distribution ◽  
Ion Temperature ◽  
Ionospheric Physics ◽  
High Energy Tail

Abstract. The shape of the electron energy distribution has long been a central question in the field of high-frequency radio-induced optical emission experiments. This report presents estimates of the electron energy distribution function, fe(E), from 0 to 60 eV, based on optical multi-wavelength (6300, 5577, 8446, 4278Å) data and 930-MHz incoherent scatter radar measurements of ion temperature, electron temperature and electron concentration. According to our estimate, the electron energy distribution has a depression at around 2 eV, probably caused by electron excitation of vibrational states in N2, and a high energy tail that is clearly supra-thermal. The temporal evolution of the emissions indicates that the electron temperature still plays an important role in providing electrons with energies close to 2 eV. At the higher energies the electron energy distribution has a non-thermal tail. Keywords. Active experiments; Ionosphere atmosphere interaction; Ionospheric physics

Sign in / Sign up

Export Citation Format

Share Document