Electron velocity distribution, function

The variation of electron velocity distribution function with operating conditions. 

Electron velocity distribution functions and rate constants... 

Electrons are the origin of most of the chemical reactions happening at atmospheric pressure plasma based processes hence, their energy distribution plays an important role in plasma chemical reactions. The electron velocity distribution function (EVDF) in our system is determined on the basis of the emission of nitrogen molecule (equations 1-13). For this... 

Earlier the velocity distribution function of quasi particles of a relativistic ideal gas for a one dimensional system, for example, fluxons in thermalized Josephson systems and electrons in a high temperature plasma was found. 

Figure 2. (lb) Distribution function of the velocity for the relativistic electrons. (2b) Distribution functions of the observable frequencies. (3b) Most probable values of the observable frequencies as a function of b. (4b) Absolute minimal realization of most probable states of system. 

Second, the velocity distribution function (VDF) of hot electrons was directly measured to clarify the energy deposition process using X-ray line polarization spectroscopy. When the plasma has electromagnetic field anisotropy, polarized X-rays corresponding to the magnetic quantum number are emitted. In the case of polarization spectroscopy in an electron beam ion trap (EBIT) [21], the polarization degree P is generally defined by... 

Figure 3. The normalized electron four velocity distribution function downstream of the shock. The dot-dashed line is a power law fit to the non-thermal high energy tail, while the dashed curve is a Lorentz boosted thermal electron population.

The primary purpose of the kinetic treatment of the electron component in anisothermal plasmas is the determination of its velocity distribution function or only its energy distribution. The various macroscopic properties of the electrons can then be obtained fi-om the velocity distribution function by appropriate averages over the velocity space of the electrons. 

Because of the negative charge of the electrons, the electric field accelerates the electrons in a direction opposite to that of the electric field. If the electric field in the plasma is parallel to a fixed space direction, as is often the case, the action of the electric field causes a change in the component of the vectorial electron velocity parallel to the fixed space direction. As a consequence of the sole field action, this velocity component plays an exceptional role in causing anisotropy of the velocity distribution function. Moreover, the sole action of the electric field naturally causes a change, generally an increase, in the individual and consequently the mean electron energy. 

The velocity distribution of the electrons in a plasma is generally a complicated function whose exact shape is detennined by many factors. It is often assumed for reasons of convenience in calculations tliat such velocity distributions are Maxwellian and tliat tlie electrons are in tliennodynamical equilibrium. The Maxwell distribution is given by... 

The probability for a particular electron collision process to occur is expressed in tenns of the corresponding electron-impact cross section n which is a function of the energy of the colliding electron. All inelastic electron collision processes have a minimum energy (tlireshold) below which the process cannot occur for reasons of energy conservation. In plasmas, the electrons are not mono-energetic, but have an energy or velocity distribution,/(v). In those cases, it is often convenient to define a rate coefficient /cfor each two-body collision process ... 

This factor is reminiscent of the radial distribution function for electron probability in an atom and the Maxwell distribution of molecular velocities in a gas, both of which pass through a maximum for similar reasons. 

Fig. 6. Schematic energy levels of a soHd as a function of interatomic distance where the vertical line represents the equiUbrium spacing (68). A band of states obeying Fermi distribution is required by the PauH principle. High electron velocities and equivalent temperatures exist in conductors even when the...

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