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Golovin A.I.,Keldysh Research Center
Applied Physics | Year: 2015

Secondary electrons appearing in stationary open discharge are taken into account in the suggested early mathematical model of processes in the discharge. This allowed estimating an energy distribution of the beam of run-away electrons. It was shown that at high voltages the energy of a significant portion of secondary electrons slightly differs from the energy of primary electrons which corresponds to an applied accelerating voltage.

Golovin A.I.,Keldysh Research Center
Applied Physics | Year: 2015

The mathematical model of processes in glow discharge with run-away electrons (an open discharge) suggested before allows to take into account influence of anode position and effective transparency of the anode on the volt-ampere curve. Numerical analyses of dependences of dimensionless parameters had been done, which have shown that in most cases influence of anode characteristics is negligible; the result is in agreement with the known experimental data.

Shagayda A.A.,Keldysh Research Center
IEEE Transactions on Plasma Science | Year: 2015

The field of application of Hall effect thrusters (HETs) is constantly expanding toward increased power and specific impulse and also toward reduced power. The modern level of plasma simulations does not allow accurate prediction of a thruster performance in advance. Therefore, the methods of scaling play an important role in the creation of new thrusters with desired characteristics. This paper describes a scaling model of HETs based on an analytical assessment of the anode mass utilization efficiency and the available experimental data. Empirical coefficients of the model are found using an extensive database containing published test results of many thrusters. The obtained expressions allow for predicting the performance of HETs for various kinds of propellant when the discharge power and voltage vary over a wide range. © 2014 IEEE.

Golovin A.I.,Keldysh Research Center
Applied Physics | Year: 2016

Equations were suggested to estimate energetic efficiency of a run-away electron beam generation by stationary open discharge. It was shown that equation for the efficiency differs from that for electron guns with high-voltage glow discharge because of formation of secondary electrons in cathode potential drop area.

Analytical studies and numerical simulations show that the electron velocity distribution function in a Hall thruster discharge with crossed electric and magnetic fields is not Maxwellian. This is due to the fact that the mean free path between collisions is greater than both the Larmor radius and the characteristic dimensions of the discharge channel. However in numerical models of Hall thrusters, a hydrodynamic approach is often used to describe the electron dynamics, because discharge simulation in a fully kinetic approach requires large computing resources and is time consuming. A more accurate modeling of the electron flow in the hydrodynamic approximation requires taking into account the non-Maxwellian character of the distribution function and finding its moments, an approach that reflects the properties of electrons drifting in crossed electric and magnetic fields better than the commonly used Euler or Navier-Stokes approximations. In the present paper, an expression for the electron velocity distribution function in rarefied spatially homogeneous stationary plasma with crossed electric and magnetic fields and predominance of collisions with heavy particles is derived in the relaxation approximation. The main moments of the distribution function including longitudinal and transversal temperatures, the components of the viscous stress tensor, and of the heat flux vector are calculated. Distinctive features of the hydrodynamic description of electrons with a strongly non-equilibrium distribution function and the prospects for further development of the proposed approach for calculating the distribution function in spatially inhomogeneous plasma are discussed. © 2012 American Institute of Physics.

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