Low-Frequency Instability in Near-Anode Region of Hall Thruster

Abstract

This paper is devoted to building a theoretical model of relatively low-frequency (nu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> Lt omega Lt radic(omega <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> omega <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> ), where nu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> is the frequency of the ionization collisions of the electron and omega <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> and omega <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">i</sub> are the electron and ion cyclotron frequencies, respectively) instability of plasma in the near-anode area of the Hall thruster acceleration channel. The behavior of 2-D perturbations, which are infinitely spread along the magnetic field lines, is considered. In the model, the two-fluid magnetohydrodynamic approximation is used. The finite temperature of electrons is taken into consideration. The instability is due to the finite temperature of the electrons and nonuniformity of both the plasma and magnetic field. By its nature, it belongs to the Rayleigh-Taylor type. The instability can be responsible for the enhanced transfer of the electrons between the ionization region and the anode.