Electric potential of a macroparticle in beam-plasma systems

Effect of Electron Emission Processes on Macroparticle Charging in Plasma Systems With Electron Beam

“…The MP can acquire the high negative charge due to bombardment of electron beam. The floating potential of MP reaches -200 V for beam electron energy of the order of a few keV [1]. If electric potential of MP with radius 0.1 µm equals -200 V, the corresponding electric field on its surface is 2•10 7 V/cm.…”

“…The steady-state potential φ, to which a MP is charged, is determined from the balance of particle fluxes which are collected by the MP surface and emitted from it: TE e e e b e i I I I I I . (1) Неre, I i is the ion current, I e is the current of plasma electrons , I b is the current of electron beam, I e-e is the current of secondary electrons emitted from the MP surface due to bombardment of electron beam, and I e,TE is the current of relevant electron emission (thermionic electron emission, field electron emission, thermal-field electron emission).…”

“…The secondary electron emission results in the sufficient increasing of absolute value of MP negative potential in the energy range of beam electrons, within which the secondary electron yield δ>1. Moreover, in the case of the equality of plasma and electron beam densities, the MP floating potential can even become positive [1].…”

“…In previous studies, MP charging in the electronbeam systems with account for the secondary electron emission has been investigated in the framework of the orbit motion limited (OML) approach [1] and on the basis of the discrete charging model [2]. The influence of field electron emission and secondary electron emission on MP potential has been studied in [3].…”

Positively Charged Microparticles in Plasma

“…Here there is a problem of microdroplets that fly out from the cathode and, falling on the substrate, worsen the properties of the coatings. To eliminate this problem, it was proposed to evaporate microdroplets with a high-energy electron beam [3,4], which is additionally introduced into the plasma, since the energy of the plasma itself is not enough to evaporate microdroplets. The created negative potential of the particles leads to a strong flow of plasma ions onto them and, as a result, to heating and evaporation of these MP.…”