The effect of image force on field emission of electrons from negatively charged solid particles has been analytically investigated and some numerical results have been presented in the form of a graph between ln (nem/F2) and 1/F, where nem is the emission rate per unit area and F is the surface field strength. The results have been compared with those obtained for a corresponding plane surface using the WKB approximation. It is seen that the variation for a spherical surface has a significant departure from the corresponding approximate straight line for a plane surface.

Effect of image force on emission of electrons from negatively charged solid particles

In this paper the authors have derived almost exact expressions for the tunneling probability of an electron through the surface potential barrier on account of a negative charge on spherical and cylindrical metallic dust particles; Debye shielding has been taken into account Expressions for the electric current density corresponding to emitted electrons from the charged spherical and cylindrical surfaces have been derived, and corresponding numerical computations have been made for typical set of parameters Based on these results, a parametric analysis of the phenomenon has been presented The investigation is of relevance to dusty plasmas in space and laboratory The results are also applicable to a number of applications, based on electric field emission from a thin metallic wire surrounded by a coaxial cylindrical surface at a high electric potential with respect to the wire

Effect of Debye shielding on electric field emission from spherical and cylindrical surfaces

This paper discusses the field emission of electrons from a wire surrounded by a coaxial cylindrical shell at a very high potential with respect to the wire. It is seen that, for many cases of interest, the results are at considerable variance with the plane surface case.

https://iopscience.iop.org/article/10.1088/0022-3727/2/11/419/pdf

Field emission from wires

A critical look at the commonly used Fowler's expression for the transmission coefficient of electrons through the potential barrier leads to the conclusion that this expressions is physically untenable. An expression for the field emission current density, corresponding to the expression for the transmission coefficient obtained from the exact solution of Schrodinger’s equation, has been derived. Numerical results have been expressed in the form of tables and graphs and discussed. It is seen that in the range of 10−4<kT/EF<10−3, the effect of temperature on the field emission current density is negligible.

A critical look at electric field emission of electrons from metallic surfaces

The authors have investigated the electron emissions (thermionic, electric field, photoelectric, and light induced field) from and electron accretion on a charged particle in a complex plasma, on the basis of a three region electrical potential model in and around a charged spherical particle in a complex plasma, characterized by Debye shielding. A continuous variation of the transmission coefficient across the surface of a particle (corresponding to emission and accretion) with the radial electron energy ɛr has been obtained. It is seen that the numerical values of the emission and accretion transmission coefficients [D(ɛr)] are almost the same. This is the necessary and sufficient condition for the validity of Saha’s equation for thermal equilibrium of a system of dust and electrons. This is in contrast to the earlier condition, which limited the range of validity of Saha’s equation to the range of the applicability of Born approximation. It is seen that D(ɛr) increases with increasing ɛr, increasing ne...

Quantum effects in electron emission from and accretion on negatively charged spherical particles in a complex plasma

The field emission from negatively charged spherical solid particles has been studied analytically, and some numerical results depicting the variation in the number of emitted electrons with the charge, radius and work function of the particle are presented.

M S Sodha

Papers

Field emission from negatively charged solid particles