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1.
The electrostatic potential of a triode field-emission system with a modulator that represents a circular diaphragm is calculated. A tip field-emission cathode serves as an emitter. The inner part of the system under study is filled with two insulators. In the calculation of the potential distribution, a real field-emission cathode is changed by a virtual cathode whose surface coincides with an equipotential surface, so that the effect of the cathode on the distribution of the electrostatic potential is simulated as the effect of a finite charged wire that is located at the axis of the system. The separation of variables is used to solve the problem. The potential is represented as an expansion in terms of eigenfunctions, and the expansion coefficients are found from the solution to a system of linear algebraic equations. 相似文献
2.
A mathematical model of a diode system based on a sharp-edged field cathode is presented. The surface of the sharp-edged cathode
is simulated by two infinitely thin spherical segments, while the anode is modeled by a single infinitely thin spherical segment.
The region occupied by the cathode is a lens (lune-shaped region). The problem of the electrostatic potential distribution
in the entire domain occupied by the system is solved. 相似文献
3.
A method for obtaining electrostatic fields of a preset form in a quasi-electrode cylindrical system is considered. “Distributed”
electrodes (filamentary conductors) make it possible to solve the inverse boundary-value problem, viz., to preset an azimuthal
electric potential distribution over the cylinder surface for obtaining the required field in the cylinder, thus ensuring
a larger working region as compared to an obviously electrode system. 相似文献
4.
Technical Physics - The electrostatic potential distribution in a 2D diode system with a blade-shaped field emitter on a flat substrate has been calculated. The anode of the system represents a... 相似文献
5.
用圆 坐标示形冰筒的表电问题 总被引:3,自引:1,他引:2
用圆环坐标分析带电球形法拉第冰筒的静电问题,得出其空间电势分布函数,证明内外同电荷的差为常量,计算其电容量,并给出静电应用的近似法。 相似文献
6.
V. A. Fedorov 《Technical Physics》2012,57(4):427-431
The electrostatic charging of an electrically insulated metal body (emitter) as a result of thermionic emission current from
the body to the ambient is investigated. The cases when the body is in vacuum and in plasma are considered. It is assumed
that electrons in the surface layer of the metal body have its temperature or are heated to the temperature of “hot” electrons.
The electric currents determining the charging/discharging processes in the body are determined. The values of the electric
charge, field strength, and potential of the metal body are estimated. 相似文献
7.
The electrostatic interaction of a charged spherical dielectric macroparticle with a point charge in a plasma in the presence of an external uniform electric field is considered. The electrostatic force and the torque acting on the macroparticle have been determined, and the form of the interaction potential has been established for a nonuniform distribution of free charge on the macroparticle surface. A simple (for calculations) expression for the interaction potential that describes well the exact potential at all interparticle distances is proposed. The angular velocity of the spinning of dust particles caused by a nonuniform distribution of free charge over their surface has been estimated. 相似文献
8.
G. Ch. Shushkevich 《Technical Physics》1998,43(7):743-748
The electrostatic problem for a thin, unclosed spherical shell and a torus is reduced to paired summation equations in the
Legendre polynomials by means of formulas relating the spherical and toroidal harmonic functions. The paired equations are
transformed to a Fredholm integral equation of the second kind. Formulas are obtained for computing the charges of the conductors
in the form of a series in a small parameter. The capacitance is computed for certain geometrical parameters of the conductors.
Zh. Tekh. Fiz. 68, 1–6 (July 1998) 相似文献
9.
T. M. Zaboronkova A. V. Kudrin E. Yu. Petrov 《Radiophysics and Quantum Electronics》1998,41(3):236-246
We consider the problem of determining the current distribution along a loop antenna consisting of an infinitely thin perfectly
conducting strip coiled into a ring. The antenna is immersed in an anisotropic plasma medium perpendicular to the external
magnetic field and is excited by a given EMF. Primary attention is focused on the frequency band in which the excitation of
electrostatic waves is possible. The problem is reduced to solving a system of integral equations with logarithmic and singular
kernels. Using the solution of these equations, we found expressions for the antenna current distribution and input impedance.
The analysis of these expressions is presented.
Radiophysical Research Institute, Lobachevsky State University, Nizhny Novgorod, Russia. Translated from izvestiya Vysshikh
Uchbnykh Zavedenii, Radiofizika, Vol. 41, No. 3, pp. 358–373, March, 1998. 相似文献
10.
V. B. Shikin 《JETP Letters》1997,66(8):581-587
It is shown that the characteristic features of the chemical potential for 2D electrons in a magnetic field, which lead to
sharp dips in the magnetic field dependence of the capacitance of a 2D system, also affect the electrostatic potential distribution
in the direction of the transport current flowing through a 2D Corbino disk under conditions of integral magnetic filling
factor. The associated details of the temperature dependence of the electrostatic potential distribution, the distances to
the screening electron, and the transport potential difference at the Corbino edges are investigated. The possibilities of
experimentally observing these features of the electrostatic potential distribution along a Corbino disk with a transport
current under conditions of the quantum Hall effect are discussed.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 8, 545–550 (25 October 1997) 相似文献
11.
Leonard Eyges 《Annals of Physics》1975,90(1):266-282
An integral equation is derived for the electrostatic potential ψ that arises when a uniform dielectric body of arbitrary shape is placed in an applied electrostatic field. By expansion of ψ in a certain basic set, the integral equation becomes a set of linear equations for the expansion coefficients, and it is often practical to solve the set by truncation. As a test, the equations are applied to the problem of a spheroid in a uniform field, and they easily yield the standard results that are usually derived by introducing spheroidal harmonics. Either the integral equation or the equivalent linear equations can be solved in an iterative approximation (the analog of the Born approximation) when the dielectric constant of the body is not too far from unity. For bodies that differ from spherical or cylindrical ones by a small parameter λ, perturbation formulae are derived that solve the equations in powers of λ. The problem of a homogeneous permeable body of arbitrary shape in an external magnetostatic field is reducible to the dielectric problem, but in addition an alternate integral equation for the magnetic problem is discussed. 相似文献
12.
A system of equations is derived for moments [averages of spherical harmonics 〈Y
l,m
〉(t)] that determine the dynamics of the magnetization M of a superparamagnetic particle in a fluctuating field. The system is derived by representing the Gilbert equation in a fluctuating
field, and the corresponding Fokker-Planck equation for the distribution function of M, in terms of angular momentum operators, which in turn makes it possible to express the coefficients of the system of moment
equations in terms of Clebsch-Gordan coefficients.
Fiz. Tverd. Tela (St. Petersburg) 41, 2020–2027 (November 1999) 相似文献
13.
A. V. Filippov 《Journal of Experimental and Theoretical Physics》2009,109(3):516-529
The electrostatic interaction of two spherical macroparticles in a plasma has been considered. Primary attention has been
focused on investigating the electrostatic interaction at short distances where polarization effects of the surface charge
of finite-size macroparticles begin to play a dominant role. The first part of this study is devoted to the interaction of
a point charge with a charged conducting sphere in an equilibrium plasma. It has been shown that the presence of a plasma
in the system leads to a decrease in the potential barrier when two like-charged macroparticles approach each other and that
this decrease proves to be the most significant in the case where the macroparticle radius is comparable to the Debye screening
length. The second part of this study is concerned with the interaction of two conducting spheres in the bispherical system
of the coordinates under the assumption that the charges of the conducting spheres are constant and under the assumption that
the surface potentials of the spheres are constant. The latter case is closer to the physics of electrostatic interaction
of two macroparticles in a plasma medium where the electrostatic potential of their surface is determined by the floating
potential of the plasma. It has been demonstrated that the interaction potentials in these two cases are substantially different
from each other and that, at constant macroparticle charges, the energy of the electrostatic field is an interaction potential,
but, in the case of macroparticles with constant surface potentials, which are independent of the interparticle distance,
the energy of the electrostatic field is not an interaction potential. In the latter case, account must be taken of the work
done by external sources on the macroparticle potentials to maintain them constant. The form of the interaction potential
has been established in this case from the analysis of the interaction force in terms of the Maxwell tension tensor. In the
third part of this study, the interaction of two macroparticles has been considered in the spherical system of coordinates
and analytical expressions for the interaction potentials have been derived for both the case of constant macroparticle charges
and the case of constant surface potentials of the macroparticles. 相似文献
14.
J.-W. Liaw 《Applied Physics A: Materials Science & Processing》2007,89(2):357-362
The local-field factor and quantum yield of a metallic nanoantenna are studied to identify its enhancement of an emitter’s
emission within the feed gap. For simplicity, a two-dimensional model, an Au nanoantenna with an emitter at the center, is
studied. The electromagnetic field is solved by a set of surface integral equations. An incident plane wave irradiating the
nanoantenna is modeled to simulate the excitation of the emitter by illuminating light, and the local-field factor is used
to evaluate the amplification of the electric field in the feed gap of the metallic nanoantenna. Once the emitter becomes
excited, a model of an electric dipole interacting with the nanoantenna is used for calculating the radiative and nonradiative
powers to obtain the quantum yield of the excited emitter in the presence of the nanoantenna. The numerical results of quantum
yield indicate that an Au nanoantenna acts as a low-pass filter for the emission of the emitter. Moreover, the smaller the
feed gap, the larger the local-field factor but the less the quantum yield.
PACS 78.67.-n; 33.80.-b; 33.50.-j; 42.30.-d; 42.50.Hz; 81.07.Pr 相似文献
15.
Semi-analytical method of calculating the electrostatic interaction of colloidal solutions 下载免费PDF全文
We present a semi-analytical method of calculating the electrostatic interaction of colloid solutions for confined and unconfined systems. We expand the electrostatic potential of the system in terms of some basis functions such as spherical harmonic function and cylinder function. The expansion coefficients can be obtained by solving the equations of the boundary conditions, combining an analytical translation transform of the coordinates and a numerical multipoint collection method. The precise electrostatic potential and the interaction energy are then obtained automatically. The method is available not only for the uniformly charged colloids but also for nonuniformly charged ones. We have successfully applied it to unconfined diluted colloid system and some confined systems such as the long cylinder wall confinement, the air–water interfacial confinement and porous membrane confinement. The consistence checks of our calculations with some known analytical cases have been made for all our applications. In theory, the method is applicable to any dilute colloid solutions with an arbitrary distribution of the surface charge on the colloidal particle under a regular solid confinement, such as spherical cavity confinement and lamellar confinement. 相似文献
16.
The problem of calculation of finite-amplitude waves on the cylindrical surface of an ideal incompressible dielectric liquid
jet in a uniform electrostatic field collinear to the unperturbed jet axis is solved using a second-order asymptotic analytic
procedure in ratio of the wave amplitude to the jet radius. Nonlinear corrections to the jet profile, velocity field potential,
and electrostatic potentials inside and outside the jet are of resonant nature. The degenerate resonant interaction between
the wave determining the initial strain and the waves excited due to nonlinearity of the hydrodynamic equations can take place
for waves with different symmetries (different azimuth numbers). 相似文献
17.
The electrostatic potential distribution is determined for a system of axisymmetric electrodes in the form of nonconcentric
spherical segments. 相似文献
18.
N. S. Bukhman 《Technical Physics》1997,42(10):1223-1225
The transverse distribution of the resonance field excited by a Gaussian electromagnetic field on the critical surface of
a radially nonuniform plasma sphere is studied. Analytical expressions are obtained for this distribution. It is shown that
when a laser beam is focused in front of or behind a spherical target, identical values of the integrated resonance coefficient
can correspond to substantially different (in width) distributions of the resonance field over the spherical critical surface.
Zh. Tekh. Fiz. 67, 125–128 (October 1997) 相似文献
19.
Würger A 《The European physical journal. E, Soft matter》2006,19(1):5-15
We study the electrostatic properties of charged particles trapped at an
interface in a water-in-oil microemulsion. The electrostatic potential and the
counterion distribution in the water droplet are given in terms of the ratio
of the Debye screening length κ-1 and the droplet radius R. In the
limit R→∞ we recover the well-known results for a flat
interface. Finite-size corrections are obtained in terms of the small
parameter 1/κR. Part of the counterions spread along the interface and
form a charged layer of one Debye length thickness. In particular, there is a
uniform surface charge contribution. We derive explicit expressions for the
electric field, the mobile charge density, and the charge-induced pressure on
the interface. 相似文献
20.
《Journal of Electrostatics》2007,65(1):21-29
The electrostatic problem of a hollow, conducting tube of finite length held at a fixed potential is solved using two methods. A two-term Galerkin solution is constructed for the surface distribution of induced charge. The sum of a uniform component and a simple edge-condition term provides a variational solution to the dual integral equations that are the equations-of-motion for the mixed boundary value problem. Comparisons are made with the numerical results of an independent boundary element or moment method. The numerical solution uses collocation or point matching and a piecewise constant basis for the charge density. 相似文献