Continuous charge distribution models of ions in polar media. Part 6.—Reltationship between quantum and classical charge distributions

1978 ◽  
Vol 74 (0) ◽  
pp. 1407-1416
Author(s):  
Parbury P. Schmidt
Keyword(s):  
Charge Distribution ◽  
Distribution Models ◽  
Charge Distributions ◽  
Polar Media ◽  
Classical Charge

On the Cherenkov radiation from extended charge distributions

2000 ◽  
Vol 77 (10) ◽  
pp. 775-784 ◽  
Author(s):  
M Villavicencio ◽  
J L Jiménez ◽  
JAE Roa-Neri
Keyword(s):  
Explicit Expression ◽  
Charge Distribution ◽  
Constant Velocity ◽  
Cherenkov Radiation ◽  
Poynting Vector ◽  
Time Dependent ◽  
Spherically Symmetric ◽  
Charge Distributions ◽  
Extended Charge ◽  
A Charge

In this work the Cherenkov effect for extended charge distributions is analyzed using two different methods. In the first method, the Poynting vector is employed to determine the energy radiated, whereas in the second one, we apply the idea of generating time-dependent elemental dipoles, induced by a charge distribution moving with constant velocity, inside a material medium. An explicit expression for the Cherenkov radiation generated by some different kinds of spherically symmetric charge, travelling inside a medium, is obtained.PACS Nos.: 03.50.De, 41.20.Bt, 41.60.-m, 41.60.Bq

MADELUNG ENERGY AND STABILITY OF ORDERED LATTICE IN A(B′B″)O3

1991 ◽  
Vol 05 (27) ◽  
pp. 1803-1807
Author(s):  
QIANG WANG ◽  
HAN RUSHAN ◽  
Z.Z. GAN
Keyword(s):  
Charge Distribution ◽  
Structural Stability ◽  
Ionic Crystal ◽  
Ordered Structure ◽  
Charge Distributions ◽  
Madelung Energy ◽  
Calculation Results ◽  
The Difference ◽  
Good Agreement

The Madelung energies of ionic crystal A(B′B″)O3 has been calculated for various B-site charge distributions, i.e., [Formula: see text], [Formula: see text] and [Formula: see text], and ordered superlattices, i.e., 1/2(111), 1/2(110) and 1/2(001). Calculation results show that the Madelung energy increases for a certain ordered structure as the difference in charge between B-site cations increases and demonstrate the experimental observations. Furthermore, the results point out that for a certain charge distribution the sequence of the structural stability is 1/2(001)<1/2(110)<1/2(111). This is in good agreement with experimental facts.

Complex charge distributions of dielectric dust grains due to plasma flow

2000 ◽  
Vol 63 (3) ◽  
pp. 269-283 ◽  
Author(s):  
J. W. MANWEILER ◽  
T. P. ARMSTRONG ◽  
T. E. CRAVENS
Keyword(s):  
Charge Distribution ◽  
Large Fraction ◽  
Dusty Plasmas ◽  
Young Stars ◽  
Dust Particles ◽  
Total Charge ◽  
Dust Grains ◽  
Charge Distributions ◽  
Flowing Plasma ◽  
Dust Grain

We examine the charging of dielectric dust grains embedded in a plasma. Our work is a continuation and refinement of our previous research into grain charging problems. In 1993, we discussed preliminary simulation results regarding the charging and intergrain forces between two dielectric dust particles [J. W. Manweiler et al., Adv. Space Res. 13, 10175 (1993)]. Then, in 1996, we discussed preliminary results with respect to dust grain charging within asymmetric plasma conditions and how these affect grain–grain collisional cross-sections [J. W. Manweiler et al., In: The Physics of Dusty Plasmas (ed. P. K. Shukla et al.), p. 22. World Scientific, Singapore (1996)]. This work was extended to evaluate how asymmetric charging affects coagulation rates for dielectric dust grains [J. W. Manweiler et al., In: Physics of Dusty Plasmas, 7th Workshop (ed. M. Horanyi et al.), p. 12. AIP Conf. Proc. 446 (1998)]. Here we report on the results of a significant refinement to our work to study the behaviour of a dielectric dust grain in a plasma with a bulk flow. Since charge transport is inhibited on our dielectric grains, we can examine how asymmetric plasma distributions affect the symmetry of the charge distributions that develop on the surfaces of the grains. A dielectric dust grain in a flowing plasma develops a negative total charge and a dipole moment in its charge distribution that points upstream. We also use this model to study how the presence of a nearby dust grain affects the development of a grain's charge distribution. We demonstrate that a smaller grain–grain separation results in a reduced net charge on each grain. For grains in a flowing plasma, dipole moments are unaffected by close approach except when one grain is directly in the ‘wake’ of the other grain. The studies here show that monopole and dipole electrostatic forces are present when dust is bathed in flowing plasma. Recent infrared studies suggest that a large fraction of young stars have dusty envelopes [G. Schilling, Science286, 66 (1999)]. In the formation of accretion discs around young stars, dust–plasma interactions are probably important. Full details on the calculations of the results discussed in this paper are summarized from a more complete treatment of the subject by Manweiler [PhD Dissertation, University of Kansas (1997)].

AXISYMMETRIC CHARGE DISTRIBUTIONS ON AN ELASTIC DIELECTRIC HALF SPACE

1998 ◽  
Vol 22 (4B) ◽  
pp. 485-499
Author(s):  
K.L. Chowdhury
Keyword(s):  
Free Surface ◽  
Boundary Value Problem ◽  
Charge Distribution ◽  
Half Space ◽  
Fundamental Solutions ◽  
Potential Fields ◽  
Point Dipole ◽  
Charge Distributions ◽  
Electric Charge Distribution ◽  
Elastic Dielectric

The solution of the axisymmetric boundary value problem of an isotropic elastic dielectric half space subjected to charge distribution on its rigid polarization free surface is constructed by Hankel transforms. For the problem of an electric point dipole applied at origin, exact expressions for the components of displacement and polarization vectors and the potential fields are obtained in terms of Bessel function and fundamental solutions 1/R and e-mR/R, R being the distance from the source point. The electric field is determined both inside and outside the polarized region. In the particular case of a continuous electric charge distribution with density of the form l/(r2+h2)1/2, the mechanical and electric stresses on the surface of the semi-space are derived. The MathematicsTM software is used to present the numerical results on graphs depicting the variation of surface stresses for the particular charge distributions.

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