Capillary Waves and Dipole Electromagnetic Radiation Generated by Nonlinear Oscillations of an Uncharged Droplet in an External Uniform Electrostatic Field

摘要

Analytical derivations of the second order of smallness with respect to dimensionless amplitude s of oscillations of an uncharged electroconducting droplet in an external electric field have yielded an analytical expression for the intensity of its dipole electromagnetic radiation related to the oscillations, with this expression enabling one to study the radiation intensity as depending on the physical parameters of the problem. This problem is of interest in connection with radio-locating probing meteorological objects, such as clouds, fogs, and tornados. The time evolution of the electromagnetic radiation intensity and its components, i.e., the magnitude of the induced charge and dipole moment, of the droplet has been studied. The dipole radiation intensity has been determined in the second order of smallness with respect to the squared ratio between the characteristic linear size of the droplet and the wavelength of the emitted radiation. The intensity has appeared to be higher by a value of similar to epsilon than the intensity obtained by the calculations linear with respect to s. However, a correction (quadratic with respect to epsilon) to the radiation of the droplet is realized in another frequency range, thereby affecting the spectrum of the electromagnetic radiation.