Particle Simulations of Radio Wave Scattering by Small Objects covered with a Charged Particle Layer

Abstract

The present paper addresses the development and demonstration of a numerical approach to study the characteristics of radio wave scattering by a solid object in space covered by a charged particle or plasma layer. The plasma conditions near the surface of the object are totally different from those of a pristine plasma in space, due to various types of ionization processes occurring at the plasma–body interface. This sometimes results in the formation of a dense plasma layer around the surface, which significantly alters the electromagnetic properties of the object. Such processes are relevant to a broad range of in-space radio applications such as radar observations of space debris, meteors, small dust grains, and re-entry objects. This paper proposes a new numerical approach of applying the particle-in-cell simulations to the scattering analysis. PIC is a well-established first-principles model that provides a kinetic description of a plasma by following the trajectories of an ensemble of charged particles in self-consistent electromagnetic fields. It is advantageous to include plasma kinetic effects as well as nonlinear behavior of the plasma in a straightforward manner. A number of numerical techniques such as improved treatments for conducting object surfaces and the field decomposition capability are implemented for the present study. The proposed method is applied to a simple situation of wave scattering from a conducting object covered by a dense electron layer. The simulation reveals an antenna-like behavior of the electron layer swayed by an incident wave, and its contribution to the differentiated wave scattering properties.