Scattering of electromagnetic waves by charged spheres and some physical consequences

Effect of electromagnetic radiation scattering on homogeneous spherical dust particle which carries excess surface electric charge is investigated. Numerical calculations are presented for the cases of (i) charged spherical particles present in the interplanetary space of the Solar System, and (ii) charged water droplets and ice grains in the Earth's atmosphere. The results show that the surface charge may influence optical properties of very small particles with size parameter x less than 0.01 (astronomical materials like amorphous carbon and silicate are affected also at x approximate to 0.03). Slightly absorbing charged particles may attenuate the electromagnetic radiation more than 10 times efficiently than equivalent non-charged particles. The effect of temperature on efficiency factors for scattering Q(sca), absorption Q(abs), and radiation pressure Q(pr) is evaluated for astronomical amorphous carbon, as cosmic dust particles may undergo large temperature changes during their motion in the circumstellar regions. The ratios Q(x)(charged)/Q(x)(neutral) (for x = abs, ext, or pr) increase with decreasing grain temperature. (C) 2007 Elsevier Ltd. All rights reserved.