Electromagnetic Wave Interactions with 2D Arrays of Single-Wall Carbon Nanotubes

We report, for the first time, the scattering, absorption, and reflection characteristics of 2D arrays of finite-length, armchair, single-walled carbon nanotubes (SWNTs) in the visible frequency regime. The analysis is based on the Finite-Element-Method formulation of Maxwell's equations and a 3D quantum electrical conductivity function. Three geometrical models have been considered: solid cylinder, hollow cylinder, and honeycomb. We demonstrate that classical electromagnetic theory is sufficient to evaluate the scattering and absorption cross sections of SWNTs, which revealed excellent agreement against measurements without the need to invoke the effective impedance boundary conditions. The solid and hollow cylindrical models fail to provide accurate results, whenbothscattering and absorption are considered. Finally, it is shown that reflection and transmission characteristics of both individual and arrays of SWNTs, which are essential for solar cell applications, are strongly influenced by the length and the phenomenological parameters of the SWNT.

Nonlinear electromagnetic wave interactions in Hall–MHD plasmas

We have developed a massively parallelized fully three-dimensional (3D) compressible Hall–magnetohydrodynamic (MHD) code to investigate inertial range electromagnetic wave cascades and dissipative processes in the regime, where characteristic length scales associated with plasma fluctuations are smaller than ion gyroradii. Such regime is ubiquitously present in the solar wind and many other collisionless space plasmas. Particularly, in the solar wind, the high time resolution databases depict a spectral break near the end of the 5/3 spectrum that corresponds to a high-frequency regime where the electromagnetic turbulent cascades cannot be explained by the usual MHD models. This refers to a second inertial range, where turbulent cascades follow a k−7/3 (where k is a wavenumber) spectrum in which the characteristic electromagnetic fluctuations evolve typically on kinetic Alfvén time scales. In this paper, we describe results from our 3D compressible Hall–MHD simulations that explain the observed k−7/3 spectrum in the solar wind plasma, energy cascade, anisotropy, and other spectral features.