Radio wave

About: Radio wave is a(n) research topic. Over the lifetime, 14571 publication(s) have been published within this topic receiving 167638 citation(s).

The computer for the 21st century

Abstract: Specialized elements of hardware and software, connected by wires, radio waves and infrared, will soon be so ubiquitous that no-one will notice their presence

The scattering of electromagnetic waves from rough surfaces

Abstract: THE SCATTERING OF ELECTROMAGNETIC WAVES FROM ROUGH SURFACES PDF Are you looking for the scattering of electromagnetic waves from rough surfaces Books? Now, you will be happy that at this time the scattering of electromagnetic waves from rough surfaces PDF is available at our online library. With our complete resources, you could find the scattering of electromagnetic waves from rough surfaces PDF or just found any kind of Books for your readings everyday.

Toward a theory of interstellar turbulence. 2. Strong Alfvenic turbulence

Abstract: We continue to investigate the possibility that interstellar turbulence is caused by nonlinear interactions among shear Alfven waves. Here, as in Paper I, we restrict attention to the symmetric case where the oppositely directed waves carry equal energy fluxes. This precludes application to the solar wind in which the outward flux significantly exceeds the ingoing one. All our detailed calculations are carried out for an incompressible magnetized fluid. In incompressible magnetohydrodynamics (MHD), nonlinear interactions only occur between oppositely direct waves. Paper I contains a detailed derivation of the inertial range spectrum for the weak turbulence of shear Alfven waves. As energy cascades to high perpendicular wavenumbers, interactions become so strong that the assumption of weakness is no longer valid. Here, we present a theory for the strong turbulence of shear Alfven waves. It has the following main characteristics. (1) The inertial-range energy spectrum exhibits a critical balance beween linear wave periods and nonlinear turnover timescales. (2) The "eddies" are elongated in the direction of the field on small spatial scales; the parallel and perpendicular components of the wave vector, k_z and k_⊥, are related by k_z ≈ k^(2/3) _⊥L^(-1/3), where L is the outer scale of the turbulence. (3) The "one-dimensional" energy spectrum is proportional to k^(-5/3) _⊥-an anisotropic Kolmogorov energy spectrum. Shear Alfvenic turbulence mixes specific entropy as a passive contaminant. This gives rise to an electron density power spectrum whose form mimics the energy spectrum of the turbulence. Radio, wave scattering by these electron density fluctuations produces anisotropic scatter-broadened images. Damping by ion-neutral collisions restricts Alfvenic turbulence to highly ionized regions of the interstellar medium. We expect negligible generation of compressive MHD waves by shear Alfven waves belonging to the critically balanced cascade. Viscous and collisionless damping are also unimportant in the interstellar medium (ISM). Our calculations support the general picture of interstellar turbulence advanced by Higdon.

Observation of a Rapidly Pulsating Radio Source

Abstract: Unusual signals from pulsating radio sources have been recorded at the Mullard Radio Astronomy Observatory The radiation seems to come from local objects within the galaxy, and may be associated with oscillations of white dwarf or neutron stars 1968 saw the first report of a curious class of astronomical radio sources, distinguished by their rapid and extremely regular pulsations Hewish et al associated them with unusually stable oscillations in compact stars They are now understood to be rapidly rotating, magnetized neutron stars, or pulsars