This work investigates the achievable information rate with the state-of-the-art turbo coding and intensity modulation / direct detection for outdoor long-distance free-space optic (FSO) communications. The channel under weak atmospheric turbulence is modeled as a log-normal intensity fading channel where on-off keying makes it look asymmetric. While no effort is made to spectrally match the co...

Recent 21 cm radio observations of HI regions in the Small Magellanic Cloud, have revealed spatial power spectra of the intensity, which are quite similar in shape to those previously deduced for the Galaxy. The similarity, in spite the differences in the physical parameters between the Galaxy and the SMC, suggests that the shape of the power spectra reflects some underlying mechanism which is ...

Submitted for the APR09 Meeting of The American Physical Society Turbulent transport of trapped electron modes in collisionless magnetized plasma YONG XIAO, University of California, Irvine — A prominent candidate for the electron heat transport in high temperature toroidal plasmas is collisionless trapped electron mode (CTEM) turbulence. Our large scale simulations of CTEM turbulence using gyr...

Formation of shock waves has an important role in supercritical flows studies. These waves are often occurring during passage of supercritical flow in the non-prismatic channels. In the present study, the effect of length of contraction wall of open-channel for two different geometries (1.5 m and 0.5 m) and fixed contraction ratio was investigated on hydraulic parameters of shock waves using ex...

Numerical simulation is performed in this study to explore filmcooling enhancement by injecting mist into the cooling air with a focus on investigating the effect of various modeling schemes on the simulation results. The effect of turbulence models, dispersed-phase modeling, inclusion of different forces (Saffman, thermophoresis, and Brownian), trajectory tracking, and mist injection scheme is...

Expressions for the average intensity of both phase-locked and non-phase-locked Airy array beams propagating through atmospheric turbulence are derived based on the extended Huygens–Fresnel principle. The evolution of the average intensity distribution of both phase-locked and non-phase-locked Airy array beams during propagation in atmospheric turbulence is examined by numerical examples and is...

We study the sporadic Forbush effects of the galactic cosmic ray intensity using neutron monitors and muon telescopes experimental data and the theoretical modeling developed based on the Parker’s transport equation for a non stationary case. We found that a hard rigidity spectrum in the minimum phase of the Forbush effects of GCR intensity determined by neutron monitors experimental data is re...

Turbulent flow over an array of wall-mounted cubic obstacles has been numerically investigated using large-eddy simulation. The simulations have been performed using high-performance computations with local cluster systems. The array of cubes are fully submerged in a simulated deep rough-wall atmospheric boundary-layer with high turbulence intensity characteristics of environmental turbulent fl...

We present an overview of the Velocity Coordinate Spectrum (VCS), a new technique for studying astrophysical turbulence that utilizes the line-of-sight statistics of Doppler-broadened spectral lines. We consider the retrieval of turbulence spectra from emission intensity observations of both high and low spatial resolution and find that the VCS allows one to study turbulence even when the emitt...