Rotating spiral waves organize spatial patterns in chemical, physical, and biological excitable systems. Factors affecting their dynamics, such as spatiotemporal drift, are of great interest for particular applications. Here, we propose a quantitative description for spiral wave dynamics on curved surfaces which shows that for a wide class of systems, including the Belousov-Zhabotinsky reaction...

Neutralized drift compression offers an effective method for particle beam focusing and current amplification. In neutralized drift compression, a linear transverse and a longitudinal velocity tilt are applied to the beam pulse, so that the beam pulse compresses as it drifts in the drift-compression section. The beam intensity can increase more than a factor of 100 in both the radial and longit...

We measured perceived velocity as a function of contrast for luminance and isoluminant sinusoidal gratings, luminance and isoluminant plaids, and second-order, amplitude-modulated, drift-balanced stimuli. For all types of stimuli perceived velocity was contrast-invariant for fast moving patterns at or above 4 deg/sec. For slowly moving stimuli the log of perceived velocity was a linear function...

Phasons are special hydrodynamic modes that occur in quasicrystals. The trajectories of particles due to a phasonic drift were recently studied by Kromer et al. (Phys. Rev. Lett. 108, 218301 (2012)) for the case where the particles stay in the minima of a quasicrystalline potential. Here, we study the mean motion of colloidal particles in quasicrystalline laser fields when a phasonic drift or d...

The drift behavior of spiral waves under the influence of a polarized electric field is investigated in the light that both the polarized electric field and the spiral waves possess rotation symmetry. Numerical simulations of a reaction-diffusion model show that the drift velocity of the spiral tip can be controlled by changing the polarization mode of the polarized electric field and some inte...

Under the weak deformation approximation, the motion of rigidly rotating spirals induced by periodic and noisy illuminations are investigated analytically. We derive an approximate but explicit formula of the spiral drift velocity directly from the original reaction-diffusion equation. With this formula we are able to explain the main features in the periodic and noisy illuminations induced spi...

The general dispersion relation for drift waves in a medium 6 ( p ( 3 m j ) l ' , ) Pia" is derived when gradients of guiding centre drift across the magnetic field are present. It is shown that for high frequency waves (U >> klluti) cross field shear in the relative velocity of ions and electrons can generate strong electrostatic and electromagnetic instabilities. Turbulence-induced anomalous ...

Electron drift velocities have been measured in liquid krypton, pure and mixed with methane at di!erent concentrations (1}10% in volume) versus electric "eld strength, and a possible e!ect of methane on electron lifetime has been investigated. While no e!ect on lifetime could be detected, since lifetimes were in all cases longer than what measurable, a very large increase in drift velocity (up ...

with τe being the electron collision time. nEQ is an equilibrium density associated with neoclassical fields and currents. K (nEQ) =−∇qJPS, which in turn is driven by the corresponding neoclassical potential JPS = 1 C (φPS). The contribution of impurities to the gross plasma density ni,0 is assumed to be negligible, i. e. ni = ni,0+nimp ≈ ni,0. For cold impurities the ion-drift velocity is give...

introduction: wind erosion is one of the most important factors in desert environments. prevailing winds can shift sand dunes and affect their accumulation and morphology. also, wind regime determines the direction of sand dune mobility in different ways. therefore, the wind regime, frequency, direction and velocity are supposed to be the most important factors to form the morphology of sand du...