Description: P.P. Shirhov Institute of Oceanology, 36 Nakhirnovsky prosp., Moscow 117218, Russia. The work considers three-dimensional crescent-shaped patterns often seen on water surface in natural basins and observed in wave tank experiments. The most common of these 'horse-shoe-like' patterns appear to be sporadic, i.e., emerging and disappearing spontaneously even under steady wind conditions. The paper suggests a qualitative model of these structures aimed at ex...
Description: Nonlinear Dynamics Group, Physics Department, University of Potsdam, PB 601553, 14469 Potsdam, Germany. Climate variability is triggered by several solar and orbital cycles as well as by the intern ocean dynamics. Consequently, paleoclimate proxy records are expected to vary on very different time scales ranging from subdecadal to millennial duration. We demonstrate, that Foster's (Foster, 1996) wavelet analysis technique is an appropriate tool for inves...
Description: LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China. Within a theoretical model context, the sensitivity and instability of the grassland ecosystem to finite-amplitude perturbations are studied. A new approach of conditional nonlinear optimal perturbations (CNOPs) is adopted to investigate this nonlinear problem. It is shown that the linearly stable grassland (desert) states can be nonlinearly unstable with finite...
Birgin, E. G., Mart\'\inez, J. M., and Raydan, M.: Nonmonotone spectral projected gradient methods on convex sets, SIAM Journal on Optimization, 10, 1196–1211, 2000.; Birgin, E. G., Mart\'\inez, J. M., and Raydan, M.: Algorithm 813: SPG–software for convex–constrained optimization, ACM Transactions on Mathematical Software, 27, 340–349, 2001.; Birgin, E. G., Mart\'\inez J. M., and Raydan, M.: Inexact Spectral Projected Gradient Methods on Convex Sets, IMA Journal of Nume...
Description: 505 Van Allen Hall, Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA. The limitations of Hall MHD as a model for turbulence in weakly collisional plasmas are explored using quantitative comparisons to Vlasov-Maxwell kinetic theory over a wide range of parameter space. The validity of Hall MHD in the cold ion limit is shown, but spurious undamped wave modes exist in Hall MHD when the ion temperature is finite. It is argue...
Coleman Jr., P J.: Turbulence, Viscosity, and Dissipation in the Solar-Wind Plasma, Astrophys J., 153, 371–388, 1968.; Abraham-Shrauner, B.: Small amplitude hydromagnetic waves for a plasma with a generalized polytrope law , Plasma Physics, 15, 375–385, 1973.; Andre, M.: Dispersion surfaces, J Plasma Phys., 33, 1–19, 1985.; Ballai, I., Erdélyi, R., Voitenko, Y., and Goossens, M.: Linear and nonlinear wave propagation in rarefied plasmas, Physics of Plasmas, 9, 2593–2603,...
Description: Space Science Center, University of New Hampshire, Durham, New Hampshire, 03824, USA. Politano and Pouquet's law, a generalization of Kolmogorov's four-fifths law to incompressible MHD, makes it possible to measure the energy cascade rate in incompressible MHD turbulence by means of third-order moments. In hydrodynamics, accurate measurement of third-order moments requires large amounts of data because the probability distributions of velocity-difference...
Balogh, A., Beek, T J., Forsyth, R J., Hedgecock, P C., Marquedant, R J., Smith, E J., Southwood, D J., and Tsurutani, B T.: The magnetic field investigation on the ULYSSES mission - Instrumentation and preliminary scientific results, Astron. Astrophys.\ Suppl. Ser., 92, 221–236, 1992.; Belcher, J W. and Davis, L.: Large-amplitude Alfvén waves in the interplanetary medium, 2., J Geophys. Res., 76, 3534–3563, 1971.; Dudok de Wit, T.: Can high-order moments be meaningfully...