Now showing items 55-68 of 68

  • Product dynamics for homoclinic attractors 

    Ashwin, Peter; Field, Michael (Royal Society, 2005)
    Heteroclinic cycles may occur as structurally stable asymptotically stable attractors if there are invariant subspaces or symmetries of a dynamical system. Even for cycles between equilibria, it may be difficult to obtain ...
  • Properties of the invariant disk packing in a model bandpass sigma-delta modulator 

    Ashwin, Peter; Fu, Xin-Chu; Deane, Jonathan (13 (3), pp. 631-641, 2003)
    In this paper we discuss the packing properties of invariant disks defined by periodic behavior of a model for a bandpass Σ–Δ modulator. The periodically coded regions form a packing of the forward invariant phase space ...
  • Reduced dynamics and symmetric solutions for globally coupled weakly dissipative oscillators 

    Ashwin, Peter; Dangelmayr, Gerhard (Taylor & Francis, 2005)
    Systems of coupled oscillators may exhibit spontaneous dynamical formation of attracting synchronized clusters with broken symmetry; this can be helpful in modelling various physical processes. Analytical computation of ...
  • The representation of snow in land surface schemes: results from PILPS 2(d) 

    Slater, Andrew G.; Schlosser, C. Adam; Desborough, C. E.; Pitman, Andrew; Henderson-Sellers, Ann; Robock, Alan; Vinnikov, Konstantin Y.; Mitchell, Ken; Boone, Aaron; Braden, Harald; Chen, F.; Cox, Peter M.; De Rosnay, Patricia; Dickinson, Robert E.; Dai, Yongjiu; Duan, Qingyun; Entin, J.; Etchevers, Pierre; Gedney, Nicola; Gusev, Yevgeniy M.; Habets, Florence; Kim, Jinwon; Koren, V.; Kowalczyk, Eva; Nasonova, Olga N.; Noilhan, Joel; Schaake, John; Shmakin, Andrey B.; Smirnova, Tatiana G.; Verseghy, Diana; Wetzel, Peter; Xue, Yongkang; Yang, Zong-Liang; Zeng, Qing-Cun (American Meteorological Society, 2001)
    Twenty-one land surface schemes (LSSs) performed simulations forced by 18 yr of observed meteorological data from a grassland catchment at Valdai, Russia, as part of the Project for the Intercomparison of Land-Surface ...
  • Robust bursting to the origin: heteroclinic cycles with maximal symmetry equilibria 

    Hawker, David; Ashwin, Peter (World Scientific Publishing Company, 2005)
    Robust attracting heteroclinic cycles have been found in many models of dynamics with symmetries. In all previous examples, robust heteroclinic cycles appear between a number of symmetry broken equilibria. In this paper ...
  • The sensitivity of global climate model simulations to the representation of soil moisture heterogeneity 

    Gedney, Nicola; Cox, Peter M. (American Meteorological Society, 2003)
    Improving the treatment of subgrid-scale soil moisture variations is recognized as a priority for the next generation of land surface schemes. Here, the impact of an improved representation of subgrid-scale soil moisture ...
  • The spiral wind-up and dissipation of vorticity and a passive scalar in a strained planar vortex 

    Bassom, Andrew P.; Gilbert, Andrew D. (Cambridge University Press, 1999)
    The response of a Gaussian vortex to a weak time-dependent external strain field is studied numerically. The cases of an impulsive strain, an on–off step function, and a continuous random strain are considered. Transfers ...
  • The spiral wind-up of vorticity in an inviscid planar vortex 

    Bassom, Andrew P.; Gilbert, Andrew D. (Cambridge University Press, 1998)
    The relaxation of a smooth two-dimensional vortex to axisymmetry, also known as `axisymmetrization', is studied asymptotically and numerically. The vortex is perturbed at t = 0 and differential rotation leads to the wind-up ...
  • Synchronization of chaos in an array of three lasers 

    Terry, John R.; Thornburg, K. Scott; DeShazer, David J.; VanWiggeren, Gregory D.; Zhu, Shiqun; Ashwin, Peter; Roy, Rajarshi (American Physical Society, 1999)
    Synchronization of the chaotic intensity fluctuations of three modulated Nd:YAG lasers oriented in a linear array with either a modulated pump or loss is investigated experimentally, numerically, and analytically. ...
  • Tangencies in invariant disc packings for certain planar piecewise isometries are rare 

    Ashwin, Peter; Fu, Xin-Chu (Taylor & Francis, 2001)
    For planar piecewise isometries (PWIs) (two-dimensional maps that restrict to isometries on some partition) there is a natural coding given by the itinerary of a trajectory between the pieces (atoms) of the partition on ...
  • Thresholds for the formation of satellites in two-dimensional vortices 

    Turner, M. R.; Gilbert, Andrew D. (Cambridge University Press, 2008)
    This paper examines the evolution of a two-dimensional vortex which initially consists of an axisymmetric monopole vortex with a perturbation of azimuthal wavenumber m = 2 added to it. If the perturbation is weak, then the ...
  • Two-state intermittency near a symmetric interaction of saddle-node and Hopf bifurcations: a case study from dynamo theory 

    Ashwin, Peter; Rucklidge, Alastair M.; Sturman, Rob (Elsevier, 2004)
    We consider a model of a Hopf bifurcation interacting as a codimension 2 bifurcation with a saddle-node on a limit cycle, motivated by a low-order model for magnetic activity in a stellar dynamo. This model consists of ...
  • Vortex motion in a weak background shear flow 

    Bajer, Konrad; Bassom, Andrew P.; Gilbert, Andrew D. (Cambridge University Press, 2004)
    A point vortex is introduced into a weak background vorticity gradient at finite Reynolds number. As the vortex spreads viscously so the background vorticity becomes wrapped around it, leading to enhanced diffusion of ...
  • What is the spatial distribution of magnetic helicity injected in a solar active region? 

    Pariat, E.; Nindos, A.; Démoulin, P.; Berger, M.A. (EDP Sciences, 2006)
    Context. Magnetic helicity is suspected to play a key role in solar phenomena such as flares and coronal mass ejections. Several investigations have recently computed the photospheric flux of magnetic helicity in active ...