Now showing items 60-72 of 72

  • 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 ...
  • Semi-analytical approach to criteria for ignition of excitation waves 

    Bezekci, B.; Idris, I.; Simitev, R. D.; Biktashev, V. N. (American Physical Society, 2015-10-19)
    We consider the problem of ignition of propagating waves in one-dimensional bistable or excitable systems by an instantaneous spatially extended stimulus. Earlier we proposed a method [I. Idris and V. N. Biktashev, Phys. ...
  • 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 ...
  • Southern Ocean buoyancy forcing of ocean ventilation and glacial atmospheric CO2 

    Watson, Andrew J.; Vallis, Geoffrey K.; Nikurashin, Maxim (Macmillan, 2015-09-28)
    Atmospheric CO2 concentrations over glacial–interglacial cycles closely correspond to Antarctic temperature patterns. These are distinct from temperature variations in the mid to northern latitudes, so this suggests that ...
  • 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 ...
  • Super-parameterisation of ocean deep convection 

    Challenor, Peter (University of Exeter, 2011-12-01)
    Sub-grid scale processes play an important role in ocean and climate modelling. Typical examples include clouds in atmospheric models, flows over restricted topographies or the resolution of con- vective plumes in ocean ...
  • 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 ...