Dissipative structure and weak turbulence in the solar corona

We have analysed, for the first time, the high resolution X-ray images of the solar corona, obtained by the Yohkoh Mission, as non-linear extended systems. To quantify the spatio-temporal complexity in this extended system, we use an asymmetric spatial fragmentation parameter computed from a matrix representing an image. Choosing different spatial scales on the same image, wave numbers are computed from the intensity contours and this yields a fragmentation spectrum. This spectrum is used to analyze the images of a complex transient event obtained by the Soft X-ray Telescope board the Yohkoh satellite. The dynamics of the fine structures of the contours suggests the origin of the observed fragmentation to be localized weak turbulence process occuring in an evolving coronal active region.     

Hysteresis Provides Self-Organization in a Plasma Model

The magnetosphere is a multi-scale spatio-temporal complex dynamical system. Self-organization is a possible solution to the seemingly contradicting observation of the repeatable and coherent substorm phenomena with underlying complex behavior in the plasma sheet. Self-organization, through spatio-temporal chaos, emerges naturally in a plasma physics model with sporadic dissipation.     

Self-organization in a current sheet model

Self-organization is a possible solution to the seemingly contradicting observation of the repeatable and coherent substorm phenomena with underlying complex behavior in the plasma sheet. Self-organization, through spatio-temporal chaos, emerges naturally in a plasma physics model with sporadic dissipation. This revised version was published online in August 2006 with corrections to the Cover Date.     

The planetary–exoplanetary environment: A nonlinear perspective

A review of the fundamental physical processes in the planetary–exoplanetary environment is presented, with emphasis on nonlinear phenomena. First, we discuss briefly the detection of exoplanets and search for radio emissions from exoplanets. Next, we give an overview of the concepts of waves, instabilities, chaos and turbulence in the planetary–exoplanetary environment based on our present knowledge of the solar-terrestrial environment. We conclude by discussing cyclotron masers and chaos in nonthermal radio emissions in the planetary–exoplanetary environment.     

Lightning induced optical emissions in the ionosphere

A discussion of lightning induced optical emissions in the ionosphere is presented. Emphasis is placed on accounting for the puzzling observation of the spatial structure in the optical emissions and the Sprite ‘seeding’ before the development of the ‘tendrils’ (or streamers). In this context we discuss the generation of spatial brightness variations, within the required lightning parameter thresholds, due to spatio-temporal electric fields and spatial neutral density perturbations. This revised version was published online in August 2006 with corrections to the Cover Date.