Thermal-convective instability of a composite plasma in a stellar atmosphere with Hall currents

The problem of thermal-convective instability of a hydromagnetic composite plasma in a stellar atmosphere has been studied with Hall effects. The criterion for monotonic instability has been found to be unchanged by the presence of Hall effects.     

Thermal-convective instability of a composite rotating stellar atmosphere in the presence of a variable magnetic field,medium permeability and solute gradient

The thermal-convective instability of a composite rotating stellar atmosphere in the presence of a variable horizontal magnetic field is considered to include, separately, the effects of medium permeability and solute gradient. The criteria for monotonic instability in each case have been obtained which generalize the Defouw's criterion derived for thermal-convective instability in the absence of above effects.     

List of forthcoming papers

List of forthcoming papers     

Thermosolutal-convective instability of a composite stellar atmosphere in the presence of a variable magnetic field

The thermosolutal-convective instability of a composite stellar atmosphere is considered in the presence of variable horizontal magnetic field and collisional effects. The criteria for monotonic instability are obtained which generalize the criterion derived for thermal-convective instability in the absence of above effects.     

Gravitational instability of a composite and rotating plasma in the presence of a variable magnetic field through a porous medium

The gravitational instability of an infinite homogeneous self-gravitating plasma through porous medium is considered to include, separately, the effects due to rotation and collisions between ionized and neutral components. The dispersion relations are obtained in both cases. It is found that the gravitational instability of a composite and rotating plasma in the presence of a variable horizontal magnetic field through porous medium is determined by the Jeans's criterion.     

A spatially explicit modeling approach to explore scenarios of sustainable agriculture futures

The transition to agricultural sustainability involves difficult choices and an understanding of the complex trade-offs associated with agricultural activities. Decision support tools and techniques assist in making the informed decisions for a transition to sustainable agriculture. Georgia Basin — Quite Useful Ecosystem Scenario Tool (GB-QUEST) is a computer-based, user-friendly tool that has been developed to look at the future sustainability scenarios of the Georgia Basin in British Columbia. The objective of this paper is to describe the agricultural model that has been developed for implementation in GB-QUEST. We present its framework, spatial methodology for land-use simulation, and the initial results of its application. The agriculture model is a spatial model that examines the social, economic and environmental consequences of user-defined agricultural development strategies. The model simulates changes in the Georgia Basin from the year 2000 to 2040 in decadal steps. User choices of local and global development factors, along with their "worldview" choices, are important inputs in the model that determine the effects on environmental and socio-economic systems. The model has two components — Generation of land-use scenarios, and Development of Indicator models. The first component uses cell-based spatial algorithms to simulate likely changes/conversions in land-use up to the year 2040. The approach used here integrates the functionality of Multi-Criteria Evaluation (MCE) and Cellular Automata (CA) techniques in order to simulate the land-use conversions. It uses Geographic Information Systems (GIS) and remote sensing techniques for creating, storing and deriving the data sets required for the model. The second component develops the indicator models for relating scenario variables to socio-economic and environmental variables such as physical and economic yields, economic operation costs and nutrient surplus per unit area. These indicator models are used to evaluate land-use scenarios generated by the users. The model encourages understanding of sustainability, by allowing one to explore different possible scenarios of the future for their environmental and socio-economic consequences.     

Remote sensing of spectral signatures of tropospheric aerosols

With the launch of the German Aerospace Agency's (DLR) Modular Opto-electronic Scanner (MOS) sensor on board the Indian Remote Sensing satellite (IRS-P3) launched by the Indian Space Research Organization (ISRO) in March 1996, 13 channel multi-spectral data in the range of 408 to 1010 nm at high radiometric resolution, precision, and with narrow spectral bands have been available for a variety of land, atmospheric and oceanic studies. We found that these data are best for validation of radiative transfer model and the corresponding code developed by one of the authors at Space Applications Centre, and called ATMRAD (abbreviated for ATMospheric RADiation). Once this model/code is validated, it can be used for retrieving information on tropospheric aerosols over ocean or land. This paper deals with two clear objectives, viz.,

Alfvénic drift Kelvin-Helmholtz instability in the presence of an equilibrium electric field

Alfvénic drift Kelvin-Helmholtz instability is discussed in the presence of equilibrium electric and magnetic fields which are perpendicular to each other. A dispersion relation is achieved with the help of WKB approximation and the instability criterion is established. A comparison is made with the previous studies and it is shown that the electric field has a stabilizing or destabilizing effect on the system according to the conditions discussed in the text.     

The periodic orbits of the second kind in terms of Giacaglia's variables with oblateness

Utilizing secular perturbing potential due to oblateness, the existence of periodic orbits of the second kind is established through analytic continuation using Giacaglia's canonical variables in the planar restricted three-body problem when the more massive primary is an oblate spheroid with its equatorial plane coincident with the plane of motion.