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Papers by Murchana Khusroo
Journal of physics, Mar 5, 2014
We investigate the formation of shock waves in a warm dusty plasma with equilibrium drift. We sho... more We investigate the formation of shock waves in a warm dusty plasma with equilibrium drift. We show that the natural decay rate of dust charge plays an important role in determining the properties of the shock front in such a plasma.
In this work we present a self-consistent and nonlinear analysis of ion-acoustic waves in the Ear... more In this work we present a self-consistent and nonlinear analysis of ion-acoustic waves in the Earth’s magnetosphere with thermal anisotropy and a radiative heat loss. The thermal anisotropy is modeled with a polybaric pressure [1], encouraged by observational evidence on near-earth plasma while the heat-loss term is given by Braginskii equation. We have analysed the effect of the Finite Larmor Radius (FLR) term through the generalized Ohm’s law [2]. The nonlinear wave is analyzed on its own rest frame which helps us develop a structure equation for the nonlinear perturbation [3]. The structure equation is then used for detailed analysis of the nonlinear waves including formation of solitons [4]. A thorough investigation is done for the system dynamics which gives us an idea about how the incorporation of the FLR term is affecting the overall behaviour of the solitary structures [5]. A good resemblance of our results with the observational data is also shown [6].
Physical Review E, 2019
We present an analysis of a Hall-magnetohydrodynamics model of the magnetospheric plasma with fin... more We present an analysis of a Hall-magnetohydrodynamics model of the magnetospheric plasma with finite Larmor radius effect. Through a bifurcation analysis of the resultant nonlinear system, we show that this nonlinear model does not possess a limit cycle, which rules out regular periodic oscillations with constant amplitude. However, it does result in a train of magnetosonic solitons, localized in space, with amplitudes increasing in time, which are largely in agreement with what is usually observed in the magnetopause region. We call these oscillations aperiodic magnetospheric oscillations. We emphasize that most of the train of solitary oscillations observed by the Cluster fleet and other spacecrafts do not have constant amplitudes: they either continuously increase or decrease. These train of solitons with nonconstant amplitudes is a primary solution of our model.
Plasma Physics and Controlled Fusion, 2015
Formation of electrostatic solitary structures are analysed for a magnetised plasma with ion and ... more Formation of electrostatic solitary structures are analysed for a magnetised plasma with ion and electron thermal anisotropies. The ion thermal anisotropy is modelled with the help of the Chew-Goldberger-Low (CGL) double adiabatic equations of state while the electrons are treated as inertia-less species with an anisotropic bi-Maxwellian velocity distribution function. A negative electron thermal anisotropy (T e⊥ /T e > 1) is found to help form large amplitude solitary structures which are in agreement with observational data.
Journal of physics, Mar 5, 2014
We investigate the formation of shock waves in a warm dusty plasma with equilibrium drift. We sho... more We investigate the formation of shock waves in a warm dusty plasma with equilibrium drift. We show that the natural decay rate of dust charge plays an important role in determining the properties of the shock front in such a plasma.
In this work we present a self-consistent and nonlinear analysis of ion-acoustic waves in the Ear... more In this work we present a self-consistent and nonlinear analysis of ion-acoustic waves in the Earth’s magnetosphere with thermal anisotropy and a radiative heat loss. The thermal anisotropy is modeled with a polybaric pressure [1], encouraged by observational evidence on near-earth plasma while the heat-loss term is given by Braginskii equation. We have analysed the effect of the Finite Larmor Radius (FLR) term through the generalized Ohm’s law [2]. The nonlinear wave is analyzed on its own rest frame which helps us develop a structure equation for the nonlinear perturbation [3]. The structure equation is then used for detailed analysis of the nonlinear waves including formation of solitons [4]. A thorough investigation is done for the system dynamics which gives us an idea about how the incorporation of the FLR term is affecting the overall behaviour of the solitary structures [5]. A good resemblance of our results with the observational data is also shown [6].
Physical Review E, 2019
We present an analysis of a Hall-magnetohydrodynamics model of the magnetospheric plasma with fin... more We present an analysis of a Hall-magnetohydrodynamics model of the magnetospheric plasma with finite Larmor radius effect. Through a bifurcation analysis of the resultant nonlinear system, we show that this nonlinear model does not possess a limit cycle, which rules out regular periodic oscillations with constant amplitude. However, it does result in a train of magnetosonic solitons, localized in space, with amplitudes increasing in time, which are largely in agreement with what is usually observed in the magnetopause region. We call these oscillations aperiodic magnetospheric oscillations. We emphasize that most of the train of solitary oscillations observed by the Cluster fleet and other spacecrafts do not have constant amplitudes: they either continuously increase or decrease. These train of solitons with nonconstant amplitudes is a primary solution of our model.
Plasma Physics and Controlled Fusion, 2015
Formation of electrostatic solitary structures are analysed for a magnetised plasma with ion and ... more Formation of electrostatic solitary structures are analysed for a magnetised plasma with ion and electron thermal anisotropies. The ion thermal anisotropy is modelled with the help of the Chew-Goldberger-Low (CGL) double adiabatic equations of state while the electrons are treated as inertia-less species with an anisotropic bi-Maxwellian velocity distribution function. A negative electron thermal anisotropy (T e⊥ /T e > 1) is found to help form large amplitude solitary structures which are in agreement with observational data.