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Whistler waves have been studied for many years in relation to turbulence and particle heating, and observations show that they are crucial to magnetic reconnection. Recent research has revealed a close relationship between magnetic reconnection and turbulence. The current work investigates the whistler turbulence caused by the energetic electron beam in the magnetic reconnection sites of magnetopause and also due to dynamic evolution of magnetic islands. For this, we develop a model based upon the two-fluid approximation to study whistler dynamics, propagating in the medium with the pre-existing chain of magnetic islands and under the influence of background density perturbation originating from ponderomotive nonlinearity of wave. Dynamics of nonlinear whistler have been solved with pseudo-spectral approach and a finite difference method with a modified predictor–corrector method and a Runge Kutta method for the semianalytical model. In the current research, we study how the nonlinear whistler wave contributes to the significant space phenomenon, i.e., turbulence, localization, and magnetic reconnection. We have also investigated the formation of a current sheet in a magnetopause region of the order of few-electron inertial length. We analyzed the power spectrum at the magnetopause when the system reached a quasi-steady condition. Our new approach to study whistler turbulence by an energetic electron beam at the magnetic reconnection sites has extensive applications to space plasmas, shedding a new light on the study of magnetic reconnection in nature. [ABSTRACT FROM AUTHOR]

Electrostatic lower hybrid waves propagating transverse to the external magnetic field in magnetized dusty plasma are investigated, using the fluid equations and also including the effect of density gradient in plasma. Lower hybrid modes are considered important in laboratory, astrophysical as well as space plasmas in interpreting low frequency noises. Unlike other electrostatic waves, lower hybrid waves can resonantly interact with electrons as well as ions in plasma. The dust and gradient terms lead to novel growth of these waves in dusty plasma. A theoretical model is developed to investigate density gradient effects on lower hybrid waves in plasma comprised of electrons, ions and dust particles. The dependence of plasma components' density, strength of magnetic field, temperature and charge of electrons, ions and dust grains on the frequency and growth rate of electrostatic lower hybrid waves has been investigated and presented graphically. It has been observed that the number density of each plasma components directly affects the growth rate. The electrostatic waves are found to grow along the positive electron gradient and the dust effect depends on the gradient length chosen. Above a certain threshold value of gradient length, the waves are found to stabilize. A correlation of the obtained theoretical results with the experimental observations is also discussed. [ABSTRACT FROM AUTHOR]

This study proposes a model to explain how energetic electron beams (produced by the magnetic reconnection process) cause whistler turbulence in the magnetic reconnection area of the magnetopause, as observed by the Magnetospheric Multiscale Mission. In this scenario, the energetic electron beam source has replaced the magnetic reconnection mechanism. We develop dynamic equations of the beam-driven whistler mode so that because of the large amplitude of the beam energy, it rises from the noise level. As a result, nonlinear effects follow due to ponderomotive force, which results in whistler wave localization; eventually, the turbulent state is achieved. A theoretical model is developed using the basic two-fluid equations and Maxwell's equations to study the dynamics of high-frequency whistler waves and low-frequency magnetosonic waves (MSWs). Then, using a pseudospectral approach and a finite difference method, a set of dimensionless equations for the whistler wave and MSWs was numerically solved. The outcomes of the numerical simulation show a localized structure and a turbulent power spectrum, which follow Kolmogorov scaling laws. It has also been clarified that the current investigations are pertinent to the most recent observations. [ABSTRACT FROM AUTHOR]

Discussion of Total Quality Management in distance education focuses on science education offered through the University Extension (UE) of the University of South Pacific (Fiji). Suggests a redesign of science curricula and a relaxing of requirements for on-campus enrollment, so that UE science learners can study up to the degree level at their own pace. (AEF)

This work demonstrates the simulation analysis of a novel device Plasma-Assisted Dual-Material Stacked Gate-Oxide Carbon Nanotube Field Effect Transistor (DM-SGCNFET) with a stacked gate oxide structure consisting of two oxides - SiO2 and HfO2. The performance metric of the simulated device is compared with a SiO2 based similar device (DM-CNFET) for varying sets of plasma parameters that corresponds to different values of channel length. Both the devices feature a PECVD grown vertically aligned semiconducting carbon nanotube implemented as the channel material. The comprehensive analysis delineates that the DM-SGCNFET offers enhanced values of drain current, transconductance, output conductance, early voltage, gain, gate capacitance, better switching ratio, and reduced channel resistance as compared to DM-CNFET. The novel structure contemplating a dual-material gate and a high-k dielectric gate stack in CNT based transistors warrants as an appropriate device for digital and analog applications providing high efficiency. The paper further explores the DM-SGCNFET device for linearity distortion performance by evaluating gm2, gm3, VIP2, VIP3, IIP3, IMD3 and 1-dB compression point for altering values of plasma parameters. [ABSTRACT FROM AUTHOR]

The theoretical modelling for the electrostatic ion cyclotron (EIC) waves in the existence of a transverse direct current (dc) electric field in a collisionless magnetized dusty plasma has been investigated using the kinetic theory model. It is examined that after incorporation of dc electric field with the dust grains can alter the dispersion properties of EIC waves in a magnetized dusty plasma. Our model developed accounts for the critical drift velocity, electron‐to‐ion temperature ratio, magnetic field, the number density of dust grains, relative density of negatively charged dust grains, and finite gyroradius parameter. Our investigation found that normalized growth rate and frequency increase with the relative density ratio and electric field. Moreover, the critical drift velocity for the excitation of the mode with negatively charged dust grains and electron‐to‐ion temperature ratio has been studied, and it was found that critical drift velocity decreases with the increase in negatively charged dust grains. The impact of dust grains on the low‐frequency waves has also been studied, and it was found that an increase in dust grain number density results in the reduction of growth rate. Some of our theoretical findings are consistent with the experimental observations. [ABSTRACT FROM AUTHOR]

This work presents a model to understand the generation of whistler turbulence in the magnetic reconnection region of magnetopause by the energetic electron beams (generated by magnetic reconnection process) as observed by magnetospheric multiscale mission [Zhao et al., J. Geophys. Res.: Space Phys. 126, e2020JA028525 (2021)]. In this model, the magnetic reconnection process has been replaced by the energetic electron beam source. Hence, the beam-driven whistler-mode dynamical equation has been set up by anticipating that it will grow from noise level due to beam energy and then will attain large amplitude such that nonlinear effects due to ponderomotive force will lead to the localization of whistler waves, and finally, this will lead to the turbulent state. For this, a non-linear two-dimensional fluid model is developed in which nonlinear interaction between high-frequency whistler wave and low-frequency ion acoustic wave (IAW) is pertinent to the magnetopause region. Due to large-amplitude whistler waves, ponderomotive force components emerge, which are included in IAW's nonlinear dynamics. The system of the dimensionless equations consists of the dynamics of whistler wave and IAW, and this has been solved by the numerical method. The results of the simulation show that the whistler's temporal evolution results in localized structures that eventually lead to turbulence. The relevance of the present investigation to the recent observations has also been pointed out. [ABSTRACT FROM AUTHOR]