Nitin Yadav

Indian Institute Of Science Education and Research, Thiruvananthapuram · School of Physics

Vortex flows, related to solar convective turbulent dynamics at granular scales and their interplay with magnetic fields within intergranular lanes, occur abundantly on the solar surface and in the atmosphere above. Their presence is revealed in high-resolution and high-cadence solar observations from the ground and from space and with state-of-the...

Vortex flows, related to solar convective turbulent dynamics at granular scales and their interplay with magnetic fields within intergranular lanes, occur abundantly on the solar surface and in the atmosphere above. Their presence is revealed in high-resolution and high-cadence solar observations from the ground and from space and with state-of-the...

Context. Ubiquitous vortex flows at the solar surface excite magnetohydrodynamic (MHD) waves that propagate to higher layers of the solar atmosphere. In the solar corona, these waves frequently encounter magnetic null points. The interaction of MHD waves with a coronal magnetic null in realistic 3D setups requires an appropriate wave identification...

We present a new MHD wave decomposition method that overcomes the limitations of existing wave identification methods. Our method allows to investigate the energy fluxes in different MHD modes at different locations of the solar atmosphere as waves generated by vortex flows travel through the solar atmosphere and pass near the magnetic null. We sim...

In the present work, turbulence generation due to the dynamic evolution of magnetic islands is investigated. The role of ambient magnetic field in the evolution of magnetic islands and turbulence generation is also investigated. The origin of magnetic islands lies in the fact that reconnection takes place in thin current sheets which becomes unstab...

Aims. We study the properties of slow magneto-acoustic waves that are naturally excited as a result of turbulent convection and we investigate their role in the energy balance of a plage region using three dimensional radiation magnetohydrodynamic simulations. Methods. To follow slow magneto-acoustic waves traveling along the magnetic field lines,...

We study the properties of slow magneto-acoustic waves that are naturally excited due to turbulent convection and investigate their role in the energy balance of a plage region using three dimensional (3D) radiation-MHD simulations. We calculate the horizontally averaged (over the whole domain) frequency power spectra for both longitudinal and vert...

In the present work, turbulence generation due to the dynamic evolution of magnetic islands is investigated. The role of ambient magnetic field in the evolution of magnetic islands and turbulence generation is also investigated. The origin of magnetic islands lies in the fact that reconnection takes place in thin current sheets which becomes unstab...

Context. Vortex flows exist across a broad range of spatial and temporal scales in the solar atmosphere. Small-scale vortices are thought to play an important role in energy transport in the solar atmosphere. However, their physical properties remain poorly understood due to the limited spatial resolution of the observations. Aims. We explore and a...

Vortex-flows exist across a broad range of spatial and temporal scales in the solar atmosphere. Small-scale vortices have been proposed to play an important role in energy transport in the solar atmosphere. However, their physical properties remain poorly understood due to the limited spatial resolution of the observations. We aim to explore and an...

The relationship between vortex flows at different spatial scales and their contribution to the energy balance in the chromosphere is not yet fully understood. We perform three-dimensional (3D) radiation-magnetohydrodynamic simulations of a unipolar solar plage region at a spatial resolution of 10 km using the MURaM code. We use the swirling-streng...

The relationship between vortex flows at different spatial scales and their contribution to the energy balance in the chromosphere is not yet fully understood. We perform three-dimensional (3D) radiation-magnetohydrodynamic (MHD) simulations of a unipolar solar plage region at a spatial resolution of 10 km using the MURaM code. We use the swirling-...

Whistler waves have ample of observations in the magnetosphere near the dayside magnetopause. Also, the role of whistler waves is well established in the context of magnetic reconnection as well as turbulence generation. In the present work, we examine the combined effect of guide field and nonlinearity in the development of turbulence in magnetic...

The present model is proposed to study the nonlinear effects related to quasi-transverse 3D whistler waves in three different regions of space plasmas which are Earth's radiation belt,magnetopause, and solar wind plasma at 1 A.U. We have analysed the effect of considering the third dimension in the dynamics of whistler waves on Localization of whis...

Kinetic Alfvén waves (KAWs) are known to play an important role in magnetic reconnection as well as in turbulence. In the present work, we have derived the dynamical equation of KAWs propagating through Harris sheet. It is assumed that background density gets modified due to nonlinearity and background field gets modified due to the presence of Har...

Observations show that whistler waves play a very crucial role both in magnetic reconnection and turbulence. In this context, linear and nonlinear dynamical equations of whistler wave have been derived and further, these equations have been solved numerically as well as semi-analytically. For application purpose, magnetotail parameters have been ch...

A mechanism based on turbulence for solar coronal heating has been introduced in the present work. Turbulence is considered as an important tool for heating. In the present work, turbulence generation takes place due to the nonlinear interaction of the magnetohydrodynamic waves. Slow magnetosonic waves get localized due to the density perturbations...

Magnetic power spectrum and formation of coherent structures have been investigated in the present work applicable to Van Allen radiation belt. The nonlinear interaction of high frequency oblique whistler wave and low frequency magnetosonic wave has been investigated. Simulation was performed of the coupled equation of these two waves. The nonlinea...

Observations show that kinetic Alfven waves (KAWs) play a very important role in turbulence as well as in magnetic reconnection and have also been a topic of debate in the context of particle heating. In this paper, we aim to investigate the effect of magnetic islands on the dynamics of the nonlinear KAW. The formation of current sheet/coherent str...

Observations show that whistler waves play a very crucial role both in magnetic reconnection and turbulence. In this context, linear and nonlinear dynamical equations of whistler wave have been derived and further these equations have been solved numerically as well as semianalytically. For application purpose, magnetotail parameters have been chos...

Whistler waves have ample of observations in the magnetosphere near the dayside magnetopause. Also, the role of whistler waves is well established in the context of magnetic reconnection as well as turbulence generation. In the present work, we examine the combined effect of guide field and nonlinearity in the development of turbulence in magnetic...

The present model is proposed to study the nonlin ear effects related to quasi-transverse 3D whistler waves in three different regions of spac e plasmas which are Earth’s radiation belt, mag- netopause, and solar wind plasma at 1 A.U. We hav e analysed the effect of considering the third dimension in the dynamics of whistler waves on Lo calization...

The governing dynamical equations of the right-handed circularly polarized dispersive Alfvén wave (DAW), which becomes dispersive owing to the finite frequency of the wave, and the slow Alfvén wave have been obtained using a two-fluid model. The wave localization at different instants of time and its power spectrum have been investigated. The ponde...

In the present work, we have examined the nonlinear interaction of pump whistler wave and low frequency kinetic Alfvén wave (KAW) in three regions viz., solar wind, earth's radiation belt, and magnetopause. The modification in the background density leads to the introduction of nonlinearity. The nonlinear ponderomotive force is responsible for this...

In the present study, we have analyzed the field localization of kinetic Alfvén wave (KAW) due to the presence of background density perturbation, which are assumed to be originated by the three dimensionally propagating low frequency KAW. These localized structures play an important role for energy transportation at smaller scales in the dispersio...

In the present study, we have analyzed the field localization of kinetic Alfvén wave (KAW) due to the pres- ence of background density perturbation, which are assumed to be originated by the three dimensionally propagating low frequency KAW. These localized structures play an im- portant role for energy transportation at smaller scales in the dispe...

Spacecraft observations indicate the signatures of highly oblique kinetic Alfvén waves (KAWs) and whistler waves in the solar wind plasma. In the present work, we explore the possible role of KAWs and whistler waves in the observed solar wind magnetic turbulent spectrum. The nonlinear spatial evolution of KAW is studied including the effects of the...

Over the years, coronalheating has been the most fascinating question among the scientific community. In the present article, a heating mechanism has been proposed based on the wave–wave interaction. Under this wave–wave interaction, the high frequency kinetic Alfvén wave interacts with the low frequency ion acoustic wave. These waves are three dim...

Nonlinear interaction between highly oblique whistler wave and ion acoustic wave pertinent to magnetopause has been investigated. The density perturbation in whistler wave is supposed to be originated due to the presence of ion acoustic wave in the background. The ponderomotive force components arising due to the high amplitude pump wave, viz., whi...

A simulation based on a pseudo-spectral method has been performed in order to study particle acceleration. A model for the acceleration of charged particles by field localization is developed for the low-\(\upbeta\) plasma. For this purpose, a fractional diffusion approach has been employed. The nonlinear interaction between a 3D inertial Alfvén wa...

Recent studies have revealed an intimate link between magnetic reconnection and turbulence. Observations show that kinetic Alfvén waves (KAWs) play a very crucial role in magnetic reconnection and have been a topic of interest from decades in the context of turbulence and particle heating. In the present paper, we study the role that KAW plays in t...

In the present paper, we have investigated the nonlinear evolution of three dimensionally (3D) propagating inertial Alfvén wave (IAW) in the presence of background density fluctuations for low β plasma. The ponderomotive force, due to IAW and modified background plasma density, has been taken into account in order to develop the model equation. The...

Waves and instabilities play a very crucial role in astrophysical plasmas e.g. solar wind, Geospace etc. The main objective of current study is to investigate the importance of nonlinear processes associated with kinetic Alfvén waves (KAWs) in order to understand the physical mechanism behind the magnetopause turbulence. Numerical simulation of the...

The present paper deals with the nonlinear interaction of Inertial Alfvén wave (IAW) and fast magnetosonic wave in the low beta plasma, where beta is the ratio of thermal pressure to the background magnetic pressure. In this paper, the localization and turbulent spectra of IAW along with the density dips correlated with the fast magnetosonic wave h...

Localization of kinetic Alfvén waves (KAW) due to ponderomotive nonlinearity can be regarded as an important mechanism for heating the space plasmas. The present paper investigates the effect of background density fluctuations on the formation of large amplitude localized structures and turbulent spectrum of KAW applicable to magnetopause. The dyna...

Our investigation mainly concerns the numerical and analytical study of nonlinear coupling of a fast magnetosonic wave (FMSW) with an ion acoustic wave (IAW). In this paper, we have proposed the FMSW as the pump wave, and its number density becomes modified in the presence of an IAW. If the ponderomotive force components of the FMSW are included in...

The mutual nonlinear interplay of kinetic Alfvén wave (KAW) and ion acoustic wave, for the high-β plasma (i.e. me/mi ≪ β ≪ 1, where β is thermal to magnetic pressure ratio) in the magnetopause has been considered in the present study. A set of dimensionless nonlinear Schrödinger equation (NLS) has been derived taking into account the finite frequen...

We have studied the nonlinear interaction between slow magnetosonic waves (SMSW) and ion acoustic waves (IAW) by numerical simulation. Our model assumes that the SMSW as a pump wave and that its density perturbation is due to IAW. If the pon- deromotive force components of SMSW are included in the dynamics of IAW, the gov- erning equations for IAW...

Density cavities, having transverse scale size of the order of electron inertial length have been observed in auroral ionosphere by Freja spacecraft [Bellan and Stasiewicz, 1998]. In the present study, density cavity formation in auroral regions has been investigated using numerical simulation techniques. Nonlinear interaction of Inertial Alfvén wa...

The localization of pump inertial Alfvén wave (IAW) in low β plasmas (β ≪ me/ mi) has been investigated by developing a model based on weak IAW and finite amplitude background density fluctuations. When IAW is perturbed by these fluctuations which are in the form of magnetosonic and ion acoustic waves, its phase velocity gets modified and IAW break...

The nonlinear interaction of 3D kinetic Alfvén wave and fast magnetosonic wave for the intermediate-β plasma in magnetopause has been considered in the present study. A set of dimensionless equations has been derived taking ponderomotive nonlinearity into account due to kinetic Alfvén wave in the fast magnetosonic wave dynamics. In order to analyze...

We have presented the localization of kinetic Alfvén wave (KAW) in intermediate β plasma (m e /m i ≪β≪1) by developing a model based on pump kinetic Alfvén wave and finite amplitude magnetosonic fluctuations. When KAW is perturbed by these background magnetosonic fluctuations, filamentary structures of KAW magnetic field are formed. First, a semi a...

We have studied the nonlinear interaction between slow magnetosonic waves (SMSW) and ion acoustic waves (IAW) by numerical simulation. Our model assumes that the SMSW as a pump wave and that its density perturbation is due to IAW. If the ponderomotive force components of SMSW are included in the dynamics of IAW, the governing equations for IAW and...

Coronal heating is one of the unresolved puzzles in solar physics from decades. In the present paper we have investigated the dynamics of vortices to apprehend coronal heating problem. A three dimensional (3d) model has been developed to study propagation of dispersive Alfvén waves (DAWs) in presence of ion acoustic waves which results in excitatio...

In the present paper, we investigate the localization of weak inertial Alfvén wave (IAW) in the presence of finite amplitude magnetosonic fluctuations in low β plasmas (β≪m e /m i ). When IAW is perturbed by these fluctuations, localized structures of IAW magnetic field intensity are formed. We have developed a semi analytical model based on paraxi...

Density cavities having transverse-scale size of the order of electron inertial length have been observed in auroral ionosphere by Freja spacecraft. In the present study, density cavity formation in auroral regions has been investigated using numerical simulation techniques. Nonlinear interaction of inertial Alfvén waves and ion acoustic waves has...

Coronal heating is one of the unresolved puzzles in solar physics from decades. In the present paper we have investigated the dynamics of vortices to apprehend coronal heating problem. A three dimensional (3d) model has been developed to study propagation of dispersive Alfvén waves (DAWs) in presence of ion acoustic waves which results in excitatio...

The paper is concerned with the analytical study of nonlinear coupling of slow Alfvén wave (SW) with ion acoustic waves (IAWs) in high-β and low-β plasmas. Here the pump wave (SW) number density gets perturbed in the presence of IAW. The model equations of IAW and SW turn out to be the modified Zakharov system of equations when the ponderomotive no...

The present paper investigates the localization of a uniform plane kinetic Alfvén wave (KAW) due to the coupling with the density/magnetic field fluctuations associated with a magnetosonic wave propagating in the transverse direction, i.e., perpendicular to the background magnetic field. To gain the physical insight into this evolution, a simplifie...