arXiv subjects

Prerana Sharma

Publications and source records attributed to Prerana Sharma.

3 recordsLinked to original sources

arXiv2026

Nonlinear Frequency Shifts due to Phase Coherent Interactions in Incompressible Hall MHD Turbulence

Turbulence in the magnetized plasma is well understood to be the consequence of wave interactions. When the Hall effect is added to the minimum magnetohydrodynamics (MHD), the MHD waves become dispersive and different nonlinear interactions are expected. The emergent turbulent state will thus be expected to be different. For incompressible Hall MHD we develop a reduced model for wave-wave interactions concentrating on those processes that will lead to phase coherent modifications to the linear dispersion of a given wave. We show that these special interactions provide an amplitude-dependent contribution to the linear dispersion relation, which yields nonlinear frequency shifts. The resonance-driven frequency shifts are dominant and add damping or growth to the linear dispersion. The damping/growth rates represent the nonlinear time scales for energy redistribution and can be used in conjunction with a conjecture like the "critical balance" to estimate the energy spectral content.

physics.plasm-ph↗

arXiv2024

Hall MHD waves: A fundamental departure from their MHD counterparts

It is demonstrated through a succinct derivation as to how the linear waves in Hall magnetohydrodynamics (HMHD) constitute a fundamental departure from the standard MHD waves. Apart from modifying the conventional MHD spectrum, the Hall current induces a distinct and new branch consisting of purely circularly polarized waves that may become the representative shear waves.

physics.plasm-ph↗

arXiv2013

Efficient Image Encryption and Decryption Using Discrete Wavelet Transform and Fractional Fourier Transform

Fractional Fourier transform and chaos functions play a key role in many of encryption-decryption algorithms. In this work performance of image encryption-decryption algorithms is quantified and compared using the computation time i.e. the time consumption of encryption-decryption process and resemblance of input image to the restored image, quantified by MSE. This work proposes an improvement in computation-time of image encryptiondecryption algorithms by utilizing image compression properties of the 2-dimensional Discrete Wavelet Transform (DWT2). Initially, computation complexity of the algorithms is evaluated and compared with that of existing algorithms. This analysis claims the proposed algorithms to be nearly 8 times faster than the existing algorithms. Further, simulations are performed using MATLAB7.7 to quantify performance of existing algorithms and the proposed algorithms using MSE and computation time. The results obtained in these simulations prove that for the proposed algorithms MSE between restored and original images is lesser than that of existing algorithms thereby maintaining the robustness of the existing algorithms. These algorithms are found sensitive to a variation of 1x10-1 in the fractional orders used in encryption-decryption process.

cs.CR↗