Nonlinear dynamics of ion temperature gradient driven modes in non-Maxwellian magnetoplasmas

Abstract

In this paper, low frequency (omega << Omega(ci)) two dimensional wave propagating in an electron-ion magnetoplasma is analytically studied in the presence of background density and ion temperature gradient using two fluid theory. Electrons are assumed to follow non-Maxwellian distribution, namely, kappa and Cairns distribution. In the linear regime, real and imaginary parts of dispersion relation are plotted for different distributions and the comparison is also drawn. In the nonlinear case, nonlinear partial differential equations (NLPDEs) are derived both for dispersive and dissipative cases for the ITG mode. The solutions of these NLPDEs are obtained using the functional variable method. The propagation characteristics of these nonlinear structures are observed by plotting them with different electron distributions for Tokamak parameters. It is found that the non-Maxwellian electrons alter the behavior of nonlinear structures for the ITG mode. The differences in the behavior of dispersive and dissipative solutions for different physical parameters of interest are also explored in detail. This work may be helpful to understand low frequency electrostatic modes in space and Tokamak plasmas where both background density inhomogeneity and nonthermal electron distributions have been observed.