A theoretical model analysis for non-thermal solar plasma fluctuations

Abstract Solar plasmas exhibit a broad spectrum of collective oscillatory modes essential to understanding helioseismic and dynamical phenomena. In this study, a linear fluctuation analysis is performed to explore the stability of non-thermal κ-modifiedviscoturbulent inhomogeneous solar plasmas. Fluid turbulence effects are incorporated using a modified Larson logabarotropic equation of state. The analysis yields a generalized linear cubic dispersion relation describing the self-gravitationally bounded solar interior plasma. We explore the influence of key physical parameters—including the non-thermality index, electron temperature, dynamic viscosity, and thermal conductivity—on the resulting dispersion signatures. The Routh–Hurwitz stability criterion is systematically applied to assess the plasma stability features. Both the helioseismic g-modes and p-modes are theoretically characterized. While the g-modes can induce large changes to the solar parameters, they cease to exhibit oscillatory behaviour beyond approximately 2.4 × 108 m from the solar core. In contrast, the p-modes propagate throughout the Sun. The excitation of the well-known five-minute oscillations is illustratively analysed and observationally validated. Our results indicate that electron non-thermality and thermal conductivity enhance mode propagation, whereas viscosity and electron temperature act as damping factors. The radially outward energy flux of the photospheric p-modes is estimated to lie in the range of 103 − 105 W m−2. These p-modes are shown to contribute substantially to chromospheric spicule formation via longitudinal-to-transverse mode conversion processes. The κ-modified wave characteristics reported here align well with prior results and are further supported by a broad range of solar observations, underscoring the robustness of our theoretical framework.