Journal Article

Dispersion of Slow Magnetoacoustic Waves in the Active Region Fan Loops Introduced by Thermal Misbalance

Zavershinskii, D. I., Molevich, N. E., Belov, S. A.

2021

Overview

Slow magnetoacoustic waves observed in the solar corona are used as seismological probes of plasma parameters. It has been shown that the dispersion properties of such waves can vary significantly under the influence of the wave-induced thermal misbalance. In the current research, we study the effect of misbalance on waves inside the magnetic-flux tube under the second-order thin-flux-tube approximation. Using the parameters of active-region-fan coronal loops, we calculated wave properties such as the phase speed and decrement. It is shown that neglecting thermal misbalance may be the reason for the substantial divergence between seismological and spectrometric estimations of plasma parameters. We also show that the frequency dependence of the phase speed is affected by two features, namely the geometric dispersion and the dispersion caused by the thermal misbalance. In contrast to the phase speed, the wave decrement primarily is affected by the thermal misbalance only. The dependencies of the phase speed and decrement of the slow wave on the magnetic field and tube cross-section are also analysed.

• Publisher: Springer Netherlands,Springer Nature B.V
• Subject: Approximation / Astrophysics and Astroparticles / Atmospheric Sciences / Cooling / Corona / Coronal loops / Dispersion / Magnetic fields / Magnetic flux / Magnetoacoustic waves / Magnetohydrodynamic (MHD) Waves and Oscillations in the Sun’s Corona and MHD Coronal Seismology / Mathematical analysis / Parameter estimation / Phase velocity / Physics / Physics and Astronomy / Plasma / Seismology / Solar corona / Solar physics / Space Exploration and Astronautics / Space Sciences (including Extraterrestrial Physics / Spectrometry / Velocity / Waves