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.

在日冕中观察到的慢磁声波被用作等离子体参数的地震学探测器。已经表明，在波引起的热失衡的影响下，这种波的色散特性会发生显着变化。在目前的研究中，我们在二阶细磁通管近似下研究失衡对磁通管内部波的影响。使用活动区-扇日冕环的参数，我们计算了波的特性，例如相位速度和衰减。结果表明，忽略热失衡可能是等离子体参数的地震学和光谱估计之间存在重大分歧的原因。我们还表明，相位速度的频率依赖性受两个特征的影响，即几何色散和热失衡引起的色散。与相位速度相反，波衰减主要仅受热失衡影响。还分析了相位速度和慢波衰减对磁场和管横截面的依赖性。