Transverse oscillations of coronal loops

几十年来，人们已经知道太阳大气层具有强烈的磁性结构。其中一个主要的磁结构是日冕环。这些环是日冕中沿磁场方向伸长的结构，其特征在于等离子体的密度和温度增加。1998年，TRACE观测到这些结构在横向上的第一次振荡是由外部扰动（很可能是由太阳耀斑产生的）引起的。在那之后，横日冕环振荡现象受到了太阳物理学家的充分关注。横向振荡特别重要，因为它们是太阳物理学中迅速兴起的新分支--日冕地震学或太阳磁震学--的主要研究对象。日冕地震学的主要思想是通过观测日冕中发生的波动和振荡来获得有关日冕等离子体和磁场参数的信息。横向日冕环振荡已被用来估计：（i）日冕环中的磁场强度;（ii）日冕中的大气尺度高度。为了达到足够的精度，在这种类型的估计一个完善的理论横向日冕环振荡是非常需要的。这个理论的主要目标是将在地震学应用中重要的冕环参数与那些不重要的，因此可以忽略的参数分开。近年来，在这方面已经取得了初步但至关重要的进展。例如，它已被证明，密度和横截面半径的变化沿着的环路是非常重要的，而环路曲率和磁扭曲是不太重要的，在目前和不久的将来的仪器分辨率的水平。然而，横向日冕环振荡的理论还远未完成。新的和更复杂的模型，以获得次分辨率诊断信息的开发。其中主要的理论挑战是横向日冕环振荡的非线性理论的发展，以及一些日冕环系统的集体振荡理论。我们的项目解决了这些关键的高级问题。

It has been known for a few decades that the solar atmosphere is strongly magnetically structured. One of the main magnetic structures are the coronal loops. These loops are the structures elongated in the magnetic field direction in the solar corona that are characterized by the enhanced density and temperature of the plasma. In 1998 TRACE observed first oscillations of these structures in the transverse direction caused by an external perturbation (most probably generated by a solar flare). After that the phenomenon of transverse coronal loop oscillations received an ample attention of solar physicists. Transverse oscillations are especially important because they are the key objects of studies in the new and fast emerging branch of solar physics called coronal seismology or solar magneto-seismology. The main idea of coronal seismology is to obtain information about parameters of the coronal plasma and magnetic field from observations of waves and oscillations taking place in the solar corona. The transverse coronal loop oscillations have been used to estimate: (i) The magnetic field magnitude in coronal loops; (ii) The atmospheric scale height in the solar corona. To achieve sufficient accuracy in the estimates of this type a well-developed theory of transverse coronal loop oscillations is much needed. The main goal of this theory is to separate coronal loop parameters that are important in seismological applications from those that are not important, and thus can be neglected. Initial but vital progress has already been made in this direction in the recent years. For example, it has been shown that the variation of the density and cross-section radius along the loop are very important, while loop curvature and the magnetic twist are less important at the level of present and near-future instrumental resolution. However, the theory of transverse coronal loop oscillations is far from being complete. New and more sophisticated models are to be developed in order to obtain sub-resolution diagnostic informations. Among the main theoretical challenges are the development of nonlinear theory of transverse coronal loop oscillations, and the theory of collective oscillations of a system of a few coronal loops. Our project addresses these crucial advanced problems.