德国马普所Hardi Peter博士将于本周作两次学术报告，全面介绍太阳过渡区的观测和模拟的最新进展。
报告一： 时间：2011年11月11日上午10：00 地点：北京大学物理大楼北415 题目：The Solar Transition Region - A Key to Understand the Corona
摘要：
The transition region is the interface between the chromosphere and the corona. It is usually defined through the emission seen from plasma at around 100.000 K. Observations, modeling and basic theoretical considerations show that this part of the solar atmosphere is in a very dynamic state, much more dynamic than the corona. Because of its immediate response to changes of the energy input, this region is ideally suited to investigate the processes heating the upper atmosphere. The prime tool to study the transition region is spectroscopy (and imaging) in the vacuum ultraviolet, where most of the prominent emission lines originating from the transition region are to be found. These spectra show characteristic Doppler shifts, line widths and also line intensities, which carry pivotal clues to understand the physics of the transition region. Also the temporal variability and the radiance carry vital information. In this lecture I will start with some very basic considerations which are long known, but still helpful to grasp the underlying ideas. I will then present some selected observations, mostly acquired with SUMER and CDS on SOHO, that that have been particularly useful to stimulate new models for the transition region structures. I will then briefly present some of these models, which will provide the motivation for the second lecture.
报告二： 时间：2011年11月16日下午3：00 地点：北京大学物理大楼北415 题目：Structure and Dynamics of the Solar Corona
摘要：
Understanding the heating of the solar corona has remained enigmatic for more than 70 years. The SOHO mission, launched to answer this problem, left us with more questions than answers. However, combination of increasingly complex numerical experiments with existing and advanced new observations allowed us to make significant steps forward. Today we have a better handle on the temporal and spatial distribution of the heat input, at least we have different (sometimes opposing) models that show more or less good agreement with the observations. Over the recent years 3D MHD numerical experiments became a most valuable tool to investigate the processes from the upper convection zone into the corona. Different models of various degrees of sophistication have been run, with some being quite realistic in reproducing observable quantities -- even though the parameter range in the 3D models is often far from being realistic. But still 1D and 2D models are of high interest, because the 3D computations are highly computationally intensive, and only 1D and 2D models allow to do also parametric studies. In this lecture I will present some 3D models and their comparison to observable quantities, such as emission measure, Doppler shifts, or the appearance of the solar corona. It will become evident, that these 3D model predict a transient heating which is concentrated in the low atmosphere, and that they can properly reproduce the above mentioned observable quantities, without employing very specific assumptions and free parameters. These results also give some interesting insights in the usability of 1D loop models to understand the corona. Finally, one major open issue remains: how is the energy really dissipated on the relevant scales, which are certainly well below the current resolution of the 3D MHD models.
