主持人：张凌 研究员

　　地点：EAST控制大厅三楼会议室

　　时间：2023年12月8日（星期五）上午9:30-11:30

　　报告题目：Physics Background for light and heavy impurity spectroscopy

　　摘要：

　　In fusion plasmas many kinds of impurities are intrinsically and extrinsically mixed with fuel hydrogen or deuterium particles.  It is well known that light impurities having small atomic number, low-Z impurities (C, O, etc.), decrease the edge temperature and dilute the core fuel ratio and heavy impurities having large atomic number, high-Z impurities (Fe, W, etc.), increase the radiation loss in core plasma.  These phenomena obviously cause a performance degradation of the fusion plasma.  In ITER, recently, a decision has been made to adopt tungsten first wall as well as BEST.  Therefore, study of impurity behavior is now further important in fusion research.  In this lecture physics background needed for impurity spectroscopy as an experimental tool for studying the impurity behavior is reviewed.  Since physics related to the impurity spectroscopy is considerably different against the impurity atomic number, the lecture is given with a clear distinction between light and heavy impurities.  In particular, it becomes prominent in terms of selection rule for line transition and relativistic effect in atomic physics, observation of allowed (electric dipole) and forbidden (magnetic dipole) transitions in plasma spectroscopy, and collisionality and mass effect in parallel and perpendicular impurity transport.  Finally, a few spectroscopic studies executable in EAST are proposed for BEST diagnostic development.  The lecture is carried out in such a way that students in master course can well understand, i.e. emphasis on a very simplified explanation of the phenomenon..