【9.19; Seminar】2025年粒子天体物理全国重点实验室系列学术报告 #25：Cascade of compressible turbulence and Cosmic ray transport

时间/Time: 9月19日周五上午9:30/Friday,September 19,9:30 a.m.

地点/Location: 多学科楼122会议室/Meeting Room 122,Multidisciplinary building

报告人/Speaker: Prof. Hui-rong Yan

题目/Title: Cascade of compressible turbulence and Cosmic ray transport

主持人/Host: 毕效军/ Prof. BI Xiaojun

摘要/Abstract:

Transport of energetic particles is determined by MHD turbulence, which is largely shaped by the forcing on large scales and damping on small scales. Recent progress on studies of compressible turbulence will be presented along with its implication on particle transport. Our new hybrid and PIC simulations on the cascade and damping of fast modes, the dominant player in particle scattering, will be presented. The CR anisotropy analysis will be confronted with earlier theoretical prediction on the scattering by fast modes. Both theoretical and observational studies will be presented. Based on an improved compressible MHD decomposition algorithm, our analysis of Cluster observations demonstrates that collisionless damping enhances the anisotropy toward the local mean magnetic field, consistent with theoretical expectations and crucial for determining the particle scattering efficiency. Different regimes of particle transport, e.g., diffusion vs. superdiffusion, isotropic vs. anisotropic diffusion, will be discussed in relation to turbulence properties.

个人简介/Biography:

Hui-rong Yan obtained his B.Sc. degree in Astrophysics from Peking University, China, in 1998, followed by an M.Sc. in Astronomy (2002) and a Ph.D. in Astronomy (2005) from the University of Wisconsin–Madison, United States. She then pursued postdoctoral research as a Fellow at the Canadian Institute for Theoretical Astrophysics (CITA) in Toronto from 2005 to 2008, and subsequently as a Theoretical Astrophysics Program Prize Fellow at the University of Arizona (2008–2010). From 2009 to 2015, she served as Research Professor at the Kavli Institute for Astronomy and Astrophysics, Peking University. Since 2015, she has held a W3 chair professorship at the Institut für Physik und Astronomie, University of Potsdam, and is also a Leading Scientist at DESY Zeuthen.

Her scientific career is centered on turbulence and plasma astrophysics,cosmic ray and high-energy astrophysics,and the physics of the interstellar medium. She has made significant contributions to the study of plasma instabilities and their astrophysical implications,atomic alignment and magnetic fields in astrophysical environments,as well as the properties of interstellar and circumstellar dust. Her work bridges theoretical,computational,and observational aspects,with a strong emphasis on understanding the role of plasma processes and magnetic fields in shaping the dynamics of astrophysical systems.