YanHR
美国威斯康星大学博士（2005年）
宇宙射线物理，星际物质，天体物理磁场，湍流，尘埃动力学，超新星，星团，γ射线暴。（科维理天文与天体物理研究所，兼天文学系教授）
电话 **，传真 **，Email hryan_at_pku.edu.cn
http://kiaa.pku.edu.cn/~hryan/
KIAA202
About myself My New Book Research Interests Cosmic Ray Acceleration and Transport in MHD turbulence Plasma Instabilities Solar flares, space physics Supernova Remnants, GRBs Astrophysical Magnetic Field and Atomic Alignment Interstellar Dust Dynamics
Accretion discsLectures Refereed publications Publications atADS / Astro-phLinks
Vacancyfor post-doctoral fellow
Huirong Yan
Kavli Institute of Astronomy and Astrophysics,
Peking University,
Beijing, China, 100871
E-Mail: hryan@pku.edu.cn
Phone: +86- (o)
Current Research Interests :
I am interested in various topics: MHD, turbulence, cosmic ray transport, dust dynamics, polarization from aligned atom, molecular clouds, star formation, etc.I study different astrophysical implications of MHD turbulence forpropagation and acceleration of cosmic rays, dynamics of dust as well asthe new ways of observational studies of magnetic fields. Using recently obtained scaling laws for MHD modes, we identified fast modes as thedominant agent for cosmic ray scattering for most of the interstellarphases. This conclusion was reached in spite of the damping of fastmodes that wetook into account. In addition, we found that the traditionalpicture of shock acceleration is incomplete, as it ignores the effect ofpreexisting turbulence in the surrounding gas. Our research revealed suppressionof streaming instability, which is an essential component of first order Fermi acceleration in shocks, by the ambient MHD turbulence. This suppressionlimits the energy of cosmic rays that can be accelerated by supernovae and invalidates many conclusions reached on cosmic ray confinement for modelsof galaxies embedded in fully ionized plasma. We found that dynamics of charged grains is dominated by MHD turbulence in a most of the interstellar environments. We introduced new mechanisms of grain acceleration and calculated shattering andcoagulation rates of grains, as well as the rate at which grainscan adsorb heavy ions, allow segregation of different grains and theiralignment. The obtained insight into grain dynamics is essential forunderstanding dust physics, chemistry and evolution.Another direction I have been working on is the observational studies of astrophysical magnetic fields. We studied alignment of atoms in thepresence of anisotropic radiation and magnetic field.Atoms can be aligned in terms of their angular momentum by anisotropic radiation which is common in astrophysical environment. The alignment is modified by magnetic fields that cause precession of atoms. We have identified atomic alignment enables a new tool to study astrophysical magnetic fields. Since it allows also temporal variations of magnetic fields, atomic alignment provides a cost effective way to study MHD turbulence at different scales. -->
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