报告时间：2018年10月9日（周二）下午2:30 - 4:30
报告人： 张彬铮 香港大学地球科学系 助理教授
It is now over three decades since the first paper was published using the code that has come to be known as LFM (Lyon-Fedder-Mobarry). The code, used since then extensively in heliophysics research, had a number of novel features: eighth-order centered spatial differencing, the Partial Donor Cell Method limiter for shock capturing, a non-orthogonal staggered spherical mesh with constrained transport, conservative averaging-reconstruction for axis singularities and the capability to handle multiple ion species. However the computational kernel of the LFM code, designed and optimized for architectures long retired, has aged and is difficult to adapt to the modern multicore era of supercomputing. To carry its legacy forward, we re-envisage the LFM as GAMERA, Grid Agnostic MHD for Extended Research Applications, which pre- serves the core numerical philosophy of LFM while also incorporating numerous algorithmic and computational improvements. The upgrades in the numerical schemes include accurate grid metric calculations using high-order Gaussian quadrature techniques, high-order upwind reconstruction, non-clipping options for interface values. The improvements in the code implementation includes the use of data structures and memory access patterns conducive to aligned, vector operations and the implementation of hybrid parallelism, using MPI and OMP. Thus, while keeping the best elements of LFM, GAMERA is designed to be a portable and easy-to-use code that provides multi-dimensional MHD simulations in non-orthogonal curvilinear geometries on modern super- computer architectures. The new, efficient and high-quality numerical kernel is currently serving as a backbone of a whole geospace model. Extended applications include magnetospheres of Jupiter/Saturn and Mercury/Venus, inner heliosphere, solar corona and a basic plasma physics simulation box.
张彬铮教授于2005年和2007年分别获浙江大学电子工程专业学士和硕士学位，2012年获美国Dartmouth College工程科学博士学位。2012-2015年在Dartmouth College担任研究科学家与讲师，2015-2017年在美国国家大气研究中心(NCAR)开展博士后研究，2018年至今受聘香港大学地球科学系，担任助理教授。张教授在MHD模拟算法、空间天气大型建模、M-I Coupling以及行星物理研究等领域均取得突出的研究成果，主持了多项美国NSF和NASA科研项目，同时也是多个NSF和NASA项目的共同负责人和重要参与人，发表高水平SCI文章40余篇，多次受邀在AGU等地球科学国际大会上做专题口头报告。