Time: 2012-01-04 13:00:00
Speaker: Liping Tian, Junhui Zhang, Huasheng Xie [IFTS]
Place: Rm. 413, Bld. 11#, Yuquan Campus
Abstract:
Speaker: Liping Tian
Title: Influence of Super-Alfvenic Shear Flow on the Nonlinear Evolution of Magnetic Reconnection
Abstract: The Super-Alfvenic shear flow has a great effect on the magnetic reconnection . It can excite Kelvin-Helmholtz-Resistive instability, which only occurs in a limited range of shear flow velocities. In addition, Alfven resonance layers appear in both sides of the current sheet and slow down the magnetic reconnection.
Speaker: Junhui Zhang
Abstract: Iteration method for 2D Poisson Equation on condition that single charge is located at the origin point, and comparison with analytic solution.
Speaker: Huasheng Xie
Topic:Darwin Model of Maxwellian Equations Revisited: Theory and PIC Simulation Aspects
Abstract: Darwin model is widely used in plasma simulation (espcially, space plasma), which can drop the high frequency electromagnetic waves automatically and then can focus on the low frequency modes (e.g., Alfven wave). The main purpose is to avoid the numerical divergence, otherwise, need very small dt. However, some critical properties haven't been identified clearly in the PIC simulation community in detailed. For examples, the differences on theoretical and numerical from the origninal Maxwellian (EM) model, the valid parameters range, the merits and drawbacks, and so on. Here, I give a detailed linear dispersion relation for Darwin model, and then solve and compare it with the EM model. The theory framework can explain the above unclear problems very well. The artificial mi/me and VA/c problem can also be studied. This theoretical results are also checked by 1&2/2D PIC simulation (by ZHU Jia).
PS: This presentation may also helpful for students who are taking the plasma waves course.