Solar wind, magnetosphere and ionosphere dynamics by using common parallel simulation codes

近年来，可用于大规模仿真的超级计算机正迅速从矢量并行机向标量并行机转变。日立和富士通甚至在日本也开始销售集群型标量并行机，只有NEC还在继续开发矢量并行机。为了实现未来将越来越成为主流的标量并行机的高效计算，需要改变数组的顺序以提高缓存的命中率，并介绍了三维域分解方法和整合系统的通信方法。通过开发满足这些条件的新型三维磁流体力学代码，首次为有效利用大型标度并联机床提供了可能。当然，高速硬传递函数是必要的。利用FUJITSU PRIMEPOWER HPC2500进行的试验计算表明，三维MHD代码在矢量并行机上的效率高达40-70%，在标量并行机上的效率也可以达到20%以上。结果表明，许多由MPI (message Passing Interface) Fortran编写的MHD/Fluid， Particle和Hybrid代码即使在标量并行的超级计算机上也可以高性能地执行。这些模拟代码开发的成功成果必将促使我们开展大规模的空间模拟，以研究空间物理中的磁层和电离层动力学以及非线性动力学现象。

In recent years, the supercomputer which can be used for large-scale simulation is changing from the vector-parallel machine quickly to the scalar-parallel machine. Hitachi and FUJITSU shift to marketing of a cluster type scalar-parallel machine even in Japan, and only NEC is continuing development of the vector-parallel machine. In order to achieve a high-efficient computation by scalar-parallel machine which will become the mainstream in future more and more, it is required that the order of array is changed in order to raise hit rate of the cache, and that the three-dimensional domain decomposition method and the communication method by the consolidation system are introduced. By development of new three-dimensional MHD (magnetohydrodynamic) code which satisfies such conditions, it can bring for the first time the possibility of the effective utilization of the large scale scalar-parallel machine. Of course, a high-speed hard transfer function is necessary. The 3D MHD code which has high efficiency of 40-70% in the vector-parallel machine can be certainly expectable that it exceeds 20% even in a scalar-parallel machine from the test calculation using this FUJITSU PRIMEPOWER HPC2500. Thus it turned out that many of MHD/Fluid, Particle and Hybrid codes written by MPI (message Passing Interface) Fortran aree executable with high performance even in the scalar-parallel supercomputers. These successful results in development of simulation codes have surely brought us to carry out a large-scale space simulation in order to study the magnetosphere and ionosphere dynamics and nonlinear kinetic phenomena in space physics.