Japan Geoscience Union Meeting 2016

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-GI General Geosciences, Information Geosciences & Simulations

[M-GI22] Development of computational sciences on planetary formation, evolution and surface environment

Tue. May 24, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Junichiro Makino(RIKEN AICS), Yoshi-Yuki Hayashi(Department of Planetology/CPS, Graduate School of Science, Kobe University), Shigeru Ida(Department of Earth and Planetary Science, Graduate School of Science and Technology, Tokyo Institute of Technology), Yuri Aikawa(Center for Computational Sciences, University of Tsukuba), Masaki Ogawa(Division of General Systems Studies, Graduate School of Arts and Sciences, University of Tokyo), Masayuki Umemura(Center for Computational Sciences, University of Tsukuba)

5:15 PM - 6:30 PM

[MGI22-P01] Toward N-Body calculations with a larger number of particles : parallel computation for Particle-Particle Particle-Tree scheme using FDPS

*Akihisa Yamakawa1, Junichiro Makino2, Saitoh Takayuki3, Junko Kominami3, Kosuke Takeyama1 (1.Tokyo Tech, 2.RIKEN, 3.ELSI)

Keywords:n-body simulations, planetary formation, planetesimals

Formation processes of terrestrial planets through planetesimal accretion have been studied using N-body calculations and several important formation processes have been found, such as the runaway growth and the oligarchic growth (Kokubo and Ida 1996, 1998). However, in almost all simulations the perfect accretion was assumed and relatively narrow region (e.g. 0.98AU-1.02AU) was simulated using small numbers of particles (< 105), because calculation cost is O(N2). To simulate planetary formation in more realistic conditions, it is necessary to take into account fragmentation, to handle a larger number of particles and to integrate them for longer time.
Therefore, we have developed a parallel implementation of P3T(Particle-Particle Particle-Tree) scheme, which reduces the calculation cost from O(N2) to O(N log N).
In P3T scheme, the gravitational force between two particles is split into short-range and long-range contributions. Short-range forces are evaluated by direct summation and integrated with the fourth order Hermite scheme with the block time steps. For long-range forces, we use a combination of Tree code and the leapfrog integrator with the constant time steps. Using this scheme, we can calculate N-Body problems accurately in low calculation cost of O(N log N). In order to accelerate P3T scheme by parallel computation, we use FDPS(Framework for Developing Particle Simulator) which is a library to process the tree part at high speed.
In this talk, we show that it is possible to perform N-Body calculations for planet formation with a larger number of particles than those in the previous studies by parallel computation with P3T scheme using FDPS.