京大工学部８号館３階南演習室

山口義幸(京都大学)

『Small traveling clusters in attractive and in repulsive HMF models』

(Julien Barre'氏(ニース大)との共同研究)

Long-lasting small traveling clusters are studied in the Hamiltonian mean-field model by comparing between attractive and repulsive interactions. Nonlinear Landau damping theory predicts that a gaussian momentum distribution on a spatially homogeneous background permits the existence of traveling clusters in the repulsive case, as in plasma systems, but not in the attractive case. Nevertheless, extending the analysis to a two-parameter family of momentum distributions of Fermi-Dirac type, we theoretically predict the existence of traveling clusters in the attractive case; these findings are confirmed by direct $N$-body numerical simulations. The parameter region with the traveling clusters is much reduced in the attractive case with respect to the repulsive case. 参考文献: Phys.Rev.E 79, 036208 (2009

Last modified: Thu Apr 16 20:36:49 2009