第58回:4月18日(土)15:00から
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