%0 Conference Paper %F Oral %T Stability of spherical stellar systems by symplectic methods : numerical test %+ Optimisation et commande (OC) %+ Laboratoire Univers et Théories (LUTH (UMR_8102)) %+ The Information School %A Perez, Jérôme %A Alimi, Jean-Michel %A Aly, Jean-Jacques %A Scholl, Hans Jochen %< avec comité de lecture %B N-body problems and gravitational dynamics %C Aussois, France %Y Observatoire de Paris %8 1993-03-15 %D 1993 %Z Physics [physics]/Astrophysics [astro-ph]Conference papers %X We present a numerical analysis of a class of radial-anisotropic collisonless spherical stellar systems in order to understand the physical ori¬gin of the radial-orbit instability. This work is motivated by new analytical results based on the symplectic formulation of a generalised energy varia¬tionnal technique. We have obtained a first confirmation that the stability of such systems is governed by their aptitude to receive a certain class of perturbations. %G English %2 https://hal.science/hal-01141498/document %2 https://hal.science/hal-01141498/file/papier3_perez.pdf %L hal-01141498 %U https://hal.science/hal-01141498 %~ OBSPM %~ INSU %~ UNIV-PARIS7 %~ ENSTA %~ CNRS %~ LUTH %~ UMA_ENSTA %~ PSL %~ UNIV-PARIS %~ UP-SCIENCES %~ OBSPM-PSL