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SUMMARY:Self-Gravity\, Resonances &amp\; Orbital diffusion in stellar disc
 s - Jean-Baptiste Fouvry (IAP)
DTSTART:20150130T113000Z
DTEND:20150130T123000Z
UID:TALK57006@talks.cam.ac.uk
CONTACT:Martin Haehnelt
DESCRIPTION:Fluctuations in a stellar system’s gravitational field cause
  the orbits of stars to evolve. The resulting evolution of the system can 
 be computed with the orbit-averaged dressed Fokker-Planck equation in angl
 e-actions coordinates. I will present the formalism that enables one to co
 mpute the diffusion tensor from a given source of noise in the gravitation
 al field when the system’s dynamical response to that noise is included.
  In the case of a cool stellar disc we are able to reduce the computation 
 of the diffusion tensor to a one-dimensional integral. The shot-noise-driv
 en formation of narrow ridges of resonant orbits is therefore recovered in
  the WKB limit of tightly wound transient spirals\, for a tepid Toomre-sta
 ble tapered disc\, so that we are able to explain analytically the princip
 al features of numerical simulations of such discs.
LOCATION:Kavli LMR\, IoA
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