Speaker
Description
The Gaia Snail—a spiral pattern in stellar phase space caused by a perturbation to the Milky Way disk—is a natural laboratory for one-dimensional collisionless gravitational dynamics. It is the sign-flipped analog of electrostatic Vlasov–Poisson physics. Linear theory reproduces the spiral but winds it too tightly and fails to reproduce salient observed features. We present nonlinear analytical results and Gkeyll simulation verification for this gravitational cousin of classic plasma kinetic problems. The self-gravity operator around the classic Spitzer equilibrium is a reflectionless soliton potential and produces an exactly zero first-order shift. The second-order shift is not zero. Self-gravity does not slow the winding. The slowing is apparent. The slab's bending motion is a mode that oscillates but does not wind, and when comparable in amplitude, it hides the spiral's wraps. The power spectrum follows a power law that can be calculated using a technique T. S. Lundgren used in his hydrodynamics spiral model.