Graduate Student / Postdoc Seminar

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Nonlinear Phase Mixing in Fluid Mechanics and Kinetic Theory: "Irreversible" Stability in Reversible Systems

Speaker: Jacob Bedrossian

Location: Warren Weaver Hall 1302

Date: Friday, November 22, 2013, 1 p.m.

Synopsis:

Phase mixing has long been established as a fundamental stability mechanism in a variety of physical systems, for example, the presence of coherent structures in turbulence (e.g. hurricanes in atmospheric dynamics) and in the dynamics of plasmas in tokamaks or astrophysical settings. During phase mixing, the system "stabilizes" by transferring information to finer and finer scales - in plasmas this is called Landau damping and in ideal fluids this is called inviscid damping. Unlike dispersive or dissipative phenomena, almost no rigorous mathematical analysis has been done on the nonlinear models. I will introduce the basic mechanics, the nonlinear difficulties and the recent advances that begin to resolve them, including (but not limited to) the recent works of Mouhot, Villani, Masmoudi and myself.