2010/02/05 by Sergei B. Kuksin, Kuksin, Sergei B. · 1 citation
Mathematics · Physics and Astronomy · #35R60 #Analysis of PDEs (math.AP) #FOS: Mathematics #FOS: Physical sciences #Mathematical Physics (math-ph) #math-ph #math.AP #math.MP #msc:35R60
paper · pdf · doi:10.48550/arxiv.1002.1294
arxiv created 2010/02/05 · arxiv updated 2010/02/26
For the damped-driven KdV equation u-νuxx+uxxx-6uux=√νη(t,x), x∈ S1, ∫ u dx≡ ∫ηdx≡0, with 0<ν≤1 and smooth in x white in t random force η, we study the limiting long-time behaviour of the KdV integrals of motions (I1,I2,...), evaluated along a solution uν(t,x), as ν→0. We prove that %if u=uν(t,x) is a solution of the equation above, for 0≤τ:= νt \lesssim1 the vector Iν(τ)=(I1(uν(τ,⋅)),I2(uν(τ,⋅)),...), converges in distribution to a limiting process I0(τ)=(I01,I02,...). The j-th component Ij0 equals \12(vj(τ)2+v-j(τ)2), where v(τ)=(v1(τ), v-1(τ),v2(τ),...) is the vector of Fourier coefficients of a solution of an \it effective equation for the dam-ped-driven KdV. This new equation is a quasilinear stochastic heat equation with a non-local nonlinearity, written in the Fourier coefficients. It is well posed.