Decoupling and coherent plasma oscillations around last scattering

Abstract

Coherent properties of the baryon-photon fluid decoupling are considered in the terms of an effective nonlinear Schrödinger equation for a macroscopic wave function that specifies the index of the coherent state. Generation of a transitional acoustic turbulence preceding formation of large-scale condensate in the plasma and its influence on the CMB power spectrum has been studied. A scaling $k^{-1}$ law is derived for the CMB Doppler spectrum $E(k)$ (angle-averaged) in the {\it wavenumber} space, for sufficiently large wavenumber $k$ and for the weak nonlinear and completely disordered initial conditions. Using the recent WMAP data it is shown that the so-called first acoustic peak represents (in a compensated spectral form) a pre-condensate fraction of the spectrum $E(k)$ at a rather advance stage of the condensate formation process.