  We examine the origins of azimuthal correlations observed in high energy
proton-nucleus collisions by considering the simple example of the scattering
of uncorrelated partons off color fields in a large nucleus. We demonstrate how
the physics of fluctuating color fields in the color glass condensate (CGC)
effective theory generates these azimuthal multiparticle correlations and
compute the corresponding Fourier coefficients v_n within different CGC
approximation schemes. We discuss in detail the qualitative and quantitative
differences between the different schemes. We will show how a recently
introduced color field domain model that captures key features of the observed
azimuthal correlations can be understood in the CGC effective theory as a model
of non-Gaussian correlations in the target nucleus.
