Scaling Distribution of Axionic Strings and Estimation of Axion Density from Axionic Domain Walls

The damping of the axionic string motion due to the surrounding plasma isestimated by a detailed calculation of the fermion scatter from a global stringand it is shown that the friction force on the string can be neglected beforethe axionic domain wall formation in most cases, which is one of the importantnecessary conditions for the scaling distribution of the strings. The energydensity of the axion produced by the collapse of the axionic domain walls isalso evaluated using the axionic string distribution, and it is found to belarger or at least comparable to the axion density which originates from theaxionic strings.Comment: 20 pages (LaTeX), 3 figures, eclepsf.sty, revised figure