Coherent radiation of relativistic nonlinear Thomson scattering

The condition for the coherent addition of the relativistic nonlinear Thomson scattered, (RNTS) radiations from a group of electrons is derived. Numerical calculations' show that under such a condition, all,the characteristics of RNTS radiation by a single electron are maintained, leading to the generation of intense attosecond x rays. Such an attosecond x ray is produced in a specific direction with a very narrow angular divergence. An x-ray radiation of similar to 10(16) W/cm(2),with a pulse width of. 7.7 as is expected for an oblique irradiation of a 20 A linearly polarized laser pulse of 4x10(19) W/cm(2) on a 7 nm thick film target. For the proof-of-principle experiment, the radiation characteristics from a 50 nm thick film target are presented and discussed. (c) 2005 American Institute of Physics.