SDI experiments will explore viability of ground-based laser

A ground-based free-electron laser technical integration experiment (GBFEL/TIE) is planned for the White Sands Missile Range to test the feasibility of operation of a ground-based FEL with hundreds of megawatts of power in SDI applications. The staged experiment will begin with a modest power ND-YAG laser and eventually test an induction-powered FEL. An RF-powered unit is also receiving consideration for the full-scale tests. The FEL is to be about 1.8 km long and will include a wiggler about 200 m long and a vacuum tunnel to permit the beam to diffuse by diffraction to avoid damaging the beam optics. Phenomena to be studied in the tests are Raman scattering, thermal blooming, ionization of the air and the effects of atmospheric turbulence. Attempts will be made to compensate for atmospheric effects by sending a calibrated laser beam from space to the facility to measure atmospheric distortions, then distorting the FEL beam to compensate for the atmospheric effects. RFPs are soon to be issued for managing the integration of the facilities.