Conceptual design of the end mirror set, FINAL REPORT for Deliverable (a).2.1 EFDA Task TW3-TPHE-ECHULB4

The work of this task is performed in close collaboration with the FOM institute, responsible for the mm-wave layout for the RS launcher. The task goal is a conceptually consistent design for the fixed mirrors. In this work: - The cross-correlations between beam optics, geometry and mechanical constraints are examined in a comprehensive way, in order to extract the main parameters concurring to the performances of the launcher, which are evaluated in terms of the merit parameters given by physics analysis (f). - The beam transversal dimension in the plasma region where the current have to be driven has been identified to be directly related to the mirror focal length together with steering range (not independently). - Mirror position, launching angles, and optimisation distances are strictly related; feedback between changes and results is required during optimization. - The concept of virtual rotation point from which all the beams are apparently coming is introduced and discussed - The astigmatic beam option is evaluated; the effect of a change of the steering plane is evidenced