  Directed energy phased array (DEPA) systems have been proposed for novel
applications such as beaming optical power for electrical use on remote
sensors, rovers, spacecraft and future moon bases, as well as planetary defense
against asteroids and photonic propulsion up to relativistic speeds. All such
scenarios involve transmission through atmosphere and beam perturbations due to
turbulence which must be quantified. Numerical beam propagation and feedback
control simulations were performed using an algorithm optimized for efficient
calculation of real-time beam dynamics in a Kolmogorov atmosphere. Results were
used to quantify the effectiveness of the system design with different degrees
of atmospheric turbulence and zenith angles, and it was found that a large
aperture DEPA system placed at a high altitude site is capable of producing a
stable diffraction limited spot (Strehl > 0.8) on space-based targets for Fried
length r_0 > 10 cm (@500nm) and zenith angles up to 60 degrees depending on
atmospheric conditions. These results are promising for the next generation of
power beaming and deep space exploration applications.
