Effects of atmospheric turbulence on the GENIE nulling interferometer

Two competitive design studies for the Ground-based European Nulling Interferometer Experiment (GENIE) have recently been initiated by the European Space Agency and the European Southern Observatory. A major issue in these studies is the influence of atmospheric turbulence on the performance of the instrument, and how atmospheric effects can be compensated in order to reach the goal performance (detection of faint exozodiacal clouds). In this paper, we review the main atmospheric processes affecting a nulling interferometer and discuss possible ways to reduce them by means of real-time control systems. Preliminary performance estimates of GENIE are then presented. The effects of the thermal background and its fluctuations (Absil & Bakker 2004) are not considered here.