Capability Summary for the 200-kW Laser Enhanced Arc Jet Facility (LEAF)

The 200-kW Laser Enhanced Arc Jet Facility (LEAF) at the Interaction Heating Facility (IHF) arc jet at NASA Ames Research Center has enabled simultaneous radiative and convective heating of material samples at high heat flux levels. During LEAF operation, IHF can convectively heat material samples with heat fluxes up to 0.16 kW/cm2 using the conical 22.86-cm nozzle or up to 0.085 kW/cm2 using the semi-elliptic nozzle. The LEAF radiant heating capability consists of four 50-kW 1070-nm lasers, and each laser can be configured independently to a variety of beam shapes. In flat-top square configuration, irradiance levels of up to 0.1 kW/cm2 total have been demonstrated over a 43.2 x 43.2 cm area, and irradiance levels up to 0.4 kW/cm2 total have been demonstrated over a 15.2 x 15.2 cm area. In super-Gaussian configuration, LEAF can deliver a peak irradiance of up to 45 kW/cm2 total for a 1/e2 radius of 1.5 cm or up to 12 kW/cm2 total at a 1/e2 radius of 3 cm. Beam sizes between these two are also available. Recently expanded capabilities include the simultaneous operation of all four lasers in super-Gaussian configuration. This presentation includes measured irradiance values for flat-top square beam and super-Gaussian beam data taken over the lifetime of the LEAF system. The presentation also covers the two methods used for irradiance calibration: the lower irradiance water-cooled calibration plate with embedded Gardon gauges, and the higher irradiance optical beam profiling calibration with an infrared camera. Comparison between the two methods in the overlapping region gives confidence in both methods.