Objectives of Laser-Induced Energy Deposition for Active Flow Control

A highly concentrated energy deposition has been proposed for a flow control concept in super- and hypersonic transportation. The plasma source can be implemented by laser-, microwave- or DC-discharge phenomena in the flow field upstream of a blunt body. In a wide range of Mach numbers the thermal modification of the gas condition mitigates the strength of the shock waves and improves the aerodynamic performance. This paper presents a discussion of the methodology and objectives of laser-induced energy deposition particularly with regard to the generation of laser-sustained plasma in supersonics. A steady-state argon plasma is maintained by an intensity field in the focal region of a continuous wave laser. The experimental results using drag, laser energy transmission and plasma radiation measurements determine the requirements for laser-sustained plasma and validate the control authority of this concept