NONINTRUSIVE METHOD FOR DETERMINING PLASMA PROFILES IN HYPERSONIC BOUNDARY LAYERS

COMPRISES IN WIND TUNNEL OPERATIONAL PARAMETERS, RELATIVE TO ACTUAL ATMOSPHERIC FLIGHT, AND INADEQUACINES IN NUMERICAL SIMULATIONS INDICATE THE REQUIREMENT FOR A NONINTRUSIVE DIAGNOSTIC TECHNIQUE WHICH CAN ENABLE PROFILES OF KEY PLASMA BOUNDARY LAYER PARAMETERS (E.E., ELECTRON DENSITY AND ELECTRON COLLISION FREQUENCY) TO BE DIRECTLY MEASURED IN REAL FLIGHT OR WIND TUNNEL ENVIRONMENT. WE PROPOSE AN INNOVATIVE APPROACH WHEREBY THE REQUIRED NONINTRUSIVE DIAGNOSITC TECHNIQUE RESULTS FROM THE ELECTROMAGNETIC PROBING OF HYPERSONIC BOUNDARY LAYERS, AND THE PLASMA SPATIAL PROFILES ARE ANALYTICALLY AND COMPUTATIONALLY RECONSTRUCTED FROM IMPEDANCE MEASUREMENTS. IN PHASE I, WE WILL DEMONSTRATE THE CONCEPT FEASIBILITYTHROUGH THE COMBINATION OF ANALYSIS, NUMERICAL COMPUTATIONS, AND EXPERIMENTS. PHASE II WILL INCLUDE EXPERIMENTAL DEMONSTRATION TESTS AND THE OPTIMIZATION OF COMPUTATIONAL ALGORITHMS FOR THE QUANTITATIVE DETERMINATION OF PLASMA SPATIAL PROFILES. THE PROPOSED TECHNIQUE COULD SIGNIFICANTLY ENHANCE THE BENCHMARK OF REAL GAS COMPUTATIONAL FLUID DYNAMIC (CFD) SIMULATION CODES, AND IT COULD ENABLE ON-LINE EVALUATIONS OF CRITICAL PLASMA PROPERTIES DURING WIND TUNNEL SIMULATED AND ACTUAL ATMOSPHERIC HYPERSONIC FLIGHT.