Federico BONI, Viviana LAGO, Benjamin KHIAR
DOI Number: N/A
Conference number: HiSST-2025-342
In this work, the design, manufacturing, and validation of a new high-frequency curling probe operating near 20 GHz is presented. This probe is capable of accessing electron densities in the 1012 – 1014 cm-3 range, typical of atmospheric re-entry plasmas. A new interpretation model, accounting for collisional effects in high-density plasmas, is developed and validated through 3D electromagnetic simulations of the probe frequency response. For the first time, the curling probe diagnostic is deployed in a high-enthalpy supersonic plasma wind tunnel (PHEDRA facility at ICARE Laboratory in Orléans, France) to characterize electron density across the shock layer of a coin-shaped model under re-entry relevant conditions. Boron nitride protective coatings have allowed the probes to withstand cumulative plasma exposure of 30 minutes under thermal fluxes of 200–300 kW/m² and gas temperatures of thousand kelvins. Curling probe measurements provided integral electron densities across several millimeters of the shock layer, yielding values on the order of 1013 cm-3. These results are in fair to good agreement with cylindrical Langmuir probe results and consistent with complementary direct Monte Carlo simulations of the plasma flow. These findings demonstrate the feasibility and robustness of curling probe for diagnosing high-density plasmas in re-entry conditions, highlighting their potential for
advanced ground-based experimental campaigns and for future in-flight applications.