Measurements of Ionospherically Relevant Ion-Ion and Ion-Neutral Cross Sections

We present experimentally determined ion-ion and ion-neutral collisional cross-sections for various ionospheric compositions at different altitudes, conducted in a laboratory environment. Cross-section measurements were performed on the Space and Beam Experiment (SABER) at West Virginia University using an ion gun to accelerate H2_22​, O2_22​, He, Ar, N2_22​, and NO ions. The ions are directed through a gas mixture and the transmitted current collected with a Faraday cup. To recreate the conditions and composition of the ionosphere at various altitudes, an array of mass flow controllers were employed controlling the H2​, O2​, He, Ar, N2, and NO composition. Additionally, a helicon source is used to produce levels of ionization corresponding to the ionospheric altitude being simulated. Current models of ionospheric ion-neutral collision frequencies show significant variability compared to estimates derived from radar observations. Accurate measurements of these collision cross-sections are crucial for developing more accurate models of Magnetosphere-Ionosphere-Thermosphere coupling.