Plasma Impedance Probe Analysis with a Finite Difference Time Domain Model

Summary form only given. Sweeping frequency plasma impedance probes have been flown on recent sounding rocket missions and also on the International Space Station. These plasma impedance probes have been used to (1) Characterize the low latitude ionosphere, (2) Study the descending layers in the E-region, (3) measure the electron temperature, density, and electron-neutral collision frequency within mid-latitude spread F and (4) measure the ambient plasma properties around the International Space Station. The impedance of the electrically short monopole, dipole or patch antenna used in these missions is determined by generating sweeps of radio frequencies between 200 kHz and 20 Mhz as the spacecraft travels through the ionospheric layers and measuring the current at the probe input terminals. The impedance data is analyzed using a plasma fluid finite difference time domain (PF-FDTD) model developed at Utah State University. In this study, the results of the PF-FDTD simulations are compared with the measured data obtained from the Sudden Atomic Layer (SAL) mission, which was launched as a part of the COQUI II campaign from Puerto Rico on 19 February 1998 at 2009 LT. The parameters that were to be determined were the electron plasma frequency, electron-neutral collision frequency, electron gyro frequency and the ambient magnetic field between 90 to 115 km attitudes. The simulations results of the PF-FDTD model and the impedance curves from the SAL rocket were found to be in close agreement and the ambient plasma electron density and electron collision frequency were able to be retrieved.