Plasma impedance probe analysis with a finite difference time domain simulation

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 frequency voltages 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 the 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^th February, 1998 at 2009 LT. The parameters that were to be determined were the electron plasma frequency, electron gyro frequency and the ambient magnetic field in the altitude range of 90 – 115 Kms.