The FGM-I instrument on the Interball Tail Probe consists of a triaxial fluxgate magnetometer and a Langmuir split probe plasma current sensor. The analog signal is transmitted to the telemetry system and to the MIF-M filter bank.
Fields and waves are measured on the Tail Probe by the ASPI consortium of experiments, which includes: MIF-M -- fluxgate and search-coil magnetometers; FGM-I -- triaxial fluxgate sensor and plasma current sensor; OPERA -- a complex of electric field instruments; and PRAM -- the digital waveform processor unit. Two more ASPI instruments, ADS and IFPE, failed to switch on, likely due to hardware problems.
The FGMI magnetometer has the next parameters: measured range 0.3-37.5 nT, frequency range 0-2 Hz, sampling rate from 1/4 to 8 measurements per second.