The wave field experiment uses magnetic and electric sensors with wide frequency ranges that can work at high sampling rate. This allows to record the electromagnetic signal waveform observed in the ionosphere and to determine its frequency distribution.

The DEMETER novelty as compared to other missions studying the Earth radio environment is the detection and characterization of the transient very low frequency (VLF) electromagnetic phenomena. Thus, the instrument uses a neuronal network processing system.

The payload will work along two main modes :

Survey Mode
Beside the control analogical parameters, average and/or reduced scientific data are generated. On board processing are applied in order to reduce the transmitted flux in the mass memory (MM); the transferred data rate is about 25 kbits / second.
 
Burst Mode
The acquired scientific data are transmitted with very few or no processing. This high rate mode is mainly activated above seismic zones; the maximal rate is about 1.7 Mbits / second.

Characteristics of the mesured parameters by the different experiments on board DEMETER

Frequency range, B   10 Hz - 18 kHz   Frequency range, E   DC - 3 MHz   Sensitivity B :   1 10-5 nT Hz-1/2 at 1 kHz   Sensitivity E :   0.2 V Hz-1/2 at 500 kHz   Particules : electrons   30 keV - 10 MeV   Ion Density :   5 10² - 5 106 ions/cm³   Ion Temperature :   1000 K - 5000 K   Ion Composition :   H+, He+, O+, NO+   Electron Density :   10² - 5 106 cm-3   Electron Temperature :   500 K - 3000 K