National Aeronautics and Space Administration

WAVES Instrument Overview

The WAVES instrument is a joint effort of the Paris-Meudon Observatory, the University of Minnesota, and the Goddard Space Flight Center.

WAVES block diagram

Sensors

1. Three electric dipolar antenna systems supplied by Fairchild Space (two are coplanar, orthogonal wire dipole antennas in the spin-plane, the other a rigid spin-axis dipole)
2. Three magnetic search coils mounted orthogonally (designed and built by the University of Iowa).

After preamplification, the sensor outputs are routed to the analysis electronics, consisting of a low frequency (DC - 10 kHz) FFT receiver, a broadband (4 kHz - 256 kHz) multi-channel analyzer designed principally to study the electron thermal noise, two dual radio receivers covering the band 20 kHz to 13.825 MHz, and a time-domain waveform sampler (sampling to 120,000/s).

The experiment is controlled by a central microprocessor (DPU) which will be used in flight to reconfigure the sensor outputs and to maximize the science return for the bit rate and power allotments that are available. A DC/DC power converter is also part of the electronics stack.

The frequency coverage is shown on the following plot:

Electronics

The principal characteristics of the analysis electronics are summarized below. The spin-plane electric antennas are referred to as Ex and Ey, the axial electric antenna as Ez and the 3 search coil magnetic axes as Bx, By and Bz.

Low Frequency FFT Receiver (FFT)

Thermal Noise Receiver (TNR)

Inputs	Ex, Ey, or Ez
Frequency range	4 kHz - 256 kHz
No. channels	32 or 16 per band (5 bands)
Bandwidth	400 Hz - 6.4 kHz
Sensitivity	7 nV/sqrt(Hz)

Radio Receiver Band 1 (RAD1)

Inputs	Ex+Ez, Ez
Frequency range	20 kHz - 1,040 kHz
No. channels	256
Bandwidth	3 kHz
Sensitivity	7 nV/sqrt(Hz)

Radio Receiver Band 2 (RAD2)

Inputs	Ey+Ez, Ez
Frequency range	1.075 MHz - 13.825 MHz
No. channels	256
Bandwidth	20 kHz
Sensitivity	7 nV/sqrt(Hz)

Time Domain Sampler (TDS)