Electromagnetic induction noise in a towed electromagnetic streamer

We have examined the idea that a towed neutrally buoyant electromagnetic (EM) streamer suffers from noise induced according to Faraday’s law of induction. A simple analysis of a horizontal streamer in a constant uniform magnetic field determined that there was no induction noise. We have developed an experiment to measure the induced noise in a prototype EM streamer suspended in the Edinburgh FloWave tank, and we subjected it to water flow along its length and to waves propagating in the same direction, at 45° and 90° to the streamer direction. The noise level was found to increase with increasing flow velocity. The motion of the prototype EM streamer in response to parallel constant current flow and wave motion was found to generate significant noise. The main finding is that wave motion was the major source of noise and was much larger than the noise of a static cable. The noise level can probably be reduced by towing the cable deeper and increasing the cable tension.