With the magnetic injection system that we currently have, we must inject lines or combs in order to see the magnetic coupling in DARM in a reasonable time. We would like to probe more of the coupling spectrum using bands rather than lines, especially since the coupling functions are more complex now that coupling is dominated by cable and connector coupling instead of coupling to permanent magnets.  In order to inject larger fields we have prototyped a large coil.

The coil is a rounded square 16’ feet on edge that is bent around the corner of the wall in the LVEA. The coil is about 30m +X and 30m +Y of the vertex (Figure 1). The coil consists of about 5000’ of 10 gauge plastic-insulated copper wire, giving 80 turns and 5 ohms of resistance. The coil is held by four 90-degree-turn cable tray segments attached at studs, and two bars that extend out from the corner of the wall at the top and bottom. We wound the coil from the ground using a system illustrated in this video: https://youtu.be/OdJbYw1uyow

Figure 2 shows that we were able to produce several times greater fields at the vertex than for our standard PEM injections, even though the big coil was further away than the 1m coil for the standard Y-manifold PEM injections.

Figure 3 shows broad band injections with the 5m coil that are, in some frequency bands, comparable in amplitude to the comb injected by the 1m coil.

Philippe N., Kara M., Richard M., Mark D., Tyler G., Robert S.