Transport AC Loss Measurements in Single- and Two-Layer Parallel Coated Conductor Arrays With Low Turn Numbers

We measure transport ac losses in planar one-layer four-turn parallel coated conductor arrays (1 × 4) and in two-layer (2L) four-turn parallel coated conductor arrays (2 × 4) with a frequency up to 1 kHz. The horizontal separation between the conductors, i.e., g_h, and the vertical separation between the neighboring superconducting layers, i.e., g_v, were varied to investigate the transport ac loss dependence on g_h and g_v. In 2L arrays, the tapes in the top layer sit either aligned with the tapes in the bottom layer or aligned with the gaps between the tapes in the bottom layer. We show that the losses differently scale in arrays with low turn numbers to the scaling expected with an infinite array of tapes.