High-resolution 2D magnetic field measurement of magnetic reconnection using printed-circuit board coils

2D high-resolution magnetic probe arrays for local 2D magnetic field measurements of magnetic reconnection have been developed using advanced printed-circuit board (PCB) technology. Each of these arrays can be equipped with all three components of magnetic pickup coils (5 × 3 mm²). Each coil is composed of a two-sided coil circuit pattern with a line width of 0.05 mm. Based on this new probe technique, we conducted high-resolution and high-accuracy measurements of the current sheet to determine the formation and ejection of plasmoid in a current sheet of two merging tokamak plasmas for the first time. (author)