Two parallel, infinitely long, z-axis oriented conducting cylinders of radius "a" are a distance "b" apart. The cylinders are in a vacuum. They are directly alongside the z axis and equidistant from it in the y-z plane. The cylinder center to center distance "b" is much, much greater than "a". Both cylinders carry a current, "I", of the same magnitude but opposite direction. The current is flowing uniformly through the cross-section of the conductors. Find the approximate H field at x = 103 "b".