Fig. 12.16. The isosensitivity lines for a unipolar single-coil magnetometer of Figure 12.15; the coil radius is 10 mm, and the volume conductor is cylindrically symmetric. The vertical axis indicates the distance h from the magnetometer and the horizontal axis the radial distance r from the symmetry axis. The symmetry axis, drawn with a thick dashed line, is the zero sensitivity line. Thin solid lines represent lead field current flow lines.