Number 201 (Story #2), November 3, 1994 by Phillip F. Schewe and Ben Stein MAGNETIC VORTEX LINES ARE INDEED LINES . The expected commercial use of ceramic superconductors in high-field magnets encourages scientists to find out what happens to the magnetic flux lines (from an external magnet) once they organize themselves into bundles as they penetrate the surface of a superconductor sample. If the magnetic field is too strong or if a current moving through the sample is too large, the flux lines inside the sample might begin to move about, causing a resistive dissipation of energy, defeating the whole reason for using superconducting materials if the first place. A new experiment at Harvard demonstrates that the vortex lines persist as relatively straight lines right through to the other side of the sample, and do not splay out into pancake shapes as some theorists had feared. The Harvard scientists used tiny magnetic particles to image the patterns of vortices at the top and bottom of the sample. They then deduced a correlation between the patterns. This information about the vortex geometry should aid in the attempt to preserve the superconducting state in the sample by pinning the vortex lines in place. (Zhen Yao et al., Nature, 27 October 1994.)