Ferromagnetic atom guide within situloading

Magneto-optic and magnetostatic trapping is realized near a surface using current carrying coils wrapped around magnetizable cores, with up to ${10}^9$ cesium atoms. Ramping up the current while maintaining optical dissipation leads to tightly confined atom clouds with an aspect ratio of 1:1000. We study the three-dimensional character of the magnetic potential and characterize the atom number and density as functions of the applied current. The field gradient in the transverse dimension has been varied from $<10\mathrm{}\mathrm{G}/\mathrm{c}\mathrm{m}$ to $>1\mathrm{}\mathrm{k}\mathrm{G}/\mathrm{c}\mathrm{m}.$