  Current and field profiles, and magnetization and ac losses are calculated
for arrays of infinitely long superconducting tapes in the critical state in a
perpendicularly applied magnetic field. The tapes are arranged both
horizontally and in a matrix configuration, which is the geometry found in many
actual high-T_c superconducting tapes. The finite thickness of the tapes and
the effects of demagnetizing fields are considered. Systematic results for the
magnetization and ac losses of the tapes are obtained as function of the
geometry and separation of the constituent tapes. Results allow to understand
some unexplained features observed in experiments, as well as to propose some
future directions.
