Comments on the merging of nonantiparallel magnetic fields


  • S. W. H. Cowley


Until recently it was commonly believed that when nonantiparallel magnetic fields merge at a current sheet, the geometry must be such that their components parallel to the X line are equal. This condition imposes severe restraints on the merging process when the fields are of unequal magnitude. Two recent calculations, however, strongly suggest that this hypothesis is not correct. It is found that while the incoming field components perpendicular to the X line must reverse across the current sheet, the change in the parallel component is arbitrary.