The director configuration of disclination lines in nematic liquid crystals
in the presence of an external magnetic field is evaluated. Our method is a
combination of a polynomial expansion for the director and of further
analytical approximations which are tested against a numerical shooting method.
The results are particularly simple when the elastic constants are equal, but
we discuss the general case of elastic anisotropy. The director field is
continuous everywhere apart from a straight line segment whose length depends
on the value of the magnetic field. This indicates the possibility of an
elongated defect core for disclination lines in nematics due to an external
magnetic field.Comment: 12 pages, Revtex, 8 postscript figure