Linear Force-free Magnetic Fields and Coronal Models

Abstract

I am grateful to Dr N. Seehafer for drawing attention to the fact that the basis vector for writing linear force-free solutions in spherical geometry is the radius vector r and not the unit radius vector r. In order to correct the results given in Section 3 of Durrant (1989). it suffices to replace the spherical Bessel functions iI. ni, hI by riI. rnI. rhI. The only effect of this replacement is to change the radial dependence of B8 and Bef> in the limit of large r to eiOCr fr. Thus the total magnetic density for the exterior volume r> R is unbounded. This result is now consistent with the fact that the cartesian components of B satisfy the Helmholtz equation.