anchor.diff:  c
   c   nominal Earth parameters
   c
  -      sigma=6.0e+05     ! Core electrical conductivity in S/m
  -      rho=11.e+03       ! Core mean density in kg m^{-3}
  -      omega=7.2924e-05  ! Rotation angular frequency
  +      sigma=6.0e+05                 ! Core electrical conductivity in S/m
  +      rho=11.e+03                   ! Core mean density in kg m^{-3}
  +      omega=7.2924e-05              ! Rotation angular frequency
         escale=sqrt(rho*omega/sigma)  ! "Elsasser number" scaling
  -      re=6.371e+06      ! Earth radius in m
  -      rc=3.485e+06      ! Core radius in m
  -      ri=1.215e+06      ! Inner core radius in m
  -      cdepth=rc-ri      ! Depth of outer core
  -      rcre=rc/re        ! core/surface radius ratio
  -      rcsqinv=(cdepth/rc)**2  ! dim-less inverse squared core radius
  +      re=6.371e+06                  ! Earth radius in m
  +      rc=3.485e+06                  ! Core radius in m
  +      ri=1.215e+06                  ! Inner core radius in m
  +      cdepth=rc-ri                  ! Depth of outer core
  +      rcre=rc/re                    ! core/surface radius ratio
  +      rcsqinv=(cdepth/rc)**2        ! dim-less inverse squared core radius
   
   c
   c  write header to cc file
  
positive.code:       dimension la(nlma),ma(nlma)
        dimension alm(lmax,lmax),blm(lmax,lmax)
        dimension glm(lmax,lmax),hlm(lmax,lmax)
        dimension cc(2.*nlma)
  c
  c   constants
  c
  
negative.code:    36 continue
  c
  
  c separate the complex spherical harmonic coefficients
  c for the poloidal magnetic potential b(lm,1) into real and
  c imaginary part and assign two new indices
  c  
        do 37 lm=1,nlma
         c1=real(b(lm,1))
         c2=aimag(b(lm,1))
  