Percent Integrated Gradient Field Ratio for hardat.ru3 at radius 0.0175 m. 
  where Integrated Gradient Field Ratio = Sum[(abs(Bn/B2*sin(-n*theta_south_pole ))] for harmonics 3-16  

    Imag        Integrated Gradient Field Ratio 
    (A)                         %                 
  ---------     ----------------------------------  
 -149.98398                    1.69784
 149.98693                    1.75441