Magnetic intensification of spectral lines

We present an in-depth investigation of the increase in equivalent width of saturated lines under the influence of strong magnetic fields, aptly called "magnetic intensification". Assuming 20 different Zeeman patterns (with the number of components ranging from 3 to 45) for a fictitious Fe II line at 4500 ? in a 10 000 K, log g=4.0 Kurucz atmosphere, we calculate equivalent widths as a function of magnetic field strength, field angle and line strength (abundance). The increase over the zero field equivalent width is found to always fall below the n/2 relation suggested by Babcock (1949), where n is the number of Zeeman components. After a discussion of the behaviour of various Zeeman patterns we turn to the influence of anomalous dispersion on magnetic intensification. Changes in line blanketing due to magnetic desaturation appear to be of negligible size. Finally we show that magnetic intensification leads to apparent enhanced abundances and to virtual abundance variations in magnetic stars with dipolar surface magnetic field configurations.