Magnetic fields in the megagauss range have been measured in experiments on plasmas generated by irradiating targets with high power lasers. A study of the morphology of these self‐generated fields is important not only for its intrinsic interest but for possible implications in laser–target physics. In this paper work on the numerical modeling of large magnetic fields generated in target experiments is reported. The results show generally satisfactory agreement with the fields measured experimentally both in terms of the magnitude of the peak fields and their morphology. In the numerical model the contribution from the Hall term in describing the evolution of the magnetic field is shown to be important especially in short pulse (&bartil;100 psec) experiments.