As carbonaceous chondrites are the least thermally-evolved and hence the most primitive of the meteorites, their residual magnetization can, in principle, be used to estimate the intensity of the magnetic field in the primordial solar nebular, which varies between 0.2 and 1 G (refs 1-4), and could be as high as 2-3 G (ref. 4). The presence of palaeomagnetic fields of such magnitude is of importance in reconstructing the early history of the Solar System and of planetary formation. Levy and Sonnet5, for example, have stressed this point in comparing the respective merits of four alternative sources of the primordial magnetic field. They claim only two of these are possible: (1) a large solar magnetic field spread into the solar nebula; (2) a hydromagnetic dynamo field generated in the solar nebula itself. We show here that there is in fact a further possibility that fits the requirements for strong magnetic field generation and energetic particle irradiation of the grains6: Magnetic field enhancement at the point of stagnation between the solar nebula and the intense solar outflows. This mechanism, which involves the interaction of the T-Tauri wind with the solar nebular, is straightforward and is supported by results from recent space research.