It is difficult to determine which one has a stronger magnetic field as it depends on various factors such as the size and shape of the torus and bolt, the type and amount of current passing through, and the material used for construction. In general, torus-shaped objects tend to have stronger magnetic fields due to their curved shape, which allows for a more concentrated flow of current. However, a bolt with a larger diameter and higher current can also produce a strong magnetic field. Ultimately, it would be best to consult a physicist or conduct experiments to determine the specific strength of the magnetic fields for each object.