In a cyclotron, I understand that a uniform magnetic field is used, oriented perpendicular to the plane in which the particles accelerate. This field is created by two cylindrical permanent magnets whose opposite poles face each other,as I understand it. What formula(e) determine the strength (flux density) of the field, based on parameters such as radius, height, separation distance, material, and temperature. The plane of acceleration for the particles is assumed to be the halfway point between the two magnets. I could not find a full concise answer for this online, and since I have few resources outside of that, this is my go to when google fails. Thanks for the help.