Magnetic moment and external fields is not part of this internal energy. The unit for magnetic moment in terms of the International System of Units (SI) base units is A⋅m, where A is the ampere (the SI unit of current) and m is the meter (the SI unit of distance). This has equivalents in other units used in SI including: where N is the newton (the SI unit of force), T is the tesla (the SI unit of magnetic flux density), and J is the joule (the SI unit of energy). In the CGS system, there are several different sets of electromagnetism
Magnetic flux space (and time) is associated with a vector that determines what force a moving charge would experience at that point (see Lorentz force). Since a vector field is quite difficult to visualize at first, in elementary physics one may instead visualize this field with field lines. The magnetic flux through some surface, in this simplified picture, is proportional to the number of field lines passing through that surface (in some contexts, the flux may be defined to be precisely the number of field lines passing through that surface; although technically misleading, this distinction is not important). Note that the magnetic