ABSTRACT
This chapter presents fundamental theoretical foundations for magnetostatics, most importantly Ampere’s law. It examines some simple and commonly encountered examples, such as calculation of the magnetic field inside a coaxial cable. The chapter provides a few common applications, such as Hall element sensors, magnetic storage, and magnetic-resonance imaging medical imaging. The magnetic flux density is produced by current-carrying conductors or by permanent magnets. Ampere’s law is not a new property of the magnetic field-it follows from the Biot-Savart law, which in turn is based on experiment. If a body is placed in a magnetic field, magnetic forces act on all moving charges within the atoms of the material. These moving charges make the atoms and molecules inside the material look like tiny current loops. In the absence of an external magnetic field, atoms and molecules of many materials have no magnetic moment. Such materials are referred to as diamagnetic materials.
