Electromagnetic Fields and Waves, 3rd Edition

CHAPTER 4

STATIC MAGNETIC FIELDS

4.1 INTRODUCTION

The static electric field is produced by stationary charges whereas static magnetic field is produced by steady currents. The movement of charges with constant velocity gives rise to constant current flow, i.e., direct current, which in turn results in static or steady magnetic field. Such a static magnetic field is also called magnetostatic field. The study of magnetic field begins with the discussion of two major laws, namely, Biot–Savart’s law and Ampere’s law, which govern magnetostatic fields. Biot–Savart’s law is the general law of magnetostatics which is similar to Coulomb’s law in electrostatics. Ampere’s law is a special case of Biot–Savart’s law and is similar to Gauss’s law in electrostatics. ...