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ELECTROMAGNETIC BOUNDARY CONDITIONS

Practical electromagnetic theory problems almost always involve materiał media and/or

finite boundaries. To solve such problems we need firstly a knowledge of how materiał

media react to the internal electromagnetic fields within them, and a knowledge of electromagnetic

boundary conditions. It is the objective of this chapter to give a comprehensive treatment of the latter topie.

Practical electromagnetic theory problems almost invariably also involve both finite geometries, and discontinuities between the parameters characterising the medium in one

section and those pertaining in another.

In a formal sense electromagnetic boundary conditions are required so that Solutions to Maxwell's equations in differential form, which Solutions involve the usual arbitrary

constants, may be suitably matched as we cross such boundaries.

In a less formal sense, our knowledge of electromagnetic boundary conditions is required

for another purpose. Any thorough understanding of electromagnetic theory must be based on a series of mental pictures of the possible electromagnetic field configurations

which can occur in various geometries. Our knowledge of the requirements on electromagnetic

field components at various piane boundaries, and in particular at metallic boundaries, is necessary for firstly the visualisationand secondly the validity checking of

such potentially correct field pictures.

It might be said that the source and vortex interpretation of Maxwell's equations in differential form, and a knowledge of the shortly to be derived results on boundary conditions, is with experience sufficient in most cases for the construction of a qualitatively

correct field solution without detailed mathematical investigation.