The three known property-specific definitions for forward and backward waves in various media and waveguides are reviewed. Criteria by which to distinguish between these waves according to their definitions are introduced. It is shown that using these criteria simultaneously can yield different or even opposite conclusions in some cases. When and where these criteria and the above definitions apply is discussed using electromagnetic waves and waveguides as an example.

PACS: 41.20.Jb, 78.20.Ci (all) DOI: 10.1070/PU2007v050n03ABEH006243 URL: https://ufn.ru/en/articles/2007/3/c/ 000248004300003 2-s2.0-34547491292 2007PhyU...50..287S Citation: Shevchenko V V "Forward and backward waves: three definitions and their interrelation and applicability" Phys. Usp. 50 287–292 (2007) BibTexBibNote ® (generic)BibNote ® (RIS)MedlineRefWorks Оригинал: Шевченко В В «Прямые и обратные волны: три определения, их взаимосвязь и условия применимости» УФН 177 301–306 (2007); DOI: 10.3367/UFNr.0177.200703c.0301