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The Time‐space‐dependent Power Spectrum for the Description of Nonstationary and Inhomogeneous Electromagnetic Fields
Author(s) -
Ponath H.E.,
Schubert M.
Publication year - 1980
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19804920204
Subject(s) - physics , fourier transform , amplitude , spectral density , electromagnetic field , space (punctuation) , spectrum (functional analysis) , field (mathematics) , connection (principal bundle) , limiting , space time , mathematical analysis , statistical physics , quantum mechanics , mathematics , pure mathematics , computer science , geometry , mechanical engineering , statistics , chemical engineering , engineering , operating system
The nonstationary analogue to the stationary Wiener Khintchine theorem is considered and applied to the multi‐dimensional case of temporally nonstationary and spatially inhomogeneous electromagnetic fields. The time‐space‐dependent power spectrum of these fields is introduced, and its connection with important measurable quantities is discussed. The dispersions relations (the mutual dependence of the Fourier variables ω, k belonging to the time and space coordinates t , ) are included into the consideration. The variable Fourier amplitudes are compared with the conventionally used slowly varying field amplitudes. The transition to the stationary limiting case is carried out.