The importance of the ''magnetic'' components of gravitational waves in the response functions of interferometers

With an enlighting analysis, Baskaran and Grishchuk have recently shown the presence and importance of the so-called ``magnetic'' components of gravitational waves (GWs), which have to be taken into account in the context of the total response functions of interferometers for GWs propagating from arbitrary directions. In this paper more detailed angular and frequency dependences of the response functions for the magnetic components are given in the approximation of wavelength much larger than the linear dimensions of the interferometer, with a specific application to the parameters of the LIGO and Virgo interferometers. Our results agree with the work of Baskaran and Grishchuk in which it has been shown that the identification of ``electric'' and ``magnetic'' contributions is unambiguous in the long-wavelength approximation. At the end of this paper the angular and frequency dependences of the total response functions of the LIGO and Virgo interferometers are given. In the high-frequency regime the division on ``electric'' and ``magnetic'' components becomes ambiguous, thus the full theory of gravitational waves has to be used. Our results are consistent with the ones of Baskaran and Grishchuk in this case too.