https://doi.org/10.1140/epjc/s10052-014-2998-9
Regular Article - Theoretical Physics
Impulsive cylindrical gravitational wave: one possible radiative form emitted from cosmic strings and corresponding electromagnetic response
1
Department of Physics, Chongqing University, Chongqing, 400044, People’s Republic of China
2
College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, People’s Republic of China
* e-mail: fangyuli@cqu.edu.cn
Received:
30
March
2014
Accepted:
25
July
2014
Published online:
20
August
2014
The cosmic strings (CSs) may be one type of important source of gravitational waves (GWs), and it has been intensively studied due to its special properties such as the cylindrical symmetry. The CSs would generate not only usual continuous GWs, but also impulsive GWs that bring about a more concentrated energy and consist of different GW components, broadly covering low-, intermediate- and high-frequency bands simultaneously. These features might underlie interesting electromagnetic (EM) responses to these GWs generated by the CSs. In this paper, with novel results and effects, we firstly calculate the analytical solutions of perturbed EM fields caused by the interaction between impulsive cylindrical GWs (which would be one of possible forms emitted from CSs) and background celestial high magnetic fields or widespread cosmological background magnetic fields, by using the exact form of the Einstein–Rosen metric rather than the planar approximation usually applied. The results show that perturbed EM fields are also in the impulsive form in accordant to the GW pulse, and the asymptotic behaviors of the perturbed EM fields are fully consistent with the asymptotic behaviors of the energy density, energy flux density, and Riemann curvature tensor of the corresponding impulsive cylindrical GWs. The analytical solutions naturally give rise to the accumulation effect (due to the synchro-propagation of perturbed EM fields and the GW pulse, because of their identical propagating velocities, i.e., the speed of light), which is proportional to the 
. Based on this accumulation effect, in consideration of very widely existing background galactic–extragalactic magnetic fields in all galaxies and galaxy clusters, we for the first time predict potentially observable effects in the region of the Earth caused by the EM response to GWs from the CSs.
© SIF and Springer-Verlag Berlin Heidelberg, 2014
