Justification is given for the application of Poynting’s theorem in electrodynamis to magnetic/magnetohydrodynamic turbulence. This completes a theoretical approach to magnetic turbulence (Treumann and Baumjohann, 2017) where Poynting’s theorem was used but was not proved. It enables determination of the complete non-compressive nonlinear turbulent response function from measurement of magnetic and electric power spectral densities in turbulence, when excluding compressive magnetic fluctuations. It also enables experimental determination of a “dispersion relation” in magnetic turbulence, which is the nonlinear relation between temporal and spatial scales in the magnetic turbulent eddies, not a solution of an eigenvalue problem.
R. Treumann and W. Baumjohann
Fri, 15 Sep 17
Comments: 4 pages, no figures, Brief communication