New determination of the local interstellar electron spectrum from the radio background

Cosmic-ray electrons are believed to generate the observed galactic radio-frequency back-ground. Previous attempts in the literature to reconcile quantitatively the measured radio-frequency intensity with the intensity deduced from the electron spectrum measured at Earth have culminated in the problem that, to get the respective emissivities to agree, an unacceptably high interstellar B field must be chosen. In the light of new experimental data on the emissivity as deduced from H II region studies, we have reexamined closely the assumptions under which the electron emissivity comparison has been made. We resolve the disparity between predicted and measured emissivity by ascribing to the magnetic fields of the Galaxy a distribution of magnetic field strengths. From modified synchrotron formulae, the interstellar electron spectrum has been constructed from the radio-frequency emission data with greatly improved precision