A new determination of the local interstellar electron spectrum from the radio background

The relationship that exists among cosmic-ray electrons, the observed galactic RF background, and the magnetic fields in the Galaxy is investigated. The nature of the galactic magnetic field is shown to be the key to understanding the observed synchrotron radiation, since conservation of energy requires the synchrotron formulas to contain to good approximation the rms magnetic-field component rather than the average field component. A simple spectral normalization argument based on the measured electron spectrum at earth and recently obtained radio data is used to determine the electron spectrum just outside the solar cavity. This electron spectrum is found to be in good agreement with that deduced by employing an argument based on the observed secondary-positron/interstellar-electron ratio at earth.