Flux of IS CR electrons (black solid line) as a function of energy. Data: Voyager 1 (Cummings et al. 2016, solid purple squares) at low energies, AMS-02 (Aguilar et al. 2014, solid cyan circles) at high energies. The red, blue, and green thick lines show the energy range that mostly contributes to synchrotron emission in the frequency range of SKA for the values of the magnetic field strength listed in the legend (see Eq. (7)). The orange dashed line shows the CR electron-positron flux obtained from Galactic synchrotron emission (Orlando 2018).