ION acceleration by the space charge electric force arising from the radiation pressure in a magnetized electron-positron plasma

It is shown that ions can be accelerated by the space charge electric force arising from the separation of electrons and positrons due to the ponderomotive force of the magnetic field-aligned circularly polarized electromagnetic (CPEM) wave in a magnetized electron-positron-ion plasma. The ion acceleration critically depends on the external magnetic field strength. The result is useful in understanding differential ion acceleration in magnetized electron-positron-ion plasmas, such as those in magnetars and in some laboratory experiments that aim to mimic astrophysical environments.