On the angular momentum transferred during electromagnetic energy absorption and emission

In the framework of classical electrodynamics, the angular momentum transported into (and/or from) a volume bounded by a rotational surface is derived. The dependences of electromagnetic field on space and time, and also the electromagnetic properties of the interacting masses are arbitrary. The results may be useful for the theory of toroidal currents induced by high-frequency heating of plasmas. A connection with the Manley-Rowe equations is given.