What is the punishment and expiation if a man has intercourse with his wife during her menstrual period?

Sexual intercourse with a menstruating woman is one of the gravest prohibitions and a major sin, for Allah the Almighty says: "And they ask you about menstruation. Say, 'It is a discomfort, so keep away from women during menstruation. And do not approach them until they are pure. And when they have purified themselves, then come to them from where Allah has ordained for you.' Indeed, Allah loves those who repent and loves those who purify themselves." The one who engages in intercourse must pay an expiation (kaffarah) of one dinar or half a dinar, or its equivalent in gold, or its value, along with repentance and seeking forgiveness. The expiation is also obligatory upon the woman who consents.