What is the ruling of Islamic law regarding a married woman asking about the permissibility of imagining intercourse with her imprisoned husband to alleviate sexual desire, and about the permissibility of masturbation for the same reason, and about the authenticity of the Prophetic Hadith: "Whoever imagines a woman has committed fornication with her"?

The questioner is advised to be patient with what she is going through and to utilize her time for good deeds, such as reading the Holy Quran, learning about the biography of the Prophet Muhammad (peace be upon him) and the righteous, and associating with righteous women. There is no harm in a woman imagining her husband, as long as it is not accompanied by masturbation. As for the mentioned hadith (definition), it has not been found.