"Legends of Tomorrow" Season 2 Episode 7, "Invasion," will reveal the identity of the woman in Professor Stein's flashback. Apparently, the woman is an aberration from 1987.
In "Legends of Tomorrow" Season 2 Episode 6, "Outlaw Country," Professor Stein saw images of a woman during his headache spells. He told Jax that he does not know the woman, of course. However, what he knows for sure is that he is in love with her.
Now, the identity of this woman remains a mystery. Obviously, she is not Clarissa. She does not look like Professor Stein's wife.
Apparently, according to the premise for "Legends of Tomorrow" Season 2 Episode 7, Professor Stein created the woman when he manipulated with his past. She is the aberration from his past life, according to Movie Pilot. The woman appeared in the professor's flashback right after he interfered with his younger self in 1987.
To recap, in "Legends of Tomorrow" Season 2 Episode 5, "Compromised," Professor Stein meddled with his personal life, when the team travelled to 1987. He met his younger self and even danced with the then young Clarissa. He also told his young self not to mess up his marriage with Clarissa.
Of course, the young Professor Stein promised to treasure his wife more than his career. However, what if he did not keep his word? What if he and Clarissa eventually separated and then the young Stein met someone new? This new woman could be the person in old Stein's visions and someone he has yet to meet in "Legends of Tomorrow" Season 2 Episode 7.
Professor Stein may have inadvertently changed his past or future when he interacted with his young self. He already did this twice, so there is no telling what he had done to alter the events in his life. Fortunately, fans do not have to wait long to find out who the woman really is. In "Legends of Tomorrow" Season 2 Episode 7, the team will travel back to 2016. There Stein will find out if there is even a Clarissa waiting for him.