> What are the prior probabilities that the system was exposed to "intense radiation"?
I suggest trying to fly with a Geiger counter. At the cruise altitude you have something like 15-20x the normal background level, when flying over the pole it can rise to 30x.
It's actually not caused by the solar radiation, it's too weak to reach the flight level. It is caused by cosmic rays, and the solar activity modulates how much of the cosmic radiation reaches the lower levels of the atmosphere.
I suggest trying to fly with a Geiger counter. At the cruise altitude you have something like 15-20x the normal background level, when flying over the pole it can rise to 30x.
It's actually not caused by the solar radiation, it's too weak to reach the flight level. It is caused by cosmic rays, and the solar activity modulates how much of the cosmic radiation reaches the lower levels of the atmosphere.