Extreme Solar Particle Storms: The hostile Sun

It is becoming increasingly clear that our modern technological society is vulnerable to the impacts of severe solar storms, as well as radiation, particle and geomagnetic disturbances. However, the potential severity of these extreme solar events and their probability of occurring are unknown. What can we expect from the Sun? What could the most severe solar particle storms look like? Does the Sun have an unlimited ability to produce severe storms? Can a destructive "black swan" event occu...