Sorry, that is complete bullsh.... Do not overreact in thinking, we all could understand how you feel, but this is no solution.
The effect of your "50 megaton experiment" would be theat the surviving fanatics would get even more fanatic. And within the next years you will have some more terrorist acts like the one that ahappend yeterday. It is should be easy for them to get a nulcear warhead in the former UdSSR. You have no sense of the way how Arabs think. For them it is a sacrifice to die in a holy war.
Every death became a hero, more death = more heros. It is more effective to eliminate the radical leaders and so the mass of senceless and stupid fanatics loose their "messias".
The only way to solve the problem in your way would be to erase all Arab countries from the map. This would cause millions of death and cause even more hate against America