I have been musing a question for a week. Does an EMP from a nuke blast slowly subside, or does it abruptly end? And is there a formula for the size of a weapon correlating to the radius of the EMP? Is there any difference for an EMP with a dirty bomb compared to a non dirty bomb. Thanks!
If you are talking about a low tech dirty nuclear bomb, then you are talking about a conventional explosion laced with various nuke materials and nuke waste to polute the hell out of an area.... no EMP involved. . A true EMP enhanced weapon would be a nuke explosion at high atmosphere to get maximum EMP effect. Lower the weapons burst the lower the coverage area. This is a high tech nuke weapon.
Nuclear Weapon EMP Effects The initial EMP pulse is very short, but there are many other effects. This fairly lengthy article explains just about all of it.
I always thought it was pretty quick and then over with no lingering 'pulses'. I'll have to defer to others for the rest of your questions.
The matter which should concern most is the more "natural" EMP provided by the sun itself. These types of EM waves generally are not as predictable and tend to cause serious problems when they occur under the right conditions. If, we say...a certain HAARP array were utilized to create a "hole" in the ionosphere, and this coincided with a strong solar flare, under certain conditions, this would be catastrophic. Something to consider.