How can I draw my ampere loop on the picture below, to show how the MMF distribution is between the blue dots in my first paint drawing?
I'm not sure you can.
Sorry i didn't have a good answer yesterday - i struggle for words and it sometimes takes days to find them.
Now since the purple flux is so much larger than that taking the red or green path we can ignore them.
But it's interesting academic exercise to calculate the mmf out there.
I still think it'd be a summation of individual mmf from each wire
or from each turn as in that first paper.
Note as observer's distance from solenoid increases, the distance from opposite sides becomes more nearly the same so the red and green mmf's cancel more and more. So MMF and flux outside drops rapidly .as one moves away from the solenoid.
Correct me if my thinking is not straight.