Caged men lift rocks, enthralling the setter in attractive region (8,5)

I believe the answer is:
magnetic field
'attractive region' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'caged men lift rocks enthralling the setter' is the wordplay.
'rocks' is an anagram indicator.
'enthralling' means one lot of letters goes inside another.
'the setter' becomes 'I' (the person who set this crossword).
'caged'+'men'+'lift'='cagedmenlift'
'cagedmenlift' anagrammed gives 'magneticfeld'.
'magneticfeld' going around 'i' is 'MAGNETIC FIELD'.
'in' is the link.
Can you help me to learn more?
(Other definitions for magnetic field that I've seen before include "It can pull some objects" , "Attractive area" .)
