One from Arctic in LA doubled power (4)
I believe the answer is:
lapp
'one from arctic' is the definition.
(someone from Lapland)
'la doubled power' is the wordplay.
'doubled' shows that letters should be duplicated.
'power' becomes 'p' (symbol in physics).
'p' duplicated is 'pp'.
'la'+'pp'='LAPP'
'in' is the link.
(Other definitions for lapp that I've seen before include "Native of N. Scandinavia" , "Northern European" , "Native of northern Scandinavia" , "Nomadic inhabitant of northern Scandinavia" , "Northern Scandinavian native" .)