Impressed by onset of emotional charge (8)
I believe the answer is:
stampede
'charge' is the definition.
(I've seen this before)
'impressed by onset of emotional' is the wordplay.
'impressed' becomes 'stamped' (stamping is a kind of impressing).
'by' means one lot of letters go next to another.
'onset of' says to take the initial letters.
The initial letter of 'emotional' is 'e'.
'stamped'+'e'='STAMPEDE'
(Other definitions for stampede that I've seen before include "herd scatter wildly" , "Sudden dash of a group of startled animals" , "Put to flight" , "Pasted me (anag.)" , "Sudden rush of people" .)