Source of spectators' impulse to create powerful rush (5)
I believe the answer is:
surge
'powerful rush' is the definition.
'surge' can be an answer for 'rush' (synonyms). I'm not sure about the 'powerful' bit.
'source of spectators' impulse' is the wordplay.
'source of' suggests taking the first letters.
'impulse' becomes 'urge' (synonyms).
The initial letter of 'spectators' is 's'.
's'+'urge'='SURGE'
'to create' is the link.
Can you help me to learn more?
(Other definitions for surge that I've seen before include "crest of a wave" , "A great wave" , "significant increase" , "Rapid increase; powerful movement" , "Jerk" .)