Days later, supply energetic particles (5,4)

I believe the answer is:

delta rays

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'energetic particles' is the definition.
The answer and definition can be both natural objects as well as being plural nouns.
Maybe you can see a link between them that I don't see?

'days later supply' is the wordplay.
'supply' indicates anagramming the letters (in a supple way).
'days'+'later'='dayslater'
'dayslater' anagrammed gives 'DELTA RAYS'.

Can you help me to learn more?

I've seen this clue in The Independent.

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