Energy of a charge configuration

[zwoodrow]

Im rereading griffiths electrodynamics and noticed all the derivations of energy to assemble a given charge config assume you can bring charges in from infinity and stick them down. In reality if you tried this inevitable some of the particles would accelerate away or towards the incoming charge- they would radiate during acceleration - energy would go missing. How to deal with this.

 

[AJ Bentley]

I don't understand - why do you need to 'deal with it'. It's a mathematical construction - a thought experiment.
It wouldn't be practical to actually assemble a charge configuration that way - you just pointed out why.

 

[zwoodrow]

I just answered my own question- the energy released in assemble a charge or current configuration is represented bythe poynting vector.

 

[Academic]

A key to the idea, what AJ Bentley is talking about, is that you bring in the charges slowly and steadily such that they don't radiate energy. Its a thought experiment on what determines the energy of a charge configuration, radiated energy has nothing to do with it.