- #1
kof9595995
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About whether energy is stored in the charge or the field, in Griffiths EM textbook, i found this:
"...(for electrostatics) it is unnecessary to worry about where the energy is located. In the context of radiation theory it is useful(and in General Relativity it is essential) to regard the energy as being stored in the field..."
I agree that in electrostatics there's no difference between these two opinions, but I always thought "field energy" should be essential in radiation, because a radiation source can pass its own energy to a test charge far away, since energy must be conserved locally, the energy has to be carried by something all the way to the test charge, but there's nothing but EM field between the source and test charge, so I concluded the energy must be stored in the EM field and transferred to the test charge.
However, according to Griffiths, even for radiation the "field energy" concept is just useful, not essential, and I can't figure out why he said that.
"...(for electrostatics) it is unnecessary to worry about where the energy is located. In the context of radiation theory it is useful(and in General Relativity it is essential) to regard the energy as being stored in the field..."
I agree that in electrostatics there's no difference between these two opinions, but I always thought "field energy" should be essential in radiation, because a radiation source can pass its own energy to a test charge far away, since energy must be conserved locally, the energy has to be carried by something all the way to the test charge, but there's nothing but EM field between the source and test charge, so I concluded the energy must be stored in the EM field and transferred to the test charge.
However, according to Griffiths, even for radiation the "field energy" concept is just useful, not essential, and I can't figure out why he said that.