The Lagrangian for electromagnetic waves shows that its energy has a kinetic part as well as a potential part (just like everything else). The potential part only exists in a medium whereas in the vacuum all energy in electromagnetic waves are kinetic.

Similar formulation exists for mechanical (e.g. elastic) waves. In this case, I understand easily that the kinetic energy is simply the intensity of shaking/amplitude of waves (e.g. in an earthquake) whereas the potential energy is the so-called strain energy which is basically just the potential energy associated for a spring.

Returning back to electromagnetic waves, I can understand that the kinetic energy is, again, the amplitude of the waves that is manifested by e.g. light brightness or heat (which originates from the motion/collision of particles). However, I am having a hard time thinking of an intuitive interpretation for potential energy for electromagnetic waves. I only know that this only exists in non-vaccum space. So, what is the potential energy for all the electromagnetic waves we create here on earth, which are traveling in the air that is non-vaccum. Are there examples of familiar electromagnetic waves that does not have (or have very little) kinetic energy but is purely all potential energy?

The Lagrangian for electromagnetic waves shows that its energy has a kinetic part as well as a potential part (just like everything else). The potential part only exists in a medium whereas in the vacuum all energy in electromagnetic waves are kinetic.

Similar formulation exists for mechanical (e.g. elastic) waves. In this case, I understand easily that the kinetic energy is simply the intensity of shaking/amplitude of waves (e.g. in an earthquake) whereas the potential energy is the so-called strain energy which is basically just the potential energy associated for a spring.

Returning back to electromagnetic waves, I can understand that the kinetic energy is, again, the amplitude of the waves that is manifested by e.g. light brightness or heat (which originates from the motion/collision of particles). However, I am having a hard time thinking of an intuitive interpretation for potential energy for electromagnetic waves. I only know that this only exists in non-vacuum space. So, what is the potential energy for all the electromagnetic waves we create here on earth, which are traveling in the air that is non-vacuum. Are there examples of familiar electromagnetic waves that does not have (or have very little) kinetic energy but is purely all potential energy?

The Lagrangian for electromagnetic waves shows that its energy has a kinetic part as well as a potential part. The potential part only exists in a medium whereas in the vacuum all energy in electromagnetic waves are kinetic.

Similar formulation exists for mechanical (e.g. elastic) waves. In this case, I understand easily that the kinetic energy is simply the intensity of shaking/amplitude of waves (e.g. in an earthquake) whereas the potential energy is the so-called strain energy which is basically just the potential energy associated for a spring.

Returning back to electromagnetic waves, I can understand that the kinetic energy is, again, the amplitude of the waves that is manifested by e.g. light brightness or heat (which originates from the motion/collision of particles). However, I am having a hard time thinking of an intuitive interpretation for potential energy for electromagnetic waves. I only know that this only exists in non-vaccum space. So, what is the potential energy for all the electromagnetic waves we create here on earth, which are traveling in the air that is non-vaccum. Are there examples of familiar electromagnetic waves that does not have (or have very little) kinetic energy but is purely all potential energy?

The Lagrangian for electromagnetic waves shows that its energy has a kinetic part as well as a potential part (just like everything else). The potential part only exists in a medium whereas in the vacuum all energy in electromagnetic waves are kinetic.

Similar formulation exists for mechanical (e.g. elastic) waves. In this case, I understand easily that the kinetic energy is simply the intensity of shaking/amplitude of waves (e.g. in an earthquake) whereas the potential energy is the so-called strain energy which is basically just the potential energy associated for a spring.

Returning back to electromagnetic waves, I can understand that the kinetic energy is, again, the amplitude of the waves that is manifested by e.g. light brightness or heat (which originates from the motion/collision of particles). However, I am having a hard time thinking of an intuitive interpretation for potential energy for electromagnetic waves. I only know that this only exists in non-vaccum space. So, what is the potential energy for all the electromagnetic waves we create here on earth, which are traveling in the air that is non-vaccum. Are there examples of familiar electromagnetic waves that does not have (or have very little) kinetic energy but is purely all potential energy?