Energy Storage In Electric Fields

Will magnetic fields store more energy than electric fields? How?

Magnetic field can store 25,000 times more energy than electric field because 1) When energy is stored in form of electric flux (usually in capacitive devices ) more chances are there to form an internal closed path for electrons . As the electric charges (represents poles for origin of electric flux) are mobile they can flow internally leads in dissipation of stored power . 2) In magnetic flux storage device ( mostly in Inductive devices ) magnetic north (N) & magnetic south poles are immobile e. the cannot form an internal magnetic circuit . Even if the change in external conditions occur , according to lenz law , the magnetic flux wil try to oppose the changes in it. hence their storing capacity is observed much higher than the electric flux storage devices.

How does an electric field store energy?

Strictly speaking, the energy does not come from the electric field itself. The energy is the interaction energy between the electromagnetic field and charges. The electric field has the ability to do work on charges, by accelerating them. In the case of a capacitor, the charges accumulate on the capacitor plates, but opposite charges are prevented from moving closer to each other by the presence of the insulator between the plates. As the plates become charged, it becomes harder and harder to push more charges to them, so work is invested. The mutual repulsion of like charges, manifested by their combined electrostatic field, is like a spring that stores energy when it is compressed. Once you provide a path for opposite charges to move and cancel each other, even if the path is through a complicated circuit, move they will, in the process canceling out the field that made them move in the first place. Free electric fields can also do work, but differently. As a free electric field diminishes, it creates a magnetic field. The magnetic field, in turn, as it diminishes, creates an electric field. This back-and-forth process propagates at the velocity of light; this is what we call electromagnetic radiation. Ultimately, this radiation may be absorbed by charges that move in response to the changing electric and magnetic fields (so once again, work is being done), canceling out those fields in the process.

How can the capacitor store the energy in an electric field and the inductor in a magnetic field? How does this process really works?

The capacitor, when charged, has two parallel plates (considering it is a parallel plate capacitor) one positively charged and the other negatively, both kept at a very close distance.So you can imagine with tons of positive charges, so close to all those electrons, the attraction force creates a huge potential energy. This energy is used to do work when the plates are connected together with a conductor and possibly a load (much like a battery).In case of an inductor, one needs to understand that inductor opposes change of current that is flowing through it. If one reads Faraday’s Law:“The most widespread version of Faraday's law states: The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit.”it becomes clear that if the current changes in an inductor, the inductor induces a reverse E.M.F (voltage basically) and hence it tries to oppose this change of current by apparently sending in a reverse current.Ideally, the inductor is supposed to send exactly that much amount of current which completely nullifies the change of current (and hence the change of flux). Hence ideally current in an inductor never drops to zero, and because a charge in motion generates a magnetic field, the inductor stores energy as magnetic field (electric current is charge in motion).It is worth noticing that energy stored in a capacitor is static, charges are not in motion, while energy stored in an inductor is dynamic.