Note on the positiveness of magnetic energy stored in the Wire-SRR metamaterial

TL;DR

This paper proves that the magnetic energy density in wire-SRR metamaterials is positive definite, confirming the physical validity of the energy density formula for these complex electromagnetic structures.

Contribution

It demonstrates the positive definiteness of the magnetic energy density in wire-SRR metamaterials, clarifying a previously uncertain aspect of their electromagnetic energy storage.

Findings

Magnetic energy density in wire-SRR metamaterials is positive definite.

Supports the validity of the energy density formula for these metamaterials.

Clarifies the physical interpretation of electromagnetic energy in complex media.

Abstract

Recently, a new energy density formula for electromagnetic waves in the metamaterial consisting of arrays of conducting wires and split-ring-resonators (SRR) has been derived [Phys. Rev. E 80, 046601 (2009), arXiv:0909.1043]. According to that formula, the positiveness is obvious for the electric part of the energy density but not clear for the magnetic part. In this paper, I show that the magnetic energy density is also positively definite.