Derivation of the Electromagnetic Wave Energy Density Formula

Within the framework of World Quantum Theory (WQT), this paper derives the electromagnetic wave energy density formula starting from the particle's own form energy V_e and run energy T_e. The electric field energy density is derived from form energy: u_E = V_e / Volume = (1/2)·ε₀·E² The magnetic field energy density is derived from run energy: u_B = T_e / Volume = B²/(2μ₀) The final formula: u = u_E + u_B = (1/2)·ε₀·E² + B²/(2μ₀) This is fully consistent with the standard physics formula. But the starting point of the derivation is different: standard physics starts from macroscopic models (capacitor, inductor), while this paper starts from the particle's own energy structure. The standard physics derivation relies on five unstated implicit premises; the derivation in this paper does not require these premises. The two 1/2 factors in the formula are treated as the same factor in standard physics; this paper reveals that their physical origins are different: the 1/2 in the electric channel comes from the ratio of form energy to electric energy (V_e/E_ε = 1/2), and the 1/2 in the magnetic channel comes from the ratio of magnetic energy to run energy (E_μ/T_e = 1/2). Keywords: electromagnetic wave energy density, form energy, run energy, implicit premises, derivation