磁気単極子
{ ( ∇ 2 − 1 c 2 ∂ 2 ∂ t 2 ) φ e = − ρ e ε 0 ( ∇ 2 − 1 c 2 ∂ 2 ∂ t 2 ) φ m = − ρ m μ 0 ( ∇ 2 − 1 c 2 ∂ 2 ∂ t 2 ) A e = − μ 0 J e ( ∇ 2 − 1 c 2 ∂ 2 ∂ t 2 ) A m = − ε 0 J m {\displaystyle {\begin{cases}{\begin{aligned}\left(\nabla ^{2}-{\dfrac {1}{c^{2}}}{\dfrac {\partial ^{2}}{\partial t^{2}}}\right)\phi _{\mathrm {e} }&=-{\dfrac {\rho _{\mathrm {e} }}{\varepsilon _{0}}}\\\left(\nabla ^{2}-{\dfrac {1}{c^{2}}}{\dfrac {\partial ^{2}}{\partial t^{2}}}\right)\phi _{\mathrm {m} }&=-{\dfrac {\rho _{\mathrm {m} }}{\mu _{0}}}\\\left(\nabla ^{2}-{\dfrac {1}{c^{2}}}{\dfrac {\partial ^{2}}{\partial t^{2}}}\right){\boldsymbol {A}}_{\mathrm {e} }&=-\mu _{0}{\boldsymbol {J}}_{\mathrm {e} }\\\left(\nabla ^{2}-{\dfrac {1}{c^{2}}}{\dfrac {\partial ^{2}}{\partial t^{2}}}\right){\boldsymbol {A}}_{\mathrm {m} }&=-\varepsilon _{0}{\boldsymbol {J}}_{\mathrm {m} }\end{aligned}}\end{cases}}}