ampere per square metre

SI coherent derived unit

Name	Symbol	Quantity	Base units
ampere per square metre	m⁻² A	current density	m⁻² A
The ampere per square metre, symbol m⁻² A, is the SI coherent derived unit of current density. An electric current of one ampere flowing through a cross-sectional area of one square metre of a conductor has a current density of one ampere per square metre.
Definition			c^-2 Δν_Cs³ e
$1 \mspace{4mu} \text{m}^{-2} \mspace{4mu} \text{A} \mspace{6mu} = \dfrac{(299 \mspace{4mu} 792 \mspace{4mu} 458)^2}{(9 \mspace{4mu} 192 \mspace{4mu} 631 \mspace{4mu} 770)^3(1.602 \mspace{4mu} 176 \mspace{4mu} 634 \times 10^{-19})} \mspace{6mu} \dfrac{{\Delta \nu _{Cs}}^3 \mspace{4mu} e}{c^2}\\ \\ \\ 1 \mspace{4mu} \text{m}^{-2} \mspace{4mu} \text{A} \mspace{6mu} \approx 7.221 \mspace{4mu} 234 \mspace{4mu} 035 \mspace{4mu} 654 \mspace{4mu} 436 \mspace{4mu} 424 \times10^{5} \mspace{6mu} c^{-2} \mspace{4mu} {\Delta \nu _{Cs}}^3 \mspace{4mu} e$

Electromagnetism

Current density is the electric current per unit area of cross section.

The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the charges at this point.