Definition:Abampere

Definition
The abampere is the CGS unrationalised electromagnetic base unit of electric current.

It is defined as being:


 * The constant current which will produce a force of attraction whose value is $2$ dynes per centimetre of length between two straight, parallel conductors of infinite length and of infinitesimal circular cross-section placed one centimetre apart in a vacuum.

By Force between Infinite Parallel Straight Conductors carrying Steady Current, we have:
 * $\mathbf F \propto \dfrac {2 I_1 I_2} r$

where:
 * $I_1$ and $I_2$ denote the current through the two conductors
 * $r$ denotes the distance between the two conductors.

In the CGS unrationalised electromagnetic system, the constant of proportion is taken to be $1$, hence:


 * $\mathbf F = \dfrac {2 I_1 I_2} r$