8. (10 points) Two infinitely long, parallel wires are lying on the ground a distance \( a \) meter apart as shown in Figure 8. A third wire, of length \( L \) meter and mass \( m \) kg, carries a current of \( I{1} \) Ampere and is levitated above the first two wires, at a horizontal position midway between them. The infinitely long wires carry equal currents \( I{2} \) in the same direction, but in the direction opposite that in the levitated wire. What current \( (I_{2}) \) must the infinitely long wires carry so that the three wires form an equilateral triangle?