*4.3. Simulations*

Simulations have been done using coil guns having one, two, three and four coils. As explained before, the overall quantity of copper and the global number of coil turns is a constant, as is the sum of the capacitors value. Delays and durations of each trigger pulses for each coil have been optimized manually in order to maximize the ball speed.

Results of simulation for an EML having one coil are presented in Figure 25. *Coil*<sup>1</sup> is triggered during 25 ms. Optimal initial position of the plunger is −92 mm. Ball speed reaches 13.45 m·s<sup>−</sup>1.

Results of simulation for an EML having two coils are presented in Figure 26. *Coil*<sup>1</sup> is triggered during 15 ms, *Coil*<sup>2</sup> is triggered during 14 ms with a delay of 10 ms. Optimal initial position of the plunger is −82 mm and optimal plunger extension length is 104 mm. Ball speed reaches 16 m·s<sup>−</sup>1.

Results of simulation for an EML having three coils are presented in Figure 27. *Coil*<sup>1</sup> is triggered during 10 ms, *Coil*<sup>2</sup> is triggered during 15 ms with a delay of 7 ms, *Coil*<sup>3</sup> is triggered during 12 ms with a delay of 11 ms. Optimal initial position of the plunger is −82 mm and optimal plunger extension length is 90 mm. Ball speed reaches 16.1 m·s<sup>−</sup>1.

Results of simulation for an EML having 4 coils are presented in Figure 28. *Coil*<sup>1</sup> is triggered during 10 ms, *Coil*<sup>2</sup> is triggered during 10 ms with a delay of 7 ms, *Coil*<sup>3</sup> is triggered during 12 ms with

a delay of 11 ms, *Coil*<sup>4</sup> is triggered during 14 ms with a delay of 15.5 ms. Optimal initial position of the plunger is −92 mm and optimal plunger extension length is 104 mm. Ball speed reaches 16.4 m·s<sup>−</sup>1.

**Figure 28.** Simulation of a four-coil EML used in an optimal way.
