In designing this jet-injection mechanism, the engineers relied on what’s known as a Lorentz force actuator (Image 3). The Lorentz force actuator in this case is a small permanent magnet surrounded by a coil of wires. The coil of wires, or solenoid, is part of a piston system that is separate from the permanent magnet which lies in the center. If we recall from high school physics, we know that when a current is passed through the wires of a solenoid, the solenoid becomes an electromagnet which, in turn, creates its own magnetic field. Now, if this new field is opposite that of the permanent magnet, meaning if their fields repel, then a repulsive force will be established. This force will accelerate the piston towards the nozzle, creating a sudden change in pressure which then ejects the medicine out of the nozzle.