What is the function of the alternating electric field in a cyclotron?

The function of the alternating electric field in a cyclotron is to accelerate charges as they cross the gap between the two D-shaped electrodes, known as 'dees.' When charged particles, such as ions or electrons, are injected into the cyclotron, they are subjected to a magnetic field that causes them to move in a circular path. As they move in that circular path, they periodically cross the gap between the dees.

The alternating electric field is synchronized with the motion of the particles, so when the charged particles enter the gap, the electric field is oriented in such a way that it pushes them forward, increasing their kinetic energy. This acceleration happens repeatedly every time the particles pass through the gap, enabling them to gain energy and spiral outward as they move in larger circles.

The effectiveness of this acceleration depends on the alternating nature of the electric field, which ensures that particles are continually energized with each crossing, thus facilitating a rapid buildup of energy. This principle is crucial for achieving the high energies required for various applications in particle physics and accelerators.