a type of particle accelerator in which the particles spiral inside two D-shaped hollow metal electrodes placed facing each other under the effect of a strong vertical magnetic field, gaining energy by a high-frequency voltage applied between these electrodes

a circular particle accelerator for positively charged ions (usually protons, deuterons, and alpha particles), normally used to initiate nuclear transformations upon collision with a suitable target: through the combined action of a constant magnetic field with an oscillating electrostatic field across two D-shaped, hollow electrodes, it causes a particle to move in an increasingly large spiral path inside the electrodes with increasing kinetic energy and velocity