Gyrotron

A gyrotron is a type of high-power vacuum electronic device that generates millimeter-wave electromagnetic waves. It functions similarly to a magnetron but uses a larger cavity and a higher magnetic field. Electrons are accelerated to relativistic energies and then interact with a resonant cavity in the presence of a strong magnetic field. This interaction causes the electrons to gyrate, or spiral, and in doing so, they transfer their energy to the electromagnetic field in the cavity, producing microwave radiation.

The output frequency of a gyrotron is determined by the magnetic field strength and the electron beam's energy. By adjusting these parameters, gyrotrons can be tuned to produce frequencies in the millimeter and sub-millimeter wave range. They are known for their ability to produce very high power outputs, often in the megawatt range, and high efficiencies.

Gyrotrons find their primary applications in areas requiring intense millimeter-wave radiation. A significant application is in nuclear fusion research, specifically for electron cyclotron resonance heating (ECRH) of plasma in tokamaks and stellarators. They are also used in industrial processing, such as the curing of polymers and the sintering of ceramics, as well as in scientific research, including spectroscopy and materials science. The development of gyrotrons has been crucial for advancing these fields.