Cavity magnetron

A vacuum tube that generates high-power microwaves as electrons moving in a magnetic field transfer energy to electromagnetic fields resonating in metal cavities.

Crossed-field device: An electron device in which electric and magnetic fields act at right angles to each other. The magnetron’s electron motion is governed by perpendicular electric and magnetic fields.
Thermionic emission: The release of electrons from a heated material when they gain enough energy to escape its surface. A heated cathode supplies the electrons that the magnetron accelerates and bunches.
Albert Hull: An American physicist and engineer who developed early magnetron designs at General Electric. Hull’s 1921 device established the magnetron principle before cavity designs emerged.
Radar: A system that detects objects by transmitting radio waves and analyzing their reflections. Cavity magnetrons made compact, high-power microwave transmitters practical for radar.
Klystron: A vacuum tube that amplifies or generates microwave signals through electron bunching in resonant cavities. Unlike the magnetron’s self-oscillating crossed-field operation, a klystron uses velocity-modulated electron beams.
Magnetron electron spokes: Rotating bunches of electrons that form in a magnetron’s interaction space under crossed electric and magnetic fields. These bunches transfer energy to the radio-frequency fields in the cavities.
Lorentz force: The force on a charged particle due to electric and magnetic fields. It determines how the electric and magnetic fields bend electron paths inside the tube.
Cavity magnetron development: The 1930s development of multi-cavity magnetrons that produced powerful microwave oscillations. This advance transformed the magnetron from a weak oscillator into a practical microwave source.
Microwave oven: An appliance that heats food by exposing it to microwave electromagnetic radiation. A cavity magnetron is the microwave source in many conventional ovens.
Traveling-wave tube: A vacuum electronic amplifier that transfers energy between an electron beam and a traveling electromagnetic wave. It amplifies a propagating wave rather than generating output through coupled magnetron cavities.

Linked from 2 pages