Gyrotron
Understanding Gyrotrons
Gyrotrons are unique because they operate at frequencies far above what conventional vacuum tubes (klystrons, TWTAs) can reach at high power. No other technology produces megawatt-level power at millimeter-wave frequencies. Gyrotrons are essential for fusion research, where they heat plasma to 100+ million degrees.
How Gyrotrons Work
- An electron beam is generated and compressed by a strong magnetic field.
- Electrons spiral in the magnetic field at the cyclotron frequency (proportional to magnetic field strength).
- A resonant cavity is tuned near the cyclotron frequency.
- The spiraling electrons transfer energy to the electromagnetic field in the cavity.
- The generated mmWave power couples out through a window.
Gyrotron Applications
- Fusion energy: ECRH (Electron Cyclotron Resonance Heating) in tokamaks. 1-2 MW per tube at 100-170 GHz.
- Industrial: Ceramic sintering, material processing at mmWave.
- Defense: Active Denial System (non-lethal crowd control at 95 GHz).
Frequently Asked Questions
What is a gyrotron?
A gyrotron generates high-power mmWave radiation using cyclotron resonance of electrons in a magnetic field. It produces 100 kW to multi-MW at 30-300+ GHz. No other device generates this much power at these frequencies. Used for fusion plasma heating.
How much power can a gyrotron produce?
A single gyrotron produces up to 2 MW CW at 170 GHz. Fusion reactors use arrays of gyrotrons totaling 20-60 MW of mmWave power. This is many orders of magnitude beyond any solid-state source at these frequencies.
What is ECRH?
Electron Cyclotron Resonance Heating uses gyrotron-generated mmWave beams to heat plasma electrons in a fusion reactor. The mmWave frequency matches the electron cyclotron resonance in the magnetic confinement field, enabling efficient energy transfer.