Electron cyclotron resonance

A free electron in a static and uniform magnetic field will move in a circle due to the Lorentz force.

The angular frequency (ω = 2πf ) of this cyclotron motion for a given magnetic field strength B is given (in SI units)[1] by where

These properties make electron cyclotron heating a very valuable research tool for energy transport studies.

Since the early 1980s, following the award-winning pioneering work done by Dr. Richard Geller,[2] Dr. Claude Lyneis, and Dr. H. Postma;[3] respectively from French Atomic Energy Commission, Lawrence Berkeley National Laboratory and the Oak Ridge National Laboratory, the use of electron cyclotron resonance for efficient plasma generation, especially to obtain large numbers of multiply charged ions, has acquired a unique importance in various technological fields.

The alternating electric field of the microwaves is set to be synchronous with the gyration period of the free electrons of the gas, and increases their perpendicular kinetic energy.

The ions produced correspond to the gas type used, which may be pure, a compound, or vapour of a solid or liquid material.

The VENUS ECR ion source at Lawrence Berkeley National Laboratory has produced in intensity of 0.25 mA (electrical) of Bi29+.

Cyclotron resonance is therefore a useful technique to measure effective mass and Fermi surface cross-section in solids.

When these conditions are satisfied, an electron will complete its cyclotron orbit without engaging in a collision, at which point it is said to be in a well-defined Landau level.

Example of cyclotron resonance between a charged particle and linearly polarized electric field (shown in green). The position vs. time (top panel) is shown as a red trace and the velocity vs. time (bottom panel) is shown as a blue trace. The background magnetic field is directed out towards the observer. Note that the circularly polarized example below assumes there is no Lorentz force due to the wave magnetic field acting on the charged particle. This is equivalent to saying that the charged particle's velocity orthogonal to the wave magnetic field is zero.
Example of cyclotron resonance between a charged particle and circularly polarized electric field (shown in green). The position vs. time (top panel) is shown as a red trace and the velocity vs. time (bottom panel) is shown as a blue trace. The background magnetic field is directed out towards the observer. Note that the circularly polarized example below assumes there is no Lorentz force due to the wave magnetic field acting on the charged particle. This is equivalent to saying that the charged particle's velocity orthogonal to the wave magnetic field is zero.