Wiggler (synchrotron)

A wiggler is an insertion device in a synchrotron radiation source. It is a series of magnets with alternating polarity designed to force a beam of charged particles, typically electrons or positrons, to follow a sinusoidal trajectory. This periodic deflection causes the particles to emit electromagnetic radiation, particularly in the X-ray and extreme ultraviolet regions of the spectrum.

Compared to bending magnets, which also produce synchrotron radiation, wigglers generate a higher intensity and broader spectrum of radiation. This is because the radiation emitted at each bend constructively interferes, leading to a significantly increased flux (number of photons per unit time). The wiggler's magnetic field is typically stronger than that of a bending magnet, resulting in a shorter wavelength of emitted radiation.

The main parameters characterizing a wiggler include the magnetic field strength, the period of the magnetic field (the distance between two consecutive poles of the same polarity), and the number of periods. These parameters determine the energy, intensity, and angular distribution of the emitted radiation.

Wigglers are widely used in synchrotron radiation facilities for a variety of scientific applications, including X-ray absorption spectroscopy, X-ray diffraction, protein crystallography, and materials science research. They are a key component in providing high-brightness X-ray beams necessary for advanced research techniques. The enhanced radiation output enables experiments that require high photon flux and short exposure times.