Ondulație de undă
Conform principiului de incertitudine al lui Heisenberg, un fenomen fizic nu poate fi descris ca o particulă clasică sau ca o undă, ci ca dualitatea formată dintre cele două.
This parameter characterizes the nature of the electron motion. In this regime of fields the device is no longer called an undulator; it is called a wiggler. The key difference between undulator and wiggler is coherence.
Cât de frumoase sunt toate aceste tipuri de păr.
In the case of an undulator, the emitted radiation is coherent with a wavelength determined by the period length and the beam energy,  while in wiggler the ondulație de undă are not coherent. The usual description of the undulator is relativistic but classical.
The slit should be small enough such that only the main cone passes, and the side lobes of the wavelength spectra can be ignored. Undulators can provide several orders of magnitude higher flux than a simple bending magnet and as such are in high demand at synchrotron radiation facilities. The first factor of Ondulație de undă occurs because the intensity is enhanced up to a factor of N at harmonic wavelengths due to the constructive interference of the fields emitted during the N radiation periods.
The usual pulse is a sine with some envelope. When the electrons come with half the period, they interfere destructively, the undulator stays dark. The same cea mai bună investiție în internet true, if they come as a bead chain.
The polarization of the emitted radiation can be controlled by using permanent magnets to induce different periodic electron trajectories through the undulator. If the oscillations are confined to a plane the radiation will be linearly polarized.
If the oscillation trajectory is helical, the radiation will be circularly polarized, with the handedness determined by the helix. If the electrons follow the Poisson distribution a partial interference leads to a linear increase in intensity.
In the free electron laser  the intensity increases exponentially with the number of electrons. History[ edit ] The Russian physicist Vitaly Ginzburg showed theoretically that undulators could be built in a paper.
Necunoașterea celor mai bune instrumente pentru sarcina la îndemână poate transforma acest avantaj minunat într-un blestem.
Julian Schwinger published a useful paper in  that reduced the necessary calculations to Bessel functionsfor which there were tables. This was significant for solving the design equations as digital computers were not available to most academics at that time.
Hans Motz and his coworkers at Stanford University demonstrated the first undulator in The design could produce a total frequency range from visible light down to millimeter waves. Physical Review.
Bibcode : PhRv Journal of Applied Physics. Bibcode : JAP External links[ edit ] D. His lecture and viewgraphs are available online.