[SLAC] [SLAC Pubs and Reports]

Studies of Nonlinear QED in Collisions of 46.6 GeV Electrons with Intense Laser Pulses


We report on measurements of quantum electrodynamic processes in an intense electromagnetic wave, where nonlinear effects (both multiphoton and vacuum polarization) are prominent. Nonlinear Compton scattering and electron-positron pair production have been observed in collisions of 46.6 GeV and 49.1 GeV electrons of the Final Focus Test Beam at SLAC with terawatt pulses of 1053 nm and 527 nm wavelengths from a Nd:glass laser. Peak laser intensities of approximately 0.5 x 1018 W/cm2 have been achieved, corresponding to a value of approximately 0.4 for the parameter eta = eErms=momegac, and to a value of approximately 0.25 for the parameter Upsilone = E*rms/Ecrit = eE*rmsh/m2c3, where E*rms is the rms electric field strength of the laser in the electron rest frame. We present data on the scattered electron spectra arising from nonlinear Compton scattering with up to four photons absorbed from the field. A convolved spectrum of the forward high energy photons is also given. The observed positron production rate depends on the fifth power of the laser intensity, as expected for a process where five photons are absorbed from the field. The positrons are interpreted as arising from the collision of a high-energy Compton scattered photon with the laser beam. The results are found to be in agreement with theoretical predictions.

Full Text


Compressed PostScript

Not available for this document.


The PDF version of this document was distilled from a PostScript file most likely created from LaTeX source which used Type 3 fonts. The resultant PDF may be unreadable on the screen at the default viewing magnification (fonts will appear bitmapped, jagged), though the type will be legible at higher magnifications.

Despite the cosmetic problems resulting from the use Type 3 fonts in the original source file, such PDF files print without problems; likewise, the onscreen text is searchable and selectable.

More Information

Full bibliographic data for this document, including its complete author list, is (or soon will be) available from SLAC's SPIRES-HEP Database.

Please report problems with this file to posting@slac.stanford.edu. The SLAC preprint inventory is provided by the SLAC Technical Publications Department.
Page generated 05 Jan 2006 @ 16:19 PST by htmlme.pl