2008/09/19 by T. J. M. Boyd, Thomas J. Boyd, R. Ondarza-Rovira
Engineering · Physics and Astronomy · #Atomic physics #Cutoff #Electron #Harmonic #Intensity (physics) #Laser #Laser-Matter Interactions and Applications #Laser-Plasma Interactions and Diagnostics #Laser-induced spectroscopy and plasma #Physics #Plasma #Quantum electrodynamics #Quantum mechanics #Range (aeronautics) #Scaling #Scaling law #Spectral density #Statistics #physics.plasm-ph
paper · pdf · doi:10.1103/physrevlett.101.125004
published as Phys. Rev. Lett. 101, 125004 (2008) · 5 pages, 4 figures
openalex publication_date 2008/09/19 · arxiv created 2008/10/03 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Laser light incident on targets at intensities such that the electron dynamics is ultrarelativistic gives rise to a harmonic power spectrum extending to high orders and characterized by a relatively slow decay with the harmonic number m that follows a power law dependence, m(-p). Relativistic similarity theory predicts a universal value for p=8/3 up to some cutoff m=m*. The results presented in this Letter suggest that under conditions in which plasma effects contribute to the emission spectrum, the extent of this contribution may invalidate the concept of universal decay. We report a decay with the harmonic number in the ultrarelativistic range characterized by an index 5/3 < or approximately p < or approximately 7/3, significantly weaker than that predicted by the similarity model.