Europhys. Lett.
Volume 70, Number 3, May 2005
Page(s) 327 - 333
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 06 April 2005
Europhys. Lett., 70 (3), pp. 327-333 (2005)
DOI: 10.1209/epl/i2004-10503-0

The intense radiation gas

M. Marklund1, 2, 3, P. K. Shukla1, 2, 3 and B. Eliasson3

1  Department of Physics, Umeå University - SE-901 87 Umeå, Sweden
2  Centre for Fundamental Physics, Rutherford Appleton Laboratory Chilton Didcot, Oxfordshire, OX11 0QX, UK
3  Institut für Theoretische Physik IV, Fakultät für Physik und Astronomie Ruhr-Universität Bochum - D-44780 Bochum, Germany

received 13 December 2004; accepted in final form 18 March 2005
published online 6 April 2005

We present a new dispersion relation for photons that are nonlinearly interacting with a radiation gas of arbitrary intensity due to photon-photon scattering. It is found that the photon phase velocity decreases with increasing radiation intensity, and it attains a minimum value in the limit of super-intense fields. By using Hamilton's ray equations, a self-consistent kinetic theory for interacting photons is formulated. The interaction between an electromagnetic pulse and the radiation gas is shown to produce pulse self-compression and nonlinear saturation. Implications of our new results are discussed.

42.55.Vc - X- and gamma-ray lasers.
12.20.Ds - Quantum electrodynamics: Specific calculations.
95.30.-k - Fundamental aspects of astrophysics.

© EDP Sciences 2005