Radiation Reaction in Intense Laser Interactions with Relativistic Electrons and Nonlinear Compton Scattering
Abstract
The main objective of this project is to study radiation reaction approaching the critical field strength of quantum electrodynamics. To do this we will exploit the fact that electric fields are not Lorentz invariant, so that a relativistic electron will experience a greatly boosted field strength in its rest frame. This leads to very strong radiation damping, i.e. significant energy loss into photons, and ultimately the decay of the photons into electron positron pairs in the strong fields by a multi photon Breit-Wheeler process. We will pursue an Òall-opticalÓ approach, using a laser- plasma based accelerator to generate electrons with near GeV energies and then collide the electron beam with a tightly focused pulse. Radiation damping is an interesting area of research because it has been scientifically controversial, but will be increasingly important for next generation high power laser systems. An ultra-relativistic electron beam will be generated by laser wakefield acceleration , which has previously demonstrated bunches of up to a 4.2 giga-electronvolt peak energy with approximately a nano-Coulomb of charge. Non-linear Compton backscattering of the accelerated electrons from a portion of the tightly focused HERCULES pulse should efficiently convert the electron beam energy into photons of energy greatly exceeding 10 MeV. One of the interesting phenomena arising from this laser-electron interaction is that the radiation forces are theoretically predicted to be so extreme that for a sufficiently intense laser, the electron beam may lose almost all its energy in the interaction time. This means that the radiation force is comparable to the accelerating force, which has the implication that the spectrum of the radiation should be strongly modified. If measured, this will provide a unique insight into strongly radiation damped electron dynamics. As the laser intensity approaches I = 10^22 Wcm?2, colliding with GeV energy electrons, we will also observe the onset of quantum effects such as stochastic energy loss and ÔstragglingÕ of the electron beam that are only now beginning to be understood theoretically. Due to the nature of the project being both laser and radiation source related, the training of graduate students will be relevant to both large scale laser facilities and radiation source facilities, and hence will prepare the next generation of young researchers for research at Army and other Department of Defense research laboratories. In addition, it could lead to the development of extremely bright, next generation photon sources for Army applications, such as directed energy and long range detection.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1610044
Entities
People
- Karl Krushelnick
Organizations
- Army Contracting Command
- United States Army
- University of Michigan