X-ray generation in an ion channel

Abstract

X-ray generation by relativistic electrons in an ion channel is studied. The emission process is analyzed in the regime of high harmonic generation when the plasma wiggler strength is large. Like for the conventional free electron laser, the synchrotron-like broadband spectrum is generated in this regime. An asymptotic expression for the radiation spectrum of the spontaneous emission is derived. The radiation spectrum emitted from an axisymmetric monoenergetic electron beam is analyzed. The stimulated emission in the ion channel is studied and the gain of the ion-channel synchrotron-radiation laser is calculated. It is shown that the use of laser-produced ion channels leads to a much higher power of x-ray radiation than the one in a self-generated channel. In addition, the mean photon energy, the number of emitted photons and the brilliance of the photon beam increase dramatically. Three-dimensional particle-in-cell simulations of a 25-GeV electron bunch propagating in a laser-produced ion channel are made. Several GeV γ-quants are produced in a good agreement with the analytical results.

Radiation-Reaction Trapping of Electrons in Extreme Laser Fields

“…Laser intensities up to 10 22 W=cm 2 have been demonstrated [1] and are expected to surpass 10 23 W=cm 2 in the course of several ongoing projects and initiatives [2,3]. At this intensity level, the laser-plasma interaction will be prompted to the exotic near-QED regime [4][5][6][7][8][9][10].…”

Advanced Channeling Technologies in Plasma and Laser Fields

“…However, on the contrary to channeling radiation in crystals when the electron is considered to be free along the channel direction (the continuous crystal potentials are transverse coordinate dependent), in our case, the electron is accelerated down the channel and known in literature as betatron radiation at laser wakefield acceleration 3 [27,92,93]. The latter results in shifting the projectile's frequency for transverse oscillations during the electron channeling in a plasma-ion channel, and thus, the radiation spectrum becomes changed [94].…”

“…Moreover, the phenomenology of beams channeling becomes very useful to describe neutral beams handling via various beam guiding structures [18,19]. Besides, channeling conditions could be realized for particles not only in medium (crystals [20], capillaries [21,22] and nanotubes [23][24][25], plasma [26][27][28][29]) but also in high intensity electromagnetic fields of specific configurations [30].…”

Positron Production by X Rays Emitted by Betatron Motion in a Plasma Wiggler

“…[15], which is well suited for a high-K wiggler. When K 1, only certain phases along the betatron trajectory contribute to the observed spectrum in the far field.…”

“…These phases correspond to the maximum positive and negative displacement regions of the electron trajectory where the acceleration is the greatest and, locally, the momentum vector of the electron is pointing towards the converter target in the far field. By Taylor expanding the electron orbit around each of these contributing phases or ''saddle points'' [15] we calculate the total spectrum as the sum of the ''synchrotronlike'' bursts at each saddle point. The result gives the energy per unit frequency per unit solid angle (…”