Direct Laser Ion Acceleration and Above-Threshold Ionization at Intensities from $10^{21}$ W/cm${}^2$ to $3\times 10^{23}$ W/cm${}^2$

Abstract

Calculations on the dynamics of ions and electrons in near-infrared laser fields at intensities up to $3\times 10^{23}$ W/cm${}^2$ are presented. We explore the acceleration of ions in a laser focus by conservation of canonical momentum during ionization events and by the ponderomotive force in the f/1 focal geometry required to reach such intensity. At intensity exceeding 10${}^{23}$ W/cm${}^2$, highly charged ions are expelled from the laser focus before they can interact with the laser pulse at peak intensity, decreasing the predicted ionization yields of deeply-bound states. We consider the interaction of a tightly-focused, f/1 laser pulse with krypton at an intensity of $3\times 10^{23}$ W/cm${}^2$ and a pulse duration of 140 fs. We find that the ions and electrons are accelerated to energies in excess of 2 MeV/nucleon and 1.4 GeV, respectively. Ponderomotive expulsion of the parent ions decreases the total number of ultra-relativistic ATI electrons produced by tunneling ionization from the K-shell states of krypton but does not change their energy spectrum.

V2: Typos corrected, references added. Some explanation in the Ionization Dynamics and Discussion Sections are added

References in corpus (3)

• Radiation Reaction Effects on Radiation Pressure Acceleration
• Electron acceleration driven by ultrashort and nonparaxial radially polarized laser pulses
• Beam Distortion Effects upon focusing an ultrashort Petawatt Laser Pulse to greater than 10${}^{22}$ W/cm${}^2$