Laser-generated proton bunches from chirped laser-plasma interaction

Detailed single- and many-particle calculations are carried out for the acceleration of protons employing linearly-polarized plane-wave and tightly-focused chirped laser pulses of several ten to several hundred femtosecond durations, petawatt peak powers and relativistic peak intensities of the order of $10^{21}-10^{22}$~W/cm$^2$ [1,2]. Analytic and numerical methods of calculation are used in the single-particle cases (in vacuum), and particle-in-cell (pic) simulations (under-dense plasma) are employed in the many-particle investigations, without and with electromagnetic particle-particle interactions, respectively. Feasibility of generating ultra-intense ($10^7$ particles per bunch) and phase-space collimated beams of protons is demonstrated. Interaction of the protons with the quasi-static part of the laser pulse allows the particles to gain sufficient kinetic energy (around $250$ MeV) required for such applications as hadron cancer therapy.\\[4pt] [1] B.~J.~Galow, Y.~I.~Salamin, T.~V.~Liseykina, Z.~Harman, and C.~H.~Keitel, Phys. Rev. Lett. {\bf 107}, 185002 (2011)\\[0pt] [2] Y.~I.~Salamin, J.-X.~Li, B.~J.~Galow, Z.~Harman, and C.~H.~Keitel, submitted (2012)