TY - JOUR

T1 - Heavy ion acceleration in the radiation pressure acceleration and breakout afterburner regimes

AU - Petrov, G. M.

AU - McGuffey, C.

AU - Thomas, A. G. R.

AU - Krushelnick, K.

AU - Beg, F. N.

N1 - This is an author-created, un-copyedited version of an article accepted for publication/published in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: 10.1088/1361-6587/aa6f30

PY - 2017/7

Y1 - 2017/7

N2 - We present a theoretical study of heavy ion acceleration from ultrathin (20 nm) gold foil irradiated by high-intensity sub-picosecond lasers. Using two-dimensional particle-in-cell simulations, three laser systems are modeled that cover the range between femtosecond and picosecond pulses. By varying the laser pulse duration we observe a transition from radiation pressure acceleration (RPA) to the relativistic induced transparency (RIT) regime for heavy ions akin to light ions. The underlying physics of beam formation and acceleration is similar for light and heavy ions, however, nuances of the acceleration process make the heavy ions more challenging. A more detailed study involving variation of peak laser intensity I-0 and pulse duration tau(FWHM) revealed that the transition point from RPA to RIT regime depends on the peak laser intensity on target and occurs for pulse duration tau(RPA -> RIT)(FWHM) [fs] congruent to 210/root I-0 [W cm (2)]/10(21) The most abundant gold ion and charge-to-mass ratio are Au51+ and q/M approximate to 1/4, respectively, half that of light ions. For ultrathin foils, on the order of one skin depth, we established a linear scaling of the maximum energy per nucleon (E/M)(max) with (q/M)(max), which is more favorable than the quadratic one found previously. The numerical simulations predict heavy ion beams with very attractive properties for applications: high directionality (10(11) ions sr(-1)) and energy (>20 MeV/nucleon) from laser systems delivering >20 J of energy on target.

AB - We present a theoretical study of heavy ion acceleration from ultrathin (20 nm) gold foil irradiated by high-intensity sub-picosecond lasers. Using two-dimensional particle-in-cell simulations, three laser systems are modeled that cover the range between femtosecond and picosecond pulses. By varying the laser pulse duration we observe a transition from radiation pressure acceleration (RPA) to the relativistic induced transparency (RIT) regime for heavy ions akin to light ions. The underlying physics of beam formation and acceleration is similar for light and heavy ions, however, nuances of the acceleration process make the heavy ions more challenging. A more detailed study involving variation of peak laser intensity I-0 and pulse duration tau(FWHM) revealed that the transition point from RPA to RIT regime depends on the peak laser intensity on target and occurs for pulse duration tau(RPA -> RIT)(FWHM) [fs] congruent to 210/root I-0 [W cm (2)]/10(21) The most abundant gold ion and charge-to-mass ratio are Au51+ and q/M approximate to 1/4, respectively, half that of light ions. For ultrathin foils, on the order of one skin depth, we established a linear scaling of the maximum energy per nucleon (E/M)(max) with (q/M)(max), which is more favorable than the quadratic one found previously. The numerical simulations predict heavy ion beams with very attractive properties for applications: high directionality (10(11) ions sr(-1)) and energy (>20 MeV/nucleon) from laser systems delivering >20 J of energy on target.

KW - particle-in-cell

KW - short pulse lasers

KW - ion acceleration

KW - LASER-PLASMA INTERACTIONS

KW - IN-CELL SIMULATIONS

KW - PROTON GENERATION

KW - DRIVEN

KW - BEAMS

KW - ENERGY

U2 - 10.1088/1361-6587/aa6f30

DO - 10.1088/1361-6587/aa6f30

M3 - Journal article

VL - 59

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 7

M1 - 075003

ER -