Proton acceleration by a pair of successive ultraintense femtosecond laser pulses
Artikel i vetenskaplig tidskrift, 2018

We investigate the target normal sheath acceleration of protons in thin aluminum targets irradiated at a relativistic intensity by two time-separated ultrashort (35 fs) laser pulses. When the full-energy laser pulse is temporally split into two identical half-energy pulses, and using target thicknesses of 3 and 6 μm, we observe experimentally that the second half-pulse boosts the maximum energy and charge of the proton beam produced by the first half-pulse for time delays below ∼0.6-1 ps. Using two-dimensional particle-in-cell simulations, we examine the variation of the proton energy spectra with respect to the time-delay between the two pulses. We demonstrate that the expansion of the target front surface caused by the first pulse significantly enhances the hot-electron generation by the second pulse arriving after a few hundreds of fs time delay. This enhancement, however, does not suffice to further accelerate the fastest protons driven by the first pulse once three-dimensional quenching effects have set in. This implies a limit to the maximum time delay that leads to proton energy enhancement, which we theoretically determine.

Författare

Julien Ferri

Chalmers, Fysik, Subatomär fysik och plasmafysik

L. Senje

Lunds universitet

M. Dalui

Lunds universitet

Krister Svensson

Lunds universitet

B. Aurand

Lunds universitet

M. Hansson

Lunds universitet

A. Persson

Lunds universitet

O. Lundh

Lunds universitet

C.G. Wahlström

Lunds universitet

Laurent Gremillet

Le Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA)

Evangelos Siminos

Göteborgs universitet

Timothy Dubois

Chalmers, Fysik, Subatomär fysik och plasmafysik

Longqing Yi

Chalmers, Fysik, Subatomär fysik och plasmafysik

Joana Luís Martins

Chalmers, Fysik, Subatomär fysik och plasmafysik

Tünde Fülöp

Chalmers, Fysik, Subatomär fysik och plasmafysik

Physics of Plasmas

1070-664X (ISSN) 1089-7674 (eISSN)

Vol. 25 4 043115

Ämneskategorier

Acceleratorfysik och instrumentering

Atom- och molekylfysik och optik

Annan fysik

DOI

10.1063/1.5026391