Transverse expansion of the electron sheath during laser acceleration of protons
Journal article, 2017

The transverse expansion of the electrostatic sheath during target normal sheath acceleration of protons is investigated experimentally using a setup with two synchronized laser pulses. With the pulses spatially separated by less than three laser spot diameters, the resulting proton beam profiles become elliptical. By introducing a small intensity difference between the two pulses, the ellipses are rotated by a certain angle, except if the spatial separation of the two laser pulses is in the plane of incidence. The rotation angle is shown to depend on the relative intensity of the two pulses. The observed effects are found to require high temporal contrasts of the laser pulses. A simple model describing how the transverse shape of the electron sheath on the rear of the target depends on the relative intensity between the foci is presented. The model assumptions are verified, and the unknown dependence of the transverse extents of the sheaths are estimated self-consistently through a series of high resolution, two-dimensional particle-in-cell simulations. The results predicted by the model are also shown to be consistent with those obtained from the experiment.

Author

Krister Svensson

Lund University

Felix Mackenroth

Chalmers, Physics, Theoretical Physics

Max Planck Society

L. Senje

Lund University

Arkady Gonoskov

Chalmers, Physics, Theoretical Physics

Christopher Harvey

Chalmers, Physics, Theoretical Physics

B. Aurand

Heinrich Heine University Düsseldorf

Lund University

M. Hansson

Lund University

A. Higginson

University of Strathclyde

M. Dalui

Lund University

O. Lundh

Lund University

P. McKenna

University of Strathclyde

A. Persson

Lund University

Mattias Marklund

Chalmers, Physics, Theoretical Physics

C.G. Wahlström

Lund University

Physics of Plasmas

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

Vol. 24 12 123109

Subject Categories

Physical Sciences

DOI

10.1063/1.5010173

More information

Latest update

6/15/2018