Transverse expansion of the electron sheath during laser acceleration of protons

Svensson, K. and Mackenroth, F. and Senje, L. and Gonoskov, A. and Harvey, C. and Aurand, B. and Hansson, M. and Higginson, A. and Dalui, M. and Lundh, O. and McKenna, P. and Persson, A. and Marklund, M. and Wahlström, C.-G. (2017) Transverse expansion of the electron sheath during laser acceleration of protons. Physics of Plasmas, 24. 123109. ISSN 1070-664X (https://doi.org/10.1063/1.5010173)

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Abstract

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.

  • Item type:Article
    ID code:62483
    Dates:
    Date
    Event
    12 December 2017
    Published
    12 December 2017
    Published Online
    21 November 2017
    Accepted
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:30 Nov 2017 11:17
    Last modified:09 Apr 2024 08:30
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/62483
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