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Title: Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions

Abstract

Multiple ion acceleration mechanisms can occur when an ultrathin foil is irradiated with an intense laser pulse, with the dominant mechanism changing over the course of the interaction. Measurement of the spatial-intensity distribution of the beam of energetic protons is used to investigate the transition from radiation pressure acceleration to transparency-driven processes. It is shown numerically that radiation pressure drives an increased expansion of the target ions within the spatial extent of the laser focal spot, which induces a radial deflection of relatively low energy sheath-accelerated protons to form an annular distribution. Through variation of the target foil thickness, the opening angle of the ring is shown to be correlated to the point in time transparency occurs during the interaction and is maximized when it occurs at the peak of the laser intensity profile. Corresponding experimental measurements of the ring size variation with target thickness exhibit the same trends and provide insight into the intra-pulse laser-plasma evolution.

Authors:
; ; ; ; ; ; ; ; ; ;  [1];  [2];  [3];  [4];  [5];  [6];  [1];  [7]
  1. SUPA Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)
  2. Centro de Laseres Pulsados (CLPU), Parque Cientifico, Calle del Adaja s/n. 37185 Villamayor, Salamanca (Spain)
  3. Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX (United Kingdom)
  4. Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)
  5. (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240 (China)
  6. Centre for Plasma Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom)
  7. (United Kingdom)
Publication Date:
OSTI Identifier:
22598941
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; BEAMS; DISTRIBUTION; EXPANSION; FOILS; INTERACTIONS; IONS; IRRADIATION; LASERS; OPACITY; PEAKS; PLASMA; PROTONS; PULSES; RADIATION PRESSURE; THICKNESS; VARIATIONS

Citation Formats

Padda, H., King, M., Gray, R. J., Powell, H. W., Gonzalez-Izquierdo, B., Wilson, R., Dance, R. J., MacLellan, D. A., Butler, N. M. H., Capdessus, R., McKenna, P., E-mail: paul.mckenna@strath.ac.uk, Stockhausen, L. C., Carroll, D. C., Yuan, X. H., Collaborative Innovation Center of IFSA, Borghesi, M., Neely, D., and Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX. Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions. United States: N. p., 2016. Web. doi:10.1063/1.4954654.
Padda, H., King, M., Gray, R. J., Powell, H. W., Gonzalez-Izquierdo, B., Wilson, R., Dance, R. J., MacLellan, D. A., Butler, N. M. H., Capdessus, R., McKenna, P., E-mail: paul.mckenna@strath.ac.uk, Stockhausen, L. C., Carroll, D. C., Yuan, X. H., Collaborative Innovation Center of IFSA, Borghesi, M., Neely, D., & Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX. Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions. United States. doi:10.1063/1.4954654.
Padda, H., King, M., Gray, R. J., Powell, H. W., Gonzalez-Izquierdo, B., Wilson, R., Dance, R. J., MacLellan, D. A., Butler, N. M. H., Capdessus, R., McKenna, P., E-mail: paul.mckenna@strath.ac.uk, Stockhausen, L. C., Carroll, D. C., Yuan, X. H., Collaborative Innovation Center of IFSA, Borghesi, M., Neely, D., and Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX. 2016. "Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions". United States. doi:10.1063/1.4954654.
@article{osti_22598941,
title = {Intra-pulse transition between ion acceleration mechanisms in intense laser-foil interactions},
author = {Padda, H. and King, M. and Gray, R. J. and Powell, H. W. and Gonzalez-Izquierdo, B. and Wilson, R. and Dance, R. J. and MacLellan, D. A. and Butler, N. M. H. and Capdessus, R. and McKenna, P., E-mail: paul.mckenna@strath.ac.uk and Stockhausen, L. C. and Carroll, D. C. and Yuan, X. H. and Collaborative Innovation Center of IFSA and Borghesi, M. and Neely, D. and Central Laser Facility, STFC Rutherford Appleton Laboratory, Oxfordshire OX11 0QX},
abstractNote = {Multiple ion acceleration mechanisms can occur when an ultrathin foil is irradiated with an intense laser pulse, with the dominant mechanism changing over the course of the interaction. Measurement of the spatial-intensity distribution of the beam of energetic protons is used to investigate the transition from radiation pressure acceleration to transparency-driven processes. It is shown numerically that radiation pressure drives an increased expansion of the target ions within the spatial extent of the laser focal spot, which induces a radial deflection of relatively low energy sheath-accelerated protons to form an annular distribution. Through variation of the target foil thickness, the opening angle of the ring is shown to be correlated to the point in time transparency occurs during the interaction and is maximized when it occurs at the peak of the laser intensity profile. Corresponding experimental measurements of the ring size variation with target thickness exhibit the same trends and provide insight into the intra-pulse laser-plasma evolution.},
doi = {10.1063/1.4954654},
journal = {Physics of Plasmas},
number = 6,
volume = 23,
place = {United States},
year = 2016,
month = 6
}
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