Collimated multi-MeV ion beams from high-intensity laser interactions with underdense plasma.
A beam of multi-MeV helium ions has been observed from the interaction of a short-pulse high-intensity laser pulse with underdense helium plasma. The ion beam was found to have a maximum energy for He2+ of (40(+3)(-8)) MeV and was directional along the laser propagation path, with the highest energy ions being collimated to a cone of less than 10 degrees. 2D particle-in-cell simulations show that the ions are accelerated by a sheath electric field that is produced at the back of the gas target. This electric field is generated by transfer of laser energy to a hot electron beam, which exits the target generating large space-charge fields normal to its boundary.
Willingale
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Blackett Laboratory, Imperial College London, London SW7 2BZ, United Kingdom.
Mangles
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Nilson
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Clarke
R J
RJ
Dangor
A E
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Kaluza
M C
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Karsch
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Lancaster
K L
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Mori
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Najmudin
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Schreiber
J
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Thomas
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Wei
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Krushelnick
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