Spot size dependence of laser accelerated protons in thin multi-ion foils

Tung-Chang Liu, Xi Shao, Chuan-Sheng Liu, Bengt Eliasson, Jyhpyng Wang, Shih-Hung Chen

Research output: Contribution to journalMeeting abstract

2 Citations (Scopus)

Abstract

We present a numerical study of the effect of the laser spot size of a circularly polarized laser beam on the energy of quasi-monoenergetic protons in laser proton acceleration using a thin carbon-hydrogen foil. The used proton acceleration scheme is a combination of laser radiation pressure and shielded Coulomb repulsion due to the carbon ions. We observe that the spot size plays a crucial role in determining the efficiency of proton acceleration. Using a laser pulse with fixed input energy and pulse length impinging on a carbon-hydrogen foil, a laser beam with smaller spot sizes can generate higher energy but fewer quasi-monoenergetic protons. We studied the scaling of the proton energy with respect to the laser spot size and obtained an optimal spot size for maximum proton energy flux. In particular, we provided a theoretical model interpreting the acceleration mechanism for non-penetration cases and the calculated optimal spot size agreed well with the 2D PIC simulation results. Using the optimal spot size, we can generate an 80 MeV quasi-monoenergetic proton beam containing more than 10^8 protons using a laser beam with power 250 TW and energy 10 J and a target of thickness 0.15 wavelength and 49 critical density made of 90\% carbon and 10\% hydrogen.

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foils
protons
lasers
ions
laser beams
carbon
proton energy
hydrogen
energy
radiation pressure
pulses
proton beams
scaling
wavelengths
simulation

Keywords

  • laser spot size
  • polarized laser beam
  • laser accelerated protons

Cite this

Liu, Tung-Chang ; Shao, Xi ; Liu, Chuan-Sheng ; Eliasson, Bengt ; Wang, Jyhpyng ; Chen, Shih-Hung. / Spot size dependence of laser accelerated protons in thin multi-ion foils. In: Bulletin of the American Physical Society. 2014 ; Vol. 59, No. 15.
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title = "Spot size dependence of laser accelerated protons in thin multi-ion foils",
abstract = "We present a numerical study of the effect of the laser spot size of a circularly polarized laser beam on the energy of quasi-monoenergetic protons in laser proton acceleration using a thin carbon-hydrogen foil. The used proton acceleration scheme is a combination of laser radiation pressure and shielded Coulomb repulsion due to the carbon ions. We observe that the spot size plays a crucial role in determining the efficiency of proton acceleration. Using a laser pulse with fixed input energy and pulse length impinging on a carbon-hydrogen foil, a laser beam with smaller spot sizes can generate higher energy but fewer quasi-monoenergetic protons. We studied the scaling of the proton energy with respect to the laser spot size and obtained an optimal spot size for maximum proton energy flux. In particular, we provided a theoretical model interpreting the acceleration mechanism for non-penetration cases and the calculated optimal spot size agreed well with the 2D PIC simulation results. Using the optimal spot size, we can generate an 80 MeV quasi-monoenergetic proton beam containing more than 10^8 protons using a laser beam with power 250 TW and energy 10 J and a target of thickness 0.15 wavelength and 49 critical density made of 90\{\%} carbon and 10\{\%} hydrogen.",
keywords = "laser spot size, polarized laser beam, laser accelerated protons",
author = "Tung-Chang Liu and Xi Shao and Chuan-Sheng Liu and Bengt Eliasson and Jyhpyng Wang and Shih-Hung Chen",
note = "Originally presented at the 56th Annual Meeting of the APS Division of Plasma Physics, Session NP8: Poster Session V: DIII-D/Diagnostics; Measurement and Diagnostic Techniques; Low Temperature Plasmas; Production, Ionization Kinetics and Sheaths; Van Allen 100; LPI Short Pulse and Beams.",
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Spot size dependence of laser accelerated protons in thin multi-ion foils. / Liu, Tung-Chang; Shao, Xi; Liu, Chuan-Sheng; Eliasson, Bengt; Wang, Jyhpyng; Chen, Shih-Hung.

In: Bulletin of the American Physical Society, Vol. 59, No. 15, 29.10.2014.

Research output: Contribution to journalMeeting abstract

TY - JOUR

T1 - Spot size dependence of laser accelerated protons in thin multi-ion foils

AU - Liu, Tung-Chang

AU - Shao, Xi

AU - Liu, Chuan-Sheng

AU - Eliasson, Bengt

AU - Wang, Jyhpyng

AU - Chen, Shih-Hung

N1 - Originally presented at the 56th Annual Meeting of the APS Division of Plasma Physics, Session NP8: Poster Session V: DIII-D/Diagnostics; Measurement and Diagnostic Techniques; Low Temperature Plasmas; Production, Ionization Kinetics and Sheaths; Van Allen 100; LPI Short Pulse and Beams.

PY - 2014/10/29

Y1 - 2014/10/29

N2 - We present a numerical study of the effect of the laser spot size of a circularly polarized laser beam on the energy of quasi-monoenergetic protons in laser proton acceleration using a thin carbon-hydrogen foil. The used proton acceleration scheme is a combination of laser radiation pressure and shielded Coulomb repulsion due to the carbon ions. We observe that the spot size plays a crucial role in determining the efficiency of proton acceleration. Using a laser pulse with fixed input energy and pulse length impinging on a carbon-hydrogen foil, a laser beam with smaller spot sizes can generate higher energy but fewer quasi-monoenergetic protons. We studied the scaling of the proton energy with respect to the laser spot size and obtained an optimal spot size for maximum proton energy flux. In particular, we provided a theoretical model interpreting the acceleration mechanism for non-penetration cases and the calculated optimal spot size agreed well with the 2D PIC simulation results. Using the optimal spot size, we can generate an 80 MeV quasi-monoenergetic proton beam containing more than 10^8 protons using a laser beam with power 250 TW and energy 10 J and a target of thickness 0.15 wavelength and 49 critical density made of 90\% carbon and 10\% hydrogen.

AB - We present a numerical study of the effect of the laser spot size of a circularly polarized laser beam on the energy of quasi-monoenergetic protons in laser proton acceleration using a thin carbon-hydrogen foil. The used proton acceleration scheme is a combination of laser radiation pressure and shielded Coulomb repulsion due to the carbon ions. We observe that the spot size plays a crucial role in determining the efficiency of proton acceleration. Using a laser pulse with fixed input energy and pulse length impinging on a carbon-hydrogen foil, a laser beam with smaller spot sizes can generate higher energy but fewer quasi-monoenergetic protons. We studied the scaling of the proton energy with respect to the laser spot size and obtained an optimal spot size for maximum proton energy flux. In particular, we provided a theoretical model interpreting the acceleration mechanism for non-penetration cases and the calculated optimal spot size agreed well with the 2D PIC simulation results. Using the optimal spot size, we can generate an 80 MeV quasi-monoenergetic proton beam containing more than 10^8 protons using a laser beam with power 250 TW and energy 10 J and a target of thickness 0.15 wavelength and 49 critical density made of 90\% carbon and 10\% hydrogen.

KW - laser spot size

KW - polarized laser beam

KW - laser accelerated protons

UR - http://meetings.aps.org/link/BAPS.2014.DPP.NP8.105

UR - http://www.aps.org/meetings/baps/

M3 - Meeting abstract

VL - 59

JO - Bulletin of the American Physical Society

T2 - Bulletin of the American Physical Society

JF - Bulletin of the American Physical Society

SN - 0003-0503

IS - 15

ER -