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Zhu XL, Liu WY, Yu TP, Chen M, Weng SM, Wang WM, Sheng ZM. Dense Polarized Positrons from Beam-Solid Interaction. PHYSICAL REVIEW LETTERS 2024; 132:235001. [PMID: 38905668 DOI: 10.1103/physrevlett.132.235001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 05/08/2024] [Indexed: 06/23/2024]
Abstract
Relativistic positron sources with high spin polarization have important applications in nuclear and particle physics and many frontier fields. However, it is challenging to produce dense polarized positrons. Here we present a simple and effective method to achieve such a positron source by directly impinging a relativistic high-density electron beam on the surface of a solid target. During the interaction, a strong return current of plasma electrons is induced and subsequently asymmetric quasistatic magnetic fields as high as megatesla are generated along the target surface. This gives rise to strong radiative spin flips and multiphoton processes, thus leading to efficient generation of copious polarized positrons. With three-dimensional particle-in-cell simulations, we demonstrate the production of a dense highly polarized multi-GeV positron beam with an average spin polarization above 40% and nC-scale charge per shot. This offers a novel route for the studies of laserless strong-field quantum electrodynamics physics and for the development of high-energy polarized positron sources.
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Affiliation(s)
| | | | | | | | | | | | - Zheng-Ming Sheng
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
- Key Laboratory for Laser Plasmas (MOE), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China
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Zaïm N, Sainte-Marie A, Fedeli L, Bartoli P, Huebl A, Leblanc A, Vay JL, Vincenti H. Light-Matter Interaction near the Schwinger Limit Using Tightly Focused Doppler-Boosted Lasers. PHYSICAL REVIEW LETTERS 2024; 132:175002. [PMID: 38728726 DOI: 10.1103/physrevlett.132.175002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 03/18/2024] [Indexed: 05/12/2024]
Abstract
Strong-field quantum electrodynamics (SF QED) is a burgeoning research topic dealing with electromagnetic fields comparable to the Schwinger field (≈1.32×10^{18} V/m). While most past and proposed experiments rely on reaching this field in the rest frame of relativistic particles, the Schwinger limit could also be approached in the laboratory frame by focusing to its diffraction limit the light reflected by a plasma mirror irradiated by a multipetawatt laser. We explore the interaction between such intense light and matter with particle-in-cell simulations. We find that the collision with a relativistic electron beam would enable the study of the nonperturbative regime of SF QED, while the interaction with a solid target leads to a profusion of SF QED effects that retroact on the interaction. In both cases, relativistic attosecond pair jets with high densities are formed.
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Affiliation(s)
- Neïl Zaïm
- Université Paris-Saclay, CEA, LIDYL, 91191 Gif-sur-Yvette, France
| | | | - Luca Fedeli
- Université Paris-Saclay, CEA, LIDYL, 91191 Gif-sur-Yvette, France
| | - Pierre Bartoli
- Université Paris-Saclay, CEA, LIDYL, 91191 Gif-sur-Yvette, France
| | - Axel Huebl
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Adrien Leblanc
- LOA, CNRS, Ecole Polytechnique, ENSTA Paris, Institut Polytechnique de Paris, Palaiseau, France
| | - Jean-Luc Vay
- Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Henri Vincenti
- Université Paris-Saclay, CEA, LIDYL, 91191 Gif-sur-Yvette, France
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Qu K, Griffith A, Fisch NJ. Pair filamentation and laser scattering in beam-driven QED cascades. Phys Rev E 2024; 109:035208. [PMID: 38632779 DOI: 10.1103/physreve.109.035208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/19/2024] [Indexed: 04/19/2024]
Abstract
We report the observation of longitudinal filamentation of an electron-positron pair plasma in a beam-driven QED cascade. The filaments are created in the "pair-reflection" regime, where the generated pairs are partially stopped and reflected in the strong laser field. The density filaments form near the center of the laser pulse and have diameters similar to the laser wavelength. They develop and saturate within a few laser cycles and do not induce sizable magnetostatic fields. We rule out the onset of two-stream instability or Weibel instability and attribute the origin of pair filamentation to laser ponderomotive forces. The small plasma filaments induce strong scattering of laser energy to large angles, serving as a signature of collective QED plasma dynamics.
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Affiliation(s)
- Kenan Qu
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA
| | - Alec Griffith
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA
| | - Nathaniel J Fisch
- Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544, USA
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Brodin G, Al-Naseri H, Zamanian J, Torgrimsson G, Eliasson B. Plasma dynamics at the Schwinger limit and beyond. Phys Rev E 2023; 107:035204. [PMID: 37073070 DOI: 10.1103/physreve.107.035204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 03/05/2023] [Indexed: 04/20/2023]
Abstract
Strong field physics close to or above the Schwinger limit are typically studied with vacuum as initial condition or by considering test particle dynamics. However, with a plasma present initially, quantum relativistic mechanisms such as Schwinger pair creation are complemented by classical plasma nonlinearities. In this work we use the Dirac-Heisenberg-Wigner formalism to study the interplay between classical and quantum mechanical mechanisms in the regime of ultrastrong electric fields. In particular, the effects of initial density and temperature on the plasma oscillation dynamics are determined. Finally, comparisons with competing mechanisms such as radiation reaction and Breit-Wheeler pair production are made.
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Affiliation(s)
- Gert Brodin
- Department of Physics, Umeå University, SE-901 87 Umeå, Sweden
| | | | - Jens Zamanian
- Department of Physics, Umeå University, SE-901 87 Umeå, Sweden
| | | | - Bengt Eliasson
- SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom
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