Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 13...Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 130, 155101(2023)], we developed a novel approach for generating such fields using multiple conventional laser beams with a twist in the pointing direction. This method is particularly well-suited for multi-kilojoule petawatt-class laser systems like SG-Ⅱ UP, which are designed with multiple linearly polarized beamlets. Utilizing three-dimensional kinetic particle-in-cell simulations, we examine critical factors for a proof-of-principle experiment, such as laser polarization, relative pulse delay,phase offset, pointing stability, and target configuration, and their impact on magnetic field generation. Our general conclusion is that the approach is very robust and can be realized under a wide range of laser parameters and plasma conditions. We also provide an in-depth analysis of the axial magnetic field configuration, azimuthal electron current, and electron and ion orbital angular momentum densities.Supported by a simple model, our analysis shows that the axial magnetic field decays owing to the expansion of hot electrons.展开更多
A linearly polarized Laguerre–Gaussian(LP-LG)laser beam with a twist index l=−1 has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam.Close to the ...A linearly polarized Laguerre–Gaussian(LP-LG)laser beam with a twist index l=−1 has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam.Close to the axis of the LP-LG beam,the longitudinal electric and magnetic fields dominate over the transverse components.This structure offers an attractive opportunity to accelerate electrons in vacuum.It is shown,using three-dimensional particle-in-cell simulations,that this scenario can be realized by reflecting an LP-LG laser off a plasma with a sharp density gradient.The simulations indicate that a 600 TW LP-LG laser beam effectively injects electrons into the beam during the reflection.The electrons that are injected close to the laser axis experience a prolonged longitudinal acceleration by the longitudinal laser electric field.The electrons form distinct monoenergetic bunches with a small divergence angle.The energy in the most energetic bunch is 0.29 GeV.The bunch charge is 6 pC and its duration is approximately 270 as.The divergence angle is just 0.57°(10 mrad).By using a linearly polarized rather than a circularly polarized Laguerre–Gaussian beam,our scheme makes it easier to demonstrate the electron acceleration experimentally at a high-power laser facility.展开更多
Low-intensity light beams carrying orbital angular momentum(OAM),commonly known as vortex beams,have garnered significant attention due to promising applications in areas ranging from optical trapping to communication...Low-intensity light beams carrying orbital angular momentum(OAM),commonly known as vortex beams,have garnered significant attention due to promising applications in areas ranging from optical trapping to communication.In recent years,there has been a surge in global research exploring the potential of high-intensity vortex laser beams and specifically their interactions with plasmas.This paper provides a comprehensive review of recent advances in this area.Compared with conventional laser beams,intense vortex beams exhibit unique properties such as twisted phase fronts,OAM delivery,hollow intensity distribution,and spatially isolated longitudinal fields.These distinct characteristics give rise to a multitude of rich phenomena,profoundly influencing laser-plasma interactions and offering diverse applications.The paper also discusses future prospects and identifies promising general research areas involving vortex beams.These areas include low-divergence particle acceleration,instability suppression,high-energy photon delivery with OAM,and the generation of strong magnetic fields.With growing scientific interest and application potential,the study of intense vortex lasers is poised for rapid development in the coming years.展开更多
基金support by the National Natural Science Foundation of China(Grant No.12322513)USTC Research Funds of the Double First-Class Initiative+1 种基金CAS Project for Young Scientists in Basic Research(Grant No.YSBR060)supported by the Office of Fusion Energy Sciences under Award No.DE-SC0023423。
文摘Strong multi-kilotesla magnetic fields have various applications in high-energy density science and laboratory astrophysics, but they are not readily available. In our previous work [Y. Shi et al., Phys. Rev. Lett. 130, 155101(2023)], we developed a novel approach for generating such fields using multiple conventional laser beams with a twist in the pointing direction. This method is particularly well-suited for multi-kilojoule petawatt-class laser systems like SG-Ⅱ UP, which are designed with multiple linearly polarized beamlets. Utilizing three-dimensional kinetic particle-in-cell simulations, we examine critical factors for a proof-of-principle experiment, such as laser polarization, relative pulse delay,phase offset, pointing stability, and target configuration, and their impact on magnetic field generation. Our general conclusion is that the approach is very robust and can be realized under a wide range of laser parameters and plasma conditions. We also provide an in-depth analysis of the axial magnetic field configuration, azimuthal electron current, and electron and ion orbital angular momentum densities.Supported by a simple model, our analysis shows that the axial magnetic field decays owing to the expansion of hot electrons.
基金supported by USTC Research Funds of the Double First-Class Initiative (YD2140002003)Strategic Priority Research Program of CAS (XDA25010200)+1 种基金CAS Project for Young Scientists in Basic Research (YSBR060)Newton International Fellows Alumni follow-on funding。
基金Y.S. acknowledges the support by USTC Research Funds of the Double First-Class Initiative, Strategic Priority Research Program of CAS (Grant No. XDA25010200)CAS Project for Young Scientists in Basic Research (Grant No. YSBR060)+1 种基金Newton International Fellows Alumni follow-on fundingD.R.B. and A.A. acknowledge the support by the National Science Foundation (Grant No. PHY 1903098)。
文摘A linearly polarized Laguerre–Gaussian(LP-LG)laser beam with a twist index l=−1 has field structure that fundamentally differs from the field structure of a conventional linearly polarized Gaussian beam.Close to the axis of the LP-LG beam,the longitudinal electric and magnetic fields dominate over the transverse components.This structure offers an attractive opportunity to accelerate electrons in vacuum.It is shown,using three-dimensional particle-in-cell simulations,that this scenario can be realized by reflecting an LP-LG laser off a plasma with a sharp density gradient.The simulations indicate that a 600 TW LP-LG laser beam effectively injects electrons into the beam during the reflection.The electrons that are injected close to the laser axis experience a prolonged longitudinal acceleration by the longitudinal laser electric field.The electrons form distinct monoenergetic bunches with a small divergence angle.The energy in the most energetic bunch is 0.29 GeV.The bunch charge is 6 pC and its duration is approximately 270 as.The divergence angle is just 0.57°(10 mrad).By using a linearly polarized rather than a circularly polarized Laguerre–Gaussian beam,our scheme makes it easier to demonstrate the electron acceleration experimentally at a high-power laser facility.
基金the support by the National Natural Science Foundation of China(Grant No.12322513)the support by the National Natural Science Foundation of China(Grant No.11935008)+3 种基金USTC Research Funds of the Double First-Class InitiativeCAS Project for Young Scientists in Basic Research(Grant No.YSBR060)Newton International Fellowshipssupported by the US DOE Office of Fusion Energy Sciences(Grant No.DE-SC0023423)。
文摘Low-intensity light beams carrying orbital angular momentum(OAM),commonly known as vortex beams,have garnered significant attention due to promising applications in areas ranging from optical trapping to communication.In recent years,there has been a surge in global research exploring the potential of high-intensity vortex laser beams and specifically their interactions with plasmas.This paper provides a comprehensive review of recent advances in this area.Compared with conventional laser beams,intense vortex beams exhibit unique properties such as twisted phase fronts,OAM delivery,hollow intensity distribution,and spatially isolated longitudinal fields.These distinct characteristics give rise to a multitude of rich phenomena,profoundly influencing laser-plasma interactions and offering diverse applications.The paper also discusses future prospects and identifies promising general research areas involving vortex beams.These areas include low-divergence particle acceleration,instability suppression,high-energy photon delivery with OAM,and the generation of strong magnetic fields.With growing scientific interest and application potential,the study of intense vortex lasers is poised for rapid development in the coming years.
