In astrophysics, the boundary conditions for plasma phenomena are provided by nature and the astronomer faces the problem of understanding them from a variety of observations [Hester J J et al 1996 Astrophys. J. 456 2...In astrophysics, the boundary conditions for plasma phenomena are provided by nature and the astronomer faces the problem of understanding them from a variety of observations [Hester J J et al 1996 Astrophys. J. 456 225], on the other hand, in laboratory plasma experiments the electromagnetic boundary conditions become a major problem in the set-up of the machine that produces the plasma, an issue that has to be investigated step by step and to be modified and adapted with great patience, in particular in the case of an innovative plasma confinement experiment. The PROTO-SPHERA machine [Alladio F et al 2006 Nucl. Fusion 46 S613] is a magnetic confinement experiment, that emulates in the laboratory the jet + torus plasma configurations often observed in astrophysics: an inner magnetized jet of plasma centered on the(approximate) axis of symmetry and surrounded by a magnetized plasma torus orthogonal to this jet. The PROTO-SPHERA plasma is simply connected, i.e., no metal current conducting rod is linked to the plasma torus, while instead it is the inner magnetized plasma jet(in the following always called the plasma centerpost) that is linked to the torus. It is mandatory that no spurious plasma current path modifies the optimal shape of the plasma centerpost. Moreover, as the plasma torus is produced and sustained, in absence of any applied inductive electric field, by the inner plasma centerpost through magnetic reconnections [Taylor J B and Turner M F 1989 Nucl.Fusion 29 219], it is required as well that spurious current paths do not surround the torus on its outboard, in order not to lower the efficiency of the magnetic reconnections that maintain the plasma torus at the expense of the plasma centerpost. Boundary conditions have been corrected,up to the point that the first sustainment in steady state has been achieved for the combined plasma.展开更多
We used the PW high-repetition laser facility VEGA-3 at Centro de Láseres Pulsados in Salamanca,with the goal of studying the generation of radioisotopes using laser-driven proton beams.Various types of targets h...We used the PW high-repetition laser facility VEGA-3 at Centro de Láseres Pulsados in Salamanca,with the goal of studying the generation of radioisotopes using laser-driven proton beams.Various types of targets have been irradiated including in particular several targets containing boron to generateα-particles through the hydrogen–boron fusion reaction.We have successfully identifiedγ-ray lines from several radioisotopes created by irradiation using lasergeneratedα-particles or protons including^(43)Sc,^(44)Sc,^(48)Sc,^(7)Be,^(11)C and^(18)F.We show that radioisotope generation can be used as a diagnostic tool to evaluateα-particle generation in laser-driven proton–boron fusion experiments.We also show the production of^(11)C radioisotopes,≈6×10~6,and of^(44)Sc radioisotopes,≈5×10~4per laser shot.This result can open the way to develop laser-driven radiation sources of radioisotopes for medical applications.展开更多
文摘In astrophysics, the boundary conditions for plasma phenomena are provided by nature and the astronomer faces the problem of understanding them from a variety of observations [Hester J J et al 1996 Astrophys. J. 456 225], on the other hand, in laboratory plasma experiments the electromagnetic boundary conditions become a major problem in the set-up of the machine that produces the plasma, an issue that has to be investigated step by step and to be modified and adapted with great patience, in particular in the case of an innovative plasma confinement experiment. The PROTO-SPHERA machine [Alladio F et al 2006 Nucl. Fusion 46 S613] is a magnetic confinement experiment, that emulates in the laboratory the jet + torus plasma configurations often observed in astrophysics: an inner magnetized jet of plasma centered on the(approximate) axis of symmetry and surrounded by a magnetized plasma torus orthogonal to this jet. The PROTO-SPHERA plasma is simply connected, i.e., no metal current conducting rod is linked to the plasma torus, while instead it is the inner magnetized plasma jet(in the following always called the plasma centerpost) that is linked to the torus. It is mandatory that no spurious plasma current path modifies the optimal shape of the plasma centerpost. Moreover, as the plasma torus is produced and sustained, in absence of any applied inductive electric field, by the inner plasma centerpost through magnetic reconnections [Taylor J B and Turner M F 1989 Nucl.Fusion 29 219], it is required as well that spurious current paths do not surround the torus on its outboard, in order not to lower the efficiency of the magnetic reconnections that maintain the plasma torus at the expense of the plasma centerpost. Boundary conditions have been corrected,up to the point that the first sustainment in steady state has been achieved for the combined plasma.
基金supported by COST(European Cooperation in Science and Technology)through Action CA21128 PROBONO(PROton BOron Nuclear Fusion:from energy production to medical applicati Ons)funding from the European Union’s 2020 research and innovation program under grant agreement No.101008126(RADNEXT project)United States Department of Energy under grant#DEFG02-93ER40773+3 种基金SMILEI simulations were performed thanks to granted access to the HPC resources of TGCC under allocation No.2023-A0140514117 made by GENCIfinancial support of the Id Ex University of Bordeaux/Grand Research Program‘GPR LIGHT’and of the Graduate Program on Light Sciences and Technologies of the University of BordeauxL.G.and V.K.acknowledge the support of the Czech Science Foundation through grant No.GACR24-11398Ssupport of HB11 Energy,Ltd.,Australia,through its Collaborative Science Program.H.L.and M.H.
文摘We used the PW high-repetition laser facility VEGA-3 at Centro de Láseres Pulsados in Salamanca,with the goal of studying the generation of radioisotopes using laser-driven proton beams.Various types of targets have been irradiated including in particular several targets containing boron to generateα-particles through the hydrogen–boron fusion reaction.We have successfully identifiedγ-ray lines from several radioisotopes created by irradiation using lasergeneratedα-particles or protons including^(43)Sc,^(44)Sc,^(48)Sc,^(7)Be,^(11)C and^(18)F.We show that radioisotope generation can be used as a diagnostic tool to evaluateα-particle generation in laser-driven proton–boron fusion experiments.We also show the production of^(11)C radioisotopes,≈6×10~6,and of^(44)Sc radioisotopes,≈5×10~4per laser shot.This result can open the way to develop laser-driven radiation sources of radioisotopes for medical applications.
