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A Tohsaki - One of the best experts on this subject based on the ideXlab platform.
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nuclear alpha particle condensates
Lecture Notes in Physics, 2012Co-Authors: T Yamada, H. Horiuchi, Y Funaki, G Ropke, P Schuck, A TohsakiAbstract:The \(\alpha\)-particle condensate in nuclei is a novel state described by a product state of \(\alpha\hbox{'s},\) all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical \(\alpha\)-particle condensate is the Hoyle state \((E_{x}=7.65\,\hbox{MeV},\;0^+_2\) state in \(^{12}\hbox{C}),\) which plays a crucial role for the synthesis of \(^{12}\hbox{C}\) in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the \(\alpha\) particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that \(\alpha\)-particle condensate states also exist in heavier \(n\alpha\) nuclei, like \(^{16}\hbox{O},\;^{20}\hbox{Ne},\) etc. For instance the \(0^+_6\) state of \(^{16}\hbox{O}\) at \(E_{x}=15.1\,\hbox{MeV}\) is identified from a theoretical analysis as being a strong candidate of a \(4\alpha\) condensate. The calculated small width (140 keV) of \(0^+_6,\) consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as \(^{11} \hbox{B}\) and \(^{13} \hbox{C},\) we discuss candidates for the product states of clusters, composed of \(\alpha\hbox{'s},\) triton’s, and neutrons etc. The relationship of \(\alpha\)-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for \(\alpha\) particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.
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alpha particle condensation in 16o studied with a full four body orthogonality condition model calculation
Physical Review Letters, 2008Co-Authors: Y Funaki, T Yamada, G Ropke, P Schuck, Hisashi Horiuchi, A TohsakiAbstract:To explore the four-$\ensuremath{\alpha}$-particle condensate state in $^{16}\mathrm{O}$, we solve a full four-body equation of motion based on the four-$\ensuremath{\alpha}$-particle orthogonality condition model in a large four-$\ensuremath{\alpha}$-particle model space spanned by Gaussian basis functions. A full spectrum up to the ${0}_{6}^{+}$ state is reproduced consistently with the lowest six ${0}^{+}$ states of the experimental spectrum. The ${0}_{6}^{+}$ state is obtained at about 2 MeV above the four-$\ensuremath{\alpha}$-particle breakup threshold and has a dilute density structure, with a radius of about 5 fm. The state has an appreciably large $\ensuremath{\alpha}$ condensate fraction of 61%, and a large component of $\ensuremath{\alpha}+^{12}\mathrm{C}({0}_{2}^{+})$ configuration, both features being reliable evidence for this state to be of four-$\ensuremath{\alpha}$-particle condensate nature.
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alpha cluster condensation in 12c and 16o
Physical Review Letters, 2001Co-Authors: A Tohsaki, Hisashi Horiuchi, Peter Schuck, G RopkeAbstract:A new alpha-cluster wave function is proposed which is of the Alpha-Particle condensate type. Applications to 12C and 16O show that states of low density close to the 3 and 4 Alpha-Particle thresholds in both nuclei are possibly of this kind. It is conjectured that all self-conjugate 4n nuclei may show similar features.
P Schuck - One of the best experts on this subject based on the ideXlab platform.
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nuclear alpha particle condensates
Lecture Notes in Physics, 2012Co-Authors: T Yamada, H. Horiuchi, Y Funaki, G Ropke, P Schuck, A TohsakiAbstract:The \(\alpha\)-particle condensate in nuclei is a novel state described by a product state of \(\alpha\hbox{'s},\) all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical \(\alpha\)-particle condensate is the Hoyle state \((E_{x}=7.65\,\hbox{MeV},\;0^+_2\) state in \(^{12}\hbox{C}),\) which plays a crucial role for the synthesis of \(^{12}\hbox{C}\) in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the \(\alpha\) particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that \(\alpha\)-particle condensate states also exist in heavier \(n\alpha\) nuclei, like \(^{16}\hbox{O},\;^{20}\hbox{Ne},\) etc. For instance the \(0^+_6\) state of \(^{16}\hbox{O}\) at \(E_{x}=15.1\,\hbox{MeV}\) is identified from a theoretical analysis as being a strong candidate of a \(4\alpha\) condensate. The calculated small width (140 keV) of \(0^+_6,\) consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as \(^{11} \hbox{B}\) and \(^{13} \hbox{C},\) we discuss candidates for the product states of clusters, composed of \(\alpha\hbox{'s},\) triton’s, and neutrons etc. The relationship of \(\alpha\)-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for \(\alpha\) particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.
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alpha particle condensation in 16o studied with a full four body orthogonality condition model calculation
Physical Review Letters, 2008Co-Authors: Y Funaki, T Yamada, G Ropke, P Schuck, Hisashi Horiuchi, A TohsakiAbstract:To explore the four-$\ensuremath{\alpha}$-particle condensate state in $^{16}\mathrm{O}$, we solve a full four-body equation of motion based on the four-$\ensuremath{\alpha}$-particle orthogonality condition model in a large four-$\ensuremath{\alpha}$-particle model space spanned by Gaussian basis functions. A full spectrum up to the ${0}_{6}^{+}$ state is reproduced consistently with the lowest six ${0}^{+}$ states of the experimental spectrum. The ${0}_{6}^{+}$ state is obtained at about 2 MeV above the four-$\ensuremath{\alpha}$-particle breakup threshold and has a dilute density structure, with a radius of about 5 fm. The state has an appreciably large $\ensuremath{\alpha}$ condensate fraction of 61%, and a large component of $\ensuremath{\alpha}+^{12}\mathrm{C}({0}_{2}^{+})$ configuration, both features being reliable evidence for this state to be of four-$\ensuremath{\alpha}$-particle condensate nature.
G Ropke - One of the best experts on this subject based on the ideXlab platform.
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nuclear alpha particle condensates
Lecture Notes in Physics, 2012Co-Authors: T Yamada, H. Horiuchi, Y Funaki, G Ropke, P Schuck, A TohsakiAbstract:The \(\alpha\)-particle condensate in nuclei is a novel state described by a product state of \(\alpha\hbox{'s},\) all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical \(\alpha\)-particle condensate is the Hoyle state \((E_{x}=7.65\,\hbox{MeV},\;0^+_2\) state in \(^{12}\hbox{C}),\) which plays a crucial role for the synthesis of \(^{12}\hbox{C}\) in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the \(\alpha\) particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that \(\alpha\)-particle condensate states also exist in heavier \(n\alpha\) nuclei, like \(^{16}\hbox{O},\;^{20}\hbox{Ne},\) etc. For instance the \(0^+_6\) state of \(^{16}\hbox{O}\) at \(E_{x}=15.1\,\hbox{MeV}\) is identified from a theoretical analysis as being a strong candidate of a \(4\alpha\) condensate. The calculated small width (140 keV) of \(0^+_6,\) consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as \(^{11} \hbox{B}\) and \(^{13} \hbox{C},\) we discuss candidates for the product states of clusters, composed of \(\alpha\hbox{'s},\) triton’s, and neutrons etc. The relationship of \(\alpha\)-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for \(\alpha\) particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.
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alpha particle condensation in 16o studied with a full four body orthogonality condition model calculation
Physical Review Letters, 2008Co-Authors: Y Funaki, T Yamada, G Ropke, P Schuck, Hisashi Horiuchi, A TohsakiAbstract:To explore the four-$\ensuremath{\alpha}$-particle condensate state in $^{16}\mathrm{O}$, we solve a full four-body equation of motion based on the four-$\ensuremath{\alpha}$-particle orthogonality condition model in a large four-$\ensuremath{\alpha}$-particle model space spanned by Gaussian basis functions. A full spectrum up to the ${0}_{6}^{+}$ state is reproduced consistently with the lowest six ${0}^{+}$ states of the experimental spectrum. The ${0}_{6}^{+}$ state is obtained at about 2 MeV above the four-$\ensuremath{\alpha}$-particle breakup threshold and has a dilute density structure, with a radius of about 5 fm. The state has an appreciably large $\ensuremath{\alpha}$ condensate fraction of 61%, and a large component of $\ensuremath{\alpha}+^{12}\mathrm{C}({0}_{2}^{+})$ configuration, both features being reliable evidence for this state to be of four-$\ensuremath{\alpha}$-particle condensate nature.
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alpha cluster condensation in 12c and 16o
Physical Review Letters, 2001Co-Authors: A Tohsaki, Hisashi Horiuchi, Peter Schuck, G RopkeAbstract:A new alpha-cluster wave function is proposed which is of the Alpha-Particle condensate type. Applications to 12C and 16O show that states of low density close to the 3 and 4 Alpha-Particle thresholds in both nuclei are possibly of this kind. It is conjectured that all self-conjugate 4n nuclei may show similar features.
S J Zweben - One of the best experts on this subject based on the ideXlab platform.
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alpha particle physics experiments in the tokamak fusion test reactor
Nuclear Fusion, 2000Co-Authors: S J Zweben, R V Budny, D S Darrow, S S Medley, R Nazikian, B C Stratton, E J SynakowskiAbstract:Alpha particle physics experiments were done on TFTR during its DT run from 1993 to 1997. These experiments utilized several new alpha particle diagnostics and hundreds of DT discharges to characterize the alpha particle confinement and wave-particle interactions. In general, the results from the alpha particle diagnostics agreed with the classical single particle confinement model in MHD quiescent discharges. The alpha loss due to toroidal field ripple was identified in some cases, and the low radial diffusivity inferred for high energy alphas was consistent with orbit averaging over small scale turbulence. Finally, the observed alpha particle interactions with sawteeth, toroidal Alfven eigenmodes and ICRF waves were approximately consistent with theoretical modelling. What was learned is reviewed and what remains to be understood is identified.
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alpha driven magnetohydrodynamics mhd and mhd induced alpha loss in the tokamak fusion test reactor
Physics of Plasmas, 1997Co-Authors: Z Chang, S J Zweben, R V Budny, R Nazikian, R B White, E D Fredrickson, S H Batha, M G Bell, R E Bell, C E BushAbstract:Alpha-driven toroidal Alfven eigenmodes (TAEs) are observed as predicted by theory in the post-neutral beam phase in high central q (safety factor) deuterium–tritium (D–T) plasmas in the Tokamak Fusion Test Reactor (TFTR) [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. The mode location, poloidal structure, and the importance of q profile for TAE instability are discussed. So far no alpha particle loss due to these modes was detected due to the small mode amplitude. However, alpha loss induced by kinetic ballooning modes (KBMs) was observed in high-confinement D–T discharges. Particle orbit simulation demonstrates that the wave–particle resonant interaction can explain the observed correlation between the increase in alpha loss and appearance of multiple high-n (n⩾6, n is the toroidal mode number) modes.
C E Bush - One of the best experts on this subject based on the ideXlab platform.
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alpha driven magnetohydrodynamics mhd and mhd induced alpha loss in the tokamak fusion test reactor
Physics of Plasmas, 1997Co-Authors: Z Chang, S J Zweben, R V Budny, R Nazikian, R B White, E D Fredrickson, S H Batha, M G Bell, R E Bell, C E BushAbstract:Alpha-driven toroidal Alfven eigenmodes (TAEs) are observed as predicted by theory in the post-neutral beam phase in high central q (safety factor) deuterium–tritium (D–T) plasmas in the Tokamak Fusion Test Reactor (TFTR) [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. The mode location, poloidal structure, and the importance of q profile for TAE instability are discussed. So far no alpha particle loss due to these modes was detected due to the small mode amplitude. However, alpha loss induced by kinetic ballooning modes (KBMs) was observed in high-confinement D–T discharges. Particle orbit simulation demonstrates that the wave–particle resonant interaction can explain the observed correlation between the increase in alpha loss and appearance of multiple high-n (n⩾6, n is the toroidal mode number) modes.