The Experts below are selected from a list of 162 Experts worldwide ranked by ideXlab platform
S T Petcov - One of the best experts on this subject based on the ideXlab platform.
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diffractive like or parametric resonance like enhancement of the Earth day night effect for solar neutrinos crossing the Earth Core
Physics Letters B, 1998Co-Authors: S T PetcovAbstract:Abstract It is shown that the strong enhancement of the Earth (day-night) effect for solar neutrinos crossing the Earth Core in the case of the small mixing angle MSW νe→νμ(τ) transition solution of the solar neutrino problem is due to a new resonance effect in the solar neutrino transitions in the Earth and not just to the MSW effect in the Core. The effect is in many respects similar to the electron paramagnetic resonance. The conditions for existence of this new resonance effect are discussed. They include specific constraints on the neutrino oscillation lengths in the Earth mantle and in the Earth Core, thus the resonance is a “neutrino oscillation length resonance”. The effect exhibits strong dependence on the neutrino energy. Analytic expression for the probability accounting for the solar neutrino transitions in the Earth, which provides a high precision description of the transitions, including the new resonance effect, is derived. The implications of our results for the searches of the day-night asymmetry in the solar neutrino experiments are also briefly discussed. The new resonance effect is operative also in the νμ→νe (νe→νμ) transitions of atmospheric neutrinos crossing the Earth Core.
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diffractive like or parametric resonance like enhancement of the Earth day night effect for solar neutrinos crossing the Earth Core
arXiv: High Energy Physics - Phenomenology, 1998Co-Authors: S T PetcovAbstract:It is shown that the strong enhancement of the Earth (day-night) effect for solar neutrinos crossing the Earth Core in the case of the small mixing angle MSW electron neutrino to muon (tau) neutrino transition solution of the solar neutrino problem is due to a new resonance effect in the solar neutrino transitions in the Earth and not just to the MSW effect in the Core. The effect is in many respects similar to the electron paramagnetic resonance. The conditions for existence of this new resonance effect are discussed. They include specific constraints on the neutrino oscillation lengths in the Earth mantle and in the Earth Core, thus the resonance is a ``neutrino oscillation length resonance''. The effect exhibits strong dependence on the neutrino energy. Analytic expression for the probability accounting for the solar neutrino transitions in the Earth, which provides a high precision description of the transitions, including the new resonance effect, is derived. The implications of our results for the searches of the day-night asymmetry in the solar neutrino experiments are briefly discussed. The new resonance effect is operative also in the muon neutrino to electron neutrino (electron neutrino to muon neutrino) transitions of atmospheric neutrinos crossing the Earth Core.
Nathanaël Schaeffer - One of the best experts on this subject based on the ideXlab platform.
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Rotating convection in stably-stratified planetary Cores
arXiv: Fluid Dynamics, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably-stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular , we show that in stably-stratified spheres, the Rayleigh numbers Ra at the onset evolve like $Ra $\sim$ Ek^{-1}$ , where Ek is the Ekman number. This differs from rotating convection in unstably-stratified spheres, for which $Ra $\sim$ Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable straficiation, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
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Rotating double-diffusive convection in stably stratified planetary Cores
Geophysical Journal International, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular, we show that in stably stratified spheres, the Rayleigh numbers $Ra$ at the onset evolve like $Ra \sim Ek^{-1}$, where $Ek$ is the Ekman number. This differs from rotating convection in unstably stratified spheres, for which $Ra \sim Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable stratification, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
R Monville - One of the best experts on this subject based on the ideXlab platform.
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Rotating convection in stably-stratified planetary Cores
arXiv: Fluid Dynamics, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably-stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular , we show that in stably-stratified spheres, the Rayleigh numbers Ra at the onset evolve like $Ra $\sim$ Ek^{-1}$ , where Ek is the Ekman number. This differs from rotating convection in unstably-stratified spheres, for which $Ra $\sim$ Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable straficiation, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
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Rotating double-diffusive convection in stably stratified planetary Cores
Geophysical Journal International, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular, we show that in stably stratified spheres, the Rayleigh numbers $Ra$ at the onset evolve like $Ra \sim Ek^{-1}$, where $Ek$ is the Ekman number. This differs from rotating convection in unstably stratified spheres, for which $Ra \sim Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable stratification, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
Jérémie Vidal - One of the best experts on this subject based on the ideXlab platform.
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Rotating convection in stably-stratified planetary Cores
arXiv: Fluid Dynamics, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably-stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular , we show that in stably-stratified spheres, the Rayleigh numbers Ra at the onset evolve like $Ra $\sim$ Ek^{-1}$ , where Ek is the Ekman number. This differs from rotating convection in unstably-stratified spheres, for which $Ra $\sim$ Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable straficiation, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
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Rotating double-diffusive convection in stably stratified planetary Cores
Geophysical Journal International, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular, we show that in stably stratified spheres, the Rayleigh numbers $Ra$ at the onset evolve like $Ra \sim Ek^{-1}$, where $Ek$ is the Ekman number. This differs from rotating convection in unstably stratified spheres, for which $Ra \sim Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable stratification, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
David Cébron - One of the best experts on this subject based on the ideXlab platform.
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Rotating convection in stably-stratified planetary Cores
arXiv: Fluid Dynamics, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably-stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular , we show that in stably-stratified spheres, the Rayleigh numbers Ra at the onset evolve like $Ra $\sim$ Ek^{-1}$ , where Ek is the Ekman number. This differs from rotating convection in unstably-stratified spheres, for which $Ra $\sim$ Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable straficiation, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.
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Rotating double-diffusive convection in stably stratified planetary Cores
Geophysical Journal International, 2019Co-Authors: R Monville, Jérémie Vidal, David Cébron, Nathanaël SchaefferAbstract:In planetary fluid Cores, the density depends on temperature and chemical composition, which diffuse at very different rates. This leads to various instabilities, bearing the name of double-diffusive convection. We investigate rotating double-diffusive convection (RDDC) in fluid spheres. We use the Boussinesq approximation with homogeneous internal thermal and compositional source terms. We focus on the finger regime, in which the thermal gradient is stabilising whereas the compositional one is destabilising. First, we perform a global linear stability analysis in spheres. The critical Rayleigh numbers drastically drop for stably stratified fluids, yielding large-scale convective motions where local analyses predict stability. We evidence the inviscid nature of this large-scale double-diffusive instability, enabling the determination of the marginal stability curve at realistic planetary regimes. In particular, we show that in stably stratified spheres, the Rayleigh numbers $Ra$ at the onset evolve like $Ra \sim Ek^{-1}$, where $Ek$ is the Ekman number. This differs from rotating convection in unstably stratified spheres, for which $Ra \sim Ek^{-4/3}$. The domain of existence of inviscid convection thus increases as $Ek^{-1/3}$. Second, we perform nonlinear simulations. We find a transition between two regimes of RDDC, controlled by the strength of the stratification. Furthermore, far from the RDDC onset, we find a dominating equatorially anti-symmetric, large-scale zonal flow slightly above the associated linear onset. Unexpectedly, a purely linear mechanism can explain this phenomenon, even far from the instability onset, yielding a symmetry breaking of the nonlinear flow at saturation. For even stronger stable stratification, the flow becomes mainly equatorially-symmetric and intense zonal jets develop. Finally, we apply our results to the early Earth Core. Double diffusion can reduce the critical Rayleigh number by four decades for realistic Core conditions. We suggest that the early Earth Core was prone to turbulent RDDC, with large-scale zonal flows.