This paper describes a Mach/Langmuir probe array with five pins and six pins, which can measure not only parallel flows and the flow perpendicular to the magnetic field but also the radial and the poloidal electric fi...This paper describes a Mach/Langmuir probe array with five pins and six pins, which can measure not only parallel flows and the flow perpendicular to the magnetic field but also the radial and the poloidal electric field E. arid E as well. Experimental measurements of the edge fluctuations, velocities of the toroidal, the poloidal flow and electric field have been carried out on both of SOL and the boundary region of HL-1M for Ohmic, biased H-mode, Lower Hybrid Current Drive (LHCD), Supersonic Molecular Beam Injection (MBI), Multi-shot Pellet Injection (MPI), Neutral Beam Injection (NBI), Ion Cyclotron Resonance Heating (ICRH) and Electric Cyclotron Resonance Heating (ECRH) discharges. The results show that the suppressions of the fluctuations are related to poloidal rotations produced by different discharge modes in the improved particle confinement property, simultaneously the change of the radial and poloidal electric field is generated and becomes more negative at the Tokamak plasma edge, and the sheared poloidal flow is related to the reduction in fluctuation level, and the poloidal velocity is mainly dominated by the E × B drift.展开更多
To improve the understanding of the turbulence intermittency, a detailed investigation of the intermittency of the density fluctuations has been performed in the boundary of J-TEXT. The intermittency of the density fl...To improve the understanding of the turbulence intermittency, a detailed investigation of the intermittency of the density fluctuations has been performed in the boundary of J-TEXT. The intermittency of the density fluctuations and its influence on the radial transport are reported. The probability distribution functions of the density fluctuations are not scale-invariant, being inconsistent with the self-organized criticality hypothesis. The underlying dynamics of the intermittency are detected using the quiet-time statistical method. The probability distribution function of the quiet times shows double-power-law regions, indicating the existence of correlations between the successive burst events.展开更多
To reveal the sediment transporting mechanism between the abandoned Huanghe River （Yellow River） Delta and radial sand ridges, “End Member” Model and grain size trend analysis have been employed to separate the “...To reveal the sediment transporting mechanism between the abandoned Huanghe River （Yellow River） Delta and radial sand ridges, “End Member” Model and grain size trend analysis have been employed to separate the “dynamic populations” in the surficial sediment particle spectra and to determine the possible sediment transporting pathway. The results reveal four “dynamic subpopulations”（EM1 to EM4） and two reverse sediment transporting directions： a northward transport tend from the radial sand ridges to mud patch, and a southward transport trend in deep water area outside the mud patch. Combined with the published hydrodynamic information, the transporting mechanism of dynamic populations has been discussed, and the main conclusion is that the transporting of finer subpopulations EM1 and EM2 is controlled by the “anticlockwise residual current circulation” forming during tidal cycle, which favor a northward transporting trend and the forming of mud patch on the north of radial sand ridges, while the transporting of coarser EM3 is mainly controlled by wind driven drift in winter, which favors a southward transporting direction.展开更多
Simulations have been performed to investigate the impact of radial variation of neutral atoms (neutral puff) on the edge plasma of small size divertor tokamak. It was demonstrated that, the variation of neutral atoms...Simulations have been performed to investigate the impact of radial variation of neutral atoms (neutral puff) on the edge plasma of small size divertor tokamak. It was demonstrated that, the variation of neutral atoms (neutral puff) in edge plasma of small size divertor tokamak generates additional large radial electric field and large radial electric field shear near separatrix which can significantly influence global confinement by affecting the transition from low (L) to high (H) confinement. This simulation was performed by using B2SOLPS0.5.2D fluid transport code based on a reduced form of the transport form of transport equations. These transport equations are implemented in B2SOLPS0.5.2D fluid transport code and solved for the parameters of Small Size Divertor tokamak. The results of simulation by fluid transport B2SOLPS0.5.2D code can be summarized as follow: 1) The Plasma Parameters are significantly effect by neutral atoms puffing in the edge plasma of small size divertor tokamak;2) Contrary to previous expectation [1] of the predominant role of neutral viscosity on toroidal flux, anomalous transport was found to be mainly effect on toroidal flux;3) Puffing of gas (neutral) in the edge plasma of small size divertor tokamak produce strong ITB;4) Puffing of gas (neutral) in the edge plasma of small size divertor increase plasma density especially in SOL through charge exchange and ionization processes;5) Puffing of gas (neutral) in the edge plasma of small size divertor has significant effect on the distribution of plasma heat flux;6) The radial electric field is affected by gas (neutral) puffing in the edge plasma of small size divertor;7) Puffing of neutral (atoms) in the edge plasma of small size divertor tokamak produce large radial electric field shear which contribute to L-H transition;8) The centrifugal effect has no influence on distribution of the radial profile of parallel (toroidal) velocity of edge plasma of small size divertor tokamak during gas (neutral) puffing;9) The bootstrap current in edge plasma of small size divertor tokamak is significantly affected by gas (neutral) puffing.展开更多
In this paper, we present evolutions of the phase space density(PSD) spectra of ring current(RC) ions based on observations made by Van Allen Probe B during a geomagnetic storm on 23–24 August 2016. By analyzing PSD ...In this paper, we present evolutions of the phase space density(PSD) spectra of ring current(RC) ions based on observations made by Van Allen Probe B during a geomagnetic storm on 23–24 August 2016. By analyzing PSD spectra ratios from the initial phase to the main phase of the storm, we find that during the main phase, RC ions with low magnetic moment μ values can penetrate deeper into the magnetosphere than can those with high μ values, and that the μ range of PSD enhancement meets the relationship: S(O^+) >S(He^+)>S(H^+). Based on simultaneously observed ULF waves, theoretical calculation suggests that the radial transport of RC ions into the deep inner magnetosphere is caused by drift-bounce resonance interactions, and the efficiency of these resonance interactions satisfies the relationship: η(O^+) > η(He^+) > η(H^+), leading to the differences in μ range of PSD enhancement for different RC ions. In the recovery phase,the observed decay rates for different RC ions meet the relationship: R(O^+) > R(He^+) > R(H^+), in accordance with previous theoretical calculations, i.e., the charge exchange lifetime of O^+ is shorter than those of H^+ and He^+.展开更多
文摘This paper describes a Mach/Langmuir probe array with five pins and six pins, which can measure not only parallel flows and the flow perpendicular to the magnetic field but also the radial and the poloidal electric field E. arid E as well. Experimental measurements of the edge fluctuations, velocities of the toroidal, the poloidal flow and electric field have been carried out on both of SOL and the boundary region of HL-1M for Ohmic, biased H-mode, Lower Hybrid Current Drive (LHCD), Supersonic Molecular Beam Injection (MBI), Multi-shot Pellet Injection (MPI), Neutral Beam Injection (NBI), Ion Cyclotron Resonance Heating (ICRH) and Electric Cyclotron Resonance Heating (ECRH) discharges. The results show that the suppressions of the fluctuations are related to poloidal rotations produced by different discharge modes in the improved particle confinement property, simultaneously the change of the radial and poloidal electric field is generated and becomes more negative at the Tokamak plasma edge, and the sheared poloidal flow is related to the reduction in fluctuation level, and the poloidal velocity is mainly dominated by the E × B drift.
基金supported in part by the National Basic Research Program of China (Grant No. 2008CB717805)the National Natural Science Foundation of China (Grant No. 50907029)
文摘To improve the understanding of the turbulence intermittency, a detailed investigation of the intermittency of the density fluctuations has been performed in the boundary of J-TEXT. The intermittency of the density fluctuations and its influence on the radial transport are reported. The probability distribution functions of the density fluctuations are not scale-invariant, being inconsistent with the self-organized criticality hypothesis. The underlying dynamics of the intermittency are detected using the quiet-time statistical method. The probability distribution function of the quiet times shows double-power-law regions, indicating the existence of correlations between the successive burst events.
文摘To reveal the sediment transporting mechanism between the abandoned Huanghe River （Yellow River） Delta and radial sand ridges, “End Member” Model and grain size trend analysis have been employed to separate the “dynamic populations” in the surficial sediment particle spectra and to determine the possible sediment transporting pathway. The results reveal four “dynamic subpopulations”（EM1 to EM4） and two reverse sediment transporting directions： a northward transport tend from the radial sand ridges to mud patch, and a southward transport trend in deep water area outside the mud patch. Combined with the published hydrodynamic information, the transporting mechanism of dynamic populations has been discussed, and the main conclusion is that the transporting of finer subpopulations EM1 and EM2 is controlled by the “anticlockwise residual current circulation” forming during tidal cycle, which favor a northward transporting trend and the forming of mud patch on the north of radial sand ridges, while the transporting of coarser EM3 is mainly controlled by wind driven drift in winter, which favors a southward transporting direction.
文摘Simulations have been performed to investigate the impact of radial variation of neutral atoms (neutral puff) on the edge plasma of small size divertor tokamak. It was demonstrated that, the variation of neutral atoms (neutral puff) in edge plasma of small size divertor tokamak generates additional large radial electric field and large radial electric field shear near separatrix which can significantly influence global confinement by affecting the transition from low (L) to high (H) confinement. This simulation was performed by using B2SOLPS0.5.2D fluid transport code based on a reduced form of the transport form of transport equations. These transport equations are implemented in B2SOLPS0.5.2D fluid transport code and solved for the parameters of Small Size Divertor tokamak. The results of simulation by fluid transport B2SOLPS0.5.2D code can be summarized as follow: 1) The Plasma Parameters are significantly effect by neutral atoms puffing in the edge plasma of small size divertor tokamak;2) Contrary to previous expectation [1] of the predominant role of neutral viscosity on toroidal flux, anomalous transport was found to be mainly effect on toroidal flux;3) Puffing of gas (neutral) in the edge plasma of small size divertor tokamak produce strong ITB;4) Puffing of gas (neutral) in the edge plasma of small size divertor increase plasma density especially in SOL through charge exchange and ionization processes;5) Puffing of gas (neutral) in the edge plasma of small size divertor has significant effect on the distribution of plasma heat flux;6) The radial electric field is affected by gas (neutral) puffing in the edge plasma of small size divertor;7) Puffing of neutral (atoms) in the edge plasma of small size divertor tokamak produce large radial electric field shear which contribute to L-H transition;8) The centrifugal effect has no influence on distribution of the radial profile of parallel (toroidal) velocity of edge plasma of small size divertor tokamak during gas (neutral) puffing;9) The bootstrap current in edge plasma of small size divertor tokamak is significantly affected by gas (neutral) puffing.
基金supported by the National Natural Science Foundation of China (41925018, 41874194)
文摘In this paper, we present evolutions of the phase space density(PSD) spectra of ring current(RC) ions based on observations made by Van Allen Probe B during a geomagnetic storm on 23–24 August 2016. By analyzing PSD spectra ratios from the initial phase to the main phase of the storm, we find that during the main phase, RC ions with low magnetic moment μ values can penetrate deeper into the magnetosphere than can those with high μ values, and that the μ range of PSD enhancement meets the relationship: S(O^+) >S(He^+)>S(H^+). Based on simultaneously observed ULF waves, theoretical calculation suggests that the radial transport of RC ions into the deep inner magnetosphere is caused by drift-bounce resonance interactions, and the efficiency of these resonance interactions satisfies the relationship: η(O^+) > η(He^+) > η(H^+), leading to the differences in μ range of PSD enhancement for different RC ions. In the recovery phase,the observed decay rates for different RC ions meet the relationship: R(O^+) > R(He^+) > R(H^+), in accordance with previous theoretical calculations, i.e., the charge exchange lifetime of O^+ is shorter than those of H^+ and He^+.
