We have examined the Wind data in 1996 and identified 21 small interplanetary magnetic flux ropes(SIMFRs),and all the 21 SIMFRs have boundary layer structures.The durations of the boundary layers varied from several m...We have examined the Wind data in 1996 and identified 21 small interplanetary magnetic flux ropes(SIMFRs),and all the 21 SIMFRs have boundary layer structures.The durations of the boundary layers varied from several minutes to 30 minutes.These boundary layers also have properties of high proton temperature,density,and plasma beta.These boundary layers are formed by magnetic reconnections.In addition,in three events magnetic reconnections were occurring inside the boundary layers.It indicates that the flux rope structures have propagated for some period of time,and their boundaries were still evolving through interaction with the background solar wind.Namely it is very possible that the SIMFRs came from the solar corona.展开更多
Magnetic reconnection is an important universal plasma dissipation process that converts magnetic energy into plasma thermal and kinetic energy,and simultaneously changes the magnetic field topology.In this paper,we r...Magnetic reconnection is an important universal plasma dissipation process that converts magnetic energy into plasma thermal and kinetic energy,and simultaneously changes the magnetic field topology.In this paper,we report the first observation of energetic electrons associated with asymmetric reconnection in the sheath of an interplanetary coronal mass ejection.The magnetic field shear angle was about 151°,implying guide-field reconnection.The width of the exhaust was about 8×104 km.The reconnection rate was estimated as 0.044-0.08,which is consistent with fast reconnection theory and previous observations.We observed flux enhancements of energetic electrons with energy up to 400 keV in this reconnection exhaust.The region where ener- getic electron fluxes were enhanced is located at one pair of separatrices in the higher density hemisphere.We discuss these observation results,and compare with previous observations and recent kinetic simulations.展开更多
The interest in the periodic orbits of the restricted three-body problem continues to grow for their significant practical application.This paper focuses on the interplanetary transfers between periodic orbits of two ...The interest in the periodic orbits of the restricted three-body problem continues to grow for their significant practical application.This paper focuses on the interplanetary transfers between periodic orbits of two different three-body systems,whose invariant manifolds have no intersection in phase space.A novel design method is proposed to obtain the optimal transfer employing the invariant manifolds and planetary gravity assist.The periapsis Poincare map is used to analyze the periapsides of invariant manifolds.On the basis of hyperbola approximation,the impulses performed on the periapsis of invariant manifolds are calculated with a simple iterative algorithm.The propellant-efficient escape and capture trajectories can be found by comparing the impulses magnitudes corresponding to different invariant manifolds,which can provide the appropriate initial guess for optimization.Further,the trajectory design is formulated as an unconstrained optimization problem under the perturbed restricted three-body model.An efficient algorithm combining simplex method and differential correction is adopted to obtain the optimal solution.The validity of the proposed approach is demonstrated through several interplanetary low energy transfer trajectories.展开更多
基金supported by the National Natural Science Foundation of China(41074124,40804034 and 40890162)the Program for Science & Technology Innovation Talents in Universities of Henan Province(HASTIT)(2010HASTIT022)the Specialized Research Fund for State Key Laboratories and Key Laboratory of Solar Activity and the Program for Science & Technology of Henan(092300410189)
文摘We have examined the Wind data in 1996 and identified 21 small interplanetary magnetic flux ropes(SIMFRs),and all the 21 SIMFRs have boundary layer structures.The durations of the boundary layers varied from several minutes to 30 minutes.These boundary layers also have properties of high proton temperature,density,and plasma beta.These boundary layers are formed by magnetic reconnections.In addition,in three events magnetic reconnections were occurring inside the boundary layers.It indicates that the flux rope structures have propagated for some period of time,and their boundaries were still evolving through interaction with the background solar wind.Namely it is very possible that the SIMFRs came from the solar corona.
基金supported by the National Natural Science Foundation of China(40890163)the Fundamental Research Funds for the Central Universitiesthe Specialized Research Fund for State Key Laboratories,Chinese Academy of Sciences
文摘Magnetic reconnection is an important universal plasma dissipation process that converts magnetic energy into plasma thermal and kinetic energy,and simultaneously changes the magnetic field topology.In this paper,we report the first observation of energetic electrons associated with asymmetric reconnection in the sheath of an interplanetary coronal mass ejection.The magnetic field shear angle was about 151°,implying guide-field reconnection.The width of the exhaust was about 8×104 km.The reconnection rate was estimated as 0.044-0.08,which is consistent with fast reconnection theory and previous observations.We observed flux enhancements of energetic electrons with energy up to 400 keV in this reconnection exhaust.The region where ener- getic electron fluxes were enhanced is located at one pair of separatrices in the higher density hemisphere.We discuss these observation results,and compare with previous observations and recent kinetic simulations.
基金supported by the National Basic Research Program of China ("973" Program) (Grant No. 2012CB720000)the National Natural Science Foundation of China (Grant No. 11102021)Foundation of Science and Technology on Space Intelligent Control Laboratory
文摘The interest in the periodic orbits of the restricted three-body problem continues to grow for their significant practical application.This paper focuses on the interplanetary transfers between periodic orbits of two different three-body systems,whose invariant manifolds have no intersection in phase space.A novel design method is proposed to obtain the optimal transfer employing the invariant manifolds and planetary gravity assist.The periapsis Poincare map is used to analyze the periapsides of invariant manifolds.On the basis of hyperbola approximation,the impulses performed on the periapsis of invariant manifolds are calculated with a simple iterative algorithm.The propellant-efficient escape and capture trajectories can be found by comparing the impulses magnitudes corresponding to different invariant manifolds,which can provide the appropriate initial guess for optimization.Further,the trajectory design is formulated as an unconstrained optimization problem under the perturbed restricted three-body model.An efficient algorithm combining simplex method and differential correction is adopted to obtain the optimal solution.The validity of the proposed approach is demonstrated through several interplanetary low energy transfer trajectories.
