In order to understand the mechanism of the confinement bifurcation and H-mode power threshold in magnetically confined plasma,a new dynamical model of the L-H transition based on edge instability phase transition（E...In order to understand the mechanism of the confinement bifurcation and H-mode power threshold in magnetically confined plasma,a new dynamical model of the L-H transition based on edge instability phase transition（EIPT） has been developed.With the typical plasma parameters of the EAST tokamak,the self-consistent turbulence growth rate is analyzed using the simplest case of pressure-driven ballooning-type instability,which indicates that the L-H transition can be caused by the stabilization of the edge instability through EIPT.The weak E？×？B flow shear in L-mode is able to increase the ion inertia of the electrostatic motion by increasing the radial wave number of the tilted turbulence structures,which play an important role for accelerating the trigger process of EIPT rather than directly to suppress the turbulent transport.With the acceleration mechanism of E？×？B flow shear,fast L-H and H-L transitions are demonstrated under the control of the input heating power.Due to the simplified scrape-offlayer boundary condition applied,the ratio between the heating powers at the H-L and L-H transition respectively differs from the ratio by Nusselt number.The results of the modeling reveal a scaling of the power threshold of the L-H transition,P_（L-H）？∝？n^（0.76） B^（0.8） for deuterium plasma.It is found finite Larmor radius induces an isotope effect of the H-mode power threshold.展开更多
在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制...在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。展开更多
基金supported by National Natural Science Foundation of China under Contract Nos.11575235 and 11422546China Postdoctoral Science Foundation under Contract No.2016M602043+2 种基金the National Magnetic Confinement Fusion Science Program of China under Contract No.2015GB101002Key Research Program of Frontier Sciences,CAS,Grant No.QYZDB-SSW-SLH001K C Wong Education Foundation
文摘In order to understand the mechanism of the confinement bifurcation and H-mode power threshold in magnetically confined plasma,a new dynamical model of the L-H transition based on edge instability phase transition（EIPT） has been developed.With the typical plasma parameters of the EAST tokamak,the self-consistent turbulence growth rate is analyzed using the simplest case of pressure-driven ballooning-type instability,which indicates that the L-H transition can be caused by the stabilization of the edge instability through EIPT.The weak E？×？B flow shear in L-mode is able to increase the ion inertia of the electrostatic motion by increasing the radial wave number of the tilted turbulence structures,which play an important role for accelerating the trigger process of EIPT rather than directly to suppress the turbulent transport.With the acceleration mechanism of E？×？B flow shear,fast L-H and H-L transitions are demonstrated under the control of the input heating power.Due to the simplified scrape-offlayer boundary condition applied,the ratio between the heating powers at the H-L and L-H transition respectively differs from the ratio by Nusselt number.The results of the modeling reveal a scaling of the power threshold of the L-H transition,P_（L-H）？∝？n^（0.76） B^（0.8） for deuterium plasma.It is found finite Larmor radius induces an isotope effect of the H-mode power threshold.
文摘在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。
