Quasi-linear modeling of gyroresonance between different MLT chorus and geostationary orbit electrons

The contributions of dayside and nightside gyroresonance of chorus waves to electron radiation belt evolution at L = 6.6 are detailedly differentiated via fully solving the two-dimensional Fokker-Plank equation.The numerical results show that the chorus waves at different regions play signiffcantly different roles.The dayside chorus waves can cause obvious loss of energetic electrons at lower pitch angles and weak energization at larger pitch angles.The nightside chorus waves can yield significant energization at larger pitch angles,but cannot efficiently resonate with the energetic electrons at lower pitch angle.Due to the numerical difficulty in fully solving Fokker-Planck equation,the cross diffusion terms are often ignored in the previous work.Here the effect of cross diffiusion at different regions is further analyzed.On the dayside,ignoring cross diffusion overestimates the electron phase space density by several orders of magnitude at lower pitch angles,and consequently the dayside chorus waves are incorrectly regarded as an effective energization mechanism.On the nightside,ignoring cross diffusion overestimates the electron phase space density(PSD) by about one order of magnitude at larger pitch angles.These numerical results suggest that cross diffusion terms can significantly affect gyroresonance of chorus waves on both the dayside and nightside,which should be included in the future radiation belt models.     

Experimental investigation on heat transfer characteristics of microcapsule phase change material suspension in array jet impingement

A closed-loop experimental system is established to investigate the heat transfer characteristics of microcapsule phase change material (MEPCM) suspension in an array jet impingement. Eicosane with a melting peak at 40.8°C is used as the capsule core of the MEPCM particle. Five kinds of array-hole nozzles with the same hole cross-sectional area are employed to analyze the influence of critical parameters, including the nozzle hole number, hole spacing, impinging distance, and jet temperature. It shows that a 5% suspension may improve the heat transfer coefficient of the array jet by up to 23.5% compared with water. The heat transfer of an array jet is obviously stronger than that of a single jet, but too much hole number is not conducive because of the entrainment interference between adjacent jets. A larger hole spacing or smaller impinging distance may weaken the cross-flow accumulation on the impinged surface, thus enhancing the heat transfer capability. The heat transfer coefficient of the array jet presents a secondary peak value at the end of the jet-core region. The latent heat absorption of the capsule core results in superior heat transfer of the suspension compared to that of water only in a specific range of jet temperatures, the optimum of which is approximately 10°C lower relative to the peak melting temperature. In addition, the melt completion time of a single MEPCM particle and the critical flow rate of the suspension are predicted theoretically.

     

Correlated observations linking loss of energetic protons to EMIC waves

Electromagnetic ion cyclotron (EMIC) emission is an efficient mechanism for scattering loss of energetic protons. Here, we report an event that provides both in-situ observation of energetic proton differential fluxes in the inner magnetosphere and precipitation of protons at ionospheric altitudes. During the 7–8 September 2015 geomagnetic storm the Van Allen Probes observed strong EMIC waves around L = 5 and a distinct decrement in fluxes of tens of keV protons around pitch angles 0°–45°. Meanwhile, precipitating protons at ionospheric altitudes were found to significantly enhanced (by several orders of magnitude), measured by NOAA 18 and 19 when they magnetically linked to the Van Allen Probe-A. By solving the Fokker-Planck diffusion equation, we show that EMIC waves can efficiently produce loss of energetic protons within about 2 h in the pitch angle range of ∼ 0°–45°, comparable to the satellite observations.

     

Multi-satellite observations on the storm-time enhancements of energetic outer zone electron fluxes driven by chorus waves

The evolution of energetic outer zone electron fluxes during the strong magnetic storm on September 28, 2002 is investigated based on the observations of SAMPEX and GOES-10 satellites. The observations of both satellites showed that energetic electron fluxes increased significantly during the storm recovery phase, and reached the maximum on October 6. The 1.5–14 MeV and 2.5–14 MeV electron fluxes observed by SAMPEX peaked around L=3.5 with values of 6×10 2 cm -2 s -1 sr -1 keV -1 and 5×10 3 cm -2 s -1 sr -1...     

椭圆曲线密码算法的硬件设计与实现

本文重点介绍了椭圆曲线密码体制(ECC)的实施过程以及用到的相关算法和优化方案。文中利用大数模运算硬件实现中常用的蒙哥马利(Montgomery)算法和心缩(Systolic)算法实现了模乘运算,并在此基础上用Ver- ilog硬件描述语言实现了ECC最核心的点乘运算。     

Influence of wave normal angle on gyroresonance between chorus waves and outer radiation belt electrons

In this paper,using a Gaussian distribution of wave normal angle X=tan,and considering contributions of harmonic resonances n up to±5,we analyze the effect of normal angle on diffusion coefficients induced by gyroresonance between chorus waves and electrons with energies 0.1 and 1.0 MeV on the dayside and nightside at L=4.5.When pitch angle e>10°,for 0.1and 1.0 MeV electrons on the dayside and nightside,diffusion coefficients of five orders(2,1,0,1,2)decrease with increasing normal angle peak,leading to the total diffusion coefficients decreasing with increasing peak.When e<10°,for 1.0MeV electrons on the dayside and 0.1 MeV electrons on the dayside and nightside,the positive order diffusion coefficients are generally smaller than the same negative order ones;in the meanwhile,diffusion coefficients of orders(2,1,2)are very small,the dominant order n=1 diffusion coefficients change very little,hence the total diffusion coefficients almost remain unchanged.However,for 1.0 MeV electrons on the nightside,diffusion coefficients of orders(2,1,2)which are larger than those of the order(1)resonance increase with increasing peak,hence the total diffusion coefficients increase with increasing peak.The current results show that the wave normal angle plays an important role in the quantitative analysis of gyroresonance between chorus waves and electrons in the outer radiation belt.     

The influence of various frequency chorus waves on electron dynamics in radiation belts

Science China Technological Sciences - Non-adiabatic behaviour induced by the chorus-electron interaction is an important contributor to the radiation belt dynamics, and largely relies on wave...