| Quantum communication is a new interdisciplinary subject developed by the combination of quantum theory and information theory.The results of the research and experiment show that the quantum communication has unparalleled security compared to other communication methods because of the inherent innate nature of quantum.And the construction of global wide area quantum network will become the focus of future quantum communication?s research.Quantum satellite communication has the advantages of security,secrecy,wide coverage and so on.It is an important part of constructing global quantum communication network.It has become a hot research topic in this field.At 1:40 on August 16(th),2016,the successful launching of ?Mozi? scientific experimental satellite,marks Chinese quantum satellite communications and space science research has taken an important step.Our researchers will make use of the satellite platform to conduct high-speed quantum key distribution experiment and wide-area quantum key network experiment,in order to make a major breakthrough in the practical application of space quantum communication.The satellite-ground quantum link based on quantum satellite communication is an indispensable and important part of establishing global wide-area quantum communication network.However,there is little research has been done on the influence of the satellite-ground quantum link communication performance under various extreme weather conditions caused by atmospheric charged particles at this stage.In this paper,based on the basic theory of quantum satellite communication,analyzes the attenuation model of the optical quantum signals transmitted by the atmospheric charged particles.Focus on research the relationship between optical quantum signals and the extreme natural environment caused by charged particles.The effects of severe weather such as thunderstorm cloud,charged dust storm on the communication performance of the satellite-ground quantum link are studied,which lays a theoretical reference for further research on quantum satellite communication.The innovation of this paper is divided into:Firstly,according to the extinction cross section and the number concentration distribution function of the charged particle in the thunderstorm cloud,the relationships among the particle concentration,charge density and link attenuation of satellite-ground quantum link can be established.For the depolarizing and amplitude damping channel,the relationship among the concentration of atmospheric charged particles,the charge density and the channel capacity of satellite-ground quantum link is established and simulated.Aiming at the depolarizing channel,the relationship among the density of charged particles,the charge density,the average fidelity of channel and the survival function are put out finally.Secondly,According to the extinction cross section and spectral distribution function of the non-spherical atmospheric charged particles,the relationship among the particle concentration,equivalent radius,charge density of the charged particle and the attenuation coefficient of the satellite-ground quantum link can be established.This paper gave the relationship among the equivalent radius of ellipsoidal and Chebyshev atmospheric charged particles,charge density,transmission diffusion time,and the entanglement of satellite-ground quantum link.We also analyzed the quantitative relationship between atmospheric visibility and quantum fidelity.And in the end,the data is compared with the previous research results for the first time.Thirdly,in order to study the relationship between the physical characteristics of the charged dust particles and the photon energy,the key distribution and the rate of channel establishment of the satellite-ground quantum link.According to the spectrum distribution of charged sand dust particles and the amplitude of forward scattering,the expression of extinction attenuation of optical quantum signals on charged sandstorms is proposed.Among them,for the first time,the charge-to-mass ratio is calculated in comparison with the parameter of the charged property.At the same time,the paper also summarizes the whole paper and looks forward to the future development of quantum satellite communication.Taking into account the multiple inter-satellites switching,and finally accomplishes the global wide area quantum network. |
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