Research On Near-Earth Space Environment And Spatial Conductivity

With the increment of Chinese space missions, especially manned space missions, the reseaches onnear-earth space environment and its effects are playing a more important role. Dissertation workfocuses on the near-earth space radiation environment, containing natural and artificial radiationenvironment, develops Near-Earth Radiation Environment Analysis software and High AltitudeNuclear Detonation X-rays Analysis software. Besides, researches on the important parameter spatialconductivity involved in both radiation environments have been done and calculations of the cosmicrays induced air conductivity have been accomplished by NER. The results coincide with the actuallymeasured value.Firstly, analyze the characteristics of the near-earth natural radiation field and study the models ofradiation belts and Cosmic Rays. Then with the Monte Carlo methods, based on the Geant4toolkit,use the spectrums of radiation particles as inputs, expand the database, create new functional modules,make it portability and packaging to develop the NER software. Caculate and analyze the energy ofradiation particles deposited in the atmosphere. Simulate the trajectory of them in the geomagneticfield.Secondly, focus on the X-rays, neutrons and gamma radiation of the artificial radiation environment.Analyze the spectrum, distribution of fluence and effects of these three factors. With programing andmaking interface based on the Matlab, develop the numerical calculation software HANDXR whichcan calculate the distribution of the X-ray’s fluence and the ionization effects of the atmosphere withdifferent equivalent,altitude and time of explosion.Thirdly, study the spatial conductivity with the CRII model, calculate the ion production rate andconductivity from the Cosmic Rays with which we can study the changes of spatial conductivity withthe latitude, altitude and solar activities. At last, compare the results of calculation with the actuallymeasured value and find them conincide with each other.