Study On The Transmission Loss And The Defocusing Characteristics Of High Power Microwave In The Ionosphere

Due to the increasing lack of ore resources,human beings need to find alternative energy sources.Solar power,which is a kind of clean and renewable energy,gets the favor of humans.However,since using solar power in the earth's surface will be affected by weather,seasons,utilization rate is not high.Space solar power station can avoid the interference of these factors,greatly improving the collection efficiency.Based on the background of space solar power,high power microwave transmission characteristics in the ionosphere is studied,including radio transmission efficiency,transmission path and the beam converging situation.The main work is as follows:1.The ratio of the particles in the ionosphere is discussed and ionospheric all kinds of model are contrasted,and using International Reference Ionosphere 2012 as the background ionosphere reference model parameters,according to the basic parameters of the model of plasma simulation,the results of numerical simulation and analysis of the related physical quantities are illustrated.2.Applying ray tracing technique,wave's transmission path in the ionosphere is simulated.The wave in the ionosphere propagation equation of two dimensional ray tracing is presented,and the important phase in the equation of refractive index is introduced,and the partial differential equation is obtained.Using Runge Kutta algorithm and variable step length,transmission path of the different latitude,different time and the different frequency radio waves from space transmission path of the incident to the ionosphere is analyzed and compared.The simulation's results show that the transmission trajectory of radio waves whose frequency is low and power is large are greatly influenced by the ionosphere and transmission path of the radio waves are different in the ionosphere of different backgrounds.Besides,the ionosphere has little effect on the radio wave trajectory of the space of the solar power station.3.The wave propagation loss is examined on the basis of the thermal nonlinear effect.In the low ionosphere,neutral particles occupy a large proportion of electron impact,but in high ionospheric ions occupy an important position,and the collision of electrons and ions is far greater than the role of neutral molecules,and combined with the influence of the magnetic field leading to a charged particle along the earth's magnetic field direction,heat transfer and diffusion transport process must be considered.The different model in the high and low ionosphere was established respectively,and the transmission loss from space incident to ionosphere is simulated by different frequency and different power waves.The transmission loss of radio waves in the low ionosphere is mainly concentrated in the range of 90-110 km.Radio transmission loss in lower ionosphere is greater than the high ionosphere.Space solar power's wave loss of the 2.45 GHz is greater than the wave of 5.8 GHz frequency.4.On the basis of the thermal nonlinear effect,expounding the defocusing effect theory,parabolic beam numerical equation in the ionosphere is numerically derived,and the defocusing parameters,defocusing angle are discussed.Considering of the ionospheric heating effect on waves,the defocusing angle,beam radius change in lower ionosphere is numerically simulated and influencing factors are analyzed.The simulation results show that the smaller the radio frequency and the greater the power,the more obvious the defusing effect.The defusing effect on the wave of space solar power station is very small.