A Study On The Prediction Of Ionospheric Storm By VLF Method

The eruption of the solar flare will spray a large amount of charged particle flow.When the charged particle flows to the earth's surface,the ionospheric anomaly will be caused and the ionospheric storm is generated.Ionospheric storms will affect the quality of short wave communication,which will lead to communication interruption and damage to electronic communication devices.It will also affect satellite signal transmission,resulting in satellite communication interruption and satellite navigation confusion.Therefore,it is one of the most important research topics to study the emergence and advance of the ionospheric storm.In this thesis,the method of VLF signal propagation will be used to predict the ionosphere storm.The phase anomaly of VLF signals is closely related to the equivalent reflection height of the ionosphere.The equivalent reflection height of the ionosphere is closely related to the X ray flux.When the solar flare erupts,it radiates a lot of energy(mainly X ray)and a large number of charged particle flows.The X ray reaches the earth's surface for about 8 minutes,while the charged particle flow reaches the surface of the earth for about 1~3 days.X rays take the lead in reaching the earth's surface,resulting in a sudden increase in the ionospheric X-ray flow,the increase of the electron concentration,and the reduction of the equivalent height.The sudden decline of the equivalent reflection height from the low ionosphere leads to the sudden advance of the VLF phase,which can identify the solar flare.Therefore,using the VLF signal propagation method,we can predict the ionospheric storm in advance 1~3 days.In general,the greater the phase change of the VLF,the greater the level of the solar flare,the greater the intensity of the ionosphere storm.A real-time remote VLF data transmission system that predict the ionospheric storm is designed.The VLF observation data display software and the VLF data FTP sending and receiving software are designed and programmed.VLF signal monitor every 3 minutes to get to the VLF data transmission computer through serial transmission through the VLF data display software is displayed on the screen,and use the VLF FTP software to send and receive data sent through the network to a remote server.When the remote server receives the data of the VLF signal,the VLF data display software is displayed on the screen.The effect of synchronous display in two places is realized,which not only saves cost,but also realizes data sharing.It is convenient for staff in two places to work together to make timely prediction of ionospheric storm.