The Strong Electromagnetic Fields On The Ionosphere To Change The Computer Numerical Simulation

This dissertation is composed of two parts. One is the study of interaction of powerful high frequency radio waveswith terrestrial ionosphere,the other is the research of the influence of quasi-electrostatic field produced by sudden discharge of thunderstorm cloud to ground on the nighttime lower ionosphere. In this dissertation, the first part is the main content. In terms of the properties of interaction of radio waves with ionospheric plasma, the self-consistent theoretical models of heating lower ionosphere (60~120km) and upper ionosphere (150~400km) are presented, respectively. By means of these models,with specifictransmitter parameters, the changesof electron temperature and electron density in ionosphere are calculated under some background conditions. The results show that there are different disturbance at whole considered ionospheric heights. In lower ionosphere, the Ohmic heating is dominant, and the charged particles. transport processes can be ignored, so, at these heights, the disturbance of electron number density is the effect of change of combination α coefficient, which is function of electron temperature. When the ionospheric height h <90km, the self-absorption effect of radio wave is evident, andelectron temperature increasesobviously, butthe effect can be ignored for h>90km, and increase value of electron temperature is small. For the upper ionosphere, in which the transport process cannot be ignored any longer, and the conduction and diffusion processes are dominant, on the contrary, the change ofcombination coefficient is not main factor, so the disturbance of electron density is drivenby the gradient of electron temperature. The maximum increase of electron temperature in ionospheric F region is in the vicinity of reflect point of radio waves, and the changes of electron density have increase and decrease. The timescale of balance of electron temperature is tens of second,whichisshorter than that of electrondensity,that is2~3 minutes, andheating time scale for electron is good symmetry with that of cooling. During heating at all ionospheric heights, the extent of influence of backgroundparameters on heating results is different, but effect of thermospheric horizontal wind in meridian is little. All these results calculated in this dissertation are good agreement with the measured values in many ionosphere-heated experiments. Basedon the abovestudy, two typical phenomena that are observed in experiments are studied by PIC electrostatic particle simulation method. Firstly, we simulate the influence of pump waves on two-streaminstability occurred at heights of equatorial ionospheric E region. The simulation results show that pump waves can controlthe two-stream instability, that.s tosay,pump radio can stabilizedor unstabilized thisinstability. Additionally, the observedSEE phenomenon in experiments is also studied by one dimension simulation, the simulation results show that electrostatic waves excited in ionospheric upper hybrid resonant layer is an important factor.