Kun Xue

Simulation of asymmetry incoherent scatter spectra with the ion acoustic wave

Under the condition of parametric decay instability excitation, the measured up-shifted ion line is higher than downshifted one. We are based on the assumption of the existence of ion acoustic velocity particles, a new ion velocity distribution function and incoherent scatter theory model with the PDI mechanism are build, and the spectra asymmetry characteristic of PDI is simulated successfully, which is consistent with experiments observations. It is great significance to understand the instability mechanism.

The influence of meteoric smoke particle attributions on polar mesospheric clouds formation

It is known that the formation of polar mesospheric clouds (PMCs) is correlated with temperature, concentration and desublimation nuclei of water vapor. The primary candidate of these nuclei is believed to be meteoric smoke particles. In this study, we have surveyed the influence of meteoric smoke particle attributions on polar mesospheric ice clouds formation. It is found that the large smoke particles with radium of 2-3 nm will dominate the nucleation of water vapor.

Application of 20-momen approximation for ion velocity distribution in calculations of incoherent scattering spectra

According to Grads theories, the ion velocity distribution function is expanded to a 20-moment approximation based on the Maxwellian distribution. The effects of the stress tensor and the heat flow vector on the ion velocity distributions are discussed. When the electric field is weak, it is reasonable to neglect the heat flow vector for 20-moment approximation in the directions parallel to E times B and the stress tensor in the directions parallel to E , respectively. According to Sheffields theories, the incoherent scattering radar spectra are calculated by using the 20-moment approximation. Effects of parameter E on spectra shape are studied in details using the 20-moment approximation. Numerical results show that it is reasonable to use the 20-moment approximation to describe the Non-Maxwellian plasma characterized by the temperature anisotropy. When the electric field becomes weak, the 20-moment approximation may be reduced, this can simplify the calculation of the incoherent scatter spectra very much.