Yang Zhiliang

Angular Distribution of Synchrotron Radiation in Low Frequency

The angular distribution of energy for synchrotron radiation in low frequency band (? ?c) is obtained by rigorously solving the Nicolo Tartaglia equation. The result shows that the critical angle increases with decreasing frequency, but it cannot exceed 90?. The relation between critical angle ?c and frequency is common covering all wavelengths. For the small angle case, it is consistent with the result obtained by Jackson. With the increase of emanative angle, the radiant intensity increases first, then decays.

A Quasi-One-Dimensional Model for a Solar Flux Tube

We develop the quasi-one-dimensional flux tube model with magnetohydrodynamical equations. In order to know whether the magnetic field can maintain their similar structure from photosphere to chromosphere, we suppose that the flux tube is thin in radius relative to the length, and that the quantities in the cross section are averaged. The radii of the flux tube and the magnetic field are numerically simulated. One of the important results shows that the flux tube does not expand as quickly as the existing model when it is out of the photosphere with high velocity. This is consistent with observations of the magnetic field in the photosphere and chromosphere.

The effect of particle number in N-body simulations of the formation of giant molecular clouds☆☆☆

Abstract In this paper, we study the effect of particle number in the N-body simulation of the formation of giant molecular clouds. The result shows that in the case of formation by aggregation of “unit” clouds, if we take the mean density of the unit clouds to be a constant (or their effective radius to be proportional to the cubic roots of their mass), then the disruption rate of the GMCs will be independent of the initial number of unit clouds.

P – ω Dynamo in Spherical Geometry

Based on the fundamental P – ω dynamo equation, using spherical polar coordinates, we carry out a study of turbulent plasma wave dynamo effect. For various rotation laws, different analytical solutions are derived. In the cases of no rotation and rigid rotation, the dynamo generates poloidal field only, while with differential rotation, regardless the differential rotation is radial or latitudinal, poloidal and toroidal fields are all generated. We may think that the solutions are the analytical forms of the magnetic field in a turbulent source region of celestial bodies.