The Study Of The Origin Of The Galactic Positrons

The origin of cosmic rays is one of the unsolved basic problems in physics and astrophysics.Although the proportion of the electrons in the cosmic rays is small(~1%),they play important roles in the study of high energy processes of high energy objects because electrons just take part in the simple electromagnetic interaction during the propagation,other than the hadronic process of protons.It is generally believed that positron originates from the interaction of cosmic rays in the Galaxy with interstellar matter,which means positron has secondary origin.However,the recent observations shown that the ratio of positrons slowly decreases with the increase of energy,and then rise from about 10 GeV to several hundred GeV,which means there must be some sources in the Galaxy that produce electrons/positrons,i.e.,there are primary sources in the Galaxy.The positrons can be produced from gamma-ray pulsars,supernova remnant,pulsar wind nebula,and also can be produced from the annihilation of dark matter particles in the Galactic halo.This paper mainly studies the contribution of gamma-ray pulsars to the Galactic positrons.In this paper,we first briefly summarize the basic knowledge and radiation mechanism of pulsars,and then we consider the physical process of positron generation in pulsar.Based on the diffusion model of cosmic ray propagation,the positrons and electrons produced in the nearby gamma-ray pulsars are considered,and the positron observation results obtained by AMS-02 are well explained.