The mode switching of PSR B2020+28

This paper reports on polarimetric radiation propertiesbased on the switching modesof normal PSR B2020+28 by analyzing the data acquired from the Nanshan 25-m radio telescopeat 1556 MHz. With nearly 8 hours quasi-continuous observation, the data presented some striking and updated phenomena. The change of relative intensity between the leading and trailing components is the predominant feature of modeswitching. The intensity ratio between the leading and trailing components are measured for the individual profiles averaged over 30 seconds. It is found that there is an excess of high ratios over the normal distribution, which indicates that two modesexist in the pulsar. The distribution of abnormal modehas a narrower width indicating that the abnormal modeis more stable than the normal mode. A total of 76 modeswitching events are detected in our data. It spends 89 % in the normal modeand 11 % in the abnormal mode. The intrinsic distributions of modetimescales are constrained with power-law distributions. The significant difference in the index of the duration distribution between normal and abnormal modespossibly indicates that the timescale for the abnormal modeto get stable is shorter than that for the normal mode. The frequent switching between both modesmay indicate that the oscillations between different magnetospheric states are rapid.