摘要
The inner vacuum gap model has become the foundation stone of most theorieson pulsar radio emission. The fundamental picture of this model is the sparking, which wasconjectured to be induced by magnetic absorption of background gamma photons. However, a questionis, can the sparking be triggered in the millisecond pulsars (MSPs) with magnetic fields (B) onlyabout 10~8 G? We investigate this problem by including the pair production above the inner gap.Under the assumption that the magnetic field is dipolar, our results show the background gamma-rayemission can not be the key factor that triggers the sparking, at least not in MSPs with B ～ 10~8G, if the temperature in the polar cap region is only so high as is observed (< 4 x 10~6K). Someother mechanisms are required.
The inner vacuum gap model has become the foundation stone of most theorieson pulsar radio emission. The fundamental picture of this model is the sparking, which wasconjectured to be induced by magnetic absorption of background gamma photons. However, a questionis, can the sparking be triggered in the millisecond pulsars (MSPs) with magnetic fields (B) onlyabout 10~8 G? We investigate this problem by including the pair production above the inner gap.Under the assumption that the magnetic field is dipolar, our results show the background gamma-rayemission can not be the key factor that triggers the sparking, at least not in MSPs with B ～ 10~8G, if the temperature in the polar cap region is only so high as is observed (< 4 x 10~6K). Someother mechanisms are required.
基金
Supported by the National Natural Science Foundation of China
