Pulsar giant pulse: Coherent instability near light cylinder

作     者：WeiYang Wang JiGuang Lu SongBo Zhang XueLei Chen Rui Luo RenXin Xu 

作者机构：Key Laboratory for Computational Astrophysics National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University National Astronomical Observatories Chinese Academy of Sciences Key Laboratory of Radio Astronomy Chinese Academy of Sciences Purple Mountain Observatory Chinese Academy of Sciences CSIRO Astronomy and Space Science Australia Telescope National Facility International Centre for Radio Astronomy Research University of Western Australia Center for High Energy Physics Peking University Kavli Institute for Astronomy and Astrophysics Peking University Department of Astronomy School of Physics Peking University 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2019年第62卷第7期

页      面：113-122页

核心收录：

学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学] 

基　　金：supported by the China Program of International ST Cooperation 2016YFE 0100300 the National Natural Science Foundation of China (Grant Nos. 11473044, 11633004, and 11653003) the Chinese Academy of Sciences (Grant No. QYZDJ-SSW-SLH017) supported by the the National Natural Science Foundation of China (Grant No. 11225314) the Open Project Program of the Key Laboratory of Radio Astronomy, Chinese Academy of Sciences supported by the National Natural Science Foundation of China (Grant No. U15311243) the National Basic Research Program of China (Grant Nos. 2015CB857101, XDB23010200, 11690024, 11373011) the Max-Planck Partner Group supported by the National Key R&D Program of China (Grant No. 2017YFA0402602) the National Natural Science Foundation of China (Grant Nos. 11673002, and U1531243) the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB23010200) supported by the National Natural Science Foundation of China (Grant Nos. 11573039, 11661161015, and 11790301) supported by the Special Funding for Advanced Users, budgeted and administrated by Center for Astronomical Mega-Science, Chinese Academy of Sciences (CAMS) 

主　　题：neutron star pulsar radiation mechanisms instabilities in plasmas 

摘      要：Giant pulses(GPs) are extremely bright individual pulses of radio pulsar. In microbursts of Crab pulsar, which is an active GP emitter, zebra-pattern-like spectral structures are observed, which are reminiscent of the zebra bands that are observed in type Ⅳ solar radio flares. However, band spacing linearly increases with the band center frequency of ～5-30 GHz. In this study, we propose that the Crab pulsar GP can originate from the coherent instability of plasma near a light cylinder. Further, the growth of coherent instability can be attributed to the resonance observed between the cyclotron-resonant-excited wave and the background plasma oscillation. The particles can be injected into the closed-field line regions owing to magnetic reconnection near a light cylinder. These particles introduce a large amount of free energy that further causes cyclotron-resonant instability, which grows and amplifies radiative waves at frequencies close to the electron cyclotron harmonics that exhibit zebra-pattern-like spectral band structures. Further, these structures can be modulated by the resonance between the cyclotron-resonant-excited wave and the background plasma oscillation. In this scenario, the band structures of the Crab pulsar can be well fitted by a coherent instability model, where the plasma density of a light cylinder should be ～10^(13-15) cm^(-3), with an estimated gradient of 5.5 × 10~5 cm^(-4). This process may be accompanied by high-energy emissions. Similar phenomena are expected to be detected in other types of GP sources that have magnetic fields of ? 106 G in a light cylinder.