Electron trapping around a magnetic null

• Published in: Geophysical research letters 2008-07, Vol.35 (14), p.n/a
• Main Authors: He, J.-S., Zong, Q.-G., Deng, X.-H., Tu, C.-Y., Xiao, C.-J., Wang, X.-G., Ma, Z.-W., Pu, Z.-Y., Lucek, E., Pedersen, A., Fazakerley, A., Cornilleau-Wehrlin, N., Dunlop, M. W., Tian, H., Yao, S., Tan, B., Fu, S.-Y., Glassmeier, K.-H., Reme, H., Dandouras, I., Escoubet, C. P.
• Format: Article
• Language: English
• Subjects: Earth sciences; Earth, ocean, space; electron trapping; Exact sciences and technology; magnetic null pair; magnetic reconnection
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2008GL034085

Magnetic reconnection is an important process in astrophysical, space and laboratory plasmas. The magnetic null pair structure is theoretically suggested to be a crucial feature of the three‐dimensional magnetic reconnection. The physics around the null pair, however, has not been explored in combination with the magnetic field configuration deduced from in situ observations. Here, we report the identification of the configuration around a null pair and simultaneous electron dynamics near one null of the pair, observed by four Cluster spacecraft in the geo‐magnetotail. Further, we propose a new scenario of electron dynamics in the null region, suggesting that electrons are temporarily trapped in the central reconnection region including electron diffusion region resulting in an electron density peak, accelerated possibly by parallel electric field and electron pressure gradient, and reflected from the magnetic cusp mirrors leading to the bi‐directional energetic electron beams, which excite the observed high frequency electrostatic waves.