Periodical Dipolarization Processes in Earth's Magnetotail

Huang, Suming; Jiang, K.; Fu, H. S.; Yuan, Zhigang; Deng, Xiaohua; Li, H. M.; Xu, S. B.; He, L. H.; Wei, Yong; Zhang, J.; Zhang, Z. H.

doi:10.1029/2019gl086136

Cited by 21 publications

(21 citation statements)

References 49 publications

(88 reference statements)

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“…During their earthward propagation, such region provides a favorable condition for particle acceleration (e.g., Ashour‐Abdalla et al., 2011; Birn et al., 2013; Duan et al., 2014; Fu et al., 2011, 2019; Fu, Khotyaintsev, et al., 2013; Gabrielse et al., 2012; Grigorenko et al., 2016, 2017; Liu, Fu, Xu, Wang, et al., 2017; Liu, Fu, Xu, Cao, & Liu, 2017; Liu, Liu, et al., 2018; Liu & Fu, 2019; Lu, Angelopoulos, & Fu, 2016; Vaivads et al., 2011; Xu et al., 2018; Wu, Lu, et al., 2013). Specifically, electrons can be efficiently accelerated by adiabatic processes, such as Fermi and betatron mechanisms, respectively (e.g., Chen et al., 2019; Fu et al., 2011, 2019; Liu, Fu, Xu, Cao, & Liu, 2017; Pan et al., 2012; Tang et al., 2021; Zhao et al., 2019); or nonadiabatic processes, for example, wave‐particle interactions (e.g., Fu, Zhao, et al., 2020; Huang et al., 2012, 2019; Hwang et al., 2014; Zhang et al., 2018).…”

Section: Introductionmentioning

confidence: 99%

Broadband Electrostatic Waves Behind Dipolarization Front: Observations and Analyses

Guo

Cao

et al. 2021

JGR Space Physics

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Using high-resolution MMS data, we report the observations of broadband electrostatic waves associated with parallel electron temperature anisotropy ( 𝐴𝐴 𝐴𝐴𝑒𝑒‖ > 𝐴𝐴𝑒𝑒⟂ ) behind a dipolarization front (DF). These electrostatic waves include electrostatic solitary waves and electron cyclotron waves. To quantify electron anisotropy, we define the parallel flux anisotropy parameter 𝐴𝐴 𝐴𝐴= 𝐹𝐹‖∕𝐹𝐹⟂ − 1 , where 𝐴𝐴 𝐴𝐴 is phase space densities at each energy. By performing correlation analyses between parallel flux anisotropies ( 𝐴𝐴 𝐴𝐴𝐴𝐴 ) and power spectral densities (PSDs) of these waves, we find that: (a)𝐴𝐴 𝐴𝐴𝐴𝐴 in 0.8-20 keV are positively correlated with the parallel electric field fluctuations in 50-3,000 Hz; (b) 𝐴𝐴 𝐴𝐴𝐴𝐴 in 0.8-20 keV are positively correlated with perpendicular electric field fluctuations in all frequency ranges; (c) the correlation between parallel flux anisotropies and perpendicular electric field fluctuations is more significant in this case. We also discuss the possibility of electron firehose instability and wave-particle interactions. Our study promotes the understanding of the properties and dynamics of DFs.Plain Language Summary Dipolarization fronts (DFs), the leading edge of the earthward high speed plasma jets in the Earth's magnetotail, are characterized by a sudden increase of northward magnetic field. It plays crucial roles in global flux transport and energy conversion during substorm. Behind DFs, there are various plasma waves related to the electron temperature anisotropies. For example, the whistler waves excited by perpendicular electron temperature anisotropy have been widely observed. However, few studies on the relationship between parallel electron temperature anisotropy and waves are reported behind DFs. In this study, using MMS data, we report the observations of broadband electrostatic waves associated with parallel electron temperature anisotropy behind a DF, and quantitatively investigate the correlation between parallel electron anisotropies and power spectral densities of these waves.

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Section: Introductionmentioning

confidence: 99%

Broadband Electrostatic Waves Behind Dipolarization Front: Observations and Analyses

Guo

Cao

et al. 2021

JGR Space Physics

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“…The electron distributions at the DF and flux pileup region behind DF are various, such as isotropy, pancake, cigar (e.g., Fu et al, 2011) and rolling‐pin (Liu et al, 2017) distribution of suprathermal electrons. Anisotropic electron distribution and gradients in magnetic field and plasma density would result in abundant waves, such as whistler waves (e.g., Huang et al, 2012, 2016; Huang, Jiang, Fu, et al, 2019; Li et al, 2015), lower hybrid waves (e.g., Huang, Fu, Yuan, et al, 2015; Pan et al, 2018; Zhou et al, 2009), ion cyclotron waves (e.g., Huang et al, 2012; Huang, Yuan, Ni, et al, 2015), and magnetosonic waves (e.g., Zhou et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Observations of Electron Vortex at the Dipolarization Front

Jiang

Huang

Yuan

et al. 2020

Geophysical Research Letters

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Dipolarization front (DF), embedded in fast plasma flow, is a sharp structure with the increase of Bz in a short time and plays an important role in the energy dissipation and particle accelerations in the magnetotail. However, detailed physics at the small scales is still unclear in the DF due to the limitation of the previous mission. In the present study, an electron‐scale plateau in Bz is observed at the DF by Magnetospheric Multiscale (MMS) mission. By analyzing the velocity of the electrons, we find that the electron‐scale plateau is surrounded by a sub‐ion‐scale electron vortex, which is the first observation of electron vortex at the DF as far as we know. The magnetic field generated by the electron vortex cancels parts of the increase of Bz and causes the plateau. Strong asymmetric electric field and demagnetization of electrons and ions are observed at the boundary of the electron vortex. These results shed new light on that small‐scale structures can develop within the ion‐scale DF and affect the evolution and kinetic effects at the DF.

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“…The DFs are frequently reported in the nightside magnetotail of the Earth, Mercury, Saturn and Jupiter (e.g., Artemyev et al, 2020;Fu et al, 2011Fu et al, , 2013Huang et al, 2012Huang et al, , 2015a2015b, 2019Sun et al, 2016;Zhou et al, 2009Zhou et al, , 2013. In present study, we performed a statistical and comprehensive investigation on the DFs in the Saturn's magnetosphere using Cassini observations from January 1, 2005 to June 15, 2011.…”

Section: Discussionmentioning

confidence: 93%

Global Spatial Distribution of Dipolarization Fronts in the Saturn's Magnetosphere: Cassini Observations

Huang

Yuan

et al. 2021

Geophysical Research Letters

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In Saturn's magnetosphere, a lot of plasmas come from Enceladus, forming the plasma torus which is distributed at the range from 2.5 to 8 Rs (R S is the Saturn's radius). This internally generated plasma source is important for the evolution of Saturn magnetosphere (Kivelson & Southwood, 2005). Due to Saturn's rapid rotation, the magnetic field configuration and the plasma in Saturn's magnetosphere present the characteristic of rotation. The interaction between the solar wind and the revolving plasma and magnetic field structure results in the formation of the "disk-like" magnetosphere called as magnetodisc, and the plasma dynamics driven by the rotation is called the Vasyliunas cycle (Vasyliunas, 1983).In such a special Saturn's magnetosphere, the magnetic reconnection, which is considered to be one of the most important physical processes in coupling energy between the solar wind and the magnetosphere, would present with some different features. Normally, magnetic reconnections in magnetospheres usually occur in the nightside magnetotail where the current sheet is long and thin, rather than the dayside magnetodisc where the thick current sheet is not conducive to reconnection (Paschmann et al., 1979). Jackman

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Periodical Dipolarization Processes in Earth's Magnetotail

Cited by 21 publications

References 49 publications

Broadband Electrostatic Waves Behind Dipolarization Front: Observations and Analyses

Broadband Electrostatic Waves Behind Dipolarization Front: Observations and Analyses

Observations of Electron Vortex at the Dipolarization Front

Global Spatial Distribution of Dipolarization Fronts in the Saturn's Magnetosphere: Cassini Observations

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