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EPP

地球与行星物理

ISSN  2096-3955

CN  10-1502/P

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An M6.9 earthquake at Mainling, Tibet on Nov.18, 2017
XueMei Zhang, GuangBao Du, Jie Liu, ZhiGao Yang, LiYe Zou, XiYan Wu
Recently Published , doi: 10.26464/epp2018009
[Abstract](139) [FullText HTML](27) [FullText PDF 0KB](18)
Abstract:
First results of optical meteor and meteor trail irregularity from simultaneous Sanya radar and video observations
GuoZhu Li, BaiQi Ning, Ao Li, SiPeng Yang, XiuKuan Zhao, BiQiang Zhao, WeiXing Wan
Recently Published , doi: 10.26464/epp2018002
[Abstract](34) [FullText HTML](20) [FullText PDF 0KB](12)
Abstract:
Meteoroids entering the Earth's atmosphere can create meteor trail irregularity seriously disturbing the background ionosphere. Although numerous observations of meteor trail irregularities were performed with VHF/UHF coherent scatter radars in the past, no simultaneous radar and optical instruments were employed to investigate the characteristics of meteor trail irregularity and its corresponding meteoroid. By installing multiple video cameras near the Sanya VHF radar site, an observational campaign was conducted during the period from November 2016 to February 2017. A total of 242 optical meteors with simultaneous non-specular echoes backscattered from the plasma irregularities generated in the corresponding meteor trails were identified. A good agreement between the angular positions of non-specular echoes derived from the Sanya radar interferometer and those of optical meteors was found, validating that the radar system phase offsets have been properly calibrated. The results also verify the interferometry capability of Sanya radar for meteor trail irregularity observation. The non-specular echoes with simultaneous optical meteors were detected at magnetic aspect angles greater than ~78°. Based on the meteor visual magnitude estimated from the optical data, it was found that the radar non-specular echoes corresponding to brighter meteors survived for longer duration. This could provide observational evidence for the significance of meteoroid mass on the duration of meteor trail irregularity. On the other hand, the simultaneous radar and video common-volume observations showed that there were some cases with optical meteors but without radar non-specular echoes. One possibility could be that some of the optical meteors appeared at extremely low altitudes where meteor trail irregularities rarely occur.
Preliminary result for the rupture process of Nov.13, 2017, Mw7.3 earthquake at Iran-Iraq border
WeiMin Wang, JianKun He, JinLai Hao, ZhenXing Yao
Recently Published , doi: 10.26464/epp2018008
[Abstract](40) [FullText HTML](46) [FullText PDF 0KB](10)
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Radiation belt electron scattering by whistler-mode chorus in the Jovian magnetosphere: Importance of ambient and wave parameters
BinBin Ni, Jing Huang, YaSong Ge, Jun Cui, Yong Wei, XuDong Gu, Song Fu, Zheng Xiang, ZhengYu Zhao
Recently Published , doi: 10.26464/epp2018001
[Abstract](210) [FullText HTML](117) [FullText PDF 12576KB](44)
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Whistler-mode chorus waves are regarded as an important acceleration mechanism contributing to the formation of relativistic and ultra-relativistic electrons in the Jovian radiation belts. Quantitative determination of the chorus wave driven electron scattering effect in the Jovian magnetosphere requires detailed information of both ambient magnetic field and plasma density and wave spectral property, which however cannot be always readily acquired from observations of existed missions to Jupiter. We therefore perform a comprehensive analysis of the sensitivity of chorus induced electron scattering rates to ambient magnetospheric and wave parameters in the Jovian radiation belts to elaborate to which extent the diffusion coefficients depend on a number of key input parameters. It is found that quasi-linear electron scattering rates by chorus can be strongly affected by the ambient magnetic field intensity, the wave latitudinal coverage, and the peak frequency and bandwidth of the wave spectral distribution in the Jovian magnetosphere, while they only rely slightly on the background plasma density profile and the peak wave normal angle, especially when the wave emissions are confined at lower latitudes. Given the chorus wave amplitude, chorus induced electron scattering rates strongly depend on Jovian L-shell to exhibit a tendency approximately proportional to LJ3. Our comprehensive analysis explicitly demonstrates the importance of reliable information of both the ambient magnetospheric state and wave distribution property to understanding the dynamic electron evolution in the Jovian radiation belts and therefore has implications for future mission planning to explore the extreme particle radiation environment of Jupiter and its satellites.

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EDITORIAL
Earth science, planetary vision——A foreword to Earth and Planetary Physics (EPP)
WeiXing Wan
2017, 1(1): 1-1   doi: 10.26464/epp2017001
[Abstract](194) [FullText HTML](125) [FullText PDF 93KB](29)
Abstract:
RESEARCH ARTICLE
Corotating drift-bounce resonance of plasmaspheric electron with poloidal ULF waves
Qiu-Gang Zong, YongFu Wang, Jie Ren, XuZhi Zhou, SuiYan Fu, Robert Rankin, Hui Zhang
2017, 1(1): 2-12   doi: 10.26464/epp2017002
[Abstract](884) [FullText HTML](278) [FullText PDF 660KB](126)
Abstract:
The purpose of this paper is to understand how low energy plasmaspheric electrons respond to ULF waves excited by interplanetary shocks impinging on magnetosphere. It is found that both energy and pitch angle dispersed plasmaspheric electrons with energy of a few eV to tens of eV can be generated simultaneously by the interplanetary shock. The subsequent period of successive dispersion signatures is around 40 s and is consistent with the ULF wave period (third harmonic). By tracing back the energy and pitch angle dispersion signatures, the position of the electron injection region is found to be off-equator at around –32° in the southern hemisphere. This can be explained as the result of injected electrons being accelerated by higher harmonic ULF waves (e.g. third harmonic) which carry a larger amplitude electric field off-equator. The dispersion signatures are due to the flux modulations (or accelerations) of " local” plasmaspheric electrons rather than electrons from the ionosphere. With the observed wave-borne large electric field excited by the interplanetary shock impact, the kinetic energy can increase to a maximum of 23 percent in one bouncing cycle for plasmaspheric electrons satisfying the drift-bounce resonance condition by taking account of both the corotating drift and bounce motion of the local plasmaspheric electron.
Ambient noise surface wave tomography of marginal seas in east Asia
Qing Wang, XiaoDong Song, JianYe Ren
2017, 1(1): 13-25   doi: 10.26464/epp2017003
[Abstract](414) [FullText HTML](198) [FullText PDF 8105KB](89)
Abstract:
We conducted ambient noise tomography in east Asia, including the Chinese coastal provinces, Korea Peninsular, Japan, Taiwan Island, and marginal seas in between. We retrieved Rayleigh Green’s functions from inter-station correlations of 12 months of continuous waveform data at 573 broadband stations in the region. We obtained group and phase velocity dispersion curves and dispersion maps for periods from 10 to 70 s and inverted for 3D Vs model of the crust and uppermost mantle. Moho and lithosphere thickness were derived from the 3D model. We observed three prominent low velocity zones in the upper mantle, two in the accretionary wedges above the Pacific and Philippine subduction slabs and one beneath the Changbai Mountain region. The crust and lithosphere are generally thin in the region. The velocity anomalies, crustal thickness, and lithosphere thickness all show a similar trend in NNE-SSW direction. The lithosphere shows a striking " sausage”-type structure with alternating thickness. The crust thickness and lithosphere thickness both decrease progressively from NW to SE direction, which coincides with the distribution of episodic magmatism in SE China. We propose that the subduction of paleo-Pacific slab and its rollback were mainly responsible for the crustal and lithosphere extension and the mantle lithosphere removal in east Asia.
A seismic model for crustal structure in North China Craton
TianYu Zheng, YongHong Duan, WeiWei Xu, YinShuang Ai
2017, 1(1): 26-34   doi: 10.26464/epp2017004
[Abstract](801) [FullText HTML](111) [FullText PDF 2592KB](75)
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We present a digital crustal model in North China Craton (NCC). The construction of crustal model is based on digitization of original seismic sounding profiles, and new results of three-dimensional structure images of receiver functions. The crustal model includes seismic velocity and thickness of crustal layers. The depths to Moho indicate a thinning crust ~30 km in the east areas and a general westward deepening to more than 40 km in the west. The P wave velocity varies from 2.0 to 5.6 km/s in the sedimentary cover, from 5.8 to 6.4 km/s in the upper crust, and from 6.5 to 7.0 km/s in the lower crust. By analyzing regional trends in crustal structure and links to tectonic evolution illustrated by typical profiles, we conclude that: (1) The delimited area by the shallowing Moho in the eastern NCC represents the spatial range of the craton destruction. The present structure of the eastern NCC crust retains the tectonic information about craton destruction by extension and magmatism; (2) The tectonic activities of the craton destruction have modified the crustal structure of the convergence boundaries at the northern and southern margin of the NCC; (3) The Ordos terrene may represent a relatively stable tectonic feature in the NCC, but with the tectonic remnant of the continental collision during the assembly of the NCC in the north-east area and the response to the lateral expansion of the Tibetan Plateau during the Cenozoic in the south-west.
Correlations between plasmapause evolutions and auroral signatures during substorms observed by Chang’e-3 EUV Camera
XiaoXin Zhang, Fei He, Bo Chen, Chao Shen, HuaNing Wang
2017, 1(1): 35-43   doi: 10.26464/epp2017005
[Abstract](434) [FullText HTML](337) [FullText PDF 1277KB](46)
Abstract:
The plasmapause locations determined from the Chang’e-3 (CE-3) Extreme Ultraviolet Camera (EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program (DMSP) Special Sensor Ultraviolet Spectrographic Imager (SSUSI) images are used to investigate the plasmaspheric evolutions during substorms. The most important finding is a nightside pointing plasmaspheric plume observed at 23:05 UT on 21 April 2014 under quiet solar wind and geomagnetic conditions, which drifted from the dusk sector. High correlations between the plasmapause evolutions and the auroral signatures exist during substorms. After substorm onset, the plasmapause erosion and the equatorward expansion of the auroral oval occur almost simultaneously in both MLT and UT, and then both the erosion and the expansion propagate westward and eastward. It is suggested that the plasmaspheric erosion and its MLT propagations are induced by the enhanced earthward plasma convection during substorm period, and the substorm dipolarization causes pitch-angle scattering of plasma sheet electrons and the resulting precipitation excites aurora emissions at the same time.
A simulation study of 630 nm and 557.7 nm airglow variations due to dissociative recombination and thermal electrons by high-power HF heating
Tong Dang, JiuHou Lei, XianKang Dou, WeiXing Wan
2017, 1(1): 44-52   doi: 10.26464/epp2017006
[Abstract](963) [FullText HTML](158) [FullText PDF 1055KB](43)
Abstract:
One of the important effects of the ionospheric modification by high-power waves is the airglow enhancement. Both the thermal electrons and the dissociation recombination contribute to generate the airglow emissions during HF heating. However, the relative importance of the airglow emission induced by dissociative recombination and thermal electrons has been rarely investigated. In this study, we carry out a simulation study on the airglow produced by high-power HF heating at nighttime associated with dissociative recombination and thermal electrons. SAMI2 (Sami2 is Another Model of the Ionosphere) is employed to simulate the ionospheric variations during the HF heating. The main conclusions from this study are as follows: (1) For the airglow induced by dissociative recombination, both 630.0 nm and 557.7 nm emissions show a decrease at the heating wave reflection height during the heating period, while when the heating is turned off, an increase is shown at lower altitudes. The reduction of airglow during the heating is caused by the rapid increase of electron temperature and the diffusion of plasmas dominates the after-heating airglow enhancement. (2) 630.0 nm emission due to thermal electrons is greatly enhanced at the wave reflection height, indicating that thermal electrons play a major role in exciting 630.0 nm emission. For the 557.7 nm emission, the excitation threshold (4.17 eV) is too high for thermal electrons. (3) The combined effect of dissociative recombination and thermal electrons could be the possible reason for the observed X-mode (extraordinary mode) suppression of 630.0 nm airglow during O-mode (ordinary mode) enhancement.
LETTER
Observations of loading-unloading process at Saturn’s distant magnetotail
ZhongHua Yao
2017, 1(1): 53-57   doi: 10.26464/epp2017007
[Abstract](351) [FullText HTML](177) [FullText PDF 684KB](36)
Abstract:
Using in-situ measurements from the Cassini spacecraft in 2013, we report an Earth substorm-like loading-unloading process at Saturn’s distant magnetotail. We found that the loading process is featured with two distinct processes: a rapid loading process that was likely driven by an internal source and a slow loading process that was likely driven by solar wind. Each of the two loading processes could also individually lead to an unloading process. The rapid internal loading process lasts for ~ 1-2 hours; the solar wind driven loading process lasts for ~ 3-18 hours and the following unloading process lasts for ~1-3 hours. In this letter, we suggest three possible loading-unloading circulations, which are fundamental in understanding the role of solar wind in driving giant planetary magnetospheric dynamics.
Exact local refinement using Fourier interpolation for nonuniform-grid modeling
JinHai Zhang, ZhenXing Yao
2017, 1(1): 58-62   doi: 10.26464/epp2017008
[Abstract](227) [FullText HTML](231) [FullText PDF 698KB](46)
Abstract:
Numerical solver using a uniform grid is popular due to its simplicity and low computational cost, but would be unfeasible in the presence of tiny structures in large-scale media. It is necessary to use a nonuniform grid, where upsampling the wavefield from the coarse grid to the fine grid is essential for reducing artifacts. In this paper, we suggest a local refinement scheme using the Fourier interpolation, which is superior to traditional interpolation methods since it is theoretically exact if the input wavefield is band limited. Traditional interpolation methods would fail at high upsampling ratios (say 50); in contrast, our scheme still works well in the same situations, and the upsampling ratio can be any positive integer. A high upsampling ratio allows us to greatly reduce the computational burden and memory demand in the presence of tiny structures and large-scale models, especially for 3D cases.
PERSPECTIVE
A planetary perspective on Earth’s space environment evolution
Yong Wei, XinAn Yue, ZhaoJin Rong, YongXin Pan, WeiXing Wan, RiXiang Zhu
2017, 1(1): 63-67   doi: 10.26464/epp2017009
[Abstract](194) [FullText HTML](82) [FullText PDF 367KB](29)
Abstract:
The planet Earth is an integrated system, in which its multi-spheres are coupled, from the space to the inner core. Whether the space environment in short to long terms has been controlled by the earth’s interior process is contentious. In the past several decades, space weather and space climate have been extensively studied based on either observation data measured directly by man-made instruments or ancient data inferred indirectly from some historical medium of past thousands of years. The acquired knowledge greatly helps us to understand the dynamic processes in the space environment of modern Earth, which has a strong magnetic dipole and an oxygen-rich atmosphere. However, no data is available for ancient space weather and climate (>5 ka). Here, we propose to take the advantage of " space-diversity” to build a " generalized planetary space family”, to reconcile the ancient space environment evolution of planet Earth from modern observations of other planets in our solar system. Such a method could also in turn give us a valuable insight into other planets’ evolution.
REPORT
Observations of the solar corona during the total solar eclipse on 21 August 2017
Hui Tian, ZhongQuan Qu, YaJie Chen, LinHua Deng, ZhengHua Huang, Hao Li, Yue Zhong, Yu Liang, JingWen Zhang, YiGong Zhang, BaoLi Lun, XiangMing Cheng, XiaoLi Yan, ZhiKe Xue, YuXin Xin, ZhiMing Song, YingJie Zhu, Tanmoy Samanta
2017, 1(1): 68-71   doi: 10.26464/epp2017010
[Abstract](204) [FullText HTML](191) [FullText PDF 1643KB](37)
Abstract:
Monitoring the geospace response to the Great American Solar Eclipse on 21 August 2017
Shun-Rong Zhang, Philip J. Erickson, Larisa P. Goncharenko, Anthea J. Coster, Nathaniel A. Frissell
2017, 1(1): 72-76   doi: 10.26464/epp2017011
[Abstract](276) [FullText HTML](100) [FullText PDF 8049KB](42)
Abstract:
show more results
Corotating drift-bounce resonance of plasmaspheric electron with poloidal ULF waves
Qiu-Gang Zong, YongFu Wang, Jie Ren, XuZhi Zhou, SuiYan Fu, Robert Rankin, Hui Zhang
2017, 1(1): 2-12   doi: 10.26464/epp2017002
[Abstract](884) [FullText HTML](278) [FullText PDF](126)
Ambient noise surface wave tomography of marginal seas in east Asia
Qing Wang, XiaoDong Song, JianYe Ren
2017, 1(1): 13-25   doi: 10.26464/epp2017003
[Abstract](414) [FullText HTML](198) [FullText PDF](89)
A seismic model for crustal structure in North China Craton
TianYu Zheng, YongHong Duan, WeiWei Xu, YinShuang Ai
2017, 1(1): 26-34   doi: 10.26464/epp2017004
[Abstract](801) [FullText HTML](111) [FullText PDF](75)
Correlations between plasmapause evolutions and auroral signatures during substorms observed by Chang’e-3 EUV Camera
XiaoXin Zhang, Fei He, Bo Chen, Chao Shen, HuaNing Wang
2017, 1(1): 35-43   doi: 10.26464/epp2017005
[Abstract](434) [FullText HTML](337) [FullText PDF](46)
Exact local refinement using Fourier interpolation for nonuniform-grid modeling
JinHai Zhang, ZhenXing Yao
2017, 1(1): 58-62   doi: 10.26464/epp2017008
[Abstract](227) [FullText HTML](231) [FullText PDF](46)
Radiation belt electron scattering by whistler-mode chorus in the Jovian magnetosphere: Importance of ambient and wave parameters
BinBin Ni, Jing Huang, YaSong Ge, Jun Cui, Yong Wei, XuDong Gu, Song Fu, Zheng Xiang, ZhengYu Zhao
doi: 10.26464/epp2018001
[Abstract](210) [FullText HTML](117) [FullText PDF](44)
A simulation study of 630 nm and 557.7 nm airglow variations due to dissociative recombination and thermal electrons by high-power HF heating
Tong Dang, JiuHou Lei, XianKang Dou, WeiXing Wan
2017, 1(1): 44-52   doi: 10.26464/epp2017006
[Abstract](963) [FullText HTML](158) [FullText PDF](43)
Monitoring the geospace response to the Great American Solar Eclipse on 21 August 2017
Shun-Rong Zhang, Philip J. Erickson, Larisa P. Goncharenko, Anthea J. Coster, Nathaniel A. Frissell
2017, 1(1): 72-76   doi: 10.26464/epp2017011
[Abstract](276) [FullText HTML](100) [FullText PDF](42)
Observations of the solar corona during the total solar eclipse on 21 August 2017
Hui Tian, ZhongQuan Qu, YaJie Chen, LinHua Deng, ZhengHua Huang, Hao Li, Yue Zhong, Yu Liang, JingWen Zhang, YiGong Zhang, BaoLi Lun, XiangMing Cheng, XiaoLi Yan, ZhiKe Xue, YuXin Xin, ZhiMing Song, YingJie Zhu, Tanmoy Samanta
2017, 1(1): 68-71   doi: 10.26464/epp2017010
[Abstract](204) [FullText HTML](191) [FullText PDF](37)
Observations of loading-unloading process at Saturn’s distant magnetotail
ZhongHua Yao
2017, 1(1): 53-57   doi: 10.26464/epp2017007
[Abstract](351) [FullText HTML](177) [FullText PDF](36)

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