Characteristics of storm time ion composition in the near-Earth plasma sheet using Geotail and RBSP measurements

Earth, Planets and Space

Masahito Nosé¹  Bhaskara Veenadhari²  Megha Pandya²  Sandeep Kumar²  A. T. Y. Lui³  Geoff D. Reeves⁴ 

[1] Data Analysis Centre for Geomagnetism and Space Magnetism, Graduate School of Science, Kyoto University;Indian Institute of Geomagnetism;Johns Hopkins University Applied Physics Laboratory;Space and Atmospheric Sciences Group, Los Alamos National Laboratory;

关键词: Inner magnetosphere;    Plasma sheet;    Ion composition;    Energy density;    Geomagnetic storm;   

DOI  :  10.1186/s40623-018-0977-3

来源: DOAJ

【 摘 要 】

Abstract Solar wind particles and ionospheric O+ ions influence the near-Earth plasma sheet and inner magnetospheric composition. We studied the behavior of H+, O+ and He+ ions (9–210 keV) for intense and moderate geomagnetic storms of solar cycle 23 and 24. An average energy density < ε > of ions over a given interval and flux enhancement is estimated using observations from satellites at different L values, namely STICS sensor on-board Geotail spacecraft and HOPE spectrometer on-board Radiation Belt Storm Probes. It provides a comprehensive understanding of the energy density variation of H+, O+ and He+ ions with the strength of IMF Bz, Psw, intensity of storms and L value. Statistically, we observed that (1) In the plasma sheet region, during main phase of the intense geomagnetic storm, < ε O+/H+ > and < ε He+/H+ > enhances, (2) < ε O+/H+ > is well correlated with Psw (CC = 0.86) and IMF Bz (CC = 0.85), (3) < ε O+/H+ > shows higher correlation (CC = 0.73) with Kp than < ε He+/H+ > (CC = 0.65), indicating a fairly good dependence on the strength of geomagnetic activity, (4) < ε O+/H+ > and < ε He+/H+ > dependence on L value indicates that O+/H+ and He+/H+ is more pronounced near L = 3. It is a cumulative extension of the previous studies on ion composition change which is in accordance with the existing picture of the plasma sheet and inner magnetosphere.

【 授权许可】

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