Details

Autor(en) / Beteiligte

• Luo, H.
• Kronberg, E. A.
• Nykyri, K.
• Trattner, K. J.
• Daly, P. W.
• Chen, G. X.
• Du, A. M.
• Ge, Y. S.

Titel

IMF dependence of energetic oxygen and hydrogen ion distributions in the near‐Earth magnetosphere

Ist Teil von

• Journal of geophysical research. Space physics, 2017-05, Vol.122 (5), p.5168-5180

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2017

Quelle

Wiley-Blackwell Full Collection

Beschreibungen/Notizen

• Energetic ion distributions in the near‐Earth plasma sheet can provide important information for understanding the entry of ions into the magnetosphere and their transportation, acceleration, and losses in the near‐Earth region. In this study, 11 years of energetic proton and oxygen observations (> ~274 keV) from Cluster/Research with Adaptive Particle Imaging Detectors were used to statistically study the energetic ion distributions in the near‐Earth region. The dawn‐dusk asymmetries of the distributions in three different regions (dayside magnetosphere, near‐Earth nightside plasma sheet, and tail plasma sheet) are examined in Northern and Southern Hemispheres. The results show that the energetic ion distributions are influenced by the dawn‐dusk interplanetary magnetic field (IMF) direction. The enhancement of ion intensity largely correlates with the location of the magnetic reconnection at the magnetopause. The results imply that substorm‐related acceleration processes in the magnetotail are not the only source of energetic ions in the dayside and the near‐Earth magnetosphere. Energetic ions delivered through reconnection at the magnetopause significantly affect the energetic ion population in the magnetosphere. We also believe that the influence of the dawn‐dusk IMF direction should not be neglected in models of the particle population in the magnetosphere. Key Points We present the statistical observation of energetic ion distributions in the dayside magnetosphere and near‐Earth plasma sheet The dawn‐dusk asymmetry of the distribution shows strong IMF dependence The location of magnetic reconnection at the magnetopause influences the dawn‐dusk asymmetry