Study of auroral current system using satellite observations and a magnetic inversion method

2014 Fiscal Year Final Research Report

• Project/Area Number: 23540524
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Space and upper atmospheric physics
• Research Institution: Nagoya University
• Principal Investigator: IEDA Akimasa 名古屋大学, 太陽地球環境研究所, 助教 (70362209)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 電離層電気伝導度 / Chapaman理論 / 電離圏 / 太陽天頂角 / 太陽放射 / 太陽EUV / 超高層物理学 / 宇宙科学

Outline of Final Research Achievements

The solar zenith angle (SZA) dependence of the conductance is studied and a simple theoretical form for the conductance is developed, using the peak plasma production height. The daytime electric conductance is associated with plasma created by solar extreme ultraviolet radiation incident on the neutral atmosphere of the Earth. However, it has been uncertain whether previous conductance models are consistent with the ideal Chapman theory for such plasma productions. We found that the SZA dependence of the conductance is consistent with the Chapman theory after simple modifications. An additional consideration is necessary for the Hall conductance, which decreases with increasing SZA more rapidly than the Pedersen conductance. This rapid decrease is presumably caused by a thinning of the Hall conductivity layer from noon toward nighttime. We expressed this thinning in terms of the peak production height in the Chapman theory.

Free Research Field

地球電離圏、地球磁気圏