摘要： This paper reports the existence of plasma caves, minima in the electron density located at 5–10° to the magnetic equator, in the bottomside ionosphere based on electron densities simulations from the International Reference Ionosphere (IRI‐2007) and clear evidences given by plasma density and drift measurements of the Dynamic Explorer 2 (DE 2) satellite during 1981–1983. The IRI simulations suggest plasma caves as daytime features (08:00–19:00 LT; length of 18,158 km in the longitudinal direction), that range from theE region up to about 300 km altitude with 10° (or 1100 km) width in the latitudinal direction. In situ measurements of the ion and electron densities probed by the DE 2 confirm the existence of the plasma caves at low altitudes of the EIA ionosphere. The unexpected downward and upward (or weakly and strongly upward) ion drifts at the magnetic equator and the two off equators seem to play an important role responsible for the plasma cave formation. Key Points Existence of ionospheric plasma cave Dynamic Explorer 2 in situ ion and electron density measurements Vertical drift in the lower ionosphere 其他題名： J. Geophys. Res 出版者： Washington, DC: Blackwell Publishing Ltd 出版日期： 2012-11 出處： Journal of Geophysical Research: Space Physics, 2012-11, Vol.117 (A11), p.n/a 資源來源： Wiley Online Library Journals AutoHoldings 版權： 2012. American Geophysical Union. All Rights Reserved. 版權： 2014 INIST-CNRS 版權： Copyright American Geophysical Union 2012 識別號： ISSN: 0148-0227 識別號： ISSN: 2169-9380 識別號： EISSN: 2156-2202 識別號： EISSN: 2169-9402 識別號： DOI: 10.1029/2012JA017868
