title: Alfvén waves as a solar-interplanetary driver of the thermospheric disturbances.
abstract: Alfvén waves have been proposed as an important mechanism for the heating of the Sun's outer atmosphere and the acceleration of solar wind, but they are generally believed to have no significant impact on the Earth's upper atmosphere under quiet geomagnetic conditions due to their highly fluctuating nature of interplanetary magnetic field (i.e., intermittent southward magnetic field component). Here we report that a long-duration outward propagating Alfvén wave train carried by a high-speed stream produced continuous (~2 days) and strong (up to ± 40%) density disturbances in the Earth's thermosphere in a way by exciting multiple large-scale gravity waves in auroral regions. The observed ability of Alfvén waves to excite large-scale gravity waves, together with their proved ubiquity in the solar atmosphere and solar wind, suggests that Alfvén waves could be an important solar-interplanetary driver of the global thermospheric disturbances.
authors.affiliation: State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jianpeng
authors.initials: J
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Fengsi
authors.initials: F
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Xueshang
authors.initials: X
authors.lastname: Feng
authors.affiliation: Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Fukuoka, 812-8581, Japan.
authors.forename: Huixin
authors.initials: H
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ionospheric Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.|Beijing National Observatory of Space Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Weixing
authors.initials: W
authors.lastname: Wan
authors.affiliation: Department of Astronomy, Beijing Normal University, Beijing 100875, China.
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Jiyao
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Chaoxu
authors.initials: C
authors.lastname: Liu