Xu, Heqiucen; Shiokawa, Kazuo; Oyama, Shin‑ichiro; Otsuka, Yuichi (2019) Thermospheric wind variations observed by a Fabry–Perot interferometer at Tromsø, Norway, at substorm onsets. Earth, Planets and Spacevolume 71, Article number: 93, https://doi.org/10.1186/s40623-019-1072-0
Thermospheric wind variations observed by a Fabry–Perot interferometer at Tromsø, Norway, at substorm onsets
|Author:||Xu, Heqiucen1; Shiokawa, Kazuo1; Oyama, Shin‑ichiro1,2,3;|
1Institute for Space‑Earth Environmental Research (ISEE), Nagoya University, Chikusa‑ku, Nagoya 464‑8601, Japan
2Space and Upper Atmospheric Sciences Group, National Institute of Polar Research, 10‑3, Midori‑cho, Tachikawa‑shi, Tokyo 190‑8518, Japan
3University of Oulu, Pentti Kaiteran katu 1, Linnanmaa, 90540 Oulu, Finland
|Online Access:||PDF Full Text (PDF, 1.4 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2019092629919
|Publish Date:|| 2019-09-26
Energy input from the magnetosphere during substorms can strongly affect the high-latitude thermosphere. The ionospheric current caused by thermospheric wind variations may also provide a feedback to the magnetosphere. In this study, we investigate the characteristics of high-latitude thermospheric wind variations at local substorm onsets at Tromsø, Norway, as well as the possibility of such feedback mechanism. A Fabry–Perot interferometer (FPI) at Tromsø provided wind measurements estimated from the Doppler shift of red-line emission (630.0 nm) of aurora and airglow. We analyzed wind data in 2009 with a time resolution of ~ 13 min. We first carefully identified the onset times of isolated local substorms at Tromsø and extracted four wind measurements from red-line emission. All these events showed increases of eastward components at local substorm onsets. For northward components, these events showed decreases except for those at midnight. The observed wind variations at local substorm onsets were less than 49 m/s. These values are much smaller than the typical plasma convection speed in the auroral zone. We speculate that the ionospheric current caused by thermospheric wind variations at local substorm onsets does not provide strong feedback to the development of substorm expansion phase in the magnetotail. We discuss the possible causes of these wind variations in the context of plasma convection, diurnal tides, and arc-associated electric field.
Earth, planets and space
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
115 Astronomy and space science
This work was supported by the Grant-in-Aid for Scientific Research (JP 15H05747, JP 15H05815, JP 16H02230, JP 16H06286, and JP 16K05569) from the Japan Society for the Promotion of Science. This work is partly supported by JSPS KAKENHI (16H06286). A part of work of SO was supported by the Academy of Finland project 314664. We are grateful for the support of the Leadership Development Program for Space Exploration and Research at Nagoya University.
|Academy of Finland Grant Number:||
314664 (Academy of Finland Funding decision)
© The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creat iveco mmons .org/licen ses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.