A study on the position variation of mid-latitude ionospheric trough minimum and its controlling factors

作者：Liu Yi Wen^*; Xu Ji Sheng; Xu Liang; Yin Fan

来源：Chinese Journal of Geophysics, 2015, 58(1): 12-19.

DOI：10.6038/cjg20150102

• Mid-latitude ionospheric trough
• Geomagnetic storm
• Position variation
• Controlling factor
• CHAMP

Based on in-situ electron density measurements from CHAMP Planar Langmuir Probe (PLP), the position variation of mid-latitude ionospheric trough (MIT) minimum and its controlling factors is investigated. The CHAMP PLP data were collected from 2000 to 2009. The gradient of electron density was used to recognize the MIT structure. Then the method of statistical analysis was used to investigate the dependence of the position of MIT minimum to the magnetic local time and geographic longitude during geomagnetic quiet time. And then the relations of the MIT minimum position with geomagnetic indexes and solar wind parameters are analyzed respectively.
The results show that: (1) In the geomagnetic quiet period, the position of the trough minimum primarily varies with magnetic local time and geographic longitude. (2) The geographic longitude dependence of the trough minimum position shows that the latitudes of the MIT in the western hemisphere are higher than those in the eastern hemisphere as a whole. (3) The position variation of the MIT has significant correlations with SYM-H and AE, which indicates that SYM-H and AE are important controlling factors of the trough position. (4) The magnitude of dawn-dark component of solar wind electric field can significantly influence the position of the trough, but the influence of its polarity is relatively weaker. The magnetic local time and geomagnetic activity were regarded as the mainly factors controlling the movement of MIT. However, this paper indicates that the geographic longitude and the magnitude of dawn-dark component of solar wind electric field can also significantly influence the position of MIT. These factors should be considered in both theoretical and modeling researches in the future.

• 出版日期2015-1
• 单位武汉大学