Statistical correlation analysis of field-aligned currents measured by Swarm

Yang, Junying and Dunlop, Malcolm G and Lühr, H. and Xiong, Chao and Yang, Yanyan and Cao, Jin Bin and Wild, James Anderson and Li, L. Y. and Ma, Yuduan and Liu, Wenlong and Fu, Huishan and Lu, Haoyu and Waters, Colin and Ritter, Patricia (2018) Statistical correlation analysis of field-aligned currents measured by Swarm. Journal of Geophysical Research: Space Physics, 123 (10). pp. 8170-8184. ISSN 2169-9402

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Abstract

We investigate the statistical, dual‐spacecraft correlations of field‐aligned current (FAC) signatures between two Swarm spacecraft. For the first time, we infer the orientations of the current sheets of FACs by directly using the maximum correlations obtained from sliding data segments. The current sheet orientations are shown to broadly follow the mean shape of the auroral boundary for the lower latitudes and that these are most well ordered on the dusk side. Orientations at higher latitudes are less well ordered. In addition, the maximum correlation coefficients are explored as a function of magnetic local time and in terms of either the time shift (δt) or the shift in longitude (δlon) between Swarms A and C for various filtering levels and choice of auroral region. We find that the low‐latitude FACs show the strongest correlations for a broad range of magnetic local time centered on dawn and dusk, with a higher correlation coefficient on the dusk side and lower correlations near noon and midnight. The positions of maximum correlation are sensitive to the level of low‐pass filter applied to the data, implying temporal influence in the data. This study clearly reflects the two different domains of FACs: small‐scale (some tens of kilometers), which are time variable, and large‐scale (>50 km), which are rather stationary. The methodology is deliberately chosen to highlight the locations of small‐scale influences that are generally variable in both time and space. We may fortuitously find a potential new way to recognize bursts of irregular pulsations (Pi1B) using low‐Earth orbit satellites.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Geophysical Research: Space Physics
Additional Information:
This is the peer reviewed version of the following article: Yang, J. ‐Y., Dunlop, M. W., Lühr, H., Xiong, C., Yang, Y.‐Y., Cao, J. ‐B., et al. (2018). Statistical correlation analysis of field‐aligned currents measured by Swarm. Journal of Geophysical Research: Space Physics, 123, 8170–8184. https://doi.org/10.1029/2018JA025205 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1029/2018JA025205 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Subjects:
ID Code:
128126
Deposited By:
Deposited On:
11 Oct 2018 12:12
Refereed?:
Yes
Published?:
Published
Last Modified:
29 Nov 2020 05:14