Statistical Correlation Analysis of Field-Aligned Currents Measured by Swarm

Yang, J.- Y.; Dunlop, M. W.; Fu, H. -S.; Lu, H. -Y.; Waters, C.; Ritter, P.; Lühr, H.; Xiong, C.; Yang, Y. -Y.; Cao, J. -B.; Wild, J. A.; Li, L. -Y.; Ma, Y. -D.; Liu, W. -L.

Title: Statistical Correlation Analysis of Field-Aligned Currents Measured by Swarm
Creator: Yang, J.- Y.; Dunlop, M. W.; Fu, H. -S.; Lu, H. -Y.; Waters, C.; Ritter, P.; Lühr, H.; Xiong, C.; Yang, Y. -Y.; Cao, J. -B.; Wild, J. A.; Li, L. -Y.; Ma, Y. -D.; Liu, W. -L.
Relation: Journal of Geophysical Research: Space Physics Vol. 123, Issue 10, p. 8170-8184
Publisher Link: http://dx.doi.org/10.1029/2018JA025205
Publisher: Wiley-Blackwell
Resource Type: journal article
Date: 2018
Description: 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 (dt) or the shift in longitude (dlon) 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.
Subject: correlations; field-aligned currents; Pi1B
Identifier: http://hdl.handle.net/1959.13/1441275
Identifier: uon:41371
Identifier: ISSN:2169-9380
Language: eng
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