A comparison of small-scale magnetic fluctuations in the Region 1 and 2 field-aligned current systems

作者:Wu J*; Bryant M S; Ridley C G; Shen Y; Yang L; Clausen L B N; McWilliams K A; Murphy K R; Mann I R; Ozeke L G; Korth H; Anderson B J; Waters C L
来源:JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS, 2017, 122(3): 3277-3290.
DOI:10.1002/2016JA023453

摘要

By determining the location and size of the Region 1 (R1) and Region 2 (R2) large-scale field-aligned currents (FACs) from Active Magnetosphere and Planetary Electrodynamics Response Experiment data, we are able to study the small-scale magnetic fluctuations observed by the Swarm satellites embedded within the large-scale FACs. A statistical comparison of R1 and R2 high-frequency fluctuations is presented in terms of different solar wind conditions and geomagnetic activities. We find that (1) the amplitude of high-frequency fluctuations in both R1 and R2 increases as the large-scale R1 and R2 FACs intensify; (2) high-frequency fluctuations in R1 peak near dayside dawn and dusk, while those in R2 peak around noon; (3) the location of the largest high-frequency fluctuations in R1 shifts in local time in response to IMF B-y, indicating a connection between the R1 fluctuation and the driving solar wind most likely explained by magnetic reconnection; and (4) high-frequency fluctuations in R2 are enhanced in a small region near local noon and respond clearly to nightside drivers, as characterized by the auroral electrojet index. Our analysis shows that the intensity of R1 and R2 high-frequency magnetic fluctuations is directly connected to the intensity of FACs, which implies that the magnetic fluctuations are closely related to the magnetospheric processes that drive them.

  • 出版日期2017-3
  • 单位Saskatoon; Saskatchewan