Associating ground magnetometer observations with current or voltage generators

M. D. Hartinger, Z. Xu, C. R. Clauer, Y. Yu, D. R. Weimer, H. Kim, V. A. Pilipenko, D. T. Welling, Rico Behlke, Anna Naemi Willer

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Abstract

A circuit analogy for magnetosphere-ionosphere current systems has two extremes for driversof ionospheric currents: ionospheric elec tric fields/voltages constant while current/conductivity vary—the“voltage generator”—and current constant while electric field/conductivity vary—the “current generator.”Statistical studies of ground magnetometer observations associated with dayside Transient High LatitudeCurrent Systems (THLCS) driven by similar mechanisms find contradictory results using this paradigm:some studies associate THLCS with voltage generators, others with current generators. We argue that mostof this contradiction arises from two assumptions used to interpret ground magnetometer observations:(1) measurements made at fixed position relative to the THLCS field-aligned current and (2) negligibleauroral precipitation contributions to ionospheric conductivity. We use observations and simulations toillustrate how these two assumptions substantially alter expectations for magnetic perturbations associatedwith either a current or a voltage generator. Our results demonstrate that before interpreting groundmagnetometer observations of THLCS in the context of current/voltage generators, the location of a groundmagnetometer station relative to the THLCS field-aligned current and the location of any auroral zoneconductivity enhancements need to be taken into account.
Original languageEnglish
JournalJournal of Geophysical Research: Space Physics
Volume122
Issue number7
Pages (from-to)7130–7141
ISSN2169-9380
DOIs
Publication statusPublished - 2017

Keywords

  • Ground magnetometer
  • TCV
  • Sudden commencement;
  • Current generator
  • Voltage generator
  • Magnetosphere-ionosphere coupling

Cite this

Hartinger, M. D., Xu, Z., Clauer, C. R., Yu, Y., Weimer, D. R., Kim, H., Pilipenko, V. A., Welling, D. T., Behlke, R., & Naemi Willer, A. (2017). Associating ground magnetometer observations with current or voltage generators. Journal of Geophysical Research: Space Physics, 122(7), 7130–7141 . https://doi.org/10.1002/2017JA024140