We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Challenging the Use of Ring Current Indices During Geomagnetic Storms.
- Authors
Sandhu, J. K.; Rae, I. J.; Walach, M.-T.
- Abstract
The ring current experiences dramatic enhancements during geomagnetic storms; however, understanding the global distribution of ring current energy content is restricted by spacecraft coverage. Many studies use ring current indices as a proxy for energy content, but these indices average over spatial variations and include additional contributions. We have conducted an analysis of Van Allen Probes' data, identifying the spatial distribution and storm-time variations of energy content. Ion observations from the HOPE and RBSPICE instruments were used to estimate energy content in L-MLT bins. The results show large enhancements particularly in the premidnight sector during the main phase, alongside reductions in local time asymmetry and intensity during the recovery phase. A comparison with estimated energy content using the Sym-H index was conducted. In agreement with previous results, the Sym-H index significantly overestimates (by up to ~4 times) the energy content, and we attribute the difference to contributions from additional current systems. A new finding is an observed temporal discrepancy, where energy content estimates from the Sym-H index maximize 3--9 h earlier than in-situ observations. Case studies reveal a complex relationship, where variable degrees of agreement between the Sym-H index and in-situ measurements are observed. The results highlight the drawbacks of ring current indices and emphasize the variability of the storm time ring current.
- Subjects
MAGNETIC storms; RING currents; SPATIAL distribution (Quantum optics); MIDNIGHT; GEOMAGNETISM
- Publication
Journal of Geophysical Research. Space Physics, 2021, Vol 126, Issue 2, p1
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2020JA028423