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SAPS intensification during substorm recovery: A multi-instrument case study

Makarevich R. A., A. C. Kellerman, J. C. Devlin, H. Ye, L. R. Lyons, Y. Nishimura, (2011), SAPS intensification during substorm recovery: A multi-instrument case study, J. of Geophys. Res. [Space Physics], 116, doi:10.1029/2011JA016916

Abstract

A case of the major intensification of the subauroral polarization stream (SAPS) during the substorm recovery phase is presented. The continuous high-time-resolution Doppler velocity measurements in the subauroral and auroral regions were conducted with the Unwin HF radar, and these are analyzed in the context of the simultaneous and coincident measurements of the auroral luminosity and the total electron content (TEC) by the IMAGE and GPS satellites. Additional information was provided by other SuperDARN radars, DMSP F15 satellite crossing the fully-developed SAPS region, ground-based measurements near the location of the substorm onset, and GOES and LANL satellites in the inner magnetosphere. The association between the SAPS and TEC trough is further substantiated at short timescales and TEC is shown to exhibit two distinct types of responses to substorm onset poleward of and within SAPS, with no evidence of a TEC decrease during SAPS intensification. It is argued that the positive feedback between the electric fields and electron densities was probably not responsible for the observed SAPS intensification. Moreover, it is proposed that the strong and steady plasma acceleration within SAPS may be triggered by a burst of auroral activity, rather than accompanied by a similarly steady variation in other observed parameters either in the ionosphere or in the inner magnetosphere. It is also argued that the SAPS intensification occurring during the recovery phase is not necessarily expected from the current models of the SAPS formation and evolution, but is consistent with the observationally-based view of a fully-developed SAPS as a substorm recovery phenomenon.

Authors (sorted by name)

Devlin Kellerman Lyons Makarevich Nishimura Ye

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Acknowledgments

TIGER is supported by a consortium of institutions: La Trobe University, Monash University, University of Adelaide, University of Newcastle, ISR Division DSTO and IPS Radio and Space Services. Additional funding toward construction of the TIGER radars was received from the ARC, US Air Force Office of Scientific Research, British Antarctic Survey and RLM Systems Pty Ltd, Australia. The authors gratefully acknowledge H. U. Frey of the Space Sciences Lab at the University of California at Berkeley for providing the IMAGE FUV data, the Center for Space Sciences at the University of Texas at Dallas and the US Air Force for the DMSP thermal plasma data, D. DeLapp and G. Reeves of Los Alamos National Laboratory for the SOPA LANL particle flux data, T. Onsager of NOAA and CDAWeb for the GOES 10 energetic particle sensor data, H. J. Singer of NOAA/SEC and CDAWeb for the GOES 10 magnetometer data, International Global Navigation Satellite Systems Service for the GPS data, Geoscience Australia for the MQI magnetometer data, and IPS Radio and Space Services for the MQI riometer data.

Bibtex

@article{doi:10.1029/2011JA016916,
author = {Makarevich, Roman A. and Kellerman, A. C. and Devlin, J. C. and Ye, H. and Lyons, L. R. and Nishimura, Y.},
title = {SAPS intensification during substorm recovery: A multi-instrument case study},
journal = {Journal of Geophysical Research: Space Physics},
year = {2011},
volume = {116},
number = {A11},
pages = {},
keywords = {coupling, ionosphere, magnetosphere, polarization stream, substorm},
doi = {10.1029/2011JA016916},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2011JA016916},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2011JA016916},
abstract = {A case of the major intensification of the subauroral polarization stream (SAPS) during the substorm recovery phase is presented. The continuous high-time-resolution Doppler velocity measurements in the subauroral and auroral regions were conducted with the Unwin HF radar, and these are analyzed in the context of the simultaneous and coincident measurements of the auroral luminosity and the total electron content (TEC) by the IMAGE and GPS satellites. Additional information was provided by other SuperDARN radars, DMSP F15 satellite crossing the fully-developed SAPS region, ground-based measurements near the location of the substorm onset, and GOES and LANL satellites in the inner magnetosphere. The association between the SAPS and TEC trough is further substantiated at short timescales and TEC is shown to exhibit two distinct types of responses to substorm onset poleward of and within SAPS, with no evidence of a TEC decrease during SAPS intensification. It is argued that the positive feedback between the electric fields and electron densities was probably not responsible for the observed SAPS intensification. Moreover, it is proposed that the strong and steady plasma acceleration within SAPS may be triggered by a burst of auroral activity, rather than accompanied by a similarly steady variation in other observed parameters either in the ionosphere or in the inner magnetosphere. It is also argued that the SAPS intensification occurring during the recovery phase is not necessarily expected from the current models of the SAPS formation and evolution, but is consistent with the observationally-based view of a fully-developed SAPS as a substorm recovery phenomenon.}
}