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Observation of two distinct, rapid loss mechanisms during the 20 November 2003 radiation belt dropout event

Bortnik J., R. M. Thorne, T. P. O’Brien, J. C. Green, R. J. Strangeway, Y. Y. Shprits, D. N. Baker, (2006), Observation of two distinct, rapid loss mechanisms during the 20 November 2003 radiation belt dropout event, J. of Geophys. Res. [Space Physics], 111, doi:10.1029/2006JA011802

Abstract

The relativistic electron dropout event on 20 November 2003 is studied using data from a number of satellites including SAMPEX, HEO, ACE, POES, and FAST. The observations suggest that the dropout may have been caused by two separate mechanisms that operate at high and low L-shells, respectively, with a separation at L ∼ 5. At high L-shells (L > 5), the dropout is approximately independent of energy and consistent with losses to the magnetopause aided by the Dst effect and outward radial diffusion which can deplete relativistic electrons down to lower L-shells. At low L-shells (L < 5), the dropout is strongly energy-dependent, with the higher-energy electrons being affected most. Moreover, large precipitation bands of both relativistic electrons and energetic protons are observed at low L-shells which are consistent with intense pitch angle scattering driven by electromagnetic ion cyclotron (EMIC) waves and may result in a rapid loss of relativistic electrons near the plasmapause in the dusk sector or in plumes of enhanced density.

Authors (sorted by name)

Baker Bortnik Green O’Brien Shprits Strangeway Thorne

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Acknowledgments

Bortnik and R. M. Thorne would like to acknowledge support by NSF grant ATM 0402615 and NASA grant NNG04GN44G. T. P. O'Brien would like to acknowledge support by NSF grant ATM 0202107 and NASA grant NAG5‐10972. This work was supported under The Aerospace Corporation's Independent Research and Development Program, The Aerospace Corporation MOIE program (via U.S. Air Force under contract FA8802‐04‐C‐0001). Y. Y. Shprits would like to acknowledge support by the NSF grant ATM‐0603191. The authors thank the SAMPEX science team for providing the data used in this study, James Weygand for the propagated ACE data covering 20–22 November 2003, and helpful discussion with Joe Mazur and Bern Blake.

Grants

ATM-0202107 ATM-0402615 ATM‐0603191 FA8802‐04‐C‐0001 NAG5‐10972 NNG04GN44G

Bibtex

@article{doi:10.1029/2006JA011802,
author = {Bortnik, J. and Thorne, R. M. and O'Brien, T. P. and Green, J. C. and Strangeway, R. J. and Shprits, Y. Y. and Baker, D. N.},
title = {Observation of two distinct, rapid loss mechanisms during the 20 November 2003 radiation belt dropout event},
journal = {Journal of Geophysical Research: Space Physics},
volume = {111},
year = {2006},
number = {A12},
pages = {},
keywords = {EMIC waves, loss process, radiation belts},
doi = {10.1029/2006JA011802},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2006JA011802},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2006JA011802},
abstract = {The relativistic electron dropout event on 20 November 2003 is studied using data from a number of satellites including SAMPEX, HEO, ACE, POES, and FAST. The observations suggest that the dropout may have been caused by two separate mechanisms that operate at high and low L-shells, respectively, with a separation at L ∼ 5. At high L-shells (L > 5), the dropout is approximately independent of energy and consistent with losses to the magnetopause aided by the Dst effect and outward radial diffusion which can deplete relativistic electrons down to lower L-shells. At low L-shells (L < 5), the dropout is strongly energy-dependent, with the higher-energy electrons being affected most. Moreover, large precipitation bands of both relativistic electrons and energetic protons are observed at low L-shells which are consistent with intense pitch angle scattering driven by electromagnetic ion cyclotron (EMIC) waves and may result in a rapid loss of relativistic electrons near the plasmapause in the dusk sector or in plumes of enhanced density.}
}