Home > Research > Publications & Outputs > The Changing Eigenfrequency Continuum during Ge...

Associated organisational unit

Electronic data

  • preprint

    Rights statement: Accepted for publication in Journal of Geophysical Research: Space Physics. Copyright 2020 American Geophysical Union. Further reproduction or electronic distribution is not permitted.

    Accepted author manuscript, 21.8 MB, PDF document

    Available under license: CC BY-NC: Creative Commons Attribution-NonCommercial 4.0 International License

Links

Text available via DOI:

View graph of relations

The Changing Eigenfrequency Continuum during Geomagnetic Storms: Implications for Plasma Mass Dynamics and ULF Wave Coupling

Research output: Contribution to journalJournal article

Published

Standard

The Changing Eigenfrequency Continuum during Geomagnetic Storms : Implications for Plasma Mass Dynamics and ULF Wave Coupling. / Wharton, S. J.; Rae, I.J.; Sandhu, J. K.; Walach, Maria; Wright, D. M.; Yeoman, T. K.

In: Journal of Geophysical Research: Space Physics, Vol. 125, No. 6, e2019JA027648, 13.06.2020.

Research output: Contribution to journalJournal article

Harvard

Wharton, SJ, Rae, IJ, Sandhu, JK, Walach, M, Wright, DM & Yeoman, TK 2020, 'The Changing Eigenfrequency Continuum during Geomagnetic Storms: Implications for Plasma Mass Dynamics and ULF Wave Coupling', Journal of Geophysical Research: Space Physics, vol. 125, no. 6, e2019JA027648. https://doi.org/10.1029/2019JA027648

APA

Wharton, S. J., Rae, I. J., Sandhu, J. K., Walach, M., Wright, D. M., & Yeoman, T. K. (2020). The Changing Eigenfrequency Continuum during Geomagnetic Storms: Implications for Plasma Mass Dynamics and ULF Wave Coupling. Journal of Geophysical Research: Space Physics, 125(6), [e2019JA027648]. https://doi.org/10.1029/2019JA027648

Vancouver

Wharton SJ, Rae IJ, Sandhu JK, Walach M, Wright DM, Yeoman TK. The Changing Eigenfrequency Continuum during Geomagnetic Storms: Implications for Plasma Mass Dynamics and ULF Wave Coupling. Journal of Geophysical Research: Space Physics. 2020 Jun 13;125(6). e2019JA027648. https://doi.org/10.1029/2019JA027648

Author

Wharton, S. J. ; Rae, I.J. ; Sandhu, J. K. ; Walach, Maria ; Wright, D. M. ; Yeoman, T. K. / The Changing Eigenfrequency Continuum during Geomagnetic Storms : Implications for Plasma Mass Dynamics and ULF Wave Coupling. In: Journal of Geophysical Research: Space Physics. 2020 ; Vol. 125, No. 6.

Bibtex

@article{1b6cb59856274f649aa6aaa81a423968,
title = "The Changing Eigenfrequency Continuum during Geomagnetic Storms: Implications for Plasma Mass Dynamics and ULF Wave Coupling",
abstract = "Geomagnetic storms are one of the most energetic space weather phenomena. Previous studies have shown that the eigenfrequencies of ultralow frequency (ULF) waves on closed magnetic field lines in the inner magnetosphere decrease during storm times. This change suggests either a reduction in the magnetic field strength and/or an increase in its plasma mass density distribution. We investigate the changes in local eigenfrequencies by applying a superposed multiple‐epoch analysis to cross‐phase spectra from 132 geomagnetic storms. Six ground magnetometer pairs are used to investigate variations from approximately 3 < L < 7 and across the whole dayside sector. We find that at L > 4, the eigenfrequencies decrease by as much as 50% relative to their quiet time values. Both a decrease in magnetic field strength and an increase in plasma mass density, in some locations by more than a factor of 2, are responsible for this reduction. The enhancement of the ring current and an increase in oxygen ion density could explain these observations. At L < 4, the eigenfrequencies increase due to the decrease in plasma mass density caused by plasmaspheric erosion.",
keywords = "ULF waves, cross phase, geomagnetic storms, plasma mass density, eigenfrequencies, ring current",
author = "Wharton, {S. J.} and I.J. Rae and Sandhu, {J. K.} and Maria Walach and Wright, {D. M.} and Yeoman, {T. K.}",
note = "Accepted for publication in Journal of Geophysical Research: Space Physics. Copyright 2020 American Geophysical Union. Further reproduction or electronic distribution is not permitted.",
year = "2020",
month = jun
day = "13",
doi = "10.1029/2019JA027648",
language = "English",
volume = "125",
journal = "Journal of Geophysical Research: Space Physics",
issn = "2169-9402",
publisher = "Blackwell Publishing Ltd",
number = "6",

}

RIS

TY - JOUR

T1 - The Changing Eigenfrequency Continuum during Geomagnetic Storms

T2 - Implications for Plasma Mass Dynamics and ULF Wave Coupling

AU - Wharton, S. J.

AU - Rae, I.J.

AU - Sandhu, J. K.

AU - Walach, Maria

AU - Wright, D. M.

AU - Yeoman, T. K.

N1 - Accepted for publication in Journal of Geophysical Research: Space Physics. Copyright 2020 American Geophysical Union. Further reproduction or electronic distribution is not permitted.

PY - 2020/6/13

Y1 - 2020/6/13

N2 - Geomagnetic storms are one of the most energetic space weather phenomena. Previous studies have shown that the eigenfrequencies of ultralow frequency (ULF) waves on closed magnetic field lines in the inner magnetosphere decrease during storm times. This change suggests either a reduction in the magnetic field strength and/or an increase in its plasma mass density distribution. We investigate the changes in local eigenfrequencies by applying a superposed multiple‐epoch analysis to cross‐phase spectra from 132 geomagnetic storms. Six ground magnetometer pairs are used to investigate variations from approximately 3 < L < 7 and across the whole dayside sector. We find that at L > 4, the eigenfrequencies decrease by as much as 50% relative to their quiet time values. Both a decrease in magnetic field strength and an increase in plasma mass density, in some locations by more than a factor of 2, are responsible for this reduction. The enhancement of the ring current and an increase in oxygen ion density could explain these observations. At L < 4, the eigenfrequencies increase due to the decrease in plasma mass density caused by plasmaspheric erosion.

AB - Geomagnetic storms are one of the most energetic space weather phenomena. Previous studies have shown that the eigenfrequencies of ultralow frequency (ULF) waves on closed magnetic field lines in the inner magnetosphere decrease during storm times. This change suggests either a reduction in the magnetic field strength and/or an increase in its plasma mass density distribution. We investigate the changes in local eigenfrequencies by applying a superposed multiple‐epoch analysis to cross‐phase spectra from 132 geomagnetic storms. Six ground magnetometer pairs are used to investigate variations from approximately 3 < L < 7 and across the whole dayside sector. We find that at L > 4, the eigenfrequencies decrease by as much as 50% relative to their quiet time values. Both a decrease in magnetic field strength and an increase in plasma mass density, in some locations by more than a factor of 2, are responsible for this reduction. The enhancement of the ring current and an increase in oxygen ion density could explain these observations. At L < 4, the eigenfrequencies increase due to the decrease in plasma mass density caused by plasmaspheric erosion.

KW - ULF waves

KW - cross phase

KW - geomagnetic storms

KW - plasma mass density

KW - eigenfrequencies

KW - ring current

U2 - 10.1029/2019JA027648

DO - 10.1029/2019JA027648

M3 - Journal article

VL - 125

JO - Journal of Geophysical Research: Space Physics

JF - Journal of Geophysical Research: Space Physics

SN - 2169-9402

IS - 6

M1 - e2019JA027648

ER -