Poloidal field line resonances driven by a fast wave

Andrew Wright; Thomas Elsden; Alexander Degeling; Ian R. Mann; Louis Ozeke; Timothy Yeoman; Jasmine Sandhu; Kazue Takahashi

doi:10.1029/2024GL111670

Poloidal field line resonances driven by a fast wave

Andrew Wright^*, Thomas Elsden, Alexander Degeling, Ian R. Mann, Louis Ozeke, Timothy Yeoman, Jasmine Sandhu, Kazue Takahashi

^*Corresponding author for this work

Applied Mathematics

Research output: Contribution to journal › Letter › peer-review

Abstract

We present numerical simulations of the excitation of resonant poloidal Alfvén waves. The resulting Alfvén waves could be loosely described as “high‐m” (m is the azimuthal wave number) in as much as the azimuthal scale of the wave is much less than the scale in the direction normal to L‐shells. Such waves are generally excited by wave‐particle interactions. In this article we show how resonant poloidal Alfvén waves can be excited by a fast mode (of large azimuthal scale) in a cold plasma. The key property that enables this is a three‐dimensional equilibrium, which facilitates the process of phasemixing in the azimuthal direction. We show that the classification of resonant Alfvén waves as high‐m and low‐m has limited applicability in 3D inhomogeneous media and suggest an alternative classification be based on the excitation mechanism.

Original language	English
Article number	e2024GL111670
Number of pages	9
Journal	Geophysical Research Letters
Volume	52
Issue number	3
Early online date	10 Feb 2025
DOIs	https://doi.org/10.1029/2024GL111670
Publication status	Published - 16 Feb 2025

Keywords

Field line resonance
MHD wave coupling

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10.1029/2024GL111670Licence: CC BY

Wright_2025_GRL_Poloidal-field-line-resonances-fast-wave_CC
© 2025. The Author(s). This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Final published version, 3.23 MBLicence: CC BY

Solar and Magnetospheric - Consolidated: Solar and Magnetospheric Magnetohydrodynamics and Plasmas: Theory and Application
Hood, A. W. (PI), Archontis, V. (CoI), De Moortel, I. (CoI), Mackay, D. H. (CoI), Neukirch, T. (CoI), Parnell, C. E. (CoI) & Wright, A. N. (CoI)
Science & Technology Facilities Council
1/04/16 → 31/03/19
Project: Standard

Data for Wright et al., 2024, submitted to JGR Space Physics
Elsden, T. (Creator), Figshare, 2024
DOI: 10.6084/m9.figshare.26379442.v1
Dataset

Cite this

@article{5182110969944b1fb3ad04d491165f81,

title = "Poloidal field line resonances driven by a fast wave",

abstract = "We present numerical simulations of the excitation of resonant poloidal Alfv{\'e}n waves. The resulting Alfv{\'e}n waves could be loosely described as “high‐m” (m is the azimuthal wave number) in as much as the azimuthal scale of the wave is much less than the scale in the direction normal to L‐shells. Such waves are generally excited by wave‐particle interactions. In this article we show how resonant poloidal Alfv{\'e}n waves can be excited by a fast mode (of large azimuthal scale) in a cold plasma. The key property that enables this is a three‐dimensional equilibrium, which facilitates the process of phasemixing in the azimuthal direction. We show that the classification of resonant Alfv{\'e}n waves as high‐m and low‐m has limited applicability in 3D inhomogeneous media and suggest an alternative classification be based on the excitation mechanism.",

keywords = "Field line resonance, MHD wave coupling",

author = "Andrew Wright and Thomas Elsden and Alexander Degeling and Mann, {Ian R.} and Louis Ozeke and Timothy Yeoman and Jasmine Sandhu and Kazue Takahashi",

note = "This research was supported by the International Space Science Institute (ISSI) in Bern, through ISSI International Team project #483 (The Identification and Classification of 3D Alfv{\'e}n Resonances). The authors are grateful to ISSI for funding the Team and hosting its meetings. ANW was partially funded by the Science and Technology Facilities Council (STFC) Grant (ST/N000609/1). KT was supported by NASA 80NSSC19K0259. JKS was funded by STFC Grant ST/W00089X/1. AWD is funded by NSFC (RFIS-III Grant 42350710200). TKY acknowledges support from STFC UKRI Grant ST/W00089X/1 and NERC UKRI Grant NE/V000748/1. LO and IRM were supported by funding from the Canadian Space Agency. IRM was also funded by a Discovery Grant from the Canadian NSERC.",

year = "2025",

month = feb,

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doi = "10.1029/2024GL111670",

language = "English",

volume = "52",

journal = "Geophysical Research Letters",

issn = "0094-8276",

publisher = "John Wiley & Sons, Ltd",

number = "3",

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TY - JOUR

T1 - Poloidal field line resonances driven by a fast wave

AU - Wright, Andrew

AU - Elsden, Thomas

AU - Degeling, Alexander

AU - Mann, Ian R.

AU - Ozeke, Louis

AU - Yeoman, Timothy

AU - Sandhu, Jasmine

AU - Takahashi, Kazue

N1 - This research was supported by the International Space Science Institute (ISSI) in Bern, through ISSI International Team project #483 (The Identification and Classification of 3D Alfvén Resonances). The authors are grateful to ISSI for funding the Team and hosting its meetings. ANW was partially funded by the Science and Technology Facilities Council (STFC) Grant (ST/N000609/1). KT was supported by NASA 80NSSC19K0259. JKS was funded by STFC Grant ST/W00089X/1. AWD is funded by NSFC (RFIS-III Grant 42350710200). TKY acknowledges support from STFC UKRI Grant ST/W00089X/1 and NERC UKRI Grant NE/V000748/1. LO and IRM were supported by funding from the Canadian Space Agency. IRM was also funded by a Discovery Grant from the Canadian NSERC.

PY - 2025/2/16

Y1 - 2025/2/16

N2 - We present numerical simulations of the excitation of resonant poloidal Alfvén waves. The resulting Alfvén waves could be loosely described as “high‐m” (m is the azimuthal wave number) in as much as the azimuthal scale of the wave is much less than the scale in the direction normal to L‐shells. Such waves are generally excited by wave‐particle interactions. In this article we show how resonant poloidal Alfvén waves can be excited by a fast mode (of large azimuthal scale) in a cold plasma. The key property that enables this is a three‐dimensional equilibrium, which facilitates the process of phasemixing in the azimuthal direction. We show that the classification of resonant Alfvén waves as high‐m and low‐m has limited applicability in 3D inhomogeneous media and suggest an alternative classification be based on the excitation mechanism.

AB - We present numerical simulations of the excitation of resonant poloidal Alfvén waves. The resulting Alfvén waves could be loosely described as “high‐m” (m is the azimuthal wave number) in as much as the azimuthal scale of the wave is much less than the scale in the direction normal to L‐shells. Such waves are generally excited by wave‐particle interactions. In this article we show how resonant poloidal Alfvén waves can be excited by a fast mode (of large azimuthal scale) in a cold plasma. The key property that enables this is a three‐dimensional equilibrium, which facilitates the process of phasemixing in the azimuthal direction. We show that the classification of resonant Alfvén waves as high‐m and low‐m has limited applicability in 3D inhomogeneous media and suggest an alternative classification be based on the excitation mechanism.

KW - Field line resonance

KW - MHD wave coupling

U2 - 10.1029/2024GL111670

DO - 10.1029/2024GL111670

M3 - Letter

SN - 0094-8276

VL - 52

JO - Geophysical Research Letters

JF - Geophysical Research Letters

IS - 3

M1 - e2024GL111670

ER -

Poloidal field line resonances driven by a fast wave

Abstract

Keywords

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Projects

Solar and Magnetospheric - Consolidated: Solar and Magnetospheric Magnetohydrodynamics and Plasmas: Theory and Application

Datasets

Data for Wright et al., 2024, submitted to JGR Space Physics

Cite this