Alfvén waves in the Earth's magnetosphere

Andrew Nicholas Wright*, Michael Hartinger, Kazue Takahashi, Tom Elsden

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

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Abstract

The environment surrounding the Earth that is dominated by the terrestrial magnetic field is called the magnetosphere. It comprises a highly structured magnetic field and plasma distribution. Transient events in the magnetosphere can arise from interaction with the solar wind or internal reconfigurations via reconnection, which are a natural source of magnetohydrodynamic (MHD) waves. We shall focus on the global scale waves that have wavelengths similar to the size of the magnetosphere. The different wave modes naturally couple to each other due to the structured nature of the magnetosphere. In particular coupling of the fast magnetoacoustic mode and the Alfven mode are common throughout the magnetosphere and are used in magneto-seismology studies. Alfven waves can also be excited when unstable particle distributions arise. Whatever the source of the Alfven waves, they are an agent for carrying field-aligned currents which can become particularly intense near the Earth. Consideration of these strong currents requires a two-fluid or kinetic treatment which indicate the need for a region (at altitudes of 1-2Re) where electrons are accelerated to keV energies and can produce optical auroral emissions. Alfven waves can also modify the ionosphere and induce ground currents, both of which have important implications for Space Weather. We review recent advances including the theory of Alfven wave excitation in a 3D equilibrium and particle acceleration.
Original languageEnglish
Title of host publicationAlfvén waves across heliophysics
Subtitle of host publicationprogress, challenges, and opportunities
EditorsAndreas Keiling
Place of PublicationHoboken, NJ
PublisherJohn Wiley & Sons, Ltd
Chapter10
Pages215-248
Number of pages34
ISBN (Electronic)9781394195985
ISBN (Print)9781394195954
DOIs
Publication statusPublished - 7 May 2024

Publication series

NameGeophysical monograph series
Volume285
ISSN (Print)0065-8448

Keywords

  • Alfvén wave
  • Earth's magnetosphere
  • Magnetoseismology
  • Magnetospheric simulations
  • Plasma sheet boundary layer
  • Poloidal waves
  • Space weather

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