Magnetospheric response to solar wind forcing: ultra-low-frequency wave–particle interaction perspective
<p>Solar wind forcing, e.g., interplanetary shock and/or solar wind dynamic pressure pulses impacting Earth's magnetosphere, manifests many fundamental important space physics phenomena, including producing electromagnetic waves, plasma heating, and energetic particle acceleration. This p...
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-02-01
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| Series: | Annales Geophysicae |
| Online Access: | https://angeo.copernicus.org/articles/40/121/2022/angeo-40-121-2022.pdf |
| Summary: | <p>Solar wind forcing, e.g., interplanetary shock and/or solar wind dynamic
pressure pulses impacting Earth's magnetosphere, manifests many fundamental important space physics phenomena, including producing electromagnetic waves, plasma heating, and energetic particle acceleration. This paper summarizes our present understanding of the magnetospheric
response to solar wind forcing in the aspects of radiation belt electrons,
ring current ions and plasmaspheric plasma physics based on in situ
spacecraft measurements, ground-based magnetometer data, magnetohydrodynamics (MHD) and kinetic simulations.</p>
<p>Magnetosphere response to solar wind forcing is not just a “one-kick” scenario. It is found that after the impact of solar wind forcing on Earth's magnetosphere, plasma heating and energetic particle acceleration
started nearly immediately and could last for a few hours. Even a small
dynamic pressure change in interplanetary shock or solar wind pressure pulse can play a non-negligible role in magnetospheric physics. The impact leads
to generation of a series of waves, including poloidal-mode ultra-low-frequency (ULF) waves. The fast acceleration of energetic electrons in the radiation belt and energetic ions in the ring current region response to the impact
usually contains two contributing steps: (1) the initial adiabatic
acceleration due to the magnetospheric compression, (2) followed by the wave–particle resonant acceleration dominated by global or localized
poloidal ULF waves excited at various <span class="inline-formula"><i>L</i></span>-shells.</p>
<p>Generalized theory of drift and drift–bounce resonance with growth- or decay-localized ULF waves has been developed to explain in situ spacecraft observations. The wave-related observational features like distorted energy spectrum, “boomerang” and “fishbone” pitch angle distributions of radiation belt electrons, ring current ions and plasmaspheric plasma can be explained in
the framework of this generalized theory. It is worth pointing out here that poloidal ULF waves are much more efficient at accelerating and modulating electrons (fundamental mode) in the radiation belt and charged ions (second
harmonic) in the ring current region. The results presented in this paper
can be widely used in solar wind interacting with other planets such as
Mercury, Jupiter, Saturn, Uranus and Neptune and other astrophysical objects with magnetic fields.</p> |
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| ISSN: | 0992-7689 1432-0576 |