Cross‐Scale Energy Transport in Space Plasmas

Nykyri, K.; Ma, Xuanye

doi:10.1002/9781119815624.ch7

Cited by 11 publications

(6 citation statements)

References 98 publications

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“…Mechanism 1B : Secondary KHI driven “Mid‐latitude,” reconnection (Ma et al., 2017). This can result in the development of shell‐like ion distribution functions (Nykyri et al., 2020). These shell distributions have free energy to drive kinetic magnetosonic waves that were previously shown to explain the observed level of ion heating at the flank magnetopause (Moore et al., 2016).…”

Section: Introductionmentioning

confidence: 99%

MMS Observations of the Multiscale Wave Structures and Parallel Electron Heating in the Vicinity of the Southern Exterior Cusp

Nykyri

Burkholder

et al. 2021

JGR Space Physics

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Understanding the physical mechanisms responsible for the cross-scale energy transport and plasma heating from solar wind into the Earth's magnetosphere is of fundamental importance for magnetospheric physics and for understanding these processes in other places in the universe with comparable plasma parameter ranges. This paper presents observations from the Magnetosphere Multiscale (MMS) mission at the dawn-side high-latitude dayside boundary layer on February 25, 2016 between 18:55 and 20:05 UT. During this interval, MMS encountered both the inner and outer boundary layers with quasiperiodic low frequency fluctuations in all plasma and field parameters. The frequency analysis and growth rate calculations are consistent with the Kelvin-Helmholtz instability (KHI). The intervals within the low frequency wave structures contained several counter-streaming, low-(0-200 eV) and mid-energy (200 eV-2 keV) electrons in the loss cone and trapped energetic (70-600 keV) electrons in alternate intervals. The counter-streaming electron intervals were associated with large-magnitude field-aligned Poynting fluxes. Burst mode data at the large Alfvén velocity gradient revealed a strong correlation between counter streaming electrons, enhanced parallel electron temperatures, strong antifield aligned wave Poynting fluxes, and wave activity from sub-proton cyclotron frequencies extending to electron cyclotron frequency. Waves were identified as Kinetic Alfvén waves but their contribution to parallel electron heating was not sufficient to explain the >100 eV electrons, and rapid nonadiabatic heating of the boundary layer as determined by the characteristic heating frequency, derived here for the first time. Plain Language Summary Electrons, The Riders of the Space Hurricane: Earth's magnetic field forms a barrier in the solar wind, called the magnetosphere, which provides some shielding against solar radiation and galactic cosmic rays. However, this shield can be penetrated by process called magnetic reconnection, and secondary processes created by giant "fluid-scale" space hurricanes (typically 20,000-36,000 km in wave length) aka Kelvin-Helmholtz (KH) waves that are whipped along the magnetic barrier by solar wind flow. One of the puzzling problems of the Earth's magnetosphere is that it is so hot: both electrons and ions are heated to tens of millions of degrees when they get transported from solar wind through the Earth's magnetic barrier. This article shows observations of multiscale wave structures, spanning the fluid-scales, ion scales and electron scales detected by the NASA's magnetosphere multiscale mission consisting of four satellites. We show how these large-scale waves contain ion and electron scale waves that are able to produce some of the observed electron heating and acceleration. We "fingerprint" the exact plasma wave modes (tornadoes) inside the space hurricane that are responsible for resonantly whipping and transferring the wave energy to the electrons surfing the wave. NYKYRI ET AL.

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Section: Introductionmentioning

confidence: 99%

MMS Observations of the Multiscale Wave Structures and Parallel Electron Heating in the Vicinity of the Southern Exterior Cusp

Nykyri

Burkholder

et al. 2021

JGR Space Physics

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“…As we shall see, this also affects the rest of the ionosphere-thermosphere system. These results will also be useful when designing spacecraft orbits and mission phases for future magnetospheric missions focusing on the KHI and secondary processes associated with the KHI that are responsible for plasma heating, acceleration, and transport 30,31 .…”

Section: Discussionmentioning

confidence: 97%

Seasonal and diurnal variations of Kelvin-Helmholtz Instability at terrestrial magnetopause

et al. 2023

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Kelvin-Helmholtz Instability is ubiquitous at Earth’s magnetopause and plays an important role in plasma entry into the magnetosphere during northward interplanetary magnetic fields. Here, using one solar cycle of data from NASA THEMIS (Time History of Events and Macro scale Interactions during Substorms) and MMS (Magnetospheric Multiscale) missions, we found that KHI occurrence rates show seasonal and diurnal variations with the rate being high near the equinoxes and low near the solstices. The instability depends directly on the Earth’s dipole tilt angle. The tilt toward or away from the Sun explains most of the seasonal and diurnal variations, while the tilt in the plane perpendicular to the Earth‐Sun line explains the difference between the equinoxes. The results reveal the critical role of dipole tilt in modulating KHI across the magnetopause as a function of time, highlighting the importance of Sun-Earth geometry for solar wind-magnetosphere interaction and for space weather.

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“…Mass transport due to KH instability can result from diffusion through thin boundaries created by the instability (e.g., Nakamura et al, 2017) and/or as the result of secondary reconnection (e.g., Otto and Nykyri, 2003;Ma et al, 2017) which results in more effective transport (Ma et al, 2019). Cross-scale energy transport associated with the KH instability may result from the generation of plasma waves leading to both ion and electron heating (Johnson and Cheng, 2001;Chaston et al, 2007;Moore et al, 2017;Nykyri et al, 2021a;Nykyri et al, 2021b;Delamere et al, 2021). The KH waves are also critical to the interaction between the solar wind and other planetary magnetospheres (McComas and Bagenal, 2008;Delamere and Bagenal, 2010;Delamere et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Coupling Between Alfvén Wave and Kelvin–Helmholtz Waves in the Low Latitude Boundary Layer

Kim

Nykyri

2022

Front. Astron. Space Sci.

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The Kelvin–Helmholtz (KH) instability of magnetohydrodynamic surface waves at the low latitude boundary layer is examined using both an eigenfrequency analysis and a time-dependent wave simulation. The analysis includes the effects of sheared flow and Alfvén velocity gradient. When the magnetosheath flows are perpendicular to the ambient magnetic field direction, unstable KH waves that propagate obliquely to the sheared flow direction occur at the sheared flow surface when the Alfvén Mach number is higher than an instability threshold. Including a shear transition layer between the magnetosphere and magnetosheath leads to secondary KH waves (driven by the sheared flow) that are coupled to the resonant surface Alfvén wave. There are remarkable differences between the primary and the secondary KH waves, including wave frequency, the growth rate, and the ratio between the transverse and compressional components. The secondary KH wave energy is concentrated near the shear Alfvén wave frequency at the magnetosheath with a lower frequency than the primary KH waves. Although the growth rate of the secondary KH waves is lower than the primary KH waves, the threshold condition is lower, so it is expected that these types of waves will dominate at a lower Mach number. Because the transverse component of the secondary KH waves is stronger than that of the primary KH waves, more efficient wave energy transfer from the boundary layer to the inner magnetosphere is also predicted.

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Cross‐Scale Energy Transport in Space Plasmas

Cited by 11 publications

References 98 publications

MMS Observations of the Multiscale Wave Structures and Parallel Electron Heating in the Vicinity of the Southern Exterior Cusp

MMS Observations of the Multiscale Wave Structures and Parallel Electron Heating in the Vicinity of the Southern Exterior Cusp

Seasonal and diurnal variations of Kelvin-Helmholtz Instability at terrestrial magnetopause

Coupling Between Alfvén Wave and Kelvin–Helmholtz Waves in the Low Latitude Boundary Layer

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