Spatial distribution of Kelvin‐Helmholtz instability at low‐latitude boundary layer under different solar wind speed conditions

Li, Wenya; Guo, Xiaocheng; Wang, C.

doi:10.1029/2012ja017780

Cited by 44 publications

(60 citation statements)

References 51 publications

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“…The solar wind dynamic and magnetic pressures are held constant in each simulation run; thus, any surface waves in the LLBL are not generated by magnetic reconnection near the subsolar point or pressure fluctuations of the solar wind. The KHW is sensitive to grid spacing, and a test run using 640×360×360 grid points confirms the reliability of the numerical results [ Li et al , ]. The spatial distribution of KHW power in the equatorial plane are studied for the 400, 600, and 800 runs [ Li et al , ], and here we choose the case of 800 km/s as an example to illustrate the global features of KHW in detail.…”

Section: Methodssupporting

confidence: 58%

Global features of Kelvin‐Helmholtz waves at the magnetopause for northward interplanetary magnetic field

Wang

Tang

et al. 2013

JGR Space Physics

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[1] We investigate the global features of Kelvin-Helmholtz waves (KHW) at the low-latitude magnetopause for constant northward interplanetary magnetic field conditions, using global magnetohydrodynamic simulations. The root-integrated power (RIP) of X component of bulk velocity is employed to analyze the magnetopause mode of KHW along the boundary layer. The RIP distribution of the outer KHW is much broader than that of the inner one, and the maximum amplitude of global KHW occurs near the dawn/dusk terminator regions. In the dayside magnetopause, the phase of the waveform at middle latitudes leads to that at low latitudes, while the situation reversed in the nightside. The global evolution of KHW phases is a representation of an interesting feature that the axis of the Kelvin-Helmholtz vortex aligns with the geomagnetic field lines. We suggest that the reported features may also exist in other KHW active regions with flow-sheared plasma.

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Section: Methodssupporting

confidence: 58%

Global features of Kelvin‐Helmholtz waves at the magnetopause for northward interplanetary magnetic field

Wang

Tang

et al. 2013

JGR Space Physics

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“…The fastest growing wavelengths should be about 10 times greater than boundary layer thicknesses, with wave amplitudes increasing with increasing shears (Walker 1981) and downstream distance (Li et al 2012). The instability is most likely to occur when strong flow shears lie perpendicular to both magnetosheath and magnetospheric magnetic field orientations, a condition most readily obtained on the equatorial flanks of the magnetosphere during intervals of strongly northward or southward IMF orientations (Southwood 1968).…”

Section: Transients At Earth's Magnetopause and In The Cuspsmentioning

confidence: 99%

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

et al. 2018

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Both heliophysics and planetary physics seek to understand the complex nature of the solar wind's interaction with solar system obstacles like Earth's magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle observations, guided by the predictions of both local and global numerical simulations, and placed in con- text by observations from far and extreme ultraviolet (FUV, EUV), hard X-ray, and energetic neutral atom imagers (ENA). Each proposed interaction mechanism (e.g., steady or transient magnetic reconnection, local or global magnetic reconnection, ion pick-up, or the KelvinHelmholtz instability) generates diagnostic plasma density structures. The significance of each mechanism to the overall interaction (as measured in terms of atmospheric/ionospheric loss at comets, Venus, and Mars or global magnetospheric/ionospheric convection at Earth) remains to be determined but can be evaluated on the basis of how often the density signatures that it generates are observed as a function of solar wind conditions. This paper reviews efforts to image the diagnostic plasma density structures in the soft (low energy, 0.1-2.0 keV) X-rays produced when high charge state solar wind ions exchange electrons with the exospheric neutrals surrounding solar system obstacles. The introduction notes that theory, local, and global simulations predict the characteristics of plasma boundaries such the bow shock and magnetopause (including location, density gradient, and motion) and regions such as the magnetosheath (including density and width) as a function of location, solar wind conditions, and the particular mechanism operating. In situ measurements confirm the existence of time-and spatial-dependent plasma density structures like the bow shock, magnetosheath, and magnetopause/ionopause at Venus, Mars, comets, and the Earth. However, in situ measurements rarely suffice to determine the global extent of these density structures or their global variation as a function of solar wind conditions, except in the form of empirical studies based on observations from many different times and solar wind conditions. Remote sensing observations provide global information about auroral ovals (FUV and hard X-ray), the terrestrial plasmasphere (EUV), and the terrestrial ring current (ENA). ENA instruments with low energy thresholds (∼ 1 keV) have recently been used to obtain important information concerning the magnetosheaths of Venus, Mars, and the Earth. Recent technological developments make these magnetosheaths valuable potential targets for high-cadence wide-field-of-view soft X-ray imagers.Section 2 describes proposed dayside interaction mechanisms, including reconnection, the Kelvin-Helmholtz instability, and other processes in greater detail with an emphasis on the plasma density structures that they generate. It focuses upon the questions that remain as yet unanswered, such as the significanc...

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“…• off the noon meridian (Guo et al 2010;Li et al 2012). The second unstable region starts prior to the terminator and lasts to about −5 R E (meaning that this location is in the anti-sunward direction).…”

Section: Shear Flow Instabilitiesmentioning

confidence: 99%

Magnetohydrodynamic Oscillations in the Solar Corona and Earth’s Magnetosphere: Towards Consolidated Understanding

Nakariakov

Пилипенко

Heilig³

et al. 2016

Space Sci Rev

188

128

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Magnetohydrodynamic (MHD) oscillatory processes in different plasma systems, such as the corona of the Sun and the Earth's magnetosphere show interesting similarities and differences, which so far received little attention and remain underexploited. The successful commissioning within the past ten years of SDO, Hinode, STEREO and THEMIS spacecraft, in combination with matured analysis of data from earlier spacecraft (Wind, SOHO, ACE, Cluster, TRACE and RHESSI) makes it very timely to survey the breadth of observations giving evidence for MHD oscillatory processes in solar and space plasmas, and state-of-the-art theoretical modelling. The paper reviews several important topics, such as Alfvénic resonances and mode conversion; MHD waveguides, such as the magnetotail, coronal loops, coronal streamers; mechanisms for periodicities produced in energy releases during substorms and solar flares, possibility of Alfvénic resonators along open field lines; possible drivers of MHD waves; diagnostics of plasmas with MHD waves; interaction of MHD waves with partly-ionised boundaries (ionosphere and chromosphere). The review is mainly oriented to specialists in magnetospheric physics and solar physics, but not familiar with specifics of the adjacent research fields.

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Spatial distribution of Kelvin‐Helmholtz instability at low‐latitude boundary layer under different solar wind speed conditions

Cited by 44 publications

References 51 publications

Global features of Kelvin‐Helmholtz waves at the magnetopause for northward interplanetary magnetic field

Global features of Kelvin‐Helmholtz waves at the magnetopause for northward interplanetary magnetic field

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Magnetohydrodynamic Oscillations in the Solar Corona and Earth’s Magnetosphere: Towards Consolidated Understanding

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