Numerical simulation of nonoscillatory mirror waves at the Earth's magnetosheath

Abstract. The data from all Rosetta plasma consortium instruments and from the ROSINA COPS instrument are used to study the interaction of the solar wind with the outgassing cometary nucleus of 67P/Churyumov-Gerasimenko. During 6 and 7 June 2015, the interaction was first dominated by an increase in the solar wind dynamic pressure, caused by a higher solar wind ion density. This pressure compressed the draped magnetic field around the comet, and the increase in solar wind electrons enhanced the ionization of the outflow gas through collisional ionization. The new ions are picked up by the solar wind magnetic field, and create a ring/ringbeam distribution, which, in a high-β plasma, is unstable for mirror mode wave generation. Two different kinds of mirror modes are observed: one of small size generated by locally ionized water and one of large size generated by ionization and pick-up farther away from the comet.

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“…A study by Price et al (1986) showed that the angle between maximum variance direction and background field was smaller than 30…”

Section: Crossing From 6 To 7 June: Mirror-mode Wavesmentioning

confidence: 99%

Mass-loading, pile-up, and mirror-mode waves at comet 67P/Churyumov-Gerasimenko

et al. 2016

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“…The second instability to operate under conditions of temperature anisotropy is the mirror instability. The growth rates of EMIC waves would be expected to dominate those of mirror structures in a purely proton plasma, but the presence of additional cold ion species, such as helium, is thought to suppress the ion cyclotron instability (Price et al, 1986;Gary et al, 1993). Empirically, therefore, the mirror instability dominates under conditions of moderate temperature anisotropy and high beta, and generates strongly compressive (frequently showing DB/B $ 1), linearly polarised, non-propagating structures.…”

Section: Introductionmentioning

confidence: 99%

Identification of magnetosheath mirror modes in Equator-S magnetic field data

et al. 1999

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Abstract. Between December 1997 and March 1998Equator-S made a number of excursions into the dawnside magnetosheath, over a range of local times between 6:00 and 10:40 LT. Clear mirror-like structures, characterised by compressive¯uctuations in |B| on occasion lasting for up to 5 h, were observed during a signi®cant fraction of these orbits. During most of these passes the satellite appeared to remain close to the magnetopause (within 1±2 Re), during sustained compressions of the magnetosphere, and so the characteristics of the mirror structures are used as a diagnostic of magnetosheath structure close to the magnetopause during these orbits. It is found that in the majority of cases mirror-like activity persists, undamped, to within a few minutes of the magnetopause, with no observable ramp in |B|, irrespective of the magnetic shear across the boundary. This suggests that any plasma depletion layer is typically of narrow extent or absent at the location of the satellite, at least during the subset of orbits containing strong magnetosheath mirror-mode signatures. Power spectra for the mirror signatures show predominately ®eld aligned power, a well de®ned shoulder at around 3± 10´10 A2 Hz and decreasing power at higher frequencies. On occasions the¯uctuations are more sinusoidal, leading to peaked spectra instead of a shoulder. In all cases mirror structures are found to lie approximately parallel to the observed magnetopause boundary. There is some indication that the amplitude of the compressional¯uctuations tends to be greater closer to the magnetopause. This has not been previously reported in the Earth's magnetosphere, but has been suggested in the case of other planets.

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“…The fact that mirrormode waves have been observed in such environments with and without the presence of ion-cyclotron waves is still an issue of study. It has been suggested, for instance, that the addition of a helium component can suppress the growth rate for ion-cyclotron waves [Price et al, 1986;Gary, 1993] and favor the growth of mirror modes. Likewise, inhomogeneites created in the background plasma by mirror modes can inhibit the growth of ion-cyclotron waves [Southwood and Kivelson, 1993].…”

Section: Introductionmentioning

confidence: 99%

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

et al. 2013

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[1] Mirror-mode structures have been found in the solar wind at various heliocentric distances with different missions. Recently, STEREO has observed mirror-mode waves present as trains of holes and also as humps in the magnetic field magnitude. In some cases, mirror-mode trains last for very long periods of time and have been called "mirror-mode storms". We present case studies of mirror-mode storms observed in the solar wind using STEREO data in three different locations: in the downstream region of the forward shock of a stream interaction region, inside a stream interaction region far from the forward shock, and also in the ambient solar wind. To make a formal identification of the mirror mode, we determine wave characteristics using minimum variance analysis. Finally, we perform a kinetic dispersion analysis and discuss the possible origin of mirror-mode structures evaluating curves of growth for different regimes of proton temperature anisotropies in a plasma with a He component.

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Numerical simulation of nonoscillatory mirror waves at the Earth's magnetosheath

Cited by 184 publications

References 47 publications

Mass-loading, pile-up, and mirror-mode waves at comet 67P/Churyumov-Gerasimenko

Mass-loading, pile-up, and mirror-mode waves at comet 67P/Churyumov-Gerasimenko

Identification of magnetosheath mirror modes in Equator-S magnetic field data

Mirror‐mode storms inside stream interaction regions and in the ambient solar wind: A kinetic study

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