Low-frequency waves in the Earth's magnetosheath: present status

Schwartz, S. J.; Burgess, David; Moses, J. J.

doi:10.1007/s00585-996-1134-z

Cited by 136 publications

(144 citation statements)

References 93 publications

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“…These peaks are likely related to the microscale physical processes taking place near these boundaries. In particular, several studies have reported intense wave activity and large amplitude magnetic field fluctuations within shock downstream regions (e.g., Schwartz et al, 1996;Bamert et al, 2004;Kataoka et al, 2005;Kajdič et al, 2012). The neighborhood of the ICME leading edge is a much less studied region in terms of plasma wave activity and plasma instabilities.…”

Section: Discussionmentioning

confidence: 99%

“…We separate the aforementioned 1 h regions around the shock and the leading edge because these are the regions where important microscale physical processes are expected to take place (e.g., Schwartz et al, 1996;Lucek et al, 2005;Blanco-Cano et al, 2006;Yordanova et al, 2008;Desai et al, 2011). We emphasize that these regions are not stretched/compressed or otherwise modified for the superposed epoch analysis.…”

Section: Label Inmentioning

confidence: 99%

“…The variations of the small-scale turbulence in the Earth's magnetosheath from the bow shock to the magnetopause have been studied relatively extensively (e.g., Luhmann, Russell, and Elphic, 1986;Schwartz, Burgess, and Moses, 1996;Sahraoui et al, 2003;Lucek et al, 2005;Shevyrev et 90 al., 2005;Yordanova et al, 2008), but there are distinct differences between the ICME sheaths and the planetary magnetosheaths (Kaymaz and Siscoe, 2006;Siscoe and Odstrcil, 2008). As pointed-out by Kaymaz and Siscoe (2006), the differences are likely attributed to the long history of accre-95 tion of inhomogenous IMF and plasma in ICME sheath regions.…”

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confidence: 99%

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Magnetic field and dynamic pressure ULF fluctuations in coronal-mass-ejection-driven sheath regions

et al. 2013

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Compressed sheath regions form ahead of interplanetary coronal mass ejections (ICMEs) that are sufficiently faster than the preceding solar wind. The turbulent sheath regions are important drivers of magnetospheric activity, but due to their complex internal structure, relatively little is known on the distribution of the magnetic field and plasma variations in them. In this paper we investigate ultra low frequency (ULF) fluctuations in the interplanetary magnetic field (IMF) and in dynamic pressure (P_dyn) using a superposed epoch analysis of 41 sheath regions observed during solar cycle 23. We find strongest fluctuation power near the shock and in the vicinity of the ICME leading edge. The IMF and P_dyn ULF power have different profiles within the sheath; the former is enhanced in the leading part of the sheath, while the latter is increased in the trailing part of the sheath. We also find that the ICME properties affect the level and distribution of the ULF power in sheath regions. For example, sheath regions associated with strong or fast ICMEs, or those that are crossed at intermediate distances from the center, have strongest ULF power and large variation in the power throughout the sheath region. The weaker or slower ICMEs, or those that are crossed centrally, have in general considerably weaker ULF power with relatively smooth profiles. The strong and abrupt decrease of the IMF ULF power at the ICME leading edge could be used to distinguish the ICME from the preceding sheath plasma

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Section: Discussionmentioning

confidence: 99%

Section: Label Inmentioning

confidence: 99%

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confidence: 99%

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Magnetic field and dynamic pressure ULF fluctuations in coronal-mass-ejection-driven sheath regions

et al. 2013

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“…A number of experimental works addressed the mirror modes using in-situ spacecraft data (for reviews see Schwartz et al, 1996, andTsurutani et al, 2011). A large majority of those studies, however, used either no ion measurements or only the measured moments of the distribution function.…”

Section: Introductionmentioning

confidence: 99%

Cluster observations of trapped ions interacting with magnetosheath mirror modes

Souček

Escoubet

2011

Ann. Geophys.

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Abstract. Mirror modes are among the most intense low frequency plasma wave phenomena observed in the magnetosheaths of magnetized planets. They appear as large amplitude non-propagating fluctuations in the magnetic field magnitude and plasma density. These structures are widely accepted to represent a non-linear stage of the mirror instability, dominant in plasmas with large ion beta and a significant ion temperature anisotropy T ⊥ /T > 1. It has long been recognized that the mirror instability both in the linear and non-linear stage is a kinetic process and that the behavior of resonant particles at small parallel velocities is crucial for its development and saturation. While the dynamics of the instability and the effect of trapped particles have been studied extensively in theoretical models and numerical simulations, only spurious observations of the trapped ions were published to date. In this work we used data from the Cluster spacecraft to perform the first detailed experimental study of ion velocity distribution associated with mirror mode oscillations. We show a conclusive evidence for the predicted cooling of resonant ions at small parallel velocities and heating of trapped ions at intermediate pitch angles.

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“…Mirror modes and ion-cyclotron waves appear to be the two most important wave modes in the (Earth's) magnetosheath (e.g., Schwartz et al, 1996), which is confined between the bow shock and the magnetopause. Both wave modes are fed from the temperature anisotropy that is characteristic to the magnetosheath: higher temperature in the plane perpendicular to the magnetic field.…”

Section: Introductionmentioning

confidence: 99%

On determining fluxgate magnetometer spin axis offsets from mirror mode observations

Plaschke

Narita

2016

Ann. Geophys.

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Abstract. In-flight calibration of fluxgate magnetometers that are mounted on spacecraft involves finding their outputs in vanishing ambient fields, the so-called magnetometer offsets. If the spacecraft is spin-stabilized, then the spin plane components of these offsets can be relatively easily determined, as they modify the spin tone content in the de-spun magnetic field data. The spin axis offset, however, is more difficult to determine. Therefore, usually Alfvénic fluctuations in the solar wind are used. We propose a novel method to determine the spin axis offset: the mirror mode method. The method is based on the assumption that mirror mode fluctuations are nearly compressible such that the maximum variance direction is aligned to the mean magnetic field. Mirror mode fluctuations are typically found in the Earth's magnetosheath region. We introduce the method and provide a first estimate of its accuracy based on magnetosheath observations by the THEMIS-C spacecraft. We find that 20 h of magnetosheath measurements may already be sufficient to obtain high-accuracy spin axis offsets with uncertainties on the order of a few tenths of a nanotesla, if offset stability can be assumed.

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Low-frequency waves in the Earth's magnetosheath: present status

Cited by 136 publications

References 93 publications

Magnetic field and dynamic pressure ULF fluctuations in coronal-mass-ejection-driven sheath regions

Magnetic field and dynamic pressure ULF fluctuations in coronal-mass-ejection-driven sheath regions

Cluster observations of trapped ions interacting with magnetosheath mirror modes

On determining fluxgate magnetometer spin axis offsets from mirror mode observations

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