Link between EMIC waves in a plasmaspheric plume and a detached sub‐auroral proton arc with observations of Cluster and IMAGE satellites

Yuan, Zhiyong; Deng, Xiaohua; Lin, Xiaohui; Pang, Y.; Zhou, Meng; Décréau, Pierrette; Trotignon, J. G.; Lucek, E.; Frey, H. U.; Wang, Jingfang

doi:10.1029/2010gl042711

Cited by 68 publications

(91 citation statements)

References 43 publications

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“…As shown in Fig. 5a the O + ion gyrofrequency (f O + eq ) and the He + ion gyrofrequency (f He + eq ) in the equatorial plane, i.e., in frequency range for He + ion cyclotron waves in the equatorial plane, in agreement with the previous observations and theory of EMIC waves (Erlandson and Ukhorskiy, 2001;Morley et al, 2009;Yuan et al, 2010Yuan et al, , 2012aYoung et al, 1981). As shown in Fig.…”

Section: Discussionsupporting

confidence: 79%

“…With density enhancements of cold ions, the anisotropic RC proton distributions can become unstable so as to easily excite EMIC waves (Gary et al, 1995). Therefore, EMIC waves in the inner magnetosphere may occur in the region of overlap between the plasmasphere and ring currents (Fraser and Nguyen, 2001;Yuan et al, 2010Yuan et al, , 2012aUsanova et al, 2013), and in regions of high cold plasma density (Yahnin et al, 2002;Halford et al, 2015). In addition, the density structure with the negative gradient of radial electron densities at the plasmapause or plasmaspheric plumes can guide EMIC waves, leading to a small wave normal angle and an order of enhancement of the wave strength (Chen et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…In addition, with the substorminduced electric field some plasma sheet protons can further be injected into the current ring region. The interaction between ring current (RC) ions and EMIC waves in the plasmapause or plasmaspheric plumes can lead to the scattering of RC ions into the loss cone and precipitating into the atmosphere at subauroral latitudes (Jordanova et al, 2007;Yahnin et al, 2009;Spasojević and Fuselier, 2009;Yuan et al, 2010). As a result, the low-altitude NOAA spacecraft crossing the auroral zone from high to low latitudes firstly detects an isotropic proton flux distribution and subsequently detects a drop of the proton flux within the loss cone and still a strong flux of trapped particles at lower latitudes (the anisotropic zones) (Yahnin et al, 2006;Yuan et al, 2011Yuan et al, , 2012bYuan et al, , 2013.…”

Section: Y Xiong Et Al: Energetic Ions Into the Loss Conementioning

confidence: 99%

“…In the dayside outer magnetosphere, EMIC waves in Pc2 band can also be generated high off the equator and in the regions of the minimum of magnetic field within Shabansky orbits (Liu et al, 2012). Through the wave-particle interactions, EMIC waves can scatter ring current (RC) ions and radiation belt relativistic electrons into the loss cone, leading to loss into the atmosphere (Yahnin et al, 2006;Jordanova, et al, 2007;Sakaguchi et al, 2008;Morley et al, 2009;Yuan et al, 2010Yuan et al, , 2012aYuan et al, , b, 2013Carson et al, 2013;Li et al, 2014;Usanova et al, 2010Usanova et al, , 2014. Therefore, EMIC waves may play an important role in the dynamics of the ring current and radiation belt through wave-particle interaction.…”

Section: Introductionmentioning

confidence: 99%

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Energetic ions scattered into the loss cone with observations of the Cluster satellite

2016

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Abstract. In this paper, we report in situ observations by the Cluster spacecraft of energetic ions scattered into the loss cone during the inbound pass from the plasma sheet into the plasmasphere. During the inbound pass of the plasma sheet, Cluster observed the isotropy ratio of energetic ions to gradually decrease from unity and the isotropic boundary extended to lower L value for higher-energy ions, implying that the field line curvature scattering mechanism is responsible for the scattered ions into the loss cone from the plasma sheet. In the outer boundary of a plasmasphere plume, Cluster 3 observed the increase of the isotropy ratio of energetic ions accompanied by enhancements of Pc2 waves with frequencies between the He + ion gyrofrequency and O + ion gyrofrequency estimated in the equatorial plane. Those Pc2 waves were left-hand circularly polarized and identified as electromagnetic ion cyclotron (EMIC) waves. Using the observed parameters, the calculations of the pitch angle diffusion coefficients for ring current protons demonstrate that EMIC waves could be responsible for the ions scattering and loss-cone filling. Our observations provide in situ evidence of energetic ion loss in the plasma sheet and the plasmasphere plume. Our results suggest that energetic ions scattering into the loss cone in the central plasma sheet and the outer boundary of the plasmaspheric plume are attributed to the field line curvature scattering mechanism and EMIC wave scattering mechanism, respectively.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Section: Y Xiong Et Al: Energetic Ions Into the Loss Conementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Energetic ions scattered into the loss cone with observations of the Cluster satellite

2016

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“…Shprits et al (2013) demonstrated that EMIC waves play a crucial role for the dynamics of the ultrarelativistic populations in the radiation belts. Detached proton subauroral arcs are caused by the precipitation of ring current protons into the atmosphere produced by EMIC waves (e.g., Jordanova et al 2007;Spasojevic and Fuselier 2009;Yuan et al 2010). As EMIC waves play an important role in the dynamics of the inner magnetosphere, in this section, we consider how heavy ions regulate EMIC wave scattering, their impact on ion heating by these waves and the minimum resonant energy during wave-particle interactions.…”

Section: Scattering and Heating Of Particles By Emic Waves In The Prementioning

confidence: 99%

Circulation of Heavy Ions and Their Dynamical Effects in the Magnetosphere: Recent Observations and Models

et al. 2014

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Knowledge of the ion composition in the near-Earth's magnetosphere and plasma sheet is essential for the understanding of magnetospheric processes and instabilities. The presence of heavy ions of ionospheric origin in the magnetosphere, in particular oxygen (O + ), influences the plasma sheet bulk properties, current sheet (CS) thickness and its structure. It affects reconnection rates and the formation of Kelvin-Helmholtz instabilities. This has profound consequences for the global magnetospheric dynamics, including geomagnetic storms and substorm-like events. The formation and demise of the ring current and the radiation belts are also dependent on the presence of heavy ions. In this review we cover recent advances in observations and models of the circulation of heavy ions in the magne- tosphere, considering sources, transport, acceleration, bulk properties, and the influence on the magnetospheric dynamics. We identify important open questions and promising avenues for future research.

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Electromagnetic ion cyclotron wave modeling during the geospace environment modeling challenge event

et al. 2014

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We investigate the temporal evolution and the spatial distribution of electromagnetic ion cyclotron (EMIC) waves during the 8-11 June 2001 geomagnetic storm, one of the storms selected for study by the Geospace Environment Modeling program. Generations of EMIC waves in the H + , He + , and O + bands are simulated using the kinetic ring current-atmosphere interactions model with a self-consistent magnetic field and a ray tracing code. Simulations show that strong wave gain occurs in the afternoon sector at L > 5 and overlaps with a high-density plasmaspheric drainage plume. EMIC wave gain maximizes during the main phase and decreases in the recovery phase. We find that EMIC wave gain is stronger in the He + band than in the other two bands in the inner magnetosphere, except the region of low L (< 3) where the H + band is dominant due to an enhancement in the ring current anisotropy. Little wave gain is obtained for the O + band. Comparison with in situ EMIC events and EMIC event proxies at five geosynchronous satellites shows consistence in the temporal and local time evolution of the wave distribution. Our simulations of the EMIC wave distribution also agree with proton aurora at subauroral latitudes observed from the Imager for Magnetopause-to-Aurora Global Exploration satellite.

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Link between EMIC waves in a plasmaspheric plume and a detached sub‐auroral proton arc with observations of Cluster and IMAGE satellites

Cited by 68 publications

References 43 publications

Energetic ions scattered into the loss cone with observations of the Cluster satellite

Energetic ions scattered into the loss cone with observations of the Cluster satellite

Circulation of Heavy Ions and Their Dynamical Effects in the Magnetosphere: Recent Observations and Models

Electromagnetic ion cyclotron wave modeling during the geospace environment modeling challenge event

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