scholarly journals A subauroral polarization stream driven by field‐aligned currents associated with precipitating energetic ions caused by EMIC waves: A case study

2016 ◽  
Vol 121 (2) ◽  
pp. 1696-1705 ◽  
Author(s):  
Zhigang Yuan ◽  
Ying Xiong ◽  
Zheng Qiao ◽  
Haimeng Li ◽  
Shiyong Huang ◽  
...  
Keyword(s):  
Energetic Ions ◽  
Emic Waves

Direct measurements of cold and hot plasma composition and EMIC waves in the outer magnetosphere: Implications for inner magnetosphere wave-particle interactions

2021 ◽  
Author(s):  
Justin Lee ◽  
Drew Turner ◽  
Sarah Vines ◽  
Robert Allen ◽  
Sergio Toledo-Redondo
Keyword(s):  
Unstable Wave ◽  
Linear Wave ◽  
Plasma Composition ◽  
Inner Magnetosphere ◽  
Hot Plasma ◽  
Emic Wave ◽  
Direct Measurements ◽  
Wave Numbers ◽  
Emic Waves

<p>Although thorough characterization of magnetospheric ion composition is rare for EMIC wave studies, convective processes that occur more frequently in Earth’s outer magnetosphere have allowed the Magnetospheric Multiscale (MMS) satellites to make direct measurements of the cold and hot plasma composition during EMIC wave activity. We will present an observation and linear wave modeling case study conducted on EMIC waves observed during a perturbed activity period in the outer dusk-side magnetosphere. During the two intervals investigated for the case study, the MMS satellites made direct measurements of cold plasmaspheric plasma in addition to multiple hot ion components at the same time as EMIC wave emissions were observed. Applying the in-situ plasma composition data to wave modeling, we find that wave growth rate is impacted by the complex interactions between the cold as well as the hot ion components and ambient plasma conditions. In addition, we observe that linear wave properties (unstable wave numbers and band structure) can significantly evolve with changes in cold and hot ion composition. Although the modeling showed the presence of dense cold ions can broaden the range of unstable wave numbers, consistent with previous work, the hot heavy ions that were more abundant nearer storm main phase could limit the growth of EMIC waves to smaller wave numbers. In the inner magnetosphere, where higher cold ion density is expected, the ring current heavy ions could also be more intense near storm-time, possibly resulting in conditions that limit the interactions of EMIC waves with trapped radiation belt electrons to multi-MeV energies. Additional investigation when direct measurements of cold and hot plasma composition are available could improve understanding of EMIC waves and their interactions with trapped energetic particles in the inner magnetosphere.</p>

scholarly journals A Case Study of Transversely Heated Low‐Energy Helium Ions by EMIC Waves in the Plasmasphere

2021 ◽  
Vol 126 (2) ◽  
Author(s):  
Khan‐Hyuk Kim ◽  
Hyuck‐Jin Kwon ◽  
Junhyun Lee ◽  
Ho Jin ◽  
Jungjoon Seough
Keyword(s):  
Low Energy ◽  
Helium Ions ◽  
Emic Waves

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

2016 ◽  
Vol 34 (2) ◽  
pp. 249-257 ◽  
Author(s):  
Ying Xiong ◽  
Zhigang Yuan ◽  
Jingfang Wang
Keyword(s):  
Field Line ◽  
Plasma Sheet ◽  
Outer Boundary ◽  
Scattering Mechanism ◽  
Loss Cone ◽  
Energetic Ions ◽  
Left Hand ◽  
Central Plasma ◽  
Emic Waves

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.

scholarly journals Radial dependence of foreshock cavities: a case study

2004 ◽  
Vol 22 (12) ◽  
pp. 4143-4151 ◽  
Author(s):  
D. G. Sibeck ◽  
K. Kudela ◽  
T. Mukai ◽  
Z. Nemecek ◽  
J. Safrankova
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Bow Shock ◽  
Radial Dependence ◽  
Energetic Ions ◽  
Interplanetary Physics ◽  
Bow Shocks

Abstract. We present a case study of Geotail, Interball-1, IMP-8, and Wind observations of density and magnetic field strength cavities excavated by the enhanced pressures associated with bursts of energetic ions in the foreshock. Consistent with theoretical predictions, the pressure of the energetic ions diminishes rapidly with upstream distance due to a decrease in the flux of energetic ions and a transition from near-isotropic to streaming pitch angle distributions. Consequently, the cavities can only be observed immediately upstream from the bow shock. A comparison of conditions upstream from the pre- and post-noon bow shock demonstrates that foreshock cavities introduce perturbations into the oncoming solar wind flow with dimensions smaller than those of the magnetosphere. Dayside geosynchronous magnetic field strength variations observed by GOES-8 do not track the density variations seen by any of the spacecraft upstream from the bow shock in a one-to-one manner, indicating that none of these spacecraft observed the precise sequence of density variations that actually struck the subsolar magnetopause. Key words. Interplanetary physics (energetic particles; planetary bow shocks) – Magnetospheric physics (solar wind-magnetosphere interactions)

A case study of EMIC waves associated with sudden geosynchronous magnetic field changes

2017 ◽  
Vol 122 (3) ◽  
pp. 3322-3341 ◽  
Author(s):  
Khan‐Hyuk Kim ◽  
Yoshiharu Omura ◽  
Ho Jin ◽  
Junga Hwang
Keyword(s):  
Magnetic Field ◽  
Emic Waves

Combined scattering loss of radiation belt relativistic electrons by simultaneous three-band EMIC waves: A case study

2016 ◽  
Vol 121 (5) ◽  
pp. 4446-4451 ◽  
Author(s):  
Fengming He ◽  
Xing Cao ◽  
Binbin Ni ◽  
Zheng Xiang ◽  
Chen Zhou ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Relativistic Electrons ◽  
Scattering Loss ◽  
Emic Waves

scholarly journals Influence of precipitating energetic ions caused by EMIC waves on the subauroral ionospheric E region during a geomagnetic storm

2014 ◽  
Vol 119 (10) ◽  
pp. 8462-8471 ◽  
Author(s):  
Zhigang Yuan ◽  
Ying Xiong ◽  
Haimeng Li ◽  
Shiyong Huang ◽  
Zheng Qiao ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Energetic Ions ◽  
E Region ◽  
Emic Waves

scholarly journals Electron precipitation from EMIC waves: A case study from 31 May 2013

2015 ◽  
Vol 120 (5) ◽  
pp. 3618-3631 ◽  
Author(s):  
Mark A. Clilverd ◽  
Roger Duthie ◽  
Rachael Hardman ◽  
Aaron T. Hendry ◽  
Craig J. Rodger ◽  
...  
Keyword(s):  
Electron Precipitation ◽  
Emic Waves

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

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