scholarly journals Correlated Pc4-5 ULF waves, whistler-mode chorus, and pulsating aurora observed by the Van Allen Probes and ground-based systems

2015 ◽  
Vol 120 (10) ◽  
pp. 8749-8761 ◽  
Author(s):  
A. N. Jaynes ◽  
M. R. Lessard ◽  
K. Takahashi ◽  
A. F. Ali ◽  
D. M. Malaspina ◽  
...  
Keyword(s):  
Ulf Waves ◽  
Whistler Mode ◽  
Van Allen Probes

Relative Contribution of ULF Waves and Whistler‐mode Chorus to the Radiation Belt Variation during the May 2017 Storm

2021 ◽  
Author(s):  
Naoko Takahashi ◽  
Kanako Seki ◽  
Mei‐Ching Fok ◽  
Yihua Zheng ◽  
Yoshizumi Miyoshi ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Ulf Waves ◽  
Whistler Mode ◽  
Relative Contribution

ULF waves and their influence on radiation belt dynamics in Earth's magnetosphere

2020 ◽  
Author(s):  
Robert Rankin ◽  
Alexander Degeling
Keyword(s):  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Low Frequency ◽  
Recovery Phase ◽  
Ulf Waves ◽  
Wave Source ◽  
Initial Plasma ◽  
Plasma State ◽  
Van Allen Probes ◽  
Geomagnetic Fields

<p>Recent observations from the Van Allen Probes mission have established that Pc3-5 ultra-low-frequency (ULF) waves can energize ions and electrons via drift-resonance and drift-bounce resonance. The extent to which these waves contribute to the space weather of the belts is relatively poorly understood and requires sophisticated modelling and characterization of the dominant wave modes that arise in the development and recovery phase of geomagnetic storms. Despite more than four decades of observations and theoretical analysis of ULF waves, there is no framework for accurately assessing the global distribution of ULF waves and their influence on the ring current. <br>In this presentation, we describe a new global model of ULF waves that incorporates non-dipolar geomagnetic fields. The model is constrained using the GCPM of cold plasma density model and a specification of the ionosphere using the IRI and MSIS models. An algorithm is applied to adjust the initial plasma state to a quasi-static equilibrium that is then driven by a global convection electric field and ULF wave source. For specific observations by the Van Allen Probes and ARASE mission, the effect of these ULF waves on radiation belt ions and electrons is evaluated utilizing test-particle methodology and Liouville's theorem, which enables the phase space density to be followed and compared one-for-one with the satellite observations.  </p>

Solar wind compression induced ULF-modulation of whistler-mode waves in the deep inner magnetosphere

2021 ◽  
Author(s):  
Xiongjun Shang ◽  
Si Liu ◽  
Fuliang Xiao
Keyword(s):  
Solar Wind ◽  
Dynamic Pressure ◽  
Source Region ◽  
Rare Event ◽  
Periodic Pattern ◽  
Ulf Waves ◽  
Wave Source ◽  
Whistler Mode ◽  
Energetic Electrons ◽  
Whistler Mode Waves

<p>With observations of Van Allen Probes, we report a rare event of quasiperiodic whistler-mode waves in the dayside magnetosphere on 20 February 2014 as a response to the enhancement of solar wind dynamic pressure (P<sub>sw</sub>). The intensities of whistler-mode waves and anisotropy distributions of energetic electrons exhibit a ~5 mins quasi-periodic pattern, which is consistent with the period of synchronously observed compressional ULF waves. Based on the wave growth rates calculation, we suggest that the quasiperiodic whistler-mode waves could be generated by the energetic electrons with modulated anisotropy. The Poynting vectors of the whistler-mode waves alternate between northward and southward direction with a period twice the compressional ULF wave's near the equator, also exhibiting a clear modulated feature. This is probably because the intense ULF waves slightly altered the location of the local magnetic minimum, and thus modulated the relative direction of the wave source region respect to the spacecraft. Current results provide a direct evidence that the P<sub>sw</sub> play an important role in the generation and propagation of whistler-mode waves in the Earth's magnetosphere.</p>

scholarly journals Van Allen Probes observations of unusually low frequency whistler mode waves observed in association with moderate magnetic storms: Statistical study

2015 ◽  
Vol 42 (18) ◽  
pp. 7273-7281 ◽  
Author(s):  
C. A. Cattell ◽  
A. W. Breneman ◽  
S. A. Thaller ◽  
J. R. Wygant ◽  
C. A. Kletzing ◽  
...  
Keyword(s):  
Statistical Study ◽  
Low Frequency ◽  
Magnetic Storms ◽  
Whistler Mode ◽  
Van Allen Probes ◽  
Whistler Mode Waves

Storm time occurrence and spatial distribution of Pc4 poloidal ULF waves in the inner magnetosphere: A Van Allen Probes statistical study

2015 ◽  
Vol 120 (6) ◽  
pp. 4748-4762 ◽  
Author(s):  
Lei Dai ◽  
Kazue Takahashi ◽  
Robert Lysak ◽  
Chi Wang ◽  
John R. Wygant ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Statistical Study ◽  
Ulf Waves ◽  
Inner Magnetosphere ◽  
Van Allen Probes

scholarly journals Early-Time Non-Equilibrium Pitch Angle Diffusion of Electrons by Whistler-Mode Hiss in a Plasmaspheric Plume Associated with BARREL Precipitation

2021 ◽  
Vol 8 ◽  
Author(s):  
R. M. Millan ◽  
J.-F. Ripoll ◽  
O. Santolík ◽  
W. S. Kurth
Keyword(s):  
Phase Space ◽  
Pitch Angle ◽  
Particle Interaction ◽  
Phase Space Density ◽  
Angle Distribution ◽  
Loss Cone ◽  
Linear Diffusion ◽  
Whistler Mode ◽  
Space Density ◽  
Van Allen Probes

In August 2015, the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) observed precipitation of energetic (<200 keV) electrons magnetically conjugate to a region of dense cold plasma as measured by the twin Van Allen Probes spacecraft. The two spacecraft passed through the high density region during multiple orbits, showing that the structure was spatial and relatively stable over many hours. The region, identified as a plasmaspheric plume, was filled with intense hiss-like plasma waves. We use a quasi-linear diffusion model to investigate plume whistler-mode hiss waves as the cause of precipitation observed by BARREL. The model input parameters are based on the observed wave, plasma and energetic particle properties obtained from Van Allen Probes. Diffusion coefficients are found to be largest in the same energy range as the precipitation observed by BARREL, indicating that the plume hiss waves were responsible for the precipitation. The event-driven pitch angle diffusion simulation is also used to investigate the evolution of the electron phase space density (PSD) for different energies and assumed initial pitch angle distributions. The results show a complex temporal evolution of the phase space density, with periods of both growth and loss. The earliest dynamics, within the ∼5 first minutes, can be controlled by a growth of the PSD near the loss cone (by a factor up to ∼2, depending on the conditions, pitch angle, and energy), favored by the absence of a gradient at the loss cone and by the gradients of the initial pitch angle distribution. Global loss by 1-3 orders of magnitude (depending on the energy) occurs within the first ∼100 min of wave-particle interaction. The prevalence of plasmaspheric plumes and detached plasma regions suggests whistler-mode hiss waves could be an important driver of electron loss even at high L-value (L ∼6), outside of the main plasmasphere.

scholarly journals A Comparative Study of ULF Waves' Role in the Dynamics of Charged Particles in the Plasmasphere: Van Allen Probes Observation

2018 ◽  
Vol 123 (7) ◽  
pp. 5334-5343 ◽  
Author(s):  
Jie Ren ◽  
Q. G. Zong ◽  
Y. Miyoshi ◽  
R. Rankin ◽  
H. E. Spence ◽  
...  
Keyword(s):  
Comparative Study ◽  
Charged Particles ◽  
Ulf Waves ◽  
Van Allen Probes

Observations and simulations of electron flux oscillations in response to broadband ULF waves

2020 ◽  
Author(s):  
Xinlin Li ◽  
Theodoros Sarris ◽  
Michael Temerin ◽  
Hong Zhao ◽  
Leng Ying Khoo ◽  
...  
Keyword(s):  
Electron Flux ◽  
Low Frequency ◽  
Transport Processes ◽  
Ulf Waves ◽  
Magnetic Fluctuations ◽  
Radial Transport ◽  
Energy Channel ◽  
Van Allen Probes ◽  
Initial Results ◽  
Energy Channels

&lt;p&gt;It has recently been demonstrated through simulations and observations that flux oscillations of hundreds-keV electrons are produced in the magnetosphere in association with broadband Ultra Low Frequency (ULF) waves (Sarris et al., JGR, 2017). These oscillations are observed in the form of drift-periodic flux fluctuations, but are not associated with drift echoes following storm- or substorm-related energetic particle injections. They are observed in particular during quiet times, and it has been shown that they could indicate ongoing radial transport processes caused by ULF waves. It has also been shown that the width of electron energy channels is a critical parameter affecting the observed amplitude of flux oscillations, with narrower energy channel widths enabling the observation of higher-amplitude flux oscillations; this potentially explains why such features were not observed regularly before the Van Allen Probes era, as previous spacecraft generally had lower energy resolution. We extend these initial results by investigating the association between the observed flux oscillations with the amplitude of electric and magnetic fluctuations in the ULF range and with Phase Space Density gradients, both of which are expected to also affect radial transport rates.&lt;/p&gt;

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