scholarly journals The relationship between the macroscopic state of electrons and the properties of chorus waves observed by the Van Allen Probes

2016 ◽  
Vol 43 (15) ◽  
pp. 7804-7812 ◽  
Author(s):  
Chao Yue ◽  
Xin An ◽  
Jacob Bortnik ◽  
Qianli Ma ◽  
Wen Li ◽  
...  
Keyword(s):  
Chorus Waves ◽  
Van Allen Probes ◽  
The Relationship

Simulations of the Relativistic Radiation Belt Electrons Using the VERB-3D Code

2021 ◽  
Author(s):  
Dedong Wang ◽  
Yuri Shprits ◽  
Alexander Drozdov ◽  
Nikita Aseev ◽  
Irina Zhelavskaya ◽  
...  
Keyword(s):  
Space Weather ◽  
Radiation Belt ◽  
Model Performance ◽  
Dynamic Evolution ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Radiation Belt Electrons ◽  
Simulation Results

<p>Using the three-dimensional Versatile Electron Radiation Belt (VERB-3D) code, we perform simulations to investigate the dynamic evolution of relativistic electrons in the Earth’s outer radiation belt. In our simulations, we use data from the Geostationary Operational Environmental Satellites (GOES) to set up the outer boundary condition, which is the only data input for simulations. The magnetopause shadowing effect is included by using last closed drift shell (LCDS), and it is shown to significantly contribute to the dropouts of relativistic electrons at high $L^*$. We validate our simulation results against measurements from Van Allen Probes. In long-term simulations, we test how the latitudinal dependence of chorus waves can affect the dynamics of the radiation belt electrons. Results show that the variability of chorus waves at high latitudes is critical for modeling of megaelectron volt (MeV) electrons. We show that, depending on the latitudinal distribution of chorus waves under different geomagnetic conditions, they cannot only produce a net acceleration but also a net loss of MeV electrons. Decrease in high‐latitude chorus waves can tip the balance between acceleration and loss toward acceleration, or alternatively, the increase in high‐latitude waves can result in a net loss of MeV electrons. Variations in high‐latitude chorus may account for some of the variability of MeV electrons. </p><p>Our simulation results for the NSF GEM Challenge Events show that the position of the plasmapause plays a significant role in the dynamic evolution of relativistic electrons. We also perform simulations for the COSPAR International Space Weather Action Team (ISWAT) Challenge for the year 2017. The COSPAR ISWAT is a global hub for collaborations addressing challenges across the field of space weather. One of the objectives of the G3-04 team “Internal Charging Effects and the Relevant Space Environment” is model performance assessment and improvement. One of the expected outputs is a more systematic assessment of model performance under different conditions. The G3-04 team proposed performing benchmarking challenge runs. We ‘fly’ a virtual satellite through our simulation results and compare the simulated differential electron fluxes at 0.9 MeV and 57.27 degrees local pitch-angle with the fluxes measured by the Van Allen Probes. In general, our simulation results show good agreement with observations. We calculated several different matrices to validate our simulation results against satellite observations.</p>

Observation of chorus waves by the Van Allen Probes: Dependence on solar wind parameters and scale size

2016 ◽  
Vol 121 (8) ◽  
pp. 7608-7621 ◽  
Author(s):  
Homayon Aryan ◽  
David Sibeck ◽  
Michael Balikhin ◽  
Oleksiy Agapitov ◽  
Craig Kletzing
Keyword(s):  
Solar Wind ◽  
Scale Size ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Solar Wind Parameters

The Relationship Between EMIC Wave Properties and Proton Distributions Based on Van Allen Probes Observations

2019 ◽  
Vol 46 (8) ◽  
pp. 4070-4078 ◽  
Author(s):  
Chao Yue ◽  
Chae‐Woo Jun ◽  
Jacob Bortnik ◽  
Xin An ◽  
Qianli Ma ◽  
...  
Keyword(s):  
Emic Wave ◽  
Van Allen Probes ◽  
The Relationship ◽  
Wave Properties

scholarly journals Intense low‐frequency chorus waves observed by Van Allen Probes: Fine structures and potential effect on radiation belt electrons

2016 ◽  
Vol 43 (3) ◽  
pp. 967-977 ◽  
Author(s):  
Zhonglei Gao ◽  
Zhenpeng Su ◽  
Hui Zhu ◽  
Fuliang Xiao ◽  
Huinan Zheng ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Low Frequency ◽  
Potential Effect ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Radiation Belt Electrons ◽  
Fine Structures

The Angular Distribution of Whistler-Mode Chorus and the Importance of Plumes in the Chorus-Hiss Mechanism

2020 ◽  
Author(s):  
David P. Hartley ◽  
Lunjin Chen ◽  
Craig Kletzing ◽  
Richard Horne ◽  
Ondrej Santolik
Keyword(s):  
Ray Tracing ◽  
Wave Vector ◽  
Initial Conditions ◽  
Large Fraction ◽  
Wave Power ◽  
Statistical Distributions ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Vector Orientation ◽  
Chorus Wave

<p>Correlations between chorus waves and plasmaspheric hiss have been directly observed, leading to the proposition that the two wave modes are causally linked. Ray tracing simulations have confirmed that chorus waves can propagate into the plasmasphere and be a source of plasmaspheric hiss, but only for a specific set of initial conditions, particularly relating to the orientation of the wave vector at the chorus source. In this study, both survey and burst mode observations from the Van Allen Probes EMFISIS Waves instrument are coupled with ray tracing simulations to determine the fraction of chorus wave power that exists with the conditions required to enter the plasmasphere. In general, it is found that only a small fraction (< 2%) of chorus wave power exists with the required wave vector orientation. An exception is found when the chorus source is located close to a plasmaspheric plume. Here, azimuthal density gradients modify the wave propagation to permit a large fraction, up to 94%, of chorus wave power to access the plasmasphere. Therefore plasmaspheric plumes are identified as an important access region if a significant fraction of chorus wave power is to enter the plasmasphere and be a source of plasmaspheric hiss. To provide context, we note that plumes are most commonly observed on the dusk side whereas chorus wave power typically peak on the dawn side. The post-noon sector, where these two statistical distributions overlap, appears to be key for observing correlations between chorus and hiss. As such, particular attention is devoted to this region.</p>

Determining the global coherence of chorus waves in the magnetosphere

2021 ◽  
Author(s):  
Shuai Zhang ◽  
Jonathan Rae ◽  
Clare Watt ◽  
Alexander Degeling ◽  
Anmin Tian ◽  
...  
Keyword(s):  
Growth Parameters ◽  
Time Lag ◽  
Spatial Coherence ◽  
Temporal Coherence ◽  
Geomagnetic Index ◽  
Outer Radiation Belt ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Temporal And Spatial ◽  
Chorus Wave

<p>Whistler mode chorus waves play a vital role in the Earth’s outer radiation belt dynamics through the cyclotron resonant pitch angle diffusion.     Recent numerical studies have shown that the temporal and spatial variability of wave growth parameters have universal importance for the diffusion process, which should be much larger than those in the traditional averaged diffusion model.       In the present study, we analyzed both the temporal and spatial coherence of chorus wave in a statistical method using data from the EMFISIS instrument onboard the Van Allen Probes A&B from November 2012 to July 2019. In total, we find 3,875 chorus wave events to calculate the correlation of wave amplitudes between Van Allen Probes A&B.      The results show that both the spatial and temporal correlation of chorus waves decrease significantly with increasing spacecraft separation and time lag, and the spatial and temporal coherence of chorus wave only last ~433 km and ~12 s. We also find that the spatial coherence of chorus waves is higher at L>6, on the dayside, or with a lower geomagnetic index (AL*), while the temporal coherence of chorus waves does not depend on the L-shell, geomagnetic index (AL*) or magnetic local time (MLT). Our results will increase the accuracy of modeling wave-particle interactions due to chorus waves.</p>

scholarly journals A statistical study of spatial distribution and source region size of chorus waves using Van Allen Probes data

2018 ◽  
Author(s):  
Shangchun Teng ◽  
Xin Tao ◽  
Wen Li ◽  
Yi Qi ◽  
Xinliang Gao ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Equatorial Plane ◽  
Statistical Study ◽  
Continuous Wave ◽  
Source Region ◽  
Occurrence Rate ◽  
Data Set ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Region Size

Abstract. Spatial distribution and source region size of chorus waves are important parameters in understanding their generation.In this work, we analyze over 3 years of continuous wave burst mode data from Van Allen Probes and build a data set of rising and falling tone chorus. For the L shell range covered by Van Allen Probes data (3.5 ≤ L ≤ 7), statistical results demonstrate that the sector where rising tones are most likely to be observed is the dayside during geomagnetically quiet and moderate times and the dawnside during active times. Moreover, rising tone chorus waves have a higher occurrence rate near the equatorial plane, while the falling tone chorus waves have a higher possibility to be observed at lower L-shell and higher magnetic latitude. By analyzing the direction of Poynting wave vector, we statistically investigate the chorus source region size along a field line, and compare the results with previous theoretical estimates. Our analysis confirms previous conclusions that both rising tone and falling tone chorus waves are generated near the equatorial plane, and shows that previous theoretical estimates roughly agree with the observation within a factor of two. Our results provide important insights into further understanding of chorus generation.

scholarly journals Wave–particle interaction effects in the Van Allen belts

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Daniel N. Baker
Keyword(s):  
Electromagnetic Waves ◽  
Radiation Belt ◽  
Particle Interaction ◽  
Outer Zone ◽  
High Energy ◽  
Particle Interactions ◽  
Magnetospheric Substorms ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Wave Particle Interactions

AbstractDiscovering such structures as the third radiation belt (or “storage ring”) has been a major observational achievement of the NASA Radiation Belt Storm Probes program (renamed the “Van Allen Probes” mission in November 2012). A goal of that program was to understand more thoroughly how high-energy electrons are accelerated deep inside the radiation belts—and ultimately lost—due to various wave–particle interactions. Van Allen Probes studies have demonstrated that electrons ranging up to 10 megaelectron volts (MeV) or more can be produced over broad regions of the outer Van Allen zone on timescales as short as a few minutes. The key to such rapid acceleration is the interaction of “seed” populations of ~ 10–200 keV electrons (and subsequently higher energies) with electromagnetic waves in the lower band (whistler-mode) chorus frequency range. Van Allen Probes data show that “source” electrons (in a typical energy range of one to a few tens of keV energy) produced by magnetospheric substorms play a crucial role in feeding free energy into the chorus waves in the outer zone. These chorus waves then, in turn, rapidly heat and accelerate the tens to hundreds of keV seed electrons injected by substorms to much higher energies. Hence, we often see that geomagnetic activity driven by strong solar storms (coronal mass ejections, or CMEs) commonly leads to ultra-relativistic electron production through the intermediary step of waves produced during intense magnetospheric substorms. More generally, wave–particle interactions are of fundamental importance over a broad range of energies and in virtually all regions of the magnetosphere. We provide a summary of many of the wave modes and particle interactions that have been studied in recent times.

Sign in / Sign up

Export Citation Format

Share Document