scholarly journals Applying the cold plasma dispersion relation to whistler mode chorus waves: EMFISIS wave measurements from the Van Allen Probes

2015 ◽  
Vol 120 (2) ◽  
pp. 1144-1152 ◽  
Author(s):  
D. P. Hartley ◽  
Y. Chen ◽  
C. A. Kletzing ◽  
M. H. Denton ◽  
W. S. Kurth
Keyword(s):  
Dispersion Relation ◽  
Cold Plasma ◽  
Whistler Mode ◽  
Wave Measurements ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Plasma Dispersion

scholarly journals Dispersion relation of electromagnetic ion cyclotron waves using Cluster observations

2013 ◽  
Vol 31 (8) ◽  
pp. 1437-1446 ◽  
Author(s):  
I. P. Pakhotin ◽  
S. N. Walker ◽  
Y. Y. Shprits ◽  
M. A. Balikhin
Keyword(s):  
Dispersion Relation ◽  
Wave Vector ◽  
Cold Plasma ◽  
High Plasma ◽  
Minimum Variance ◽  
Ion Cyclotron Waves ◽  
Hot Plasma ◽  
Ion Cyclotron ◽  
Electromagnetic Ion Cyclotron Waves ◽  
Plasma Dispersion

Abstract. Multi-point wave observations on Cluster spacecraft are used to infer the dispersion relation of electromagnetic ion cyclotron (EMIC) waves. In this study we use a phase differencing method and observations from STAFF and WHISPER during a well-studied event of 30 March 2002. The phase differencing method requires the knowledge of the direction of the wave vector, which was obtained using minimum variance analysis. Wave vector amplitudes were calculated for a number of frequencies to infer the dispersion relation experimentally. The obtained dispersion relation is largely consistent with the cold plasma dispersion relation. The presented method allows inferring the dispersion relation experimentally. It can be also used in the future to analyse the hot plasma dispersion relation of waves near the local gyrofrequency that can occur under high plasma beta conditions.

Improved derivation of the modified BGK collision term and applications to the Hall effect and cold plasma dispersion relation

1983 ◽  
Vol 30 (3) ◽  
pp. 371-387 ◽  
Author(s):  
M. Nagata
Keyword(s):  
Dispersion Relation ◽  
Hall Effect ◽  
Cyclotron Resonance ◽  
Velocity Vector ◽  
Cold Plasma ◽  
Collision Frequency ◽  
Collision Term ◽  
Macroscopic Equation ◽  
Plasma Dispersion ◽  
The Magnetic Field

We improve our previously derived addition to the BGK collision term, and express it in a simple form. The collision frequency for scattering now depends anisotropically on the velocity vector. We also apply the improved macroscopic equation of momentum flow to the Hall effect, the cold plasma dispersion relation and the cyclotron resonance. The Hall coefficient which is constant in the case of the BGK collision term now depends on the magnetic field. It is also shown that, compared with the almost symmetric classical curves of cyclotron resonance, the new curves are considerably asymmetric and their half-widths are about 3/2 times the classical ones.

Lag-correlated rising tones of electron cyclotron harmonic and whistler-mode upper-band chorus waves

2021 ◽  
Author(s):  
Zhonglei Gao
Keyword(s):  
Electron Cyclotron ◽  
Hot Electrons ◽  
Time Lags ◽  
Discrete Elements ◽  
Loss Cone ◽  
Whistler Mode ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Gain Energy ◽  
Cyclotron Harmonic

<p>Electron cyclotron harmonic (ECH) and whistler-mode chorus waves can contribute significantly to the magnetospheric dynamics. In the frequency-time spectrogram, ECH usually appears as a series of harmonic structureless bands, while chorus often exhibits successive discrete elements. Here, we present surprising observations by Van Allen Probes of lag-correlated rising tones of ECH and upper-band chorus waves. The time lags of ECH elements with respect to chorus elements range from 0.05 to 0.28 s, negatively correlated with the chorus peak amplitudes. The ECH elements seemingly emerge only when the chorus elements are sufficiently intense (peak amplitude >3 mV/m), and their peak amplitudes are positively correlated. Our data and modeling suggest that upper-band chorus may promote the generation of ECH through rapidly precipitating the ~keV electrons near the loss cone. This phenomenon implies that ECH and chorus may not grow independently but competitively or collaboratively gain energy from hot electrons.</p>

scholarly journals Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Y. Miyoshi ◽  
K. Hosokawa ◽  
S. Kurita ◽  
S.-I. Oyama ◽  
Y. Ogawa ◽  
...  
Keyword(s):  
High Energy ◽  
Daily Basis ◽  
Maximum Energy ◽  
Energy Electron ◽  
High Energy Electron ◽  
Whistler Mode ◽  
Chorus Waves ◽  
Mesospheric Ozone ◽  
Field Lines ◽  
Eiscat Radar

AbstractPulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.

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>

scholarly journals Resonant scattering of plasma sheet electrons leading to diffuse auroral precipitation: 2. Evaluation for whistler mode chorus waves

2011 ◽  
Vol 116 (A4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Binbin Ni ◽  
Richard M. Thorne ◽  
Nigel P. Meredith ◽  
Richard B. Horne ◽  
Yuri Y. Shprits
Keyword(s):  
Plasma Sheet ◽  
Resonant Scattering ◽  
Whistler Mode ◽  
Chorus Waves

Relativistic plasma dispersion relation

1969 ◽  
Vol 11 (11) ◽  
pp. 899-902 ◽  
Author(s):  
B N A Lamborn
Keyword(s):  
Dispersion Relation ◽  
Relativistic Plasma ◽  
Plasma Dispersion
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