scholarly journals Diffuse auroral scattering by whistler mode chorus waves: Dependence on wave normal angle distribution

2011 ◽  
Vol 116 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
Binbin Ni ◽  
Richard M. Thorne ◽  
Nigel P. Meredith ◽  
Yuri Y. Shprits ◽  
Richard B. Horne
Keyword(s):  
Angle Distribution ◽  
Whistler Mode ◽  
Chorus Waves ◽  
Wave Normal ◽  
Normal Angle

scholarly journals Sensitivity of EMIC Wave‐Driven Scattering Loss of Ring Current Protons to Wave Normal Angle Distribution

2019 ◽  
Vol 46 (2) ◽  
pp. 590-598 ◽  
Author(s):  
Xing Cao ◽  
Binbin Ni ◽  
Danny Summers ◽  
Yuri Y. Shprits ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Ring Current ◽  
Angle Distribution ◽  
Scattering Loss ◽  
Emic Wave ◽  
Wave Normal ◽  
Normal Angle

Oblique whistler-mode propagation in a hot anisotropic plasma

1982 ◽  
Vol 27 (2) ◽  
pp. 199-204 ◽  
Author(s):  
S. S. Sazhin ◽  
E. M. Sazhina
Keyword(s):  
Magnetic Field ◽  
Dispersion Relation ◽  
Plasma Temperature ◽  
Anisotropic Plasma ◽  
Mode Propagation ◽  
Whistler Mode ◽  
Energy Focusing ◽  
Wave Normal ◽  
The Magnetic Field ◽  
Normal Angle

An approximate dispersion relation is obtained for quasi-longitudinal whistler mode propagation in the hot anisotropic plasma. The influence of plasma temperature and anisotropy on whistler energy focusing along the magnetic field and whistler trapping in the magnetospheric ducts are considered for the case when the whistler wave normal angle is not equal to zero.

scholarly journals Electron Microbursts Induced by Nonducted Chorus Waves

2021 ◽  
Vol 8 ◽  
Author(s):  
Lunjin Chen ◽  
Xiao-Jia Zhang ◽  
Anton Artemyev ◽  
Liheng Zheng ◽  
Zhiyang Xia ◽  
...  
Keyword(s):  
Field Line ◽  
Particle Simulation ◽  
Electron Precipitation ◽  
Outer Radiation Belt ◽  
Energetic Electrons ◽  
Chorus Waves ◽  
Wave Normal ◽  
Intense Electron ◽  
The Magnetic Field ◽  
Normal Angle

Microbursts, short-lived but intense electron precipitation observed by low-Earth-orbiting satellites, may contribute significantly to the losses of energetic electrons in the outer radiation belt. Their origin is likely due to whistler mode chorus waves, as evidenced by a strong overlap in spatial correlation of the two. Despite previous efforts on modeling bursty electron precipitation induced by chorus waves, most, if not all, rely on the assumption that chorus waves are ducted along the field line with zero wave normal angle. Such ducting is limited to cases when fine-scale plasma density irregularities are present. In contrast, chorus waves propagate in a nonducted way in plasmas with smoothly varying density, allowing wave normals to gradually refract away from the magnetic field line. In this study, the interaction of ducted and nonducted chorus waves with energetic electrons is investigated using test particle simulation. Substantial differences in electron transport are found between the two different scenarios, and resultant electron precipitation patterns are compared. Such a comparison is valuable for interpreting low Earth-orbiting satellite observations of electron flux variation in response to the interaction with magnetospheric chorus waves.

Wave Normal Angle Distribution of Fast Magnetosonic Waves: A Survey of Van Allen Probes EMFISIS Observations

2019 ◽  
Vol 124 (7) ◽  
pp. 5663-5674 ◽  
Author(s):  
Zhengyang Zou ◽  
Pingbing Zuo ◽  
Binbin Ni ◽  
Fengsi Wei ◽  
Zhengyu Zhao ◽  
...  
Keyword(s):  
Angle Distribution ◽  
Van Allen Probes ◽  
Wave Normal ◽  
Normal Angle

scholarly journals Propagation and Dispersion of Lightning-Generated Whistlers Measured From the Van Allen Probes

2021 ◽  
Vol 9 ◽  
Author(s):  
J.-F. Ripoll ◽  
T. Farges ◽  
D. M. Malaspina ◽  
G. S. Cunningham ◽  
G. B. Hospodarsky ◽  
...  
Keyword(s):  
Refractive Index ◽  
Standard Deviation ◽  
Wave Power ◽  
Angle Distribution ◽  
Large Wave ◽  
Small Wave ◽  
Van Allen Probes ◽  
Wave Normal ◽  
Normal Angle ◽  
Field Wave

We study the propagation and attenuation of lightning-generated whistler (LGW) waves in near-Earth space (L ≤ 3) through the statistical study of three specific quantities extracted from data recorded by NASA’s Van Allen Probes mission, from 2012 to 2019: the LGW electric and magnetic power attenuation with respect to distance from a given lightning stroke, the LGW wave normal angle in space, and the frequency-integrated LGW refractive index. We find that LGW electric field wave power decays with distance mostly quadratically in space, with a power varying between -1 and -2, while the magnetic field wave power decays mostly linearly in space, with a power varying between 0 and -1. At night only, the electric wave power decays as a quadratic law and the magnetic power as a linear law, which is consistent with electric and magnetic ground measurements. Complexity of the dependence of the various quantities is maximal at the lowest L-shells (L < 1.5) and around noon, for which LGW are the rarest in Van Allen Probes measurements. In-space near-equatorial LGW wave normal angle statistics are shown for the first time with respect to magnetic local time (MLT), L-shell (L), geographic longitude, and season. A distribution of predominantly electrostatic waves is peaked at large wave normal angle. Conversely, the distribution of electromagnetic waves with large magnetic component and small electric component is peaked at small wave normal angle. Outside these limits, we show that, as the LGW electric power increases, the LGW wave normal angle increases. But, as the LGW magnetic power increases, the LGW wave normal angle distribution becomes peaked at small wave normal angle with a secondary peak at large wave normal angle. The LGW mean wave-normal angle computed over the whole data set is 41.6° with a ∼24° standard deviation. There is a strong MLT-dependence, with the wave normal angle smaller for daytime (34.4° on average at day and 46.7° at night). There is an absence of strong seasonal and continental dependences of the wave-normal angle. The statistics of the LGW refractive index show a mean LGW refractive index is 32 with a standard deviation of ∼26. There is a strong MLT-dependence, with larger refractive index for daytime 36) than for nighttime (28). Smaller refractive index is found during Northern hemisphere summer for L-shells above 1.8, which is inconsistent with Chapman ionization theory and consistent with the so-called winter/seasonal anomaly. Local minima of the mean refractive index are observed over the three continents. Cross-correlation of these wave parameters in fixed (MLT, L) bins shows that the wave normal angle and refractive index are anti-correlated; large (small) wave normal angles correspond with small (large) refractive indexes. High power attenuation during LGW propagation from the lightning source to the spacecraft is correlated with large refractive index and anti-correlated with small wave normal angle. Correlation and anti-correlation show a smooth and continuous path from one regime (i.e. large wave normal angle, small refractive index, low attenuation) to its opposite (i.e. small wave normal angle, large refractive index, large attenuation), supporting consistency of the results.

On whistler-mode trapping in the magnetospheric ducts

1984 ◽  
Vol 31 (3) ◽  
pp. 487-493 ◽  
Author(s):  
S. S. Sazhin
Keyword(s):  
Electron Temperature ◽  
Electron Density ◽  
Mode Propagation ◽  
Plasma Model ◽  
Whistler Mode ◽  
Whistler Mode Waves ◽  
Average Wave ◽  
Wave Normal ◽  
Normal Angle ◽  
Simplified Formula

Conditions for whistler-mode trapping in the magnetospheric ducts are considered. The plasma model includes electron temperature and anisotropy, and there are no restrictions on the value of the wave normal angle. It is pointed out that the range of the wave normal angles for which whistler-mode waves can be trapped in the ducts with enhanced electron density increases when the electron temperature and (or) anisotropy increases; the corresponding increase also takes place for the average wave normal angle when whistler-mode waves are trapped in the ducts that have a deficiency in electron density. The limits of applicability of a simplified formula derived by Sazhin & Sazhina, for whistler-mode propagation in a hot anisotropic plasma, are clarified.

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.

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