Pitch angle diffusion of low-energy electrons by whistler mode waves

1993 ◽  
Vol 98 (A4) ◽  
pp. 5959-5967 ◽  
Author(s):  
A. D. Johnstone ◽  
D. M. Walton ◽  
R. Liu ◽  
D. A. Hardy
Keyword(s):  
Pitch Angle ◽  
Low Energy ◽  
Whistler Mode ◽  
Low Energy Electrons ◽  
Whistler Mode Waves

scholarly journals On the origin of low‐energy electrons in the inner magnetosphere: Fluxes and pitch‐angle distributions

2017 ◽  
Vol 122 (2) ◽  
pp. 1789-1802 ◽  
Author(s):  
M. H. Denton ◽  
G. D. Reeves ◽  
B. A. Larsen ◽  
R. H. W. Friedel ◽  
M. F. Thomsen ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Low Energy ◽  
Inner Magnetosphere ◽  
Low Energy Electrons

Electron Pitch Angle Distributions in the Compressional Pc5 Waves

2021 ◽  
Author(s):  
Xiao Ma ◽  
Anmin Tian ◽  
Quanqi Shi ◽  
Shichen Bai ◽  
Ji Liu ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Interaction Effects ◽  
Plasma Pressure ◽  
Whistler Waves ◽  
Whistler Mode ◽  
Compressional Waves ◽  
The Earth ◽  
Pressure Anisotropy ◽  
Electron Distributions ◽  
Whistler Mode Waves

<p>In the two flanks of the Earth’s magnetosphere, the compressional Pc5 waves are often observed. Previous study suggests that these waves are usually excited by plasma pressure anisotropy such as drift mirror instability. Interestingly, whistler mode waves are often observed in the magnetic trough regions of the compressional Pc5 waves. In this study, we use 10 years (2007-2016) THEMIS A data to study the electron distributions in the compressional Pc5 waves associated with the whistler mode waves. We find three typical electron pitch angle distributions (PADs) in these compressional waves: cigar-shape, donut-shape and pancake-shape. They predominantly occur at tens to hundreds eV, several keV and >10 keV, respectively. The interaction effects between the electrons and whistler waves inside the magnetic troughs are stressed in understanding the formation of these PADs.</p>

scholarly journals Evidence of stronger pitch angle scattering loss caused by oblique whistler-mode waves as compared with quasi-parallel waves

2014 ◽  
Vol 41 (17) ◽  
pp. 6063-6070 ◽  
Author(s):  
W. Li ◽  
D. Mourenas ◽  
A. V. Artemyev ◽  
O. V. Agapitov ◽  
J. Bortnik ◽  
...  
Keyword(s):  
Pitch Angle ◽  
Whistler Mode ◽  
Scattering Loss ◽  
Angle Scattering ◽  
Whistler Mode Waves

scholarly journals The generation of Ganymede's diffuse aurora through pitch angle scattering

2017 ◽  
Vol 35 (2) ◽  
pp. 239-252
Author(s):  
Arvind K. Tripathi ◽  
Rajendra P. Singhal ◽  
Onkar N. Singh II
Keyword(s):  
Electron Temperature ◽  
Pitch Angle ◽  
Atomic Oxygen ◽  
Particle Interaction ◽  
Distribution Functions ◽  
Dissociative Excitation ◽  
Kappa Distribution ◽  
Loss Cone ◽  
Whistler Mode ◽  
Whistler Mode Waves

Abstract. Diffuse auroral intensities of neutral atomic oxygen OI λ1356 Å emission on Ganymede due to whistler mode waves are estimated. Pitch angle diffusion of magnetospheric electrons into the loss cone due to resonant wave–particle interaction of whistler mode waves is considered, and the resulting electron precipitation flux is calculated. The analytical yield spectrum approach is used for determining the energy deposition of electrons precipitating into the atmosphere of Ganymede. It is found that the intensities (4–30 R) calculated from the precipitation of magnetospheric electrons observed near Ganymede are inadequate to account for the observational intensities (≤ 100 R). This is in agreement with the conclusions reached in previous works. Some acceleration mechanism is required to energize the magnetospheric electrons. In the present work we consider the heating and acceleration of magnetospheric electrons by electrostatic waves. Two particle distribution functions (Maxwellian and kappa distribution) are used to simulate heating and acceleration of electrons. Precipitation of a Maxwellian distribution of electrons can produce about 70 R intensities of OI λ1356 Å emission for electron temperature of 150 eV. A kappa distribution can also yield a diffuse auroral intensity of similar magnitude for a characteristic energy of about 100 eV. The maximum contribution to the estimated intensity results from the dissociative excitation of O2. Contributions from the direct excitation of atomic oxygen and cascading in atomic oxygen are estimated to be only about 1 and 2 % of the total calculated intensity, respectively. The findings of this work are relevant for the present JUNO and future JUICE missions to Jupiter. These missions will provide new data on electron densities, electron temperature and whistler mode wave amplitudes in the magnetosphere of Jupiter near Ganymede.

scholarly journals Study of whistler mode instability in Saturn's magnetosphere

2006 ◽  
Vol 24 (6) ◽  
pp. 1705-1712 ◽  
Author(s):  
R. P. Singhal ◽  
A. K. Tripathi
Keyword(s):  
Diffusion Coefficients ◽  
Pitch Angle ◽  
Temperature Anisotropy ◽  
Mode Instability ◽  
Whistler Mode ◽  
Energy Diffusion ◽  
Whistler Mode Waves ◽  
Magnetosphere Of Saturn ◽  
Temporal Growth Rate ◽  
Good Agreement

Abstract. A dispersion relation for parallel propagating whistler mode waves has been applied to the magnetosphere of Saturn and comparisons have been made with the observations made by Voyager and Cassini. The effect of hot (suprathermal) electron-density, temperature, temperature anisotropy, and the spectral index parameter, κ, on the temporal growth rate of the whistler mode emission is studied. A good agreement is found with observations. Electron pitch angle and energy diffusion coefficients have been obtained using the calculated temporal growth rates.

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