Unified theory of whistler mode instability in the presence of a parallel electric field

1984 ◽  
Vol 31 (2) ◽  
pp. 263-274
Author(s):  
Indra Mohan Lal Das ◽  
R. P. Singh
Keyword(s):  
Electric Field ◽  
Full Range ◽  
Present Theory ◽  
Parallel Electric Field ◽  
Temperature Anisotropy ◽  
Whistler Mode ◽  
Plasma Injection ◽  
Whistler Mode Waves ◽  
Particle Pressure ◽  
Analytical Expressions

The propagation characteristics of right-hand circularly polarized whistler mode waves propagating parallel to the external magnetic field in an anisotropic plasma have been reformulated including the effect of a parallel electric field. Analytical expressions for the real frequency and growth rate have been obtained for the full range of the parameters β (the ratio of particle pressure to magnetic pressure of the hot particles), A (temperature anisotropy) and P ( = βA(A + 1)2) without any restriction on the magnitude of the imaginary part of the wave frequency. The effect of cold plasma injection on the marginal instability has also been studied. Possible application of the present theory to the atmospheres of Earth and Jupiter has been discussed.

scholarly journals Impact of hot injected beam on whistler mode with alternating electric field (AC) in the magnetosphere of Saturn

2021 ◽  
Vol 2062 (1) ◽  
pp. 012019
Author(s):  
Kumari Neeta Shukla ◽  
Devi Singh ◽  
R S Pandey
Keyword(s):  
Growth Rate ◽  
Distribution Function ◽  
Electric Field ◽  
Particle Interaction ◽  
Wide Frequency Range ◽  
Temperature Anisotropy ◽  
Mode Instability ◽  
Whistler Mode ◽  
Plasma Injection ◽  
Magnetosphere Of Saturn

Abstract Whistlers are believed to be generated by its own and responsible to evolve dynamical properties of magnetized planetary environment. Growing whistler instability can cause other uncertainties in the magnetosphere and evident to be generated by mean of injection events and temperature variance in plasma environment. In this paper the empirical dispersion relation has developed for parallel propagating whistler mode instability in an infinite saturnian magneto plasma in the presence of perpendicular electric field for ring distribution function having non-monotonous nature. Method of characteristics solutions alongside kinetic approach found to be most suitable in order to achieve perturbed plasma states. The perturbed and unperturbed particle trajectories have taken into consideration to determine perturbed distribution function. A remarkable growth rate expression with added hot plasma injection has been calculated in inner magnetosphere near 6.18 Rs. The results obtained using demonstrative value of the parameters suited to the Saturnian magnetosphere have been computed and discussed. Pressure (Temperature) anisotropy is found to be a peculiar source of free energy for whistler mode instability. The AC frequency irrespective of its magnitude, affects the growth rate significantly. The bulk of energetic hot electrons injection influences the growth rate by increasing its peak value. The result obtained provide the important view of wave particle interaction and useful to analyze the VLF emissions observed over a wide frequency range.

scholarly journals Parker Solar Probe Evidence for the Absence of Whistlers Close to the Sun to Scatter Strahl and to Regulate Heat Flux

2022 ◽  
Vol 924 (2) ◽  
pp. L33
Author(s):  
C. Cattell ◽  
A. Breneman ◽  
J. Dombeck ◽  
E. Hanson ◽  
M. Johnson ◽  
...  
Keyword(s):  
Heat Flux ◽  
Electric Field ◽  
Acoustic Waves ◽  
Electron Distribution Function ◽  
The Sun ◽  
Temperature Anisotropy ◽  
Ion Acoustic Waves ◽  
Plasma Properties ◽  
Electron Distributions ◽  
Whistler Mode Waves

Abstract Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from ∼16 R s to ∼130 R s, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside ∼28 R s (∼0.13 au). Outside 28 R s, they occur within a narrow range of parallel electron beta from ∼1 to 10, and with a beta-heat flux occurrence consistent with the whistler heat flux fan instability. Because electron distributions inside ∼30 R s display signatures of the ambipolar electric field, the lack of whistlers suggests that the modification of the electron distribution function associated with the ambipolar electric field or changes in other plasma properties must result in lower instability limits for the other modes (including the observed solitary waves and ion acoustic waves) that are observed close to the Sun. The lack of narrowband whistler-mode waves close to the Sun and in regions of either low (<0.1) or high (>10) beta is also significant for the understanding and modeling of the evolution of flare-accelerated electrons and the regulation of heat flux in astrophysical settings including other stellar winds, the interstellar medium, accretion disks, and the intragalaxy cluster medium.

scholarly journals Study of Oblique Propagating Whistler Mode Waves in Presence of Parallel DC Electric Field in Magnetosphere of Saturn

2017 ◽  
Vol 6 (2) ◽  
pp. 26 ◽  
Author(s):  
R. Kaur ◽  
R. S. Pandey
Keyword(s):  
Growth Rate ◽  
Distribution Function ◽  
Energy Density ◽  
Wave Number ◽  
Number Density ◽  
Temperature Anisotropy ◽  
Loss Cone ◽  
Whistler Mode ◽  
Whistler Mode Waves ◽  
Magnetosphere Of Saturn

In this paper whistler mode waves have been investigated in magnetosphere of Saturn. The derivation for perturbed distribution function, dispersion relation and growth rate have been determined by using the method of characteristic and kinetic approach. Analytical expressions for growth rate and real frequency of whistlers propagating oblique to magnetic field direction are attained. Calculations have been performed at 6 radial distances in plasma sheet region of Saturn’s magnetosphere as per data provided by Cassini. Work has been extended for bi-Maxwellian as well as Loss-cone distribution function. Parametric analysis show that temperature anisotropy, increase in number density, energy density and angle of propagation increases the growth rate of whistler waves along with significant shift in wave number. In case of Loss-cone distribution, increase in growth rate of whistlers is significantly more than for bi-Maxwellian distribution function. Generation of second harmonics can also be seen in the graphs plotted. It is concluded that parallel DC field stabilizes the wave and temperature anisotropy, angle of propagation, number density and energy density of electrons enhances the growth rate. Thus the results are of importance in analyzing observed VLF emissions over wide spectrum of frequency range in Saturnian magnetosphere. The analytical model developed can also be used to study various types of instabilities in planetary magnetospheres. 

scholarly journals Plasma magnetosphere of slowly rotating magnetized neutron star in branewold

2019 ◽  
Vol 49 ◽  
pp. 1960019 ◽  
Author(s):  
Rayimbaev Javlon ◽  
Turimov Bobur ◽  
Palvanov Satimbay
Keyword(s):  
Neutron Star ◽  
Electric Field ◽  
Charge Density ◽  
Poisson Equation ◽  
Maxwell Equations ◽  
Scalar Potential ◽  
Parallel Electric Field ◽  
Polar Cap ◽  
Analytical Expression ◽  
Analytical Expressions

The analytical expression for Goldreich-Julian (GJ) charge density at the polar cap of magnetized neutron star has been obtained in braneworlds for inclined neutron star through solving Maxwell equations and shown that the value of GJ charge density decreases with increasing the value of the brane charge. The analytical expressions for scalar potential and parallel electric field on the region greater than the polar cap region of the neutron star have also been obtained by solving Poisson equation in braneworlds.

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