Effect of parallel electric field on Alfven waves in multi-component magnetospheric plasma: Kinetic approach

2020 ◽  
Author(s):  
Vishnu P. Ahirwar ◽  
G. Ahirwar
Keyword(s):  
Electric Field ◽  
Alfven Waves ◽  
Magnetospheric Plasma ◽  
Kinetic Approach ◽  
Alfvén Waves ◽  
Parallel Electric Field ◽  
Plasma Kinetic

scholarly journals Parallel electric field in the auroral ionosphere: excitation of acoustic waves by Alfvén waves

2004 ◽  
Vol 22 (8) ◽  
pp. 2797-2804 ◽  
Author(s):  
P. L. Israelevich ◽  
L. Ofman
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Acoustic Waves ◽  
Finite Amplitude ◽  
Alfven Waves ◽  
Plasma Pressure ◽  
Alfvén Waves ◽  
Small Scale ◽  
Auroral Ionosphere ◽  
Parallel Electric Field

Abstract. We investigate a new mechanism for the formation of a parallel electric field observed in the auroral ionosphere. For this purpose, the excitation of acoustic waves by propagating Alfvén waves was studied numerically. We find that the magnetic pressure perturbation due to finite amplitude Alfvén waves causes the perturbation of the plasma pressure that propagates in the form of acoustic waves, and gives rise to a parallel electric field. This mechanism explains the observations of the strong parallel electric field in the small-scale electromagnetic perturbations of the auroral ionosphere. For the cases when the parallel electric current in the small-scale auroral perturbations is so strong that the velocity of current carriers exceeds the threshold of the ion sound instability, the excited ion acoustic waves may account for the parallel electric fields as strong as tens of mV/m.

scholarly journals Observations of polar patches generated by solar wind Alfvén wave coupling to the dayside magnetosphere

1999 ◽  
Vol 17 (4) ◽  
pp. 463-489 ◽  
Author(s):  
P. Prikryl ◽  
J. W. MacDougall ◽  
I. F. Grant ◽  
D. P. Steele ◽  
G. J. Sofko ◽  
...  
Keyword(s):  
Solar Wind ◽  
Electric Field ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Alfvén Waves ◽  
Convection Cell ◽  
Convection Flow ◽  
Vhf Radar ◽  
Sky Imager ◽  
The Imf

Abstract. A long series of polar patches was observed by ionosondes and an all-sky imager during a disturbed period (Kp = 7- and IMF Bz < 0). The ionosondes measured electron densities of up to 9 × 1011 m-3 in the patch center, an increase above the density minimum between patches by a factor of \\sim4.5. Bands of F-region irregularities generated at the equatorward edge of the patches were tracked by HF radars. The backscatter bands were swept northward and eastward across the polar cap in a fan-like formation as the afternoon convection cell expanded due to the IMF By > 0. Near the north magnetic pole, an all-sky imager observed the 630-nm emission patches of a distinctly band-like shape drifting northeastward to eastward. The 630-nm emission patches were associated with the density patches and backscatter bands. The patches originated in, or near, the cusp footprint where they were formed by convection bursts (flow channel events, FCEs) structuring the solar EUV-produced photoionization and the particle-produced auroral/cusp ionization by segmenting it into elongated patches. Just equatorward of the cusp footprint Pc5 field line resonances (FLRs) were observed by magnetometers, riometers and VHF/HF radars. The AC electric field associated with the FLRs resulted in a poleward-progressing zonal flow pattern and backscatter bands. The VHF radar Doppler spectra indicated the presence of steep electron density gradients which, through the gradient drift instability, can lead to the generation of the ionospheric irregularities found in patches. The FLRs and FCEs were associated with poleward-progressing DPY currents (Hall currents modulated by the IMF By) and riometer absorption enhancements. The temporal and spatial characteristics of the VHF backscatter and associated riometer absorptions closely resembled those of poleward moving auroral forms (PMAFs). In the solar wind, IMP 8 observed large amplitude Alfvén waves that were correlated with Pc5 pulsations observed by the ground magnetometers, riometers and radars. It is concluded that the FLRs and FCEs that produced patches were driven by solar wind Alfvén waves coupling to the dayside magnetosphere. During a period of southward IMF the dawn-dusk electric field associated with the Alfvén waves modulated the subsolar magnetic reconnection into pulses that resulted in convection flow bursts mapping to the ionospheric footprint of the cusp.Key words. Ionosphere (polar ionosphere). Magneto- spheric physics (magnetosphere-ionosphere interactions; polar wind-magnetosphere interactions).

Kinetic Alfvén waves in an inhomogeneous anisotropic magnetoplasma in the presence of an inhomogeneous electric field: particle aspect analysis

2000 ◽  
Vol 63 (4) ◽  
pp. 311-328 ◽  
Author(s):  
A. BARONIA ◽  
M. S. TIWARI
Keyword(s):  
Growth Rate ◽  
Dispersion Relation ◽  
Electric Field ◽  
Alfven Waves ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Temperature Anisotropy ◽  
Inhomogeneous Electric Field ◽  
Kinetic Alfvén Waves

Kinetic Alfvén waves in the presence of an inhomogeneous electric field applied perpendicular to the ambient magnetic field in an anisotropic, inhomogeneous magnetoplasma are investigated. The particle aspect approach is adopted to investigate the trajectories of charged particles in the electromagnetic field of a kinetic Alfvén wave. Expressions are found for the field-aligned current, the perpendicular current, the dispersion relation and the particle energies. The growth rate of the wave is obtained by an energy- conservation method. It is predicted that plasma density inhomogeneity is the main source of instability, and an enhancement of the growth rate by electric field inhomogeneity and temperature anisotropy is found. The dispersion relation and growth rate involve the finite-Larmor-radius effect, electron inertia and the temperature anisotropy of the magnetoplasma. The applicability of the investigation to the auroral acceleration region is discussed.

scholarly journals Plasma Heating by Alfvén Waves - Kinetic Properties of Magnetohydrodynamic Disturbances

1985 ◽  
Vol 107 ◽  
pp. 381-389
Author(s):  
Akira Hasegawa
Keyword(s):  
Electric Field ◽  
Plasma Heating ◽  
Alfven Wave ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Kinetic Properties ◽  
Parallel Electric Field ◽  
Astrophysical Plasmas ◽  
Finite Larmor Radius ◽  
Wave Heating

Mechanisms of Alfvén wave heating in space-astrophysical plasmas are presented with particular emphasis on the parallel electric field generated in the magnetohydrodynamic perturbations due to the finite Larmor radius effects.

Role of trapped and circulating particles in inducing current drive and radial electric field by Alfvén waves in tokamaks

2002 ◽  
Vol 67 (5) ◽  
pp. 301-308 ◽  
Author(s):  
V. S. TSYPIN ◽  
R. M. O. GALVÃO ◽  
I. C. NASCIMENTO ◽  
M. TENDLER ◽  
J. H. F. SEVERO ◽  
...  
Keyword(s):  
Electric Field ◽  
Radial Electric Field ◽  
Alfven Waves ◽  
Current Drive ◽  
Alfvén Waves ◽  
Trapped Particles ◽  
Transport Barriers

Absorption by trapped particles is supposed to seriously hinder current drive by Alfvén waves. However, it is shown in this paper that the same effect is rather beneficial for the emergence of the radial electric field induced by these waves, which is important for creating and maintaining transport barriers in tokamaks.

Effect of the radial electric field, induced by Alfvén waves, on transport processes in tokamaks

1999 ◽  
Vol 39 (11Y) ◽  
pp. 2119-2125
Author(s):  
V.S Tsypin ◽  
I.C Nascimento ◽  
R.M.O Galvão ◽  
A.G Elfimov ◽  
M Tendler ◽  
...  
Keyword(s):  
Electric Field ◽  
Radial Electric Field ◽  
Alfven Waves ◽  
Transport Processes ◽  
Alfvén Waves
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