Density variation effect on multi-ions with kinetic Alfven wave around cusp region—a kinetic approach

Tamrakar, Radha; Varma, P.; Tiwari, Meenakshi

doi:10.1007/s10509-017-3224-7

Cited by 6 publications

(7 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…KAW is the extension of the shear Alfvén wave branch as the transverse spatial scale is comparable with or smaller than the ion scale (Hasegawa & Chen, ; Lysak & Lotko, ). KAW has been studied in a wide variety of plasmas and in magnetic reconnection (Angelopoulos et al, ; Chaston et al, , ; Chen et al, ; Cheng & Johnson, ; Johnson & Cheng, ; Keiling, ; Liang et al, ; Lin et al, ; Shi et al, ; Stasiewicz et al, ; Tamrakar et al, ; Wu et al, ; Wygant et al, ). In a reconnection layer, the polarity of KAW is consistent with that of Hall signals.…”

Section: Theoretical Analysismentioning

confidence: 99%

Structures of Hall Fields in Asymmetric Magnetic Reconnection

Dai

2018

JGR Space Physics

View full text Add to dashboard Cite

Unlike a quadrupolar Hall magnetic field in symmetric magnetic reconnection, a bipolar or quadrupolar Hall magnetic field occurs in asymmetric reconnection as indicated by recent observations from the Magnetospheric Multiscale (MMS) mission. Here we present analytic calculations of the structures of Hall magnetic fields in asymmetric reconnection. The Hall magnetic fields are analyzed in terms of kinetic Alfvén wave eigenmodes of the reconnection layer. The bipolar and quadrupolar patterns of Hall magnetic fields correspond to a dominance of the n = 0 and n = 1 kinetic Alfvén wave eigenmode, respectively. The asymmetry of Hall fields is linked to the asymmetry of the Alfvé speed profile. The Hall magnetic fields are shifted toward and enhanced on the low Alfvén speed side of the reconnection layer. The asymmetry in the magnetic field strength of the reconnection layer has a major effect on the structures of Hall magnetic fields.

show abstract

Section: Theoretical Analysismentioning

confidence: 99%

Structures of Hall Fields in Asymmetric Magnetic Reconnection

Dai

2018

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…So, it is not possible to study the effect of electrons in the complete absence of multi-ions. Recently, kinetic Alfvén wave propagation in multi-ions plasma has been considered by Tamrakar et al (2018aTamrakar et al ( , 2018bTamrakar et al ( , 2018c. This paper goes beyond the previous investigations and demonstrate the behaviour of inertial Alfvén waves in the presence of H + , He + and O + ions dominated background plasma in auroral acceleration region.…”

Section: Introductionmentioning

confidence: 57%

“…Here, we have considered the collisionless, homogeneous, low beta (β m e /m i ) plasma with external magnetic field B 0 along z-direction. The basic dispersion tensor elements D xx (k, ω), D xz (k, ω), D zx (k, ω) and D zz (k, ω) of kinetic theory (Lysak and Lotko 1996;Tamrakar et al 2018aTamrakar et al , 2018c are used as,…”

Section: Mathematical Modelmentioning

confidence: 99%

“…n represents wave harmonics, J n (b i ) is the Bessel function of first kind of order n and F i is the distribution function (here bi-Maxwellian distribution is used), m i is mass and q i is charge of ith ion, subscript 'i' stands for denotes H + , He + , O + ions. The expressions are derived using bi-Maxwellian distribution function (Tamrakar et al 2018a)…”

Section: Mathematical Modelmentioning

confidence: 99%

See 1 more Smart Citation

Inertial Alfvén waves in auroral acceleration region with H+, He+ and O+ ions plasma

Tamrakar

Varma

Tiwari

2019

Astrophys Space Sci

Self Cite

View full text Add to dashboard Cite

The propagation of inertial Alfvén wave is investigated in cold, low-β, homogeneous and bi-Maxwellian plasma consisting of multi-ions (H + , He + and O + ). Kinetic approach is adopted to derive the dispersion relation, damping rate, group velocity and growth/ damping length of the wave. Figures are exhibited with respect to ck ⊥ /ω pe . Effects of density variation with multi-ions are analysed on frequency, damping rate, parallel and perpendicular components of group velocity and growth/ damping length of the inertial Alfvén wave. It is found that varying densities of multi-ions significantly influence the frequency, damping rate and group velocity of inertial Alfvén wave. The wave frequency is observed between 0.5 to 18 s −1 pertaining to observational data. The increasing density of heavy ions reduces the frequency of waves. The presence of He + and O + enhances the damping of wave showing more transfer of energy from wave to particles leading to increase in electron acceleration. The order of parallel and perpendicular group velocity is found to be 10 9 cm/s and 10 5 cm/s respectively. Maximum perpendicular growth length is observed corresponding to the minimum damping rate of wave at ck ⊥ /ω pe < 1, signifying the dynamics in transverse direction to the magnetic field which are more significant in the present analysis. The parameters relevant to auroral acceleration region are used for graphical analysis. The applications of present study may be towards the electron acceleration in the dynamics of auroral acceleration region consisting of heavy ions in background plasma.

show abstract

“…In this article, motivated by recent works that have reported observations of KAW modes in the inner magnetosphere propagating at about 60 • with respect to the magnetic field (Chaston et al, 2014;Moya et al, 2015), considering plasma parameters relevant for the ring current region, we present a study on the effect of O + ions on the dispersion relation of Alfvénic waves propagating at a oblique angle with respect to the background magnetic field, analyzing the changes that these heavy ions introduce on the dispersion relation, stability and polarization (all as function of wave-number) of Kinetic Alfvén Waves when compared with the electron-proton case. To the best of our knowledge, unlike previous works in which fluid models (Yang and Wu, 2005) or approximate versions of the kinetic dispersion relation (Samuel et al, 2011;Venugopal et al, 2014;Tamrakar et al, 2017) were studied, here for the first time we consider the full dispersion tensor with no approximations and choose on wave-normal angles < 70 • to focus on the transition between left-handed to right-handed solutions and the role of the O+ ions on the properties of the waves.…”

Section: Introductionmentioning

confidence: 99%

The effect of oxygen ions on the stability and polarization of Kinetic Alfvén Waves in the magnetosphere

Moya

Gallo-Méndez

Zenteno-Quinteros

2021

Journal of Atmospheric and Solar-Terrestrial Physics

View full text Add to dashboard Cite

One of the most striking properties of Kinetic Alfvén Waves (KAW) is that, unlike the also Alfvénic Electromagnetic Ion Cyclotron (EMIC) waves, these waves are right-hand polarized in the plasma frame. In particular, this signature property is key for the identification of KAW from in situ measurements of plasma waves. From the theoretical point of view, both the dispersion relation and the polarization of KAW has been mostly studied in proton-electron plasmas. However, most astrophysical and space plasmas are multi-species, and therefore in these systems the dispersion properties of the KAW may not depend only on the macroscopic parameters of proton and electron distributions, but also on the parameters of heavier ions. Here, using Vlasov linear theory we study the dispersion properties of Alfvénic modes in multi-species plasmas composed by electrons, protons, and O + ions, with macroscopic plasma parameters relevant to the inner magnetosphere. In consistency with recent observations, our numerical results show that the presence of O + ions allows the existence of KAW in a wider wave-number range and at smaller wave-normal angles compared to the electron-proton case, but at the same time isotropic O + ions tend to reduce (or even inhibiting) the growth rates of unstable KAW triggered by anisotropic protons. These results suggest that magnetospheric ions may play an important role on the energy transfer from large macroscopic scales to sub-ionic and electronic scales, especially during intense geomagnetic storms in which O + ions can dominate the plasma composition in the inner magnetosphere.

show abstract

Density variation effect on multi-ions with kinetic Alfven wave around cusp region—a kinetic approach

Cited by 6 publications

References 38 publications

Structures of Hall Fields in Asymmetric Magnetic Reconnection

Structures of Hall Fields in Asymmetric Magnetic Reconnection

Inertial Alfvén waves in auroral acceleration region with H+, He+ and O+ ions plasma

The effect of oxygen ions on the stability and polarization of Kinetic Alfvén Waves in the magnetosphere

Contact Info

Product

Resources

About