Evolution of FMS and Alfven waves produced by the initial disturbance in the FMS waveguide

Dmitrienko, I. S.

doi:10.1017/s0022377812000608

Cited by 23 publications

(17 citation statements)

References 16 publications

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“…But at any point with given y coordinate, after time interval

τ = \frac{l}{u},

the radial components of the wave vector exceeds the azimuthal one, and soon the wave acquires toroidal polarization state. It is yet another manifestation of the phase mixing phenomenon (Dmitrienko, ; Elsden & Wright, ; Klimushkin & Mager, ; Leonovich & Mazur, ; Mann & Wright, ; Tataronis & Grossmann, ; Uberoi, ; Uberoi & Sedlaček, ). Note that the estimate agrees with the estimate of the poloidal to toroidal mode conversion time by Mann and Wright ().…”

Section: Discussionmentioning

confidence: 99%

Alfvén Wave Generation by a Compact Source Moving on the Magnetopause: Asymptotic Solution

et al. 2019

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The spatiotemporal structure of Alfvén waves excited by a moving pressure pulse on the magnetopause is analytically explored. These waves are supposed to be responsible for field-aligned currents generating traveling convection vortices in the ionosphere. It is found that a moving source generates two wave modes, a primary and a secondary mode, having different azimuthal wave vectors and frequencies. Both modes represent surface waves with amplitudes exponentially decreasing from the magnetopause. At a given azimuthal location, they also decrease with time as the source passes away. For the primary mode, the wave frequency equals the Alfvén resonant frequency on the surface of the source, while for the secondary mode the frequency equals the local resonant frequency. The dependence of the frequency of the secondary mode on the radial coordinate results in phase mixing, which leads to a change of the wave polarization from mixed into toroidal polarization. For both primary and secondary modes, the azimuthal component of the wave vector equals the corresponding wave frequency divided by the speed of the source. Superposition of the primary and secondary modes produces plasma vortices behind the source. Plain Language SummaryThe spatiotemporal structure of Alfvén waves excited by a moving pressure pulse on the magnetopause is analytically explored. It is found that a moving source generates two wave modes, a primary and a secondary mode, having different azimuthal wave vectors and frequencies.Both modes represent surface waves with amplitudes exponentially decreasing from the magnetopause. At a given azimuthal location, they also decrease with time as the source passes away. For the primary mode, the wave frequency equals the Alfvén resonant frequency on the surface of the source, while for the secondary mode the frequency equals the local resonant frequency. For both primary and secondary modes, the azimuthal component of the wave vector equals the corresponding wave frequency divided by the speed of the source. Superposition of the primary and secondary modes produces plasma vortices behind the source.In general plasma physics, the generation of Alfvén waves by a moving source (a specific kind of the Cerenkov radiation problem) was first considered by Dokuchaev (1968). The idea of a moving source was

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“…But at any point with given y coordinate, after time interval

τ = \frac{l}{u},

Section: Discussionmentioning

confidence: 99%

Alfvén Wave Generation by a Compact Source Moving on the Magnetopause: Asymptotic Solution

et al. 2019

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“…To date, the problems of large‐scale ULF wave generation on the magnetopause [ Mann et al ., ; Fujita et al ., ; Plaschke and Glassmeier , ; Turkakin et al ., ; Dmitrienko , ; Hartinger et al ., ] and penetration of the ULF waves from solar wind inside the Earth's magnetosphere [ Walker , , ; Leonovich et al ., ; Mazur , , ] as well as mechanisms of wave amplification at the magnetopause [ Fujita et al ., ; Leonovich and Mishin , ; McKenzie , ] were well theoretically studied in details as separate physical problems in different models of the medium. Nevertheless, one theory considering wave penetration, generation, amplification, and dissipation due to field line resonance (FLR) effect and the resulting distribution of the wave energy along the magnetopause has not been proposed yet.…”

Section: Introductionmentioning

confidence: 99%

Energy flux in 2‐D MHD waveguide in the outer magnetosphere

Mazur

Chuiko

2017

JGR Space Physics

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The problems of large‐scale wave propagation and amplification in the outer magnetosphere are considered. Kelvin‐Helmholtz (KH) instability growth rate of the magnetospheric waveguide eigenmodes is investigated as a function of a coordinate along the magnetopause. The problem of solar wind MHD wave penetration into the waveguide is investigated for a broad range near Pc3 and Pc5 geomagnetic pulsation frequencies and realistic models of the magnetospheric waveguide. The expression for the waveguide eigenmode energy flux is obtained. This expression includes the effects of external wave penetration and mode amplification due to the KH instability, as well as losses due to dissipation in the vicinity of the Alfven resonance which are incorporated into the growth rate coefficient together with the instability.

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“…The magnetic field structure and plasma distribution pattern in the outer magnetosphere provide for a MHD waveguide for fast magnetosonic waves in that region [ Dmitrienko , ; Fedorov et al ., ; Harrold and Samson , ; Kivelson and Southwood , ; Mann and Chisham , ; Mann et al ., ; Rickard and Wright , , ; Samson et al ., ; Sung et al ., ; Walker , ; Wright , ; Wright and Mann , ]. The equatorial and meridional sections of the waveguide are shown in Figures and .…”

Section: Introductionmentioning

confidence: 99%

“…In the most earlier work on the theory of MHD waveguide in the outer magnetosphere, the one‐dimensional inhomogeneous model of the magnetosphere was used (so‐called box model), which takes into account only an inhomogeneity across magnetic shells [ Kivelson and Southwood , ; Harrold and Samson , ; Samson et al ., ; Wright , ; Rickard and Wright , , ; Walker , ; Mann et al ., ; Wright and Mann , ; Dmitrienko , ]. This is the most important and strongest kind of the plasma inhomogeneity, because it provides for the wave trapping across magnetic shells.…”

Section: Introductionmentioning

confidence: 99%

Azimuthal inhomogeneity in the MHD waveguide in the outer magnetosphere

Mazur

Chuiko

2015

JGR Space Physics

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Geomagnetic field and plasma inhomogeneities in the outer equatorial part of the magnetosphere create a channel with low Alfvén speeds which spans from the nose to the far flanks of the magnetosphere, in both the morning and the evening sectors. This channel plays the role of a waveguide for fast magnetosonic waves. The waveguide eigenmodes and corresponding Alfvén resonance (field line resonance) regions are directly related to geomagnetic pulsations Pc3 and Pc5. U-shaped model of the waveguide allows for full analytical investigation of waveguide eigenmodes. Quantities such as mode wave numbers, group velocities, and their energy density distribution are found as functions of coordinate along the waveguide. The linkage of the waveguide magnetosonic oscillation energy to the Alfvén waves in the vicinity of the field line resonance deeper inside the magnetosphere is investigated, and corresponding energy leakage coefficient is found. Thus, the influence of longitudinal (i.e., azimuthal) waveguide inhomogeneity on wave propagation is analytically investigated. Obtained results can be used for interpretation of the observed wave power distribution in the frequency bands of geomagnetic pulsations Pc3 and Pc5, as well as for explanation of their spectral properties in the outer magnetosphere.

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Evolution of FMS and Alfven waves produced by the initial disturbance in the FMS waveguide

Cited by 23 publications

References 16 publications

Alfvén Wave Generation by a Compact Source Moving on the Magnetopause: Asymptotic Solution

Alfvén Wave Generation by a Compact Source Moving on the Magnetopause: Asymptotic Solution

Energy flux in 2‐D MHD waveguide in the outer magnetosphere

Azimuthal inhomogeneity in the MHD waveguide in the outer magnetosphere

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