Dispersion relation for ballooning modes and condition of their stability in the near-earth plasma

Mazur, N. G.; Fedorov, E. N.; Пилипенко, В. А.

doi:10.1134/s0016793212050118

Cited by 27 publications

(37 citation statements)

References 11 publications

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“…When H has a maximum at the magnetospheric equator, which is usually the case, the opaque region is located in the vicinity of the magnetospheric equator, where the field line curvature reaches its highest value (Mager et al, 2009b;Mazur et al, 2012). Thus, two sub-resonators (regions I and II in Fig.…”

Section: The Wave Structure In the Direction Of The Ambient Magnetic mentioning

confidence: 99%

“…A possible solution is suggested by the strong compressional magnetic field component of giant pulsations which is an indicator of the role of finite plasma pressure in ULF wave formation (Klimushkin et al, 2004). Indeed, Pgs are a subclass of the poloidal Alfvén wave, but the poloidal eigenfrequency is very sensitive to plasma pressure (e.g., Klimushkin, 1997;Mager and Klimushkin, 2002;Agapitov and Cheremnykh, 2011;Mazur et al, 2012). A combined effect of the field line curvature and finite plasma pressure can result in trans- verse resonators forming in some magnetospheric regions (plasmapause, ring current).…”

Section: Modeling and The Purpose Of This Papermentioning

confidence: 99%

“…The η term in Eq. (3) hints that the poloidal eigenfrequency is significantly influenced by the finite plasma pressure and the equilibrium current (Klimushkin, 1997;Mager and Klimushkin, 2002;Klimushkin et al, 2004;Agapitov and Cheremnykh, 2011;Mazur et al, 2012).…”

Section: Main Equationsmentioning

confidence: 99%

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Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

Mager

Klimushkin

2013

Earth Planet Sp

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The paper assumes that the giant pulsations are oscillations trapped within a resonator resulting from finite plasma pressure on the outer edge of the plasmapause. This resonator is bounded, across the L-shells, by two turning points allowing the wave energy to be channeled azimuthally. This assumption can explain the basic properties of the giant pulsations: strong localization across magnetic shells, poloidal polarization, presence of a significant compressional component in the Pg magnetic field, the fact that their frequency does not depend on the radial coordinate. The wave field structure both across the L-shells and along the field lines is studied. In order to explain the amplitude modulation it is sufficient to suppose that the resonator is excited by some non-stationary process. Generation by a moving source comprised of substorm-injected particles is considered.

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Section: The Wave Structure In the Direction Of The Ambient Magnetic mentioning

confidence: 99%

Section: Modeling and The Purpose Of This Papermentioning

confidence: 99%

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Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

Mager

Klimushkin

2013

Earth Planet Sp

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“…In the low-pressure limit (0 < β 1) the ballooning term (11) takes the form H = β[κ P κ R + (7/2)κ 2 R ], which coincides with the one obtained in papers dealing with MHD theory (e.g., low-β limit of Denton, 1998;Klimushkin et al, 2004;Mazur et al, 2012) at the adiabatic index γ = 7/4. There is a difference (κ 2 R terms) with the ballooning term obtained in Miura et al (1989) and Miura (2000Miura ( , 2004.…”

Section: Discussionmentioning

confidence: 62%

“…Due to the coupling, the Alfvén mode acquires a longitudinal magnetic field component (e.g., Pokhotelov et al, 1985;Klimushkin and Mager, 2011). Recently, in the singlefluid MHD treatment, Mazur et al (2012) found that the compressional mode stabilizes the Alfvénic branch, but can be unstable itself. The influence of drift effects was studied in two-fluid MHD by Miura et al (1989), who calculated the instability threshold of the drift Alfvén wave.…”

Section: Introductionmentioning

confidence: 99%

On the ballooning instability of the coupled Alfvén and drift compressional modes

2012

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The paper examines the ballooning instability in gyrokinetic approximation taking into account the effects of finite-β, magnetic field line curvature, and diamagnetic drift. We used a simple model with a constant curvature of magnetic field lines which enabled us to obtain analytical results. The possible plasma oscillatory modes comprise the poloidal Alfvén and drift compressional modes, coupled due to the magnetic field line curvature and plasma inhomogeneity. The frequencies of these modes depend on the westward current value. As this value grows, the frequencies of these two branches approach to each other, and the branches are merged at some critical value of the current. Then an instability develops which is called the drift ballooning coupling instability. There are three major differences of the drift ballooning coupling instability from the ordinary MHD ballooning instability: (1) the drift ballooning coupling instability is not aperiodic, there is a real part of the oscillation frequency of the order of the drift frequency, (2) only the mode with the same direction of the azimuthal phase speed as the velocity of the ion diamagnetic drift can be unstable, (3) the instability threshold depends on the diamagnetic drift frequency.

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How to distinguish between kink and sausage modes in flapping oscillations?

et al. 2014

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Flapping waves are most noticeable large‐scale perturbations of the magnetotail current sheet, whose nature is still under discussion. They represent rather slow (an order of magnitude less than typical Alfven speed) waves propagating from the center of the sheet to its flanks with a typical speed of 20–60 km/s, amplitude of 1–2 Re and quasiperiod of 2–10 min. The double‐gradient MHD model, which was elaborated in Erkaev et al. (2007) predicts two (kink and sausage) modes of the flapping waves with differences in their geometry and propagation velocity, but the mode structure is hard to resolve observationally. We investigate the possibility of mode identification by observing the rotation of magnetic field and plasma velocity vectors from a single spacecraft. We test theoretical results by analyzing the flapping oscillations observed by Time History of Events and Macroscale Interactions during Substorms spacecraft and confirm that character of observed rotation is consistent with kink mode determination made by using multispacecraft methods. Also, we checked how the existence of some obstructive conditions, such as noise, combined modes, and multiple sources of the flapping oscillations, can affect on the possibility of the modes separation with suggested method.

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Dispersion relation for ballooning modes and condition of their stability in the near-earth plasma

Cited by 27 publications

References 11 publications

Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

On the ballooning instability of the coupled Alfvén and drift compressional modes

How to distinguish between kink and sausage modes in flapping oscillations?

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