Kelvin-Helmholtz unstable magnetotail flow channels: Deceleration and radiation of MHD waves

Turkakin, H.; Mann, I. R.; Rankin, R.

doi:10.1002/2014gl060450

Cited by 19 publications

(24 citation statements)

References 18 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cécere et al [] investigated numerically the occurrence of the KHI on the boundaries of SADs but did not investigate the possibility of the KH‐driven modes generating the emission of propagating fast magnetosonic modes. Similar to the breaking of BBFs suggested in Turkakin et al [], propagating wave emission due to the KHI along SAD boundaries may be possible and can potentially explain observed deceleration of SADs. Coronal plumes and coronal streamer boundaries have similar characteristics to SADs [ Andries and Goossens , ; Feng et al , ] and can thus support MHD wave emission as well.…”

Section: Resultssupporting

confidence: 70%

“…Some studies have assumed a zero thickness boundary, which is appropriate if the wavelengths of the generated waves are significantly larger than the thickness of the boundary [ Pu and Kivelson , ; Mann et al , ; Turkakin et al , , ]. The effects of a finite boundary thickness have also been investigated in several studies [ Ong and Roderick , ; Walker , ; Farrugia et al , ; Contin et al , ; Gratton et al , ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Emission of magnetosound from MHD‐unstable shear flow boundaries

2016

Self Cite

View full text Add to dashboard Cite

The emission of propagating MHD waves from the boundaries of flow channels that are unstable to the Kelvin‐Helmholtz Instability (KHI) in magnetized plasma is investigated. The KHI and MHD wave emission are found to be two competing processes. It is shown that the fastest growing modes of the KHI surface waves do not coincide with efficient wave energy transport away from a velocity shear boundary. MHD wave emission is found to be inefficient when growth rates of KHI surface waves are maximum, which corresponds to the situation where the ambient magnetic field is perpendicular to the flow channel velocity vector. The efficiency of wave emission increases with increasing magnetic field tension, which in Earth's magnetosphere likely dominates along the nightside magnetopause tailward of the terminator, and within earthward Bursty Bulk Flows (BBFs) in the inner plasma sheet. MHD wave emission may also dominate in Supra‐Arcade Downflows (SADs) in the solar corona. Our results suggest that efficient emission of propagating MHD waves along BBF and SAD boundaries can potentially explain observations of deceleration and stopping of BBFs and SADs.

show abstract

Section: Resultssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Emission of magnetosound from MHD‐unstable shear flow boundaries

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…A continuous deceleration of flow bursts along their propagation toward Earth has already been suggested in the above statistical investigations [Baumjohann et al, 1990;Shiokawa et al, 1997]; however, what mechanisms are causing this flow braking is not fully understood. For example, it has been suggested that the growth of Kelvin-Helmholtz waves on the boundary of flow channels can be important for flow braking in the magnetotail [Volwerk et al, 2007;Turkakin et al, 2014]. In this article we will instead investigate the possibility that compressed magnetic flux tubes in DFs can constitute local impediments to flow bursts along their earthward propagation.…”

Section: Introductionmentioning

confidence: 99%

Evidence for the braking of flow bursts as they propagate toward the Earth

et al. 2014

View full text Add to dashboard Cite

In this article we use energy conversion arguments to investigate the possible braking of flow bursts as they propagate toward the Earth. By using E·J data (E and J are the electric field and the current density) observed by Cluster in the magnetotail plasma sheet, we find indications of a plasma deceleration in the region −20 RE < X < − 15 RE. Our results suggest a braking mechanism where compressed magnetic flux tubes in so‐called dipolarization fronts (DFs) can decelerate incoming flow bursts. Our results also show that energy conversion arguments can be used for studying flow braking and that the position of the flow velocity peak with respect to the DF can be used as a single‐spacecraft proxy when determining energy conversion properties. Such a single‐spacecraft proxy is invaluable whenever multispacecraft data are not available. In a superposed epoch study, we find that a flow burst with the velocity peak behind the DF is likely to decelerate and transfer energy from the particles to the fields. For flow bursts with the peak flow at or ahead of the DF we see no indications of braking, but instead we find an energy transfer from the fields to the particles. From our results we obtain an estimate of the magnitude of the deceleration of the flow bursts, and we find that it is consistent with previous investigations.

show abstract

“…The dipolarization front (e.g., Schmid et al, 2015Schmid et al, , 2016Sergeev et al, 2009), signed by the sharp enhanced Bz, has been proposed to be the possibly mechanism to decelerate the BBF (Hamrin et al, 2014). Another mechanism is the dissipation of the BBF kinetic energy by emitting KAW (e.g., Angelopoulos et al, 2002;Chaston et al, 2012;Higashimori & Hoshino, 2015;Turkakin et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

BBF Deceleration Down‐Tail of X < −15 R_E From MMS Observation

et al. 2020

View full text Add to dashboard Cite

We report the direct observation on bursty bulk flow (BBF) deceleration down‐tail of X < −15 RE by MMS satellite. Two typical events are presented in the paper. In the first event on 05 June 2018, MMS1 is located at X ~ −16.1 RE and records four individual bursty flows (BFs). Each burst flow has distinctly lower velocity than the preceding one. Accompanying with the decelerated BFs, the Bz/Bx continuously increases/decreases. Simultaneous Vx‐decrease and Bz‐increase are in coincidence with the scenario of the local BBF deceleration and formation of the magnetic pileup region. In the second event on 03 July 2017, MMS stays in the neutral sheet of X ~ −24.5 RE, and encounters similar BBF deceleration process. For both events, the decelerated BF series exhibit prominent medium‐energy ion component (2–10 KeV). Analyses show enhanced parallel current (J//) and Kinetic Alfvénic wave (KAW) emitting during the BF intervals. The strength of the emitted KAW has a clear tendency to decay with the BBF decreasing. Power spectra density analysis confirms the substantial Joule dissipation during the BBF deceleration, both J// and J⊥. Combined analyses support BBF dissipation via Joule heating as well as KAW emitting. Finally, we propose a possible mechanism on the BBF deceleration, i.e., “collision” with the tailward flow.

show abstract

Kelvin-Helmholtz unstable magnetotail flow channels: Deceleration and radiation of MHD waves

Cited by 19 publications

References 18 publications

Emission of magnetosound from MHD‐unstable shear flow boundaries

Emission of magnetosound from MHD‐unstable shear flow boundaries

Evidence for the braking of flow bursts as they propagate toward the Earth

BBF Deceleration Down‐Tail of X < −15 R_E From MMS Observation

Contact Info

Product

Resources

About

Kelvin-Helmholtz unstable magnetotail flow channels: Deceleration and radiation of MHD waves

Cited by 19 publications

References 18 publications

Emission of magnetosound from MHD‐unstable shear flow boundaries

Emission of magnetosound from MHD‐unstable shear flow boundaries

Evidence for the braking of flow bursts as they propagate toward the Earth

BBF Deceleration Down‐Tail of X < −15 RE From MMS Observation

Contact Info

Product

Resources

About

BBF Deceleration Down‐Tail of X < −15 R_E From MMS Observation