Kelvin-Helmholtz unstable magnetotail flow channels: Deceleration and radiation of MHD waves
Year: 2014
Type: article
Abstract: The Kelvin-Helmholtz instability (KHI) of magnetotail flow channels associated with bursty bulk flows (BBFs) is investigated. MHD oscillations of the channel in both kink and sausage modes are investigated for KHI, and both the primary and secondary KHIs are found that drive MHD waves. These instabilities are likely to be important for flow channel braking where the KHI removes energy from the flow. At flow speeds above the peak growth rate, the MHD modes excited by KHI develop from surface modes into propagating modes leading to the radiation of MHD waves from the flow channel. The coupling of BBF-driven shear flow instabilities to MHD waves presented here represents a new paradigm to explain BBF excitation of tail flapping. Our model can also explain, for the first time, the generation mechanism for the observations of waves propagating toward both flanks and emitted from BBF channels in the magnetotail.
Source: Geophysical Research Letters
DOI: 10.1002/2014gl060450
Authors: H. Turkakin, I. R. Mann, R. Rankin
Institution: University of Alberta
Language: English
Subfield: Space and Planetary Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2145804569