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dc.contributor.authorPalmroth, M
dc.contributor.authorArcher, M
dc.contributor.authorVainio, R
dc.contributor.authorHietala, H
dc.contributor.authorPfau-Kempf, Y
dc.contributor.authorHoilijoki, S
dc.contributor.authorHannuksela, O
dc.contributor.authorGanse, U
dc.contributor.authorSandroos, A
dc.contributor.authorAlfthan, SV
dc.contributor.authorEastwood, JP
dc.date.accessioned2017-11-15T15:56:51Z
dc.date.available2017-11-15T15:56:51Z
dc.date.issued2015-10
dc.date.submitted2017-11-06T12:00:34.256Z
dc.identifier.citationPalmroth, M., Archer, M., Vainio, R., Hietala, H., Pfau-Kempf, Y., Hoilijoki, S., Hannuksela, O., Ganse, U., Sandroos, A., Alfthan, S. and Eastwood, J. (2015). ULF foreshock under radial IMF: THEMIS observations and global kinetic simulation Vlasiator results compared. [online] Journal of Geophysical Research: Space Physics. Available at: http://onlinelibrary.wiley.com/doi/10.1002/2015JA021526/abstract [Accessed 15 Nov. 2017].en_US
dc.identifier.issn2169-9380
dc.identifier.urihttp://qmro.qmul.ac.uk/xmlui/handle/123456789/28717
dc.description.abstractFor decades, monochromatic large-scale ultralow frequency (ULF) waves with a period of about 30 s have been observed upstream of the quasi-parallel bow shock. These waves typically propagate obliquely with respect to the interplanetary magnetic field (IMF), while the growth rate for the instability causing the waves is maximized parallel to the magnetic field. It has been suggested that the mechanism for the oblique propagation concerns wave refraction due to the spatial variability of the suprathermal ions, originating from the E × B drift component. We investigate the ULF foreshock under a quasi-radial IMF with Vlasiator, which is a newly developed global hybrid-Vlasov simulation solving the Vlasov equation for protons, while electrons are treated as a charge-neutralizing fluid. We observe the generation of the 30 s ULF waves and compare their properties to previous literature and multipoint Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft observations. We find that Vlasiator reproduces the foreshock ULF waves in all reported observational aspects. We conclude that the variability of the density and velocity of the reflected back streaming ions determines the large-scale structure of the foreshock, which affects the wave frequency, wavelength, and oblique propagation. We conclude that the wave refraction may also be at work for radial IMF conditions, which has earlier been thought of as an exception to the refraction mechanism due to the small E × B drift component. We suggest that additional refraction may be caused by the large-scale spatial variability of the density and velocity of the back streaming ions.en_US
dc.description.sponsorshipEuropean Research Council Starting grant (200141-QuESpace). Grant Number: ST/K001051/1; German Research Foundation (DFG)en_US
dc.format.extent8782 - 8798
dc.publisherWileyen_US
dc.relation.ispartofJournal of Geophysical Research A: Space Physics
dc.rightsThis is a pre-copyedited, author-produced version of an article accepted for publication in Journal of Geophysical Research: Space Physics following peer review. The version of record is available http://onlinelibrary.wiley.com/doi/10.1002/2015JA021526/abstract
dc.titleULF foreshock under radial IMF: THEMIS observations and global kinetic simulation Vlasiator results compareden_US
dc.rights.holder© 2015. American Geophysical Union
dc.identifier.doi10.1002/2015JA021526
pubs.issue10
pubs.organisational-group/Queen Mary University of London
pubs.organisational-group/Queen Mary University of London/Faculty of Science & Engineering
pubs.organisational-group/Queen Mary University of London/Faculty of Science & Engineering/Physics and Astronomy
pubs.publication-statusPublished
pubs.volume120


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