On the parallel and perpendicular propagating motions visible in polar plumes : an incubator for (fast) solar wind acceleration?
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We combine observations of the Coronal Multi-channel Polarimeter and the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory to study the characteristic properties of (propagating) Alfvenic motions and quasi-periodic intensity disturbances in polar plumes. This unique combination of instruments highlights the physical richness of the processes taking place at the base of the (fast) solar wind. The (parallel) intensity perturbations with intensity enhancements around 1% have an apparent speed of 120 km s(-1) (in both the 171 and 193 angstrom passbands) and a periodicity of 15 minutes, while the (perpendicular) Alfvenic wave motions have a velocity amplitude of 0.5 km s(-1), a phase speed of 830 km s(-1), and a shorter period of 5 minutes on the same structures. These observations illustrate a scenario where the excited Alfvenic motions are propagating along an inhomogeneously loaded magnetic field structure such that the combination could be a potential progenitor of the magnetohydrodynamic turbulence required to accelerate the fast solar wind.
Liu , J , McIntosh , S W , De Moortel , I & Wang , Y 2015 , ' On the parallel and perpendicular propagating motions visible in polar plumes : an incubator for (fast) solar wind acceleration? ' Astrophysical Journal , vol 806 , no. 2 , 273 . DOI: 10.1088/0004-637X/806/2/273
© 2015. The American Astronomical Society. All rights reserved. This work is made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at http://dx.doi.org/10.1088/0004-637X/806/2/273
J.L. was a student visitor at HAO. J.L. acknowledges the financial support for his visit to HAO from the Chinese Scholarship Council (CSC). The authors acknowledge support from NSFC 41131065, 41121003, 973 Key Project 2011CB811403, and CAS Key Research Program KZZD-EW-01-4. We also acknowledge support from NASA contracts NNX08BA99G, NNX11AN98G, NNM12AB40P, NNG09FA40C (IRIS), and NNM07AA01C (Hinode). The research leading to these results has also received funding from the European Commission Seventh Framework Programme (FP7/ 2007-2013) under the grant agreement SOLSPANET (project No. 269299, www.solspanet.eu/solspanet) Date of Acceptance: 25/05/2015
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