Propagation of alfvénic waves from corona to chromosphere and consequences for solar flares

Russell, A.J.B. and Fletcher, L. (2013) Propagation of alfvénic waves from corona to chromosphere and consequences for solar flares. Astrophysical Journal, 765(2), Art. 81. (doi:10.1088/0004-637X/765/2/81)

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Abstract

How do magnetohydrodynamic waves travel from the fully ionized corona, into and through the underlying partially ionized chromosphere, and what are the consequences for solar flares? To address these questions, we have developed a two-fluid model (of plasma and neutrals) and used it to perform one-dimensional simulations of Alfvén waves in a solar atmosphere with realistic density and temperature structure. Studies of a range of solar features (faculae, plage, penumbra, and umbra) show that energy transmission from corona to chromosphere can exceed 20% of incident energy for wave periods of 1 s or less. Damping of waves in the chromosphere depends strongly on wave frequency: waves with periods 10 s or longer pass through the chromosphere with relatively little damping, however, for periods of 1 s or less, a substantial fraction (37%-100%) of wave energy entering the chromosphere is damped by ion-neutral friction in the mid- and upper chromosphere, with electron resistivity playing some role in the lower chromosphere and in umbras. We therefore conclude that Alfvénic waves with periods of a few seconds or less are capable of heating the chromosphere during solar flares, and speculate that they could also contribute to electron acceleration or exciting sunquakes.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fletcher, Professor Lyndsay and Russell, Dr Alexander
Authors: Russell, A.J.B., and Fletcher, L.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Astrophysical Journal
ISSN:0004-637X
ISSN (Online):1538-4357

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
542081Rolling Programme in Solar and Plasma AstrophysicsLyndsay FletcherScience & Technologies Facilities Council (STFC)ST/I001808/1P&A - PHYSICS & ASTRONOMY