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Are Self-Organised Critical Dislocation Dynamics Relevant to Ice Sheet Flow?

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Title: Are Self-Organised Critical Dislocation Dynamics Relevant to Ice Sheet Flow?
Authors: Louchet, François Browse this author
Duval, Paul Browse this author
Montagnat, Maurine Browse this author
Weiss, Jérôme Browse this author
Keywords: creep
critical dynamics
ice sheets
Hall-Petch law
normal grain growth
rotation recrystallization
Issue Date: Dec-2009
Publisher: Institute of Low Temperature Science, Hokkaido University
Citation: Physics of Ice Core Records II : Papers collected after the 2nd International Workshop on Physics of Ice Core Records, held in Sapporo, Japan, 2-6 February 2007. Edited by Takeo Hondoh
Journal Title: 低温科学
Journal Title(alt): Low Temperature Science
Volume: 68
Issue: Supplement
Start Page: 25
End Page: 33
Abstract: It was recently shown thai crystals (including ice) plastically deform in an intermittent manner in usual laboratory conditions. The present paper aims at discussing whether such self-organised critical dynamics still apply to polar ice sheet conditions. Field data suggest that grains should contain between zero and one dislocation moving at a time. However, this is nothing but an average estimate. Field data also show that strong back-stresses are present, collesponding to a significant density of potentially mobile dislocations. These findings, together with the very low loading level, are consistent with critical dislocation dynamics, in which collective motion events occur for a short time, followed by long periods of inactivity during which grain growth, rotation recrystallization and other recovery processes contribute to the reduction of the long range internal stress field. The stress and grain size dependencies of the strain rate are derived on this basis. The applicability of the Hall-Petch law is also discussed.
Description: I. Microphysical properties, deformation, texture and grain growth
Type: bulletin (article)
Appears in Collections:低温科学 = Low Temperature Science > vol. 68, Supplement Issue

Submitter: 低温科学研究所図書室

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