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2018年11月5・4日に、愛媛大学においてPatrick Cordier教授(リール第1大学)による国際セミナー・レクチャーを開催しました。




MEXT Shin-Gakujutsu “Core-Mantle Coevolution” International Lecture

Date 2018年11月5日(月)6日(火)
Venue 愛媛大学理学部 総合研究棟I
(11/5) 4F #486 共通会議室 
(11/6) 3F 共通ゼミ室
Lecturer Prof. Patrick Cordier (Universite Lille 1)
Title Rheology of Deep Earth Materials 
Schedule Nov.5th
13:00 – 14:30 Lecture 1st slot

Point defects – Diffusion – Nabarro Hering creep
15:00 – 16:30 Lecture 2nd slot
Line defects – Dislocations core structure and mobility (mostly glide)
13:00 – 14:30 Lecture 3rd slot
From dislocations to creep – Dislocation dynamics
15:00 – 16:30 Lecture 4th slot
Advanced TEM techniques for characterizing dislocations and plasticity

The 19th MEXT Shin-Gakujutsu “Core-Mantle Coevolution”
International Frontier Seminar

Date/Time 2018年11月5日(月)17:00 – 18:00
Venue 愛媛大学理学部 総合研究等I 4F #486
Lecturer Prof. Patrick Cordier (Universite Lille 1)
Title On the role of dislocation climb for the convection of planetary interiors
Abstract Planetary interiors are characterized by high confining pressures. Evacuating heat by convection needs activation of creep mechanisms which are efficient enough under high pressures and small deviatoric stresses. In case of a silicate like bridgmanite, dislocation modeling demonstrates that glide is strongly inhibited by pressure. Standard dislocation creep mechanisms are thus inefficients. Since diffusion is also slower under high pressure, activation of diffusion creep places very strong constraints on grain sizes which are questionnable.
In this presentation, we discuss an alternative where plastic strain is produced by pure climb creep. Dislocations in climb configurations act as sources and sinks of point defects which are exchanged between (at least) two dislocation families. The resulting rheology is non linear (stress exponent 3), but it does not produce crystal preferred orientations which is in agreement with the absence of strong seismic anisotropy in the lower mantle.