氷天体内部対流運動の物質科学 : 氷の粘性流動と高圧相転移
久保, 友明
Permalink : http://hdl.handle.net/2115/34721
Abstract
氷天体の外殻氷層や氷マントルで起こる対流運動は,その熱的進化,内部海の存在,内部ダイナミクス,表面テクトニクスなどに大きな影響を与え,天体の運命を握っているとも言える重要なプロセスである.本稿では,対流運動に密接に関連した物質科学に着目し,氷の粘性流動と高圧相転移を取り
上げて概説する.特に,低応力下で卓越する結晶粒径に依存した流動則を確立するとともに,氷天体内部の結晶粒径をコントロールするカイネティクスを明らかにすることが必要不可欠であり,それらに関する予備的な実験結果を報告する.
Convection in icy outer shell and icy mantle has great influences on thermal evolution, internal dynamics, and survival of internal ocean in icy bodies. Plastic deformation and high-pressure transformations of water ice are important processes affecting the convective current in the interiors of icy bodies. It is indispensable to examine the grain-size sensitive flow law dominant at low stress conditions and kinetic processes controlling the grain-size evolution such as grain growth, dynamic recrystallization, and high-pressure transformation. Results of preliminary experiments on these properties are presented in this article.
Convection in icy outer shell and icy mantle has great influences on thermal evolution, internal dynamics, and survival of internal ocean in icy bodies. Plastic deformation and high-pressure transformations of water ice are important processes affecting the convective current in the interiors of icy bodies. It is indispensable to examine the grain-size sensitive flow law dominant at low stress conditions and kinetic processes controlling the grain-size evolution such as grain growth, dynamic recrystallization, and high-pressure transformation. Results of preliminary experiments on these properties are presented in this article.
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