地球の内核における超電離鉄合金とその地震速度
Yu He1,2, Shichuan Sun3,4, Duck Young Kim5
1Key Laboratory of High-Temperature and High-Pressure Study of the Earth's Interior, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, China. heyu@mail.gyig.ac.cn.
Nature
|February 10, 2022
まとめ
地球の内核は固体ではなく 超離子体かもしれません 水素や酸素のような 軽い元素は 液体のように振る舞い 地震観測と核の柔らかさを説明します
科学分野:
- 地理学
- 材料科学
- 計算物理
背景:
- 地球の内核 (IC) は純粋な鉄よりも密度が低く,軽い元素の存在を暗示しています.
- 以前の研究では 鉄と軽元素の合金の性質に焦点を当てていたが,これらの元素の状態はめったに考慮されなかった.
- 軽い元素の候補には,シリコン,硫黄,炭素,酸素,水素が含まれています.
研究 の 目的:
- 内核の条件下で六角形の密集した鉄の中で軽い元素 (水素,酸素,炭素) の状態を調査する.
- これらの軽い要素がスーパーイオン状態と,その内核特性への影響を決定する.
主な方法:
- アブ・イニシオ分子動力学シミュレーションを用いた.
- 地球の内核をシミュレートする高圧,高温条件下での鉄光元素合金モデル.
主要な成果:
- 水素,酸素,炭素は内核条件下で超イオン状態に変化し,液体のような拡散を示します.
- この超音波状態は地震速度を大幅に減らし,地震学的観測と一致します.
- この発見は,観測された低シア波速度の説明となり",柔らかい"内核を示しています.
結論:
- 地球の内核は通常の固体状態ではなく 超離子状態に存在するかもしれません
- 超イオン状態の軽い元素の液体のような振る舞いは,内核の主要な地震特性を説明します.
- 超音波状態の光元素のコンベクションは 内核の地震学的構造とジオダイナモに影響を与えます
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