関連する実験動画
Updated: Jul 9, 2026
07:16
Extraction of the EPP Component from the Surface EMG
Published on: December 16, 2009
地磁気振動の起源について
Jeremy Bloxham1, Stephen Zatman, Mathieu Dumberry
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138, USA. Jeremy_Bloxham@harvard.edu
Nature
|November 8, 2002
まとめ
地磁気振動は,地球の磁場における突然の変化である. 私たちの研究は,これらの出来事を,地球の核内の安定した,時間によって変化する流体流れの組み合わせを使用して説明しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 地球科学 地球科学 地球科学
- 地磁気学とは地磁気学です.
背景:
- 地磁気振動 (Geomagnetic jerks) とは,地球の磁場における恒久的な加速の急激な変化である.
- 周期的に発生するこれらの現象は,磁場の世俗的な変動の再編成を示しています.
- 地磁気振動の内部起源と核表面流体流動の動態は知られているが,その物理的な原因は不明である.
研究 の 目的:
- 地磁気振動の物理的起源を解明する.
- 地球の磁場における突然の変化を説明するために,世俗的な加速.
- 地磁気振動を地球の核内の流体力学と結びつけるため.
主な方法:
- 地磁気的世俗的な変動データの分析.
- 地球の核表面における流体流れのモデリング.
- 現象の内部起源を決定するための球体ハーモニー分析.
主要な成果:
- 地磁気揺れは,コア表面の安定した時間変動のトロイド状ゾナルの流れの組み合わせによって説明できます.
- この流れは軸対称と赤道対称である.
- 提案されたフローモデルは,地球のコアにおけるトルション振動と一致しています.
結論:
- 地磁気振動の物理的起源は,地球の核心内のトルション振動と関連しています.
- この発見は,理論的な期待と,コアフローとダイナモモデルの観測を裏付けている.
- この研究は,地磁気振動に対する新しいダイナミックな説明を提供します.
関連する概念動画
01:30Magnetism
Magnets are commonly found in everyday objects, such as toys, hangers, elevators, doorbells, and computer devices. Experimentation on these magnets shows that all magnets have two poles: one is labeled north (N) and the other south (S). Magnetic poles repel if they are alike and attract if unlike. Moreover, both poles of a magnet attract unmagnetized pieces of iron.
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
An individual magnetic pole cannot be isolated. No matter how small, every piece of a magnet contains a north pole and a south...
01:19Magnetic Field Lines
The representation of magnetic fields by magnetic field lines is very useful in visualizing the strength and direction of the magnetic field. Each of the magnetic field lines forms a closed loop. The field lines emerge from the north pole (N), loop around to the south pole (S), and continue through the bar magnet back to the north pole.
Magnetic field lines follow several hard-and-fast rules:
Magnetic field lines follow several hard-and-fast rules:
01:25Magnetic Field due to Moving Charges
A stationary charge creates and interacts with the electric field, while a moving charge creates a magnetic field.
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
Consider a point charge moving with a constant velocity. Like the electric field, the magnetic field at any point is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the source point and the field point. However, unlike the electric field, the magnetic field is always perpendicular to the plane containing the line...
01:18Magnetic Field Due to Two Straight Wires
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01:24Potential Due to a Magnetized Object
Magnetic dipoles in magnetic materials are aligned when placed under an external magnetic field. For paramagnets and ferromagnets, dipole alignment occurs in the direction of the magnetic field. However, the dipoles align opposite to the field in the case of diamagnets. This state of magnetic polarization due to the external field is called magnetization. Magnetization is defined as the dipole moment per unit volume. It plays a similar role to polarization in electrostatics.
The vector...
The vector...
01:28Magnetostatic Boundary Conditions
An electric field suffers a discontinuity at a surface charge. Similarly, a magnetic field is discontinuous at a surface current. The perpendicular component of a magnetic field is continuous across the interface of two magnetic mediums. In contrast, its parallel component, perpendicular to the current, is discontinuous by the amount equal to the product of the vacuum permeability and the surface current. Like the scalar potential in electrostatics, the vector potential is also continuous...