相关实验视频
Updated: May 17, 2026

06:42
Magnetically Induced Rotating Rayleigh-Taylor Instability
Published on: March 3, 2017
对于振荡的真极流浪的机制
J R Creveling1, J X Mitrovica, N-H Chan
1Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA. jcrevel@gps.caltech.edu
Nature
|November 9, 2012
概括
真极流浪 (TPW) 事件可能与地球弹性石化层有关. 新的地力学模型显示TPW路径与古磁数据一致,表明了过去TPW振荡的机制.
科学领域:
- 地质物理学 地质物理学
- 地球科学 地球科学 地球科学
- 板块构造学是一种板块构造学.
背景情况:
- 古磁学研究表明,地球历史上发生了大型,快速的真正极地流浪 (TPW) 事件.
- 这些TPW游览可能遵循围绕超级大陆的振荡模式.
- 现有的地力学模型需要相反的负载阶段来解释振荡TPW.
研究的目的:
- 通过包括石层弹性应力来扩展旋转稳定性理论.
- 为了研究驱动振荡TPW的地力学机制.
- 为了使古磁证据与地球自转的理论模型相协调.
主要方法:
- 开发了一个非线性旋转稳定理论.
- 嵌入TPW诱导的岩层中的弹性应力.
- 在非水静态地球上利用带有对流驱动的惯性扰动的地球动力学模型.
主要成果:
- 证明有效的弹性石质层厚度为~10公里可以产生与古磁数据相匹配的振荡TPW路径.
- 表明TPW诱导的弹性应力稳定了旋转轴.
- 发现过多的圆性可以降低所需的弹性厚度,甚至达到零.
结论:
- 由TPW引起的弹性应力为振荡式TPW提供了稳定机制.
- 一个时间变化的地幔流场,结合稳定,可以连接不同的TPW事件超过数十亿年.
- 拟议的机制为观察到的古磁TPW模式提供了可行的解释.
相关概念视频
Oscillations about an Equilibrium Position
Stability is an important concept in oscillation. If an equilibrium point is stable, a slight disturbance of an object that is initially at the stable equilibrium point will cause the object to oscillate around that point. For an unstable equilibrium point, if the object is disturbed slightly, it will not return to the equilibrium point. There are three conditions for equilibrium points—stable, unstable, and half-stable. A half-stable equilibrium point is also unstable, but is named so because...
Gyroscope: Precession
Precession can be demonstrated effectively through a spinning top. If a spinning top is placed on a flat surface near the surface of the Earth at a vertical angle and is not spinning, it will fall over due to the force of gravity producing a torque acting on its center of mass. However, if the top is spinning on its axis, it precesses about the vertical direction, rather than topple over due to this torque. Precessional motion is a combination of a steady circular motion of the axis and the...
Forced Oscillations
When an oscillator is forced with a periodic driving force, the motion may seem chaotic. The motions of such oscillators are known as transients. After the transients die out, the oscillator reaches a steady state, where the motion is periodic, and the displacement is determined.
Damped Oscillations
In the real world, oscillations seldom follow true simple harmonic motion. A system that continues its motion indefinitely without losing its amplitude is termed undamped. However, friction of some sort usually dampens the motion, so it fades away or needs more force to continue. For example, a guitar string stops oscillating a few seconds after being plucked. Similarly, one must continually push a swing to keep a child swinging on a playground.
Although friction and other non-conservative...
Although friction and other non-conservative...
Standing Electromagnetic Waves
Electromagnetic waves can be reflected; the surface of a conductor or a dielectric can act as a reflector. As electric and magnetic fields obey the superposition principle, so do electromagnetic waves. The superposition of an incident wave and a reflected electromagnetic wave produces a standing wave analogous to the standing waves created on a stretched string.
Suppose a sheet of a perfect conductor is placed in the yz-plane, and a linearly polarized electromagnetic wave traveling in the...
Suppose a sheet of a perfect conductor is placed in the yz-plane, and a linearly polarized electromagnetic wave traveling in the...
Travelling Waves
A wave is a disturbance that propagates from its source, repeating itself periodically, and is typically associated with simple harmonic motion. Mechanical waves are governed by Newton's laws and require a medium to travel. A medium is a substance in which a mechanical wave propagates, and the medium produces an elastic restoring force when it is deformed.
Water waves, sound waves, and seismic waves are some examples of mechanical waves. For water waves, the wave propagation medium is water;...
Water waves, sound waves, and seismic waves are some examples of mechanical waves. For water waves, the wave propagation medium is water;...

