由来自ELFIN低海拔视角的电磁离子周期波驱动的能量电子沉
V Angelopoulos1, X-J Zhang1,2, A V Artemyev1
1Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA.
概括
电磁离子循环电子 (EMIC) 波驱动高能电子沉,导致>0.5 MeV电子的突然爆发. 来自ELFIN任务的数据证实EMIC波对于地球磁层中相对论电子损失至关重要.
科学领域:
- 空间物理 空间物理
- 等离子体物理学的物理学
- 磁层物理 磁层物理
背景情况:
- 能量电子沉是地球磁层中电子损失的一个关键机制.
- 众所周知,电磁离子循环子 (EMIC) 波与能量电子相互作用,但这种相互作用的精确机制和特征需要进一步研究.
研究的目的:
- 综合审查EMIC波驱动的能量电子沉的观测结果.
- 分析这种降水的独特特征,时空演变和统计特性.
- 确认EMIC波在相对论电子损失中的作用.
主要方法:
- 利用了来自能量电子探测器的数据,用于电子损失和电场调查 (ELFIN) 任务,该任务由两个北极轨道立方体卫星组成.
- 分析了沉与被捕流量比率的能量谱图,以确定EMIC波动驱动的沉特征.
- 使用多个ELFIN通过相同的磁性局部时间 (MLT) 部门进行时空演变研究.
- 使用结合的地面或赤道EMIC波观测进行的案例研究.
- 从多年的ELFIN数据收集了大约50个强烈的EMIC波驱动降雨事件的统计数据库.
主要成果:
- 埃米克波驱动的降水表现出明显的,突发的 (爆发性) 峰值 (>0.5 MeV),其基层在降水与被捕流量比率中.
- 爆发性归因于赤道的EMIC波场的空间范围和结构性.
- 沉特征,包括能量和光谱形状,通常与对循环子共振相互作用和准线性扩散理论的理论预期一致.
- 统计分析显示,大多数事件发生在黄昏 (L~4-6),其中有一小部分发生在午夜后 (L~6-8).
- 低于MeV的电子沉与高频EMIC波的散射相一致,而~100keV的沉可能涉及哨子模式合唱团.
结论:
- EMIC波在驱动地球磁层的相对论电子损失方面发挥着至关重要的作用.
- 观测到的降水特征和统计分布与理论预测非常一致.
- 非线性和非共振效应也可能导致观察到的降水,这需要进一步调查.
相关概念视频
Electrospray Ionization (ESI) Mass Spectrometry
940
Higher molecular weight biomolecules are nonvolatile compounds that may decompose before ionizing or vaporizing during mass analysis with conventional electron impact ionization methods. Accordingly, electrospray ionization (ESI) is the favored method for vaporizing and ionizing biomolecules as it circumvents rapid fragmentation and enables the recording of mass signals for the entire biomolecule.
ESI utilizes electrical energy to transfer ions from the liquid phase of the sample into the...
ESI utilizes electrical energy to transfer ions from the liquid phase of the sample into the...
940
Energy Carried By Electromagnetic Waves
3.0K
Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes, this energy is obvious, such as in the summer sun's warmth. At other times, it is subtle, such as the unfelt energy of gamma rays, which can destroy living cells. Electromagnetic waves bring energy into a system through their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. However, there is energy in an electromagnetic wave,...
3.0K
Momentum And Radiation Pressure
2.0K
An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave. This force occurs because electromagnetic waves contain and transport momentum. The force accounts for the wave's radiation pressure exerted on the object. Maxwell's prediction was confirmed in 1903 by Nichols and Hull by precisely measuring radiation pressures with a torsion balance. The measuring instrument had mirrors suspended from a fiber kept inside a glass container.
2.0K
Electromagnetic Fields
2.2K
Electric fields generated by static charges, often referred to as electrostatic fields, are characteristically different from electric fields created by time-varying magnetic fields. While the former is a conservative field, implying that no net work is done on a test charge if it goes around in a complete loop in the field, the latter is, by definition, not a conservative field; net work is done, and it is proportional to the rate of change of magnetic flux.
However, the observation of...
However, the observation of...
2.2K
Scanning Electron Microscopy
4.3K
A scanning electron microscope (SEM) is used to study the surface features of a sample by using an electron beam that scans the sample surface in a two-dimensional manner. Typically, areas between ~1 centimeter to 5 micrometers in width can be imaged. SEM can be used to image bacteria, viruses, tissues as well as larger samples like insects. Conventional SEM gives a magnification ranging from 20X to 30,000X and spatial resolution of 50 to 100 nanometers.
Fundamental Principles
Accelerated...
Fundamental Principles
Accelerated...
4.3K
Electromagnetic Waves
8.8K
James Clerk Maxwell formulated a single theory combining all the electric and magnetic effects scientists knew during that time, calling the phenomena his theory predicted “Electromagnetic waves”. He brought together all the work that had been done by brilliant physicists such as Oersted, Coulomb, Gauss, and Faraday and added his own insights to develop the overarching theory of electromagnetism. Maxwell’s equations, combined with the Lorentz force law, encompass all the laws...
8.8K


