概括
旅行者旅行者旅行者旅行者
科学领域:
- 行星科学 行星科学
- 等离子体物理学的物理学
- 空间物理 空间物理
背景情况:
- 旅行者号航天器的低能带电粒子仪器被设计用于研究木星的磁层.
- 以前的理论表明,行星的风流出来自木星的磁层.
研究的目的:
- 测量木星磁层的热等离子体组成部分.
- 为了研究这种等离子体的组成,温度,密度和动态.
- 将观测结果与现有的磁层外流理论进行比较.
主要方法:
- 利用旅行者低能带电粒子仪器检测电子和离子.
- 分析的粒子能量,组成,温度,密度和能量密度.
- 在进出轨道期间,跟踪的粒子流量变化与经度和时间.
主要成果:
- 探测到热等离子 (15-30 keV电子,30+ keV离子) 距离木星近0.3 AU.
- 识别了等离子组成,主要是质子,氧和硫,具有非热尾.
- 观测到等离子体旋转,没有证据表明行星风的外流.
- 能量粒子 (>200 keV/核子) 包括质子,,氧,硫和,可能起源于Io.
- 观察到纵向流量增强和5小时和10小时的周期性在出行轨道.
- 在Io流管附近检测到高能电子的部分吸收.
结论:
- 木星的热等离子体在很大程度上是旋转的,没有显著的外流.
- 伊奥是外磁层中几种能量粒子物种的可能来源.
- 磁层动力学显示了纵向变化和时间周期性,特别是在外向路径上.
相关概念视频
Equilibrium Conditions for a Particle
When an object is in equilibrium, it is either at rest or moving with a constant velocity. There are two types of equilibrium: static and dynamic. Static equilibrium occurs when an object is at rest, while dynamic equilibrium occurs when an object is moving with a constant velocity. In both cases, there must be a balance of forces acting on the object.
To understand the concept of equilibrium, let us first consider the forces acting on an object. When different forces act on an object, they can...
To understand the concept of equilibrium, let us first consider the forces acting on an object. When different forces act on an object, they can...
Energy Associated With a Charge Distribution
The work done to bring a charge through a distance r is given by the potential difference between the initial and the final position. To assemble a collection of point charges, the total work done can be expressed in terms of the product of each pair of charges divided by their separation distance, defined with respect to a suitable origin. Solving this expression gives the energy stored in a point charge distribution.
First Law: Particles in One-dimensional Equilibrium
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If we...
Acceleration due to Gravity on Other Planets
The gravitational acceleration of an object near the Earth's surface is called the acceleration due to gravity. It can be measured by conducting simple experiments on Earth. However, such an experiment is impossible to conduct on the surface of other planets.
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...
Motion Of A Charged Particle In A Magnetic Field
A charged particle experiences a force when moving through a magnetic field. Consider the field to be uniform and the charged particle to move perpendicular to it. If the field is in a vacuum, the magnetic field is the dominant factor determining the motion. Since the magnetic force is perpendicular to the direction of motion, a charged particle follows a curved path. The particle continues to follow this curved path until it forms a complete circle. Another way to look at this is that the...
Kepler's First Law of Planetary Motion
In the early 17th century, German astronomer and mathematician Johannes Kepler postulated three laws for the motion of planets in the solar system. He formulated his first two laws based on the observations of his forebears, Nikolaus Copernicus and Tycho Brahe.
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...
Polish astronomer Nikolaus Copernicus put forth a theory that stated a heliocentric model for the solar system. According to this heliocentric theory, all the planets, including Earth, orbit the Sun in circular orbits.
On the other hand,...


