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Frozen-in Condition. E + V × B =0. 3. Solar Wind and Interplanetary Magnetic Field. Outline:. 太阳风的发现 太阳风的特性 太阳风的形成 太阳风传播的范围 1AU 处太阳风的测量 Coronal Magnetic field Interplanetary Magnetic Field Park Spiral and Heliospheric Current Sheet Corotating Interaction Region. 太阳风的发现. 彗星中的双拖尾结构
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Frozen-in Condition • E+V×B=0
Outline: • 太阳风的发现 • 太阳风的特性 • 太阳风的形成 • 太阳风传播的范围 • 1AU 处太阳风的测量 • Coronal Magnetic field • Interplanetary Magnetic Field • Park Spiral and Heliospheric Current Sheet • Corotating Interaction Region
太阳风的发现 彗星中的双拖尾结构 • Diffused one is caused by solar radiation pressure; • The sharp one is caused by solar wind.
Parker’s solar wind model (1958) • 从磁流体理论出发; • 假设太阳大气层存在一个加热源; • 得到supersonic solar wind.
Solar coronal outflow • 假设日冕处于平衡态 即受重力场约束 • 连续性方程 • 流体的运动方程 Vlasov equation • 流体的能量方程
Interstellar wind The majority of the interstellar gas and dust that we see was produced by star death
行星际中的磁场 Flux conservation
Interstellar wind and background pressure about 10-13Pa
Solution: introducing a standing shock wave Total pressure balanced at the shock front
Voyager 1 和 2的发现 Voyager 1 crossed the termination shock, September 23, 2005 Voyager 2 crossed the termination shock, August 30, 2007
Voyager mission Voyager mission
Solar wind at 1AU • Solar wind is fully ionized into electrons, protons, and He2+(3%); Solar wind parameters measured by spacecraft near the Earth
Quiz 4 • 如果没有太阳风的直接测量,请问有什么自然现象支持太阳风的存在?列举两种以上。 • 说说源自太阳赤道上和太阳极区的磁场有什么差别,哪一种随日球层距离下降的快?
Interplanetary Magnetic Field Introduction of Space Physics by M. G. Kivelson and C. T. Russell
行星际中性电流片 The radial current in the circuit is on the order of 3×109 amperes. However, the maximum current density is 10-10A/m2 Image courtesy J. Jokipii, University of Arizona
MHD模拟的CIRs http://www.physics.usyd.edu.au/~cairns/teaching/lecture11/node4.html
Summary • 简单介绍了太阳风经典理论; • 探讨了太阳风在Termination Shock的减速问题; • Parker Spiral行星际磁场,中性电流片,CIR;