日球参数的卡林顿共转变化(Ⅰ)——第20太阳活动周的平均特性

本文统计分析了第20太阳周在地球轨道处观测到的有关的日球参数, 系统地给出了各种参数的平均共转变化规律:20太阳活动周的平均卡林顿周变化普遍具有双峰特征.能流极大值出现在高速流与低速流相互作用区内, 两峰能流输出并不均衡.声速的变化与太阳风速相似, 但高速流的马赫数反比低速流的低.等离子体参数对反映共转高速流并不灵敏. 

The Corotating Variation of Heliospheric Quantities (I) -Average Features in the 20th Solar Cycle

The corotating variation of various heliospheric quantities at 1 AUis studied statistically for the 20th solar cycle, and the results obtained are organized in this paper as a function of the ordinal days in the Carrington rotation. The discussion given here involves the basic quantities, i.e. the solar wind speed, temperature, number density and the IMPintensity; the flux densities of kinetic and magnetic energy, enthalpy and particle; the various sound speeds, i.e. the adiabatic sonic and the Alfvenic wave speeds, and the magnetosonic speed; as well as the Mach numbers, i.e. the thermal sonic, the Alfvenic and the magnetosonic Mach numbers. The main results can be summarized as follows:(1) The average corotating variation of heliospheric quantities shows a marked two-peak feature characterizing the two-stream structure of the longitudinal distribution of coronal-hole high-speed stream in the Carrington rotation.(2) The various energy densities and flux densities reach the maxima in the interaction region between the high and low speed streams.(3) The high speed stream always has the higher sonic velocities and the pressure to kinetic energy ratios, and in particular, the lower Mach numbers as compared to the low speed stream.(4) On the average, it is statistically insensitive for the plasma p parameter to the variation in the coronal-hole high-speed stream.