A new parameter to define interplanetary coronal mass ejections

The interplanetary manifestations of coronal mass ejections, ICMEs, have many signatures in the solar wind but none of these signatures in the velocity, density, temperature, magnetic field, plasma composition or energetic particles uniquely and unambiguously identifies the occurrence of an ICME. Different investigators identify different events when confronted with the same data. Herein, we present a single physical parameter that combines information from multiple plasma components and that holds the promise of defining a beginning and an end of the region of influence ICME and an indication of the location of the encounter with the ICME relative to its central meridian. This parameter is the total plasma pressure perpendicular to the magnetic field, consisting of the sum of the magnetic pressure and plasma kinetic or thermal pressure. It provides a vehicle for classifying the nature of the ICME encounter and, in many cases, provides an unambiguous start and stop time of the event. However, it does not provide a start and stop time for any embedded flux rope. This identification depends on examination of the magnetic field.     

Response of the low latitude geomagnetic field to the major proton event of November 2001

A major solar flare eruption occurred at 16:20 UT on 4 November 2001, followed by strong solar radiation storm and proton event recorded by the SOHO and other interplanetary satellites. Coronal mass ejection associated with the flare event triggered an interplanetary shock, which impacted the geomagnetic field after about 33 h. The shock impact was quite intense to produce a SSC magnitude of 80 nT in the low latitude ground magnetic records followed by sharp and deep main phase (Dst −300 nT) in the first stage, following the density (N_p) enhancement. High time resolution digital magnetic field data from the equatorial and low latitude stations in India are analyzed to study the influence of various IP parameters on the intensity and duration of the magnetic storm. A double step storm was found to be in progress caused by the multiple injections. During the period of recovery, after a period of 8 h, a third stage of depression in the ground magnetic field was set in, which corresponded to the southward directed Bz. The energy transfer processes associated with the event is presented.     

Force-free magnetic field in a cylindrical flux rope without a constant alpha

It is generally assumed that magnetic fields inside interplanetary magnetic clouds and flux ropes in the solar photosphere are force-free. In order to model such fields, the solution of rot B = B is commonly used where  = const. But comparisons of this solutions with observations show significant difference. To treat this problem,we examine the solutions with .     

高密度数字磁带记录器磁带伺服信号处理电路

介绍磁带记录器在“磁带伺服”方式中磁带信号频率的选择、重放时磁带伺服信号的处理和使用效果     

FY-1C/D极轨气象卫星姿控分系统及其在轨运行

简要介绍了风云一号(FY-1)C，D极轨气象卫星姿态控制分系统的主要任务、技术指标和系统构成。给出了两星发射后动量轮、红外地平仪、太阳敏感器和三轴磁强计等的运行情况。卫星姿态在轨测试结果表明，FY-1C，D星的姿态稳定，满足甚至优于技术指标要求。最后概述了姿控分系统在可靠性、长寿命和稳定性等方面的技术进步。     

四轴型磁悬浮动量轮变结构控制

根据空间飞行器姿态控制用四轴主动控制型混合磁悬浮动量轮的动力学方程,采用变结构控制(VSC)法设计了一种多输入多输出系统控制器。二次型最优控制用于确定最终滑模运动方程,趋近律用于决定变结构控制输入,实现了磁悬浮动量轮快速稳定的鲁棒性控制。仿真结果表明,VSC的动静态特性较好,其滑模运动的不变性可有效消除陀螺力矩的影响,并能实现控制能量的优化。     

DYNAMO: a Mars upper atmosphere package for investigating solar wind interaction and escape processes, and mapping Martian fields

DYNAMO is a small multi-instrument payload aimed at characterizing current atmospheric escape, which is still poorly constrained, and improving gravity and magnetic field representations, in order to better understand the magnetic, geologic and thermal history of Mars. The internal structure and evolution of Mars is thought to have influenced climate evolution. The collapse of the primitive magnetosphere early in Mars history could have enhanced atmospheric escape and favored transition to the present arid climate. These objectives are achieved by using a low periapsis orbit. DYNAMO has been proposed in response to the AO released in February 2002 for instruments to be flown as a complementary payload onboard the CNES Orbiter to Mars (MO-07), foreseen to be launched in 2007 in the framework of the French PREMIER Mars exploration program. MO-07 orbital phase 2b (with an elliptical orbit of periapsis 170 km), and in a lesser extent 2a, offers an unprecedented opportunity to investigate by in situ probing the chemical and dynamical properties of the deep ionosphere, thermosphere, and the interaction between the atmosphere and the solar wind, and therefore the present atmospheric escape rate. Ultraviolet remote sensing is an essential complement to characterize high, tenuous, layers of the atmosphere. One Martian year of operation, with about 5,000 low passes, should allow DYNAMO to map in great detail the residual magnetic field, together with the gravity field. Additional data on the internal structure will be obtained by mapping the electric conductivity, sinergistically with the NETLANDER magnetic data. Three options have been recommended by the International Science and Technical Review Board (ISTRB), who met on July 1st and 2nd, 2002. One of them is centered on DYNAMO. The final choice, which should be made before the end of 2002, will depend on available funding resources at CNES.     

磁暴期间中低纬电离层暴形态和物理机制分析

本文利用东亚地区１２个低纬电离层台站的测高仪观测数据，对１９７８年８月２７日发生的一次曲型磁暴期间电离层峰值高度和密度的变化进行了分析。采用滑动平均区分开电离层中不同时间尺度的扰动，分析了影响中低纬度电离层暴的几种扰动形态特征，并对其物理机制进行了讨论。结果表明：伴随磁暴急始的磁层压缩，电离层中表现出峰值密度增加和峰值高度下降；磁暴主相期间热层大气暴环流及其所引起的中性大气成分变化控制着电离层的大     

各向异性等离子体中磁场重联的混合模拟研究

应用二维三分量混合模拟方法数值研究了各向异性等离子体中的磁场重联过程．计算结果表明，当等离子体垂直于磁场方向的压强大于平行方向的压强时(P⊥／P∥＝1．5)，等离子体不稳定性的增长率会大大增强，重联速度也会加快；当等离子体垂直方向的压强小于平行方向的压强时(P⊥／P∥＝0．6)，会出现火蛇管不稳定性，将抑制撕裂模不稳定性和磁场重联过程．     

Blue light-dependent phosphorylations of cryptochromes are affected by magnetic fields in Arabidopsis

The blue light receptor cryptochrome that could form radical pairs after exposure to blue light was suggested to be a magnetoreceptor based on the proposition that radical pairs were involved in the magnetoreception. But the effects of magnetic fields on the function of cryptochrome are poorly understood. Phosphorylation of cryptochrome in Arabidopsis was closely associated with the function of this photoreceptor. Here, we grew Arabidopsis seedlings in a 500 μT magnetic field and a near-null magnetic field and found that the 500 μT magnetic field enhanced the blue light-dependent phosphorylations of CRY1 and CRY2, and the near-null magnetic field weakened the blue light-dependent phosphorylation of CRY2 but not CRY1. Dephosphorylations of CRY1 and CRY2 in the darkness were slowed down in the 500 μT magnetic field, whereas dephosphorylations of CRY1 and CRY2 were accelerated in the near-null magnetic field. These results suggest that magnetic field with strength higher or weaker than the local geomagnetic field affects the activated states of cryptochromes, which thus modifies the functions of cryptochromes.