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141.
Profiles of the visible Fe X (6374 Å) coronal emission line as a function of height above the limb were obtained out to 1.16 solar radii in a coronal hole using the NSO/Sacramento Peak Observatory Coronagraph, Universal Spectrograph and a CCD camera. These are the first coronal line profiles obtained as a function of height in a coronal hole from the ground. Analysis of the line widths suggests a large component of nonthermal broadening which increases with height ranging from 40 to 60 km/s, depending upon the assumed temperature or thermal component of the profile. 相似文献
142.
在鸭式布局的基础上 ,对飞行器各部件及部件间的连接方式进行了外形隐身设计。对初步形成的鸭翼 -翼身融合体改变机身头部形状和立尾配置等进行 RCS优化。给出了飞行器各种状态下的 RCS平均值和迎头± 45°区内的 RCS值。测试结果表明 ,尖头机身、 30°双立尾 (立尾与垂直平面成± 30°角 )的鸭翼 -翼身融合体的 RCS值最小。对 RCS优化后的外形 ,风洞测力试验表明其气动性能也较好 (最大升阻比达到 8,失速迎角超过 2 6°) 相似文献
143.
We review work on diffusion coefficients of energetic particles with an attempt to extract implications on their behaviour at high latitudes. In the ecliptic plane results from solar energetic particle propagation between the Sun and about 5 AU can be described by an effective radial mean free path
r
which is approximately constant as a function of distancer. When particle propagation in three dimensions in the heliosphere is considered it is not sufficient to consider
r
only. Jovian electrons can be used as probes to determine the parameters of three-dimensional diffusion. In the polar regions diffusion is dominated by its parallel component. Some predictions how should vary with latitude are discussed. For different choices of this variation we present expectations for intensity-time profiles of solar particle events during the Ulysses polar passages. 相似文献
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146.
C. Fröhlich 《Space Science Reviews》2006,125(1-4):53-65
Since November 1978 a set of total solar irradiance (TSI) measurements from space is available, yielding a time series of
more than 25 years. Presently, there are three TSI composites available, called PMOD, ACRIM and IRMB, which are all constructed
from the same original data, but use different procedures to correct for sensitivity changes. The PMOD composite is the only
one which also corrects the early HF data for degradation. The results from the detailed analysis of the VIRGO radiometry
allow a good understanding of the effects influencing the long-term behaviour of classical radiometers in space. Thus, a re-analysis
of the behaviour of HF/NIMBUS-7 and ACRIM-I/SMM was indicated. For the former the situation is complicated by the fact that
there are no in-flight means to determine changes due to exposure to solar radiation by comparison with a less exposed radiometer
on the same spacecraft. The geometry and optical property of the cavity of HF is, however, very similar to the PMO6-type radiometers,
so the behaviour of the PMO6V radiometers on VIRGO can be used as a model. ACRIM-I had to be revised mainly due to a henceforth
undetected early increase and a more detailed analysis of its degradation. The results are not only important for solar radiometry
from space, but they also provide a more reliable TSI during cycle 21. The differences between the revised PMOD composite
and the ACRIM and IRMB are discussed by comparison with a TSI reconstruction from Kitt-Peak magnetograms. As the PMOD composite
is the only one which has reliable data for cycle 21, the behaviour of the three solar cycles can now be compared and the
similarities and differences discussed. 相似文献
147.
Y. Futaana S. Barabash A. Grigoriev D. Winningham R. Frahm M. Yamauchi R. Lundin 《Space Science Reviews》2006,126(1-4):315-332
As a part of the global plasma environment study of Mars and its response to the solar wind, we have analyzed a peculiar case
of the subsolar energetic neutral atom (ENA) jet observed on June 7, 2004 by the Neutral Particle Detector (NPD) on board
the Mars Express satellite. The “subsolar ENA jet” is generated by the interaction between the solar wind and the Martian
exosphere, and is one of the most intense sources of ENA flux observed in the vicinity of Mars. On June 7, 2004 (orbit 485
of Mars Express), the NPD observed a very intense subsolar ENA jet, which then abruptly decreased within ∼10 sec followed
by quasi-periodic (∼1 min) flux variations. Simultaneously, the plasma sensors detected a solar wind structure, which was
most likely an interplanetary shock surface. The abrupt decrease of the ENA flux and the quasi-periodic flux variations can
be understood in the framework of the global response of the Martian plasma obstacle to the interplanetary shock. The generation
region of the subsolar ENA jet was pushed towards the planet by the interplanetary shock; and therefore, Mars Express went
out of the ENA jet region. Associated global vibrations of the Martian plasma obstacle may have been the cause of the quasi-periodic
flux variations of the ENA flux at the spacecraft location. 相似文献
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