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11.
空间等离子体导致高电压太阳阵的电流收集 总被引:3,自引:0,他引:3
给出一种能方便计算空间等离子体引起高电压太阳阵(HVSA)电流收集的理论统计模式,通过对物理过程分析认为空间等离子体致HVSA的功率损耗对HVASA的设计是不应忽视的。 相似文献
12.
D. B. Melrose 《Space Science Reviews》1994,68(1-4):159-170
The theory of electron cyclotron maser emission and its application to solar spike bursts are reviewed. By analogy with the Earth's AKR, three sources of free energy are considered: a loss-cone anisotropy, a velocity-space hole, and a trapped distribution. The problem of how the radiation escapes through the second harmonic absorption layer is emphasized. Harmonic emission due to z mode coalescence may operate for some bursts, but the 2–5s delay between hard X-ray bursts and spike bursts suggests that some other mechanisms is required for most spike bursts. A model involving formation of a trapped distribution in low-density regions neighboring the flaring flux tube is considered. 相似文献
13.
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
14.
L. J. Gray S. A. Crooks M. A. Palmer C. L. Pascoe S. Sparrow 《Space Science Reviews》2006,125(1-4):357-370
Observational evidence of the 11-year solar cycle (SC) modulation of stratosphere temperatures and winds from the ERA-40 dataset
is reviewed, with emphasis on the Northern winter hemisphere. A frequency modulation of sudden warming events is noted, with
warmings occurring earlier in solar minimum periods than in solar maximum periods. The observed interaction between the influence
of the SC and the quasi biennial oscillation (QBO) on the frequency of sudden warmings is noted as a possible clue for understanding
their mechanism of influence. A possible transfer route for the 11-year solar cycle from the equatorial stratopause region
to the lowest part of the stratosphere is proposed, via an influence on sudden warming events and the associated induced meridional
circulation. SC and QBO composites of zonal wind anomalies show anomalous wind distributions in the subtropical upper stratosphere
in early winter. Mechanistic model experiments are reviewed that demonstrate a sensitivity of sudden warmings to small wind
anomalies in this region. Various diagnostics from these experiments are shown, including EP fluxes and their divergence and
also the synoptic evolution of the polar vortex, in order to understand the mechanism of the influence. Some recent GCM experiments
to investigate the SC/QBO interaction are also described. They simulate reasonably well the observed SC/QBO interaction of
sudden warming events and appear to support the hypothesis that tropical/subtropical upper stratospheric wind anomalies are
an important influence on the timing of sudden warmings. 相似文献
15.
We present preliminary results from high resolution observations obtained with the Michelson Doppler Imager (MDI) instrument
on the SOHO of two large solar flares of 14 July 2000 and 24 November 2000. We show that rapid variations of the line-of-sight
magnetic field occured on a time scale of a few minutes during the flare explosions. The reversibility/irreversibility of
the magnetic field of both active regions is a very good tool for understanding how the magnetic energy is released in these
flares. The observed sharp increase of the magnetic energy density at the time of maximum of the solar flare could involve
an unknown component which deposited supplementary energy into the system.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
17.
18.
Alexeev Igor I. Belenkaya Elena S. Bobrovnikov Sergey Yu. Kalegaev Vladimir V. 《Space Science Reviews》2003,107(1-2):7-26
A magnetohydrodynamic model of the solar wind flow is constructed using a kinematic approach. It is shown that a phenomenological
conductivity of the solar wind plasma plays a key role in the forming of the interplanetary magnetic field (IMF) component
normal to the ecliptic plane. This component is mostly important for the magnetospheric dynamics which is controlled by the
solar wind electric field. A simple analytical solution for the problem of the solar wind flow past the magnetosphere is presented.
In this approach the magnetopause and the Earth's bow shock are approximated by the paraboloids of revolution. Superposition
of the effects of the bulk solar wind plasma motion and the magnetic field diffusion results in an incomplete screening of
the IMF by the magnetopause. It is shown that the normal to the magnetopause component of the solar wind magnetic field and
the tangential component of the electric field penetrated into the magnetosphere are determined by the quarter square of the
magnetic Reynolds number. In final, a dynamic model of the magnetospheric magnetic field is constructed. This model can describe
the magnetosphere in the course of the severe magnetic storm. The conditions under which the magnetospheric magnetic flux
structure is unstable and can drive the magnetospheric substorm are discussed. The model calculations are compared with the
observational data for September 24–26, 1998 magnetic storm (Dst
min=−205 nT) and substorm occurred at 02:30 UT on January 10, 1997.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
THERESEARCHOFINCREASINGLIFTANDREDUCINGDRAGFORWING-TIPSAILSChenMingyan,QiMengbu(NanjingUniversityofAeronauticsandAstronautics,... 相似文献
20.
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